A'-A091 422 SINGER CO BINGHAMTON NY LINK DIV F/6 19/DESIGN DEFINITION STUDY REPORT. FULL CREW INTERACTION SIMULATOR--FTJUN 78 N61339-77-C-0185

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AD A09 1422Design Definition Study Reo.if. .

Full CrewInteraction SimulatorLaboratory Mode (FcS-LM)Device X17B7

prepereforNaal TrainingEquipfent CenterOrlando, Fbonda

i. i1~"~LinkI

I,

I

Report No: NAVTRAEQUIPCEN 77-C-0185-0001LR-895

DESIGN DEFINITION STUDY REPORT

FULL CREW INTERACTION SIMULATOR-LABORATORY MODEL

(DEVICE X17B7)

VOLUME I - PROBLEM ANALYSIS

Link Division, The SINGER COMPANYBinghamton, New York 13902

I FINALJune 1978

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Reproduction of this publication inwhole or in part is permitted forany purpose of the United States

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Prepared for:NAVAL TRAINING EQUIPMENT CENTEROrlando, Florida 32813

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0. TILE (ad SubilS. Type OF REPORT a PERIOD COVEREDI DESIGN DEFINITION STUDY REPORT FinalFULL CREW INTERACTION SIMULATOR-LAB. -MODEL June 1978'(EVICE X17B7) 41. PERFORMING ORG. REPORT HUMMER

I____________________ LR-8957. AUITHOR(&) S. CONTRACT OR GRANT NUW5 EtF)

N61339-77-C-O185

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM LEENT. PROJECT. TASK

Lnk Division, The SINGER COMPANY AREA & WOR UNOT MUMBERS

Bigmo, New York 13902

11I. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATENAVAL TRAINING EQUIPMENT CENTER June 1978Orlando, Florida 32813 13. MUMMER OF PAGES

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19I. SUPPLEMENTARY NOTES

Report consists of twelve sections bound in 7 volumes.

it. KEY WORDS (CoahUbw an reerse aide it ao~evan ident~ify bp Wkombee)

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IFOREWORD

i This Design Definition Study is submitted bythe Link Division of the SINGER COMPANY inaccordance with the requirements of NTEC Con-tract N61339-77-C-0185, item 0001. It documentsthe study effort performed by Link in definingthe requirements for, and the design approachto be followed in providing, a FULL CREW INTER-ACTION SIMULATOR-LABORATORY MODEL (FCIS-L.M)for the M60A3 Battle Tank.

In the performance of this work, Link acknow-ledges the efforts of the Human ResourcesResearch Organization (HumRRO), who, in the roleof subcontractor, has provided valuable assist-ance in the analysis of tank operation and thedetermination of training requirements. The Linkteam is also grateful to the following US Govern-ment Agencies and DOD Contractors for theirsupport and cooperation, without which this workcould not have been completed in the time allo-cated.

I Farrand Optical Co., Valhalla, N.Y.

0 General Electric Co., Syracuse, N.Y.

0 Systems Research Labs., Dayton, Ohio

0 Chrysler Corporation, Warren, Michigan

o US Army M60 Program Office, Detroit, Michigan

1 US Army Training Center (Armor), Ft. Knox, Ky.

I • Naval Training Equipment Center (NTEC)

!I

I.i|i-

SUMMARY STATEMENT

The FCIS-LM configuration resulting from the Link study effort isa two crew station configuration, a fighting station and driverstation. Each station is mounted on a six degree of freedommotion system. The display medium for each visual system is aprojector/dome configuration. The image generator is the LinkDIG (Digital Image Generation). All optical instruments, includingI the tank commander's binoculars, are simulated with the DIG andsmall CRT's. The computational system is a multiprocessor Inter-data 8/32 complex. Vehicle dynamics will be simulated using aI kinematics approach. All vehicle systems will be simulated. Maingun simulation will use properly weighted ammo and will providerecoil and spent ammo ejection. The ballistics computer will besimulated in software. An instructor/experimenter station willprovide display and control capability, visual system monitorsand instructor driving controls.

I

TABLE OF CONTENTS

l VOLUME 1

SECTION TITLE PAGE

I I

1. INTRO DUCTIOND O ........... 1-1

1.2 Scope . 0...... 0. i -11.3 Study Methodology . . . . . . . . . . . 1-71.4 Data Sources . . .. . . . . . . . . . . 1-101.5 Cross-Reference Matrix . . . . . . . . . 1-101.6 Statement of the Problem . . . . . . . . 1-10

I II

2. VEHICLE PERFORMANCE ANALYSIS . . . . . . 2-1

2.1 Vehicle Motion Analysis 2-1

2.1.1 Vehicle Performance Characteristics . . 2-32.2 Internal Environment Analysis . . . . . 2-42.2.1 Crew Station Air Conditions . . . . . . 2-42.2.2 Vehicle Noise and Sound Levels . . . . . 2-52.2.3 Vehicle Vibrations . . . . . . . . . . . 2-62.2.4 Communications D v c s .. . * ... 2-72.3 Optical Sighting Devices . . . . . . . . 2-72.3.1 Driver Compartment . . . . . . . . . . . 2-72.3.2 Loader Station . . . 0 0 0 0 0 0 0 0 . 2-112.3.3 Gunner Station . . . . . .0 0 2-112.3.4 Tank Commander Station . . . . . . . . . 2-12.4 Weapons Systems . . . . 0 0 ... . . 0 2-142.4.1 Guns and Ammunition-Main Gun . . . . . . 2-142.4.2 Sighting and Fire Control System . . . . 2-162.4.3 Stabilization System . .. . . . * . a 2-212.5 Power Train . . . . . . . . . . . . . . 2-212.6 Vehicle Systems . . . . . . . . . . . . 2-242.6.1 Hydraulic System . . . . . . . . . . . . 2-242.6.2 Traversing Gearbox Hydraulic Motor .

Assembly * ._ . . . 0 a .. . . a . 2-242.6.3 Gun Elevation Mechanisms . . . . . . . . 2-262.6.4 Electrical System * 9 @. e * * * 9 a 9 2-262.6.5 Fire Extinguisher System . . . . . . . . 2-82.6.6 Personnel Heater, Ventilation System,

and Gas Particulate System . . . . . . 2-282.6.7 Hull-Turret Inflatable Sea! . . . . . . 2-29I 2.6.8 Fuel System ..... . . 2-292.6.9 Bilge Pump ...... . . 2-292.7 Crew Station Configuration 2-292.7.1 Hull . . . . . . . . . . . . . . . . . 2-30

'2e7%2 Turret . ........ ae e* 2-30

2.7.3 Cupola . . . . . . . . . . . . . . 0 0 . 2-31

I. iv.

I

U TABLE 0? CONTENTS

3 VOLUME 1 (con't.)

SECTION TITLE PAGE

3 III

3.1 Geographical and Terrain Conditions . . . 3-13.1.1 Tactical Considerations . . .. . . 3-13.1.2 Vehicle Mobility Considerations . . . 3-23.2 Climatic Conditions . . . . . . . . . . . 3-43.3 Threats and Friendly Forces . . . . . . . 3-43.4 Tactical Information a . . ... . .3-8

I iv4. MISSION/CREW TASK/CUE ANALYSIS . . . . . 4-1

4.1 Mission Profiles . . . . . . . . . . . . 4-34.2 Target Search and Recognition . . . . . . 4-34.3 Battle Conditions . . . . . . . . . . . . 4-54.3.1 Engagement Frequency and Duration . . . . 4-54.4 Crew Task Analysis . . . . . . . . . . . 4-124.4.1 Tank Commander Tasks . . . . . . . . . . 4-174.4.2 Loader Tasks . . . . . . . . . . . . . . 4-294.4.3 Gunner Tasks . . . . . . . . . . . . . . 4-334.4.4 Tank Driver Tasks . . . . . . . . . . . . 4-414.4.5 Crew Interactive Tasks . . . . . . . . . 4-514.6 Utilization of Tactical Information . . . 4-57

IllIIr [

I

I LIST OF TABLES

VOLUME I

NUMBER TITLE PAGE

1-1 FCIS-LM Data and Reference Material Sources . 1-52-1 Hydraulic System Data ... ............ . 2-252-2 Turret Traversing System Data ........... .. 2-25-2-3 Gun Elevation System Data ............. .. 2-274-1 Combinations of Tank Fire Control and Weapon

Systems Utilization in M60A3 Engagements . . 4-7-4-2 Engagement of Target Types .. ........... 4-84-3 M60A3 Weapon System Ammunition and Its

Employment ................. 4-94-4 Range Characteristics of Ammunition Types . . 4-104-5 Range/Effectiveness of M60A3 Weapons Systems . 4-114-6 Interactive Crew Tasks - Main Gun, Precision

Engagement ..... ................. . 4-534-7 Interactive Crew Tasks - .50 Caliber Machine-

gun Engagement .... ............... . 4-544-8 Interactive Crew Tasks - Coaxial Machinegun

Engagement ..... ................. . 4-554-9 Interactive Crew Tasks - Main Gun, Range CardEngagement ..... ................. . 4-56

I LIST OF ILLUSTRATIONS

VOLUME I

NUMBER TITLE PAGE

1-1 Study Report Structure ...... . . . . . . 1-21-2 Crew/Vehicle/Environment Influences . . . . . 1-41-3 Study Methodology .............. 1-92-1 M60A3 Tank (General Arrangement) . . . . . . . 2-22-2 M60A3 Communications System Block . . ....

Diagram . . . . . . . . . . . . . . . . . . 2-82-3A Driver's Vision Blocks . ........... 2-92-3B Maximum Field of View for M27 Periscopes . . . 2-92-3C Nominal and Extreme Position of the

AN/VVS2 Night Vision Viewing Device . . . . 2-102-3D Driver Eyepoint Positions . . . . . . . . . . 2-102-4 Commander's Vision Blocks . . . . . . . . . . 2-132-5 105mm Main Gun - Major Components . . . . . . 2-152-6 XM21 Ballistic Computer System-Block Diagram 2-204-1 M60A3 Interactive Crew Tasks and Courses . . .

of Action . . . . . . . . . . . . . . . . . 4-18

C vi

I

I SECTION I

* 1. INTRODUCTION

3 1.1 Purpose

This Design Definition Study Report is the preliminary phase ofa three-part task performed by the Link Division of the SingerCompany to determine the technical feasibility and optimum de-sign for a Full Crew Interactive Simulator-Laboratory Model(FCIS-LM) for the M60A3 main battle tank. The report documentsthe investigative and analytical efforts conducted to establishtraining objectives and requirements for the FCIS-1M device, andthe development of critical simulation area design approaches to

i meet those training requirements.

Subsequent phases 2 and 3, the FCIS-LM Performance Specificationand FCIS-LM Technical Proposal respectively, utilize the find-ings and design concepts provided in the study report to estab-lish the final design and proposed approach to providing a com-plete FCIS-LM device.

I 1.2 Scope

The study necessitates the performance of three essential func-tions that are common to most problem solving tasks;

1. Define the problem, establish and assemble the rele-vant facts

2. Analyze and evaluate the facts to determine objectives,3 realistic goals, and requirements for a solution

3. Formulate conceptual approaches, and by means of'Trade-Off-Analyses', select and develop a design formeeting the requirements with valid qualitative andquantitative criteria.

I Figure 1-1 provides a structural breakdown of the report bysection, subject, and volume.

Sectibn I, besides explaining the scope and purpose of thereport, presents a list of the data sources and reference mater-ial used throughout the report, a cross-reference matrix forthe 5 contractual documents involved (i.e., the NTEC Study Out-line, the NTEC Work Statement WS-2234-016, the Link FCIS-LMPerformance Specification, the Link FCIS-LM Technical Proposal,this study report) and a statement of the tank training problem.

The following sections (2, 3, and 4), treat the vehicle, thecrew, and the environment as a triad of forces where each in-fluences each other, and analyzes the effects of these influ-f 1.

III

SECTION SUBJECT VOLUME PURPOSE

1 INTRODUCTION

3 2 VEHICLE PERFORMANCE ESTABLISH ANDANALYSIS

A - SEMBLE THE3 TACTICAL ENVIRONMENT

ANALYSIS RELEVANT FACTS

4 MISSION/CREW TASK5 ANALYSIS

5 INTERACTIVE CREW TRAINING ANALYSE AND

REQUIREMENTS EVALUATE THE FACTS6 FCIS-LM EXPERIMENTAL II -

REQUIREMENTS TO DETERMINE GOALS

7 FCIS-LM SIMULATION AND REQUIREMENTSREQUIREMENTS

8 VISUAL STUDY AND CONCEPT - IIIFORMULATIONFORMUATIONFORMULATE APPROACHES

9 MOTION STUDY AND CONCEPT - IV

FORMULATIOJ 'TRADE-OFF-ANALYS IS

1 10 VEHICLE STUDY AND CONCEPT - V SELECT AND DEVELOPFOI(MULATION

DESIGN TO MEET REQTS.11 TRAINING SYSTEMS STUDY AND - VI

CONCEPT FORMULATION WITH VALID CRITERIA

12 STUDY CONCLUSIONS - VII

II

I Figure 1-1 FCIS-LM Study Report Structure

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I ences. Section 2 presents an analysis of the vehicle's (M60A3Tank) performance and systems, including controls, weaponssystems, optical sighting devices, and communications equipment.Section 3 examines the tactical environment including terrain,climatic conditions, and threats and friendly forces. Section4 considers tank msinprofiles; the information availablein the tactical environment that is utlized by the crew andthe individual and interactive crew tasks performed during themission. Figure 1-2 serves to indicate the relationships betweenthe crew, the vehicle and the environment in terms of motion,

visual and aural influences.

Section 5 identifies and establishes the need for specificI training requirements based on the analysis described in theprevious sections. This section reviews the current tank crewtraining programs presently employed at the U. S. Army TrainingCenter (ARMOR) and provides information on individual and inter-active crew task criticality and task performance conditionsbased on interviews with tank crew instructors and other exper-ienced tank personnel.

Section 6 determines and specifies the need for FCIS experimen-tal capabilities. It addresses the requirements for systemI flexibility (both hardware and software) and investigates thepossibility of adaptive training features (varying task diffi-culty) and evaluates the merits of using very advanced highlyflexible plasma type display and control panel hardware.

Section 7 specifies the simulation goals based on the previousinvestigations and analyses. This section does not recognizeany constraints or limitations but defines simulation require-ments regardless of cost, complexity or state-of-the-art so as

to establish goals for meeting the training requirements.Sections 8, 9, 10 and 11 describe the studies required for con-ceptual design approaches, trade-off analysis and ultimate se-I lection and further development of the visual, motion, vehicleand training systems respectively. These sections include allof the technical arguments and rationales that form the basisfor the selections, together with the achievable performance

parameters and tolerance criteria.

Section 12 summarizes the results of all previous sections and1 further defines the critical simulation approaches to achievecorrect cue correlation, particularly between the visual andmotion disciplines. This section also serves to present the1 overall study conclusions and recommendations.

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3 1.3 Study Methodology

Over the past several years the Link Division of the SingerCompany has undertaken numerous study and development contractsmost all of which have been dedicated to the study of aircraftsimulation and the training of aircrews, both for military andcommercial purposes. The common objective in all of these pro-I grams has been the study of the simulation problems associatedwith complex equipment operating in the real-world environment,and each with the ultimate goal of achieving maximum training

in the most cost-effective manner.

The simulation of complex equipment has ceased to be the majorproblem. Link has accrued a vast amount of experience in thesimulation of all types of equipment including engines, enginerelated systems, transmissions, electronic equipment, radiocommunication and radar equipment together with a large selectionof instruments and sophisticated display devices. Moreover, inthese areas, a great deal of data is usually available to spec-ify the detailed performance and operational characteristics,I and furthermore the state of the art in digital computationtechnology permits a high degree of simulation fidelity to berealised.

This is not the case for simulation of the real-world and theenvironment in which the equipment operates, particularly invisual scene simulation where the state of the art has not yetprogressed to the point where 100% realistic simulation can beachieved. Whilst a great deal of training can be obtained fromthe simulation technologies presently available, there still1 remains many problems to be solved in this area, especially withrespect to dynamic realism or the presentation of subtle visualcues that are observed and translated by the human eye and brain1 into meaningful information._

The visual simulation problem is further complicated by the re-I quirement for motion and the resultant need for exact correla-tion of the motion and visual cues. This is particularly truefor the case of the FCIS-LM simulation requirements, since thevisual scene with its associated tactical information, andsagacious vehicle movement together with precise target ac-quisition and gun laying are the most crucial factors to beconsidered in any tank combat training device. For thisreason, the major portion of the FCIS-L4 study effort hasbeen devoted to the solving of the visual and motion problems.Figure 1-3 illustrates the methodology employed and indicatesthe most significant study steps and/or the factors involvedirq the design concept and development process.

To help define the FCIS-LM problem, to identify specific crewtraining requirements, to assist in relating theme training re-

* quirements to available simulation technology, and to provide in-depth support for the analytical study Link engaged the services

l.74

I of the Human Resources Research Organization (HumRRO). Thisorganization has a great deal of knowledge in armor trainingrequirements by virtue of extenzive study work in this and

related areas.Link study team personnel participated in the FCIS-LM Famil-iarization Conference, and also visited the U.S. Army TrainingCenter (ARMOR) at Ft. Knox, partaking in a Tank Indoctrinationcourse and where they were given opportunities to talk to seas-oned tank crew members, and training instructors.

A data acquisition trip was also made to the Chrysler Corpora-tion at Warren, Michigan for the purpose of obtaining vehicleI specifications, drawings, reports and other forms of data.This information was supplemented by other data obtained fromg U.S. Army Technical and Field Training manuals.

A large portion of the study effort concerns the tradeoffanalysis required to determine the most cost-effective designapproaches, both in overall concepts and in specific systems.In those areas, the ultimate approach selections have been madeon the basis of performance, complexity, system compatibility,1 reliability/maintainability and cost.

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I1.4 Data Sources

Table 1-1 lists the sources and types of data acquired by Linkand utilized for the study effort. A complete list of the dataitems (in alphanumerical order) will be provided as an appendixto the final submission of this report.

1.5 Cross-Reference Matrix

U A cross-reference matrix between the NTEC Study Outline and theNTEC Work Statement WS 2234-016 and the Link responses, i.e., theStudy Report, the Performance Specification, and the Technical

Proposal,is included in the Technical Proposal.

1.6 Statement of the Problem

I Tank crews have traditionally, learned a major part of theirmost critical skills in combat. The complexity of tank crew tasksand of the tactical environment in which they are employed de-I mand extensive training, but effective training necessarilyinvolves crew interactions with the tank and the terrain, withthreats and other friendly elements, which greatly exceed theI resources available. Evaluation of the threats facing U.S. Arm-ored units,mnake effective training absolutely essential. Theinitial losses of tanks, crews, and objectives in the early learn-ing stages of armored warfare cannot be tolerated. Future engage-ments,if they take placs8,must be fought by crews who are thorough-ly qualified to interact effectively with each other and with the

1 pressures and stresses of tank combat.Crew familiararity with the tank and its weapon systems can bedeveloped in relatively simple and inexpensive settings, buttactical skills require practice in interacting with many com-plex situations which are impossible to provide in real-worldsettings. So far, these have not been represented by synthetictraining systems, to the extent required for crew interactiontraining. Other military and civilian training programs haverealized substantial savings in training costs through the'useof simulation. In many of these programs normal proficiencylevels have been exceeded through increased training efficiency,and through training which would be too expensive or too hazard-ous to accomplish in real world settings. Simulation promises to) permit similar savings and training efficiencies for M60A3 crews,but the complexity of the crew training requirement seems to ex-ceed the capabilities of the simulation approaches so far devel-I oped for other training programs.

1-10

The tank crew's interaction with the tactical environment reliesheavily on dynamic visual information about the terrain, the threatand the effects of friendly and hostile weapons. The crew alsooperates in a complex motion environment which provides task in-formation, and which also makes effective performance of mostskills more difficult. In addition,* the tank crew operates as aI precisely articulated team. Each individual task is preciselytailored to the tactical situation and to the performance ofeach other member of the crew. The driver's selection of aroute, and the way he negotiates it influences the ability ofthe commander and the gunner to acquire and engage threats.The ability of the loader to keep the tank's guns operating in-fluences its ability to survive on the battlefield, while theaccuracy of the commander and the gunner in threat detection andengagement influences the survival of the tank and the effective-ness of its mission. The degree of integration required of theM60A3 crew requires practice and quidance in carefully-controlledsettings, not available in real-world training exercises.

while simulation appears to have promise for the representationof the M60A3 and its environment, and for the systematic controlof crew training, the technology must be adapted to the crew'sspecific needs. one of the purposes of this study has been toidentify those needs in terms of critical training objectives,relevant to the employment of the M60A3 tank in a combat environ-ment. Another purpose has been to define simulation and trainingI concepts capable of supporting these objectives, while a thirdfunction was to identify research issues to be explored in therefinement of simculation and training system characteristics for

maximum support of tank crew training.The problem for the study has been to identify M60A3 crew inter-action training objectives, to define simulation concepts nomin-ally capable of supporting them, and to develop system designconcepts capable of supporting crucial experiments in the designof specific crew interaction training features. Much of the at-I tention of the study has been devoted to the identification anddescription of the information used by the crew in performing itstasks, and essential to tank learning. Much of the effort hasI been oriented toward visual information and visual cueing, be-cause of the inherent complexity of the visual environment ofeach individual crewmember, and of the crew as a coordinatedfeaku.

The information value and the distractions and stresses associ-ated with tank motion have also been studied in detail. In manycases, the motion of the tank is the most useful cue available tothe crew about the performance of the driver. -In many situationsalso the motion of the tank determines the way in which the restIof the crew must perform; many critical skills must be performeddifferently when the tank is in motion than when it is stationary.

I Lack of experience in the systematic development of crew interac-tion skills necessitated attention to the instructional technologyto be employed in the full crew interaction simulator. IndividualI skills, in the M60A3, are rarely practiced in isolation from therest of the crew. Each function of the tactically employed tankinvolves responsibilities on the part of each individual. Learn-I ing to execute these responsibilities in the crew tactical situa-tion involves training problems which seem to be almost totallyunique to the tank environment, requiring in turn, unique approachesto instruction.

Finally, a major problem in the study has been to identify and de-fine capabilities required of the simulator, and training systemI design resources. The technology available for tank crew inter-action training, especially in the simulation of visual cues andin the optimal control training has never been demonstrated inI any training problem similar to that faced by tank crews. Ex-trapolations of the available technology to tank crew trainingwill be to some extent inaccurate, ineffective and costly, untilexperimentation has been able to establish adequate, economicalapproaches. Much of the current technology was developed in theaviation context but the tank crew's demands on the technology,especially in the representation of the visual environment, ex-I ceed those so far placed on it by the aviation community. Inaddition of course, the level, precision, and timing of crewinteractions and the stresses on the crew are almost unequalled1 in any other weapon system. Extensive research is required in tankcrew training to make the FCIS concept capable of maximum support

to Armor.

1-1

I SECTION II

3 2. VEHICLE PERFORMANCE ANALYSIS

This section examines the M60A3 Combat Tank's performance and3 analyzes the relationship between the tank as a vehicle (includ-ing its equipment and weapons system) and, (a) the tank crew,and (b the tactical environment in which the tank and crew op-3 erate.

Much of the information for this examination and analysis wasobtained by Link Study Team personnel during a field trip toI the U.S. Army Training Center (ARMOR), Ft. Knox, Kentucky. AtFt. Knox, study personnel participated in a short, but exten-sive tank indoctrination course, during which they were permit-ted to interview experienced tank crewmei and training instruc-tors. In persuance of the study program, additional data wereobtained from manufacturer's specifications, reports, and draw-ings, and U.S. Army technical manuals.

It is the intent of this section not to define or specify M60A3tank performance characteristics (this information is well docu-I mented elsewhere), but to identify its most salient featuresand operational characteristics from a simulation viewpoint.These features are used to establish meaningful criteria forI vehicle and turret motion, aural cues, armament and ancilliarysystems, optical sensing devices, and crew station configuration.

2.1 Vehicle motion Analysis

The M60A3 Combat Tank is a heavily armored track-laying vehiclemanned by a crew of 4. In operation, the tank traverses theI terrain at varying speeds with the tank attitude at all timesbeing dictated by the terrain geometry and the vehicle's centerof gravity and related footprint. In movement, the vehicle isI subjected to kinematic forces in all 6 degrees of freedom ofmovement. At relatively high speeds (in excess of ten mph (16kph.) and over rough or severely undulating terrain, these for-ces become appreciable with pitch, roll and heave being themost dominant. Longitudinal, lateral and yawing moments arealso present, but less noticeable to the crew. Accelerationand deceleration effects due to starting and stopping the tankI are apparent along the longitudinal axis . Movement and relateddynamic effects of the vehicle suspension system, combined withreactionary forces due to the tank engine and transmission, alsocause considerable vibration of the vehicle structure. Kines-thetic effects of vehicle motion and vibration on the crew havean important bearing on their ability to perform the physicalI tasks required in tactical operations. Because of locations ofthe crewmembers in the tank, vehicle motion has different ef-fects on each of them. Figure 2-1 illustrates the relative lo-cations of the individual crewmembers with respect to the tankI and its major components.

2-1

COMMANDER'S CUPOLA COMMANDER

ILRE

SIDE ELEVATION

HULL D~VRFUEL TANK - ENGINE TRALNSMISSION FINAL DRIVE

IARI O ODN

IFNE STOPAELE I CLEANER

PLAN VIEW

Figure 2-1 £460A3 Tank (General Arrangement)

2-2

The following subsection identifies major vehicle performanceparameters and characteristics that were analyzed and evaluated

* to determine motion simulation requirements and to define vehi-* cle dynamics presented in Sections 7 and 9 of this report.

2.1.1 Vehicle Performance Characteristics. The M60A3 is power-ed by an air-cooled, 750 horsepower die-sel engine with powertransmitted to the final drive through a cross-drive transmis-sion. The cross-drive transmission includes differential,steering, and braking functions. The following are the vehiclecharacteristics effecting motion performance:

a) Total vehicle weight (less crew, storage 104,186 poundsI and fuelb) Total vehicle weight, combat loaded 113,730 poundsc) Nominal center of gravityIo X longitudinal (from bow to hull) 128.0 inches

o Y lateral (positive, right of centerline) 0.6 incheso Z vertical (from ground line) 54.4 inches

d) Forward maximum speedo High 30 mpho Low 10 mph

e) Reverse maximum speed 7 mphIf) Maximum gradeability (i.e., implies maximumpitch) 60 %

g) Maximum side-slope (i.e., implies maximum1roll) 30 %h) maximum trench 102 inchesi) Maximum fording depth (without kit) 48 inchesj) Cruising range (paved, level roads) 300 miles at 20

mphk) Acceleration (hard road)

* 10 to 30 mph 100 feetIo 10 to 20 mph 43 feet* 0 to 10 mph 11 feet

m) Maximum tractive effort 77,000 lb at1960 rpm

n) Towing effort (drawbar pull) 8,300 lb at12 mph

The track data (T142) relevant to the mobility of the vehicleare:

a) Width 28 inchesb) Length 166.72 inchesc) Height (above steel grouser) 0.89 inches

Therefore, the ground pressure for the M60A3, combat loaded tankwith the T142 track is 12.1 psi. The track is driven by therear drive sprockets and support hulls attached to the finaldrive assemblies.

The M460A3 combat tank is equipped with a torsion bar suspensionsystem connected to six individually suspended roadwheels per

2-3

side. Compensating idler wheels and track adjusting linkagesare installed at the front of the tank and connected to thefront roadwheel. Correct track tension is provided via theI track adjusting linkage. The twisting action of the torsionbars aids in maintaining maximum ground/track contact.

Tracked vehicle mobility can be described as the ability of theI soil to support the vehicle statically or in motion, as well asto provide thrust. Mobility can be assessed only by a combina-tion of relevant physicogeometrical values pertaining to bothI the soil and the vehicle. Relevent vehicle data is generallythe load-form size relationship of a given design as describedin this section. Appropriate terrain characteristics are des-I cribed in Section 3.1.2 "Vehicle Mobility Considerations".

2.2 Internal Environment Analysis

This section examines the internal working environment of thevehicle,and how this environment influences the crew from thestandpoint of;

o Condition of air and ambient temperatures

o Vehicle noise and sound levels

o Vehicle Vibration

o Crew Communications

2.2.1 Crew Station Air Conditions. Whenever a number of peo-ple have to work in closely confined quarters (particularlyunder arduous and high stress conditions), the quality of thebreathing air takes on a significant importance. In the M60A3vehicle, the quality of the air, specifically purity (presenceof toxic funes and/or homogeneous compounds) and temperature,are likely to approach undesirable levels. This is especiallytrue in closed-hatch combat situations when vehicle engine sys-tems are taxed for maximum performance and the main gun is be-ing fired. Also, in extreme climates (subfreezing or tropicalcircumstances), the temperature of the air and surrounding con-tact surfaces of the vehicle, particularly the driver's com-partment, will not be conducive to the high-efficiency requiredfor the performance of M60A3 mission tasks. Study and evalua-tions at Ft. Knox were conducted in an "open hatch" configura-tion. Therefore, "closed hatch" combat conditions were not gperienced. The outside air temperature was in the 50OF to 55 FI range and moreover the operational tempo was considerably slowerthan that encountered under actual combat conditions. However theconditions alluded to are very real and play an important role inthe operation of the vehicle and it's systems and therefore mustbe considered in any training concept to develop individual andinteractive crew skills.

2-4

To minimize effects of temperature and air conditions on crewperformance, the M60A3 Vehicle is equipped with the following

* systems:

o Personnel Heater

o Ventilation System

o Gas Particulate System

These equipments and systems and their operation are describedin Section 2.6.6.

2.2.2 Vehicle Noise and Sound Levels. Tank sound characteris-tics can be categorized by four areas of tank operation. Theseare: engine starting and running, mobility or driving, weaponsystem operations, and miscellaneous internal turret and hullequipment operation.

Engine starting and running sounds are typical of a diesel en-gine. Since the engine is air cooled, sounds produced by rapidmoving air are also a characteristic. Intake and air-cleaningfans and the turbosupercharger create additional moving airI sounds as well as a whining sound similar to a jet engine.Electrical fuel pumps located within the fuel tanks, also cre-ate quiet but noticeable hum.

Mobility sounds consist of track squeak, a transmission andfinal drive moan typical of heavy equipment, and an automatictransmission whine typical of hydramatic transmissions. Also,intermittant hull and turret vibrations due to vehicle motioncreate internal rattles and clatters in base equipment, plumb-ing, and sheet metal.

Weapon system operation, related to firing the tank guns, pro-vides explosive as well as mechanical sounds. The main gunexplosion also creates a blast effect typical of its size andcaliber. The hydraulic mechanical ejection mechanism of themain gun and the ejected shell casing also produce sounds, ty-pical of this type of operation. Firing of the coaxial (7.62MM)and the 0.50-caliber tank commander's machine gun cause sharpstaccato reports. Automatic operation of ejection mechanismsalso generate characteristic sounds. Cartridge casing ejectionand cartridge belt feed also produce sounds associated withautomatic machine gun operation.

Miscellaneous internal turret and hull equipment sounds are ob-vious when the engine is off and weapons are not firing. Thesesounds are generated by the ballistic and super elevation driveunit (motor driven gear train), the electrically driven hydrau-lic pump, the turret drive unit, the main gun elevation actua-tor, and the stabilization system gyros. Also included in theunique equipment sounds are those of the bilge pump, exhaustfan, and personnel heater. The clatter of heavy duty relays

2-5

I and solenoids, as well as the clicks of switches generate soundsof electrically controlled equipment. Squeaks, thumps, andknocks are the sounds typical of mechanically controlled equip-

ment.Sounds generated by turret equipment tend to echo and rever-berate due to the confined space, type of material used in con-struction, and lack of sound-deadening material. opening orclosing hatches does not noticeably reduce the echo effect.

* Also, the echo effect decreases the capability of determining* the direction of a sound. Externally generated sounds entering

through the hatch also create an echo within the turret.

I Internally, sounds emanating from the hydraulic pump, turretdrive and blower prevent the crew from carrying on conversa-tions. Regardless of whether hatches are opened or closed itI is difficult to conduct a conversation, even at shouting levels.Sound levels from internal and external sources reach levelsthat can be dangerous to human ears. It is estimated that am-bient sound levels reach an amplitude of 110 db. This noiselevel is substantially reduced (approximately 25%) when protec-tive helmets are worn. The crew's helmets also provide built-in communications equipment as well as physical protection.

Closed hatch operation does not appreciably reduce the noiselevel of externally produced sounds as there are openings be-I tween the hull and turret, through the blower assembly, in thefire wall, and around the gun mount. The cupola also has manyopenings that allow external noises to penetrate to the hull'sf interior.

2.2.3 Vehicle Vibrations. The tank crew senses vibrations dueto both the engine operation and the vehicle/terrain motion.I Terrain motion induces relatively low frequency (less than 1.0HZ) vibrations on the vehicle while the engine contributeshigher frequencies (5-15HZ). However, the terrain causes the

- crew to be subjected to higher accelerations than the engines.Vibration is sensed at all crew stations, but the engine vibra-tions tend to be of larger magnitude at the turret than at thedriver's station.

2-6

I

2.2.4 Communications. The tank communication system is themedium for effective crew interaction and as such is an impor-tant element in rapid target engagement. The M60A3 is equippedwith an intercommunications set AN/VIC-l (V) which facilitatescrew intercommunications and allows individual crewmen to usethe tank's radio set. An external unit permits personnel out-side the tank to communicate with the tank crew members and touse the tank's radio set. This external unit may also be util-ized to connect the inter-communications set to an existingtelephone line.

The M60A3 may also be equipped with any of the following radiosets; AN/VRC-12, -46, -47, -53 or -64. These radio sets pro-vide short range (5 to 20 miles), two-way, frequency modulated(FM) radio communication in the frequency range of 30.00 to75.95 megahertz (Mhz).

A typical M60A3 communication system configuration in which anAN/VRC-12 radio set is integrated with the AN/VIC-l(V) intercomsystem is presented in Figure 2-2 . Power is provided by thetank's battery system. An electrical transient suppressor pro-tects the cormunication system from transient voltages in thevehicular electrical system. This unit also contains a circuitI breaker to interrupt power in case of an overload. It may benoted that the tank's generator, electric fuel pumps, powerpackelectric motor, ventilating blower motor, air cleaner blowermotors and personnel heater motor are designed to minimizeradio interference by the use of shielding, feed-through capa-citors, plated tooth-type lockwashers, and braided bond straps.Control and frequency selectors, shown in Figure 2-2, provideremote selection of any of the 10 preset frequencies of the RT-246/VRC. The preset frequencies may be changed at the receiver-transmitter. Control boxes are employed to provide crewmemberaudio control and to interface with intercom accessories (CVChelmet, etc.).

Radio sets AN/VRC-12, -46 and -47 have dual-band frequencyranges (Band A, 30.00 to 52.95 Mhz; Band B, 53.00 to 75.95 Mhz).The high power range of these units is 20 miles stationary, 15miles moving, and 1 mile submerged. Output RF power is 1 to3 watts in low power and 35 watts minimum in high power. AN/VRC-12 has 10 preset frequencies while AN/VRC-46 and -47 havenone. The AN/VRC-53 and -64 radio sets are single-band (30.00to 75.95 Mhz), low power units (1 to 3 watts) with a five milerange. The AN/VRC-53 and -66 have 2 preset frequencies. Allunits have 920 channels, each separated by 0.05 Mhz. Each hasa squelch tone signal of 150 Hz.

2.3 Optical Sighting Devices

2.3.1 Driver Compartment. The M60A3 tank driver has two opti-cal sighting devices available - a set of 3 M27 periscopes andan AN/VVS-2 Night Vision Viewer.

2-7

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2-8

-~-----. - - -

I

I The three M27 periscopes act as vision blocks for the driver toallow him to see out of the tank when the hatch is closed. Theperiscopes are located in front of and to the lgft and right ofthe driver and are separated by an angle of 144 from his eye-point. (See figure 2-3A)i

iNOMINALIEYPOINTI, 0..,

1000 1" M27 PERISCOPES

1

1Figure 2-3A Driver's Vision BlocksEach M27 periscope permits viewing a rather wide FOV if thedriver moves his head to enable him to see the extreme of theFOV. Measurements taken on the tank indicate that the maximumFOV for any one periscope is 1200 horizontal by 320 vertical.Thus there is considerable overlap between adjacent windows.(See figures 2-3B and 2-3C)

IA450

IFigure 2-3B Maximum Field of View for

M27 Periscopes

2-9

I\45o45I

I5

Figure 2-3C Nominal and Extreme Positions of the

AN/VVS-2 Night Vision Viewing Device

DRIVER'S EYEE 2_ -'(CRACK H ATCH)

5.5" PR

EFFECTIVE EYEEl POSITION WHENSM2 IN ~USE

100, TANK BODY

IIleDRIVER'S NORMAL

DRIVE'S EE 0-EYE (IN HATCH)

E POSITION 1

DRIVR'SVISION BLOCKM27 PERISCOPE

I Figure 2-3D Driver Eyepoint Positions

1 2-10

More commonly, only about 80% of the FOV is used.

Note that whenever an M27 periscope is used, the effective eyepoint is very nearly equal to the eye position of the driverwhen he is driving with his head out of the hatch. See Fig-ure 2-3D.

The AN/VVS-2 Driver's Night vision viewer is a 1-power, totallypassive viewing device which allows the driver to see at nightor in conditions of poor visibility. The device, installed inthe driver's hatch, permits vision through one large eyepieceand does not require facila contact against the bump padding.

The AN/VVS-2 has a field of view of 450 horizontally and 380vertically. In addition it can be horizontally rotated +45° .

2.3.2 Loader Station. The primary viewing device for theloader is an M37 Periscope. This instrument is a unity-powerviewing device used for surveillance when the vehicle is "but-toned up". The M37 is manually capable of full 3600 ro8ation.The instantaneous field of view is 720 horizontal by 26 verti-cal.

2.3.3 Gunner Station. The gunner has two sighting devicesavailable for use. These are the M35E1 periscope and the M105Articulating Telescope.

The M35E1 periscope is the gunner's primary sighting device.The periscope has a unity-power and 8-power daylight viewingsystem and an 7.1 power passive night capability. The unityviewer provides a panoramic observation view and is equippedwith an aiming circle for use with the coaxial machinegun. The8-power systems are used during sighting and main gun laying ineither daylight or limited visibility conditions. The passivesystem requires no other lighting system such as a searchlightor a high voltage IR power system to operate.

In addition, the reticles produced in the 8X sight are projectedby the XM21 Reticle Projector and reflect adjustments made bythe ballistics computer to account for range deflection, windspeeds, etc.

The unity power system has a field of view of 30 degrees 32'horizontally by 5 degrees 48' vertically and is aligned coaxi-ally with the main gun. Field of view for the 8X visual andthe 7.lX thermal devices is 8 degrees and 7.3 degrees respec-tively.,

Both of the powered sights require that the gunner place hiseye to an eye rest in order to view the image.

The gunner's backup sighting device is the M105 ArticulatingTelescope. This device, also mounted coaxially with the maingun, contains a dual ballistic reticle with patterns for three

2-11

--.- W77m

I

I types of ammunition. The telescope has 8-power magnificationand a field of view of 7 degrees 30'. It is capable of 10 de-

i grees of depression and 20 degrees of elevation.

2.3.4 Tank Commander Station. The tank commander's opticaldevices include the M36E1 periscope, AN/VVG-2 Laser Range Find-

I er, and binoculars.

The M36E1 periscope is used by the commander (in the cupola)for surveillance and sighting of the 0.50 caliber machine gun.This perisocpe is similar to the gunner's M35 in that it has aunity, an 8-power daylight, and an 8-power passive night capa-bility. The systems differ in the field of view presented tothe commander and the type of reticles. In the M36, the peri-scope is mechanically linked to the machine gun and presents a600 X 280 field of view in the unity system, a 100 field ofview for the 8X visible, and a 7.30y field of view for the ther-mal eyepiece.

Unlike the gunner's periscope, reticles on the 8X eyepiece arenot controlled by the XM21 reticle projector.

The periscope is capable of 600 of travel in elevation and 200

of travel in depression.

The laser rangefinder (AN/VVG-2) is used by the commander to de-termine ranges of various objects. Range is determined bytransmitting laser light pulse at a target and converting thetime from transmission to reception into range. The rangefindercan store data on as many as three targets in the path of thelaser.

The laser rangefinder optical system is equipped with a lowmagnification viewing mode for acquiring targets and a highmagnification viewing mode for ranging and gun laying. In ad-dition, the optical system of the laser rangefinder serves asthe commander's primary sight for directing fire of the maingun. The optical system provides a means of introducing azi-muth corrections into the pointing of the laser rangefinderto compensate for target lead. The laser rangefinder's opticalsystem provides means whereby boresight of the laser range-finder, with respect to the main weapon, can be checked and ad-justed.

A detailed description of the Laser Rangefinder is located in

fSection 2.4.2.1.The following data characterizes the AN/VVG-2 rangefinder:

Model AN/VVG-2Operating Range 200 to 5,000 metersRange Resolution Capable of resolving two tar-

gets a minimum of 20 metersapart.

Range Accuracy +10 meters

r- 2-12

- : .... .. . . . ,7

RangingMaximum recycle time 4 secondsMinimum sustained ranging W/OOverheating 3 per minute sustained or 6

per minute for 2 minutes with3-minute intervals betweeneach 2-minute ranging period

Telescope Low Power High PowerMagnification 6 power +5% 12 power +5%Field of view 10 degrees +5% 5 degrees-+5%

Exit pupil diameter 7.0mm +5% 4.2mm +5%Eye relief l.l-inEh minimum

Reticle Ballistic reticle

Another optical instrument available for use by the tank com-mander is his binoculars. The binoculars are used in detectingdistant objects, searching for information about an area'sability to conceal threats, and searching for good tacticalrouses. Normal binoculars give about 7x magnification over a7.5 field of view.

The commander also has eight unity-powered vision blocks in thecupola to allow him to view 3600 when all hatches are closed.The vision blocks are 2 -inches high by 8 -inches wide. Thefields of view of adjacent blocks overlap. All of the visionblocks have slightly different fields of view due to tank super-structure. Figure 2-4 shows two typical (extreme) cases.!

Loader's Right SideSide

(Typical)

Figure 2-4 Commander's Vision Blocks

2-13

2.4 Weapons System

The M60A3 weapons system is comprised of 3 major componentgroups:

o The 105mm (main) gun, a.50 caliber machine gun, a 7.62mmcoaxial machine gun, and the associated ammunition for eachweapon.

o Sighting and Fire Control System.

" Stabilization System.

2.4.1 Guns and Ammunition- main Gun. The major components ofthe Main Gun are shown in Figure 2-5. The gun is mounted inthe turret on trunion pins and stabilized in the vertical planeby attachment to the elevation mechanism. Traverse and eleva-tion motions of the gun are hydraulically actuated and control-led from either the gunner's or the tank commander's controlhandles. The commander can override the controls at any time.Manual controls are available at the gunner's station. Ballis-tic computer is operated by the gunner and critical data suchas the type of round, cross-in, air temperature, etc. are com-pensated for in the computation of gun superelevation and azi-muth. Stabilization mode is available for target tracking whilethe tank is in inotion.

Ammunition consists of five, standard round configurations,namely; armor piercing, two types of high explosive, anti-per-sonnel and white phosphorus. Storage for 63 rounds is providedin the turret and hull. once ammunition is loaded into the gun,firing can begin as soon as the loader has moved the "loader'ssafety switch" to the FIRE position. When a round is fired,recoil energy is dissipated through the recoil mechanism. Ac-cording to Chrysler data, the approximate recoil time is 0.12second, while counter recoil is about 0.50 second. The recoilmechanism is a concentric hydraulic shock absorber with an in-tegral compression spring for counter recoil. The hydraulicfluid level in the system is monitored after each firing to en-sure an adequate supply.

Machine Guns - The 7.62 mm guin is attached to the loader's side ofte min gunii. This gun'is coaxially aligned for firing, util-izing main gun ballistic sights. it can be operated separatelyor concurrently with the main gun. Controls for firing are atboth the gunner and tank commander positions.

Ammunition (6000 rounds) for the coaxial gun is stored in theturret. A ready box containing 2200 rounds is mounted to theturret wall (loader's side) and feeds through a chute to theI gun. An additional 3800 rounds is stored on the floor behindthe gunner. Expended rounds are ejected into a storage bag alsolocated on the main gun. A .50 caliber machine gun is mounted-I: on the cupola. This gun is traversed and elevated by manually

2-14

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>4.00

0

Ln

E-4.

2-15

cranking the cupola for traverse motion and the gun elevationdrive for elevation motion. This weapon can be fired only fromthe Tank Commander's position.

Vehicle motion, induced by the firing of the main 105 nmn gun isa function of position and elevation of the main gun/turret.If the main gun is in the nominal position, that is, the barreldirectly over the driver's head, the induced primary vehiclemotion due to operation of the gun would be in the longitudinaland pitch directions. Similarly, if the main gun position isin a +90 azimuth position, the induced primary vehicle motiondue t6 gun operation would be in the lateral and roll directions.For a +45 degree azimuth position, the primary induced vehiclemotion-due to gun fire would be a combination of longitudinal,lateral, yaw, roll and pitch. The contribution in each direc-tion in the above examples is a function of the elevation of themain gun.

Assuming the main gun is in the nominal position, preliminary 0/Chrysler data indicates that the maximum pitch velocity is 5.5/second attained 1.0 second after gun fire with maximum pitchexcursion of approximately 10 attained 0.3 second after firing.The total time duration of vehicle pitch motion due to gun fireis approximately 1.4 seconds.

2.4.2 Sighting and Fire Control System. The M60A3 tank em-ploys a primary direct fire control system, a secondary directfire control system, an indirect fire control system for themain gun, and a fire control system for the cupola machine gunand the turret coaxial machine gun.

When a target can be seen through the sights, and all systemsare functioning, the primary direct fire control system is used.The primary direct sighting and fire control system for theM60A3 consists of the laser rangefinder AN/VVG-2, ballistic-computer XM2l, ballistics drive MlOA3, gunner's periscope M35E1and the superelevation actuator.

The secondary direct sighting and fire control system consistsof the telescope 14105E1, telescope mount M114, instrument lightM50 (an auxiliary light for illumination of the reticle), afilter box and three filters. The secondary direct fire con-trol system is used when a malfunction precludes the use of theballistic computer system.

The indirect sighting and fire control system consists of theelevation quadrant M13A3, a control light source, and an azimuthindicator with instrument light. This system is used when thetarget selected is hidden from direct observation through thefire control optical instruments or for preparing range cards.

The .50 caliber machine gun sighting and fire control systemconsists of periscope M36E1, periscope mount M4119, and instru-ment light to provide illumination to the periscope reticle.

2-16

F This sighting system is linked to the machine gun cradle trun-nion so that the line of sight moves with the gun when it iselevated or depressed to enable the commander to lay on thetarget when the tank is "buttoned-up".

The sighting and fire control system for 7.62mm machine gunconsists of a portion of the XM21 reticle projector which pro-vides a reticle in the unity-power optical system of the peri-scope M35E1 to provide target engagement for the 7.62nmm machinegun.

Sighting optics were described in Section 2.3. The followingparagraphs describe the remaining major components of the sight-ing and Fire Control System.

2.4.2.1 Laser Rangefinder System. The AN/VVG-2 Laser Range-finder (LRF) system consists of a Receiver-Transmitter Unit anda Power Supply Synchronizer. The system provides the M60 crewa fast, accurate, line-of-sight target-ranging capability alongwith a combined high-and-low-power optical system to assist thetank commander in target acquisition, ranging and gun laying.Ranging is accomplished by measuring the time delay between atransmitted pulse of laser energy and the reflected return.The LEF has the capability of storing data on as many as threetargets that intercept the laser beam. The stored ranges maybe separately displayed using the range return selection switchesand LED range indicator on the Receiver-Transmitter controlpanel. Selected range information is fed into the BallisticComputer for use in computations for firing at moving or sta-tionary targets.

The Laser Rangefinder is located at the tank commander's sta-tion. The Laser Rangefinder optical system is equipped with alow magnification viewing mode for acquiring targets and a highmagnification viewing mode for ranging and gun laying. In ad-dition, the optical system of the Laser Rangefinder serves asthe commander's primary sight for directing fire from the maingun. The optical system provides a means of introducing azimuthcorrections into the pointing of the Laser Rangefinder to com-pensate for target lead. The Laser Rangefinder's optical sys-tem provides means whereby boresight of the Laser Rangefinder,with respect to the main weapon, can be checked and adjusted.Elevation corrections emanating from the computer as well asweapon elevation are introduced into the LRF by rotating itabout its elevation axis. A built-in internal test capabilityis provided to check overall Laser Rangefinder system operationand pinpoint malfunctions to the unit level.

The transmitter-receiver unit contains a transmitter to generatethe laser pulses, a receiver for converting the reflected lightfrom the targets to electrical signals, and built-in test cir-cuitry. The unit also contains a selectable dual power 6X-12Xtelescope.

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The commander's control panel is located to the left of thetransmitter-receiver. Basic panel controls are: mode selec-tion, Return selection, Battle Range selection, Range, and Re-set and Feed. Each control has associated lighting feedback.LED indicators display the number of returns and the range ofthe selected return. A Select light indicates a ranging condi-tion that requires the commander to select and transfer one ofthe returned ranges. A Go light indicates that a range hasbeen automatically or manually transferred to the computer.A malfunction light is provided to indicate when there is aspecific malfunction in the transmitter or data processing cir-cuits as a result of improper circuit or logic conditions. Thespecific trouble area is indicated by a digit display on therange indicator.

The power supply synchronizer contains the data processing cir-cuits for storing range data for the three targets that mightbe detected, power supplies and the built-in test circuitry.

An auxiliary input to the LRF system is the Laser Control thumbswitch on the Gunner's Control Handle. The gunner, utilizinghis own optics for sighting, may depress this switch to firethe laser. However, unless assistance is provided by the com-mander, the returned range will be input to the Ballistics Com-puter only if the LRF is in "AUTO" mode.

The AN/VVG-2 has an operating range of 200 to 5000 meters. Thesystem has a range accuracy of +10 meters and accordingly iscapable of resolving two targetF a minimum of 20 meters apart.The maximum ranging recycle time is 4 seconds. The minimumranging period, without overheating is 3 per minute sustainedor 6 per minute for 2 minutes with 3 minute intervals betweeneach 2 minute ranging period. Battle range is 1200 meters atthe gunner's sight and 2000 meters at the laser, which allowsfor minimum parallax. Boresight adjustment is +5 mils in bothelevation and deflection. Target lead capability is +36.5 mils.

2.4.2.2 Ballistic Computer System. The XM21 Ballistic Computersystem (BCS) provides the computations necessary to aim, trackand fire against moving or stationary targets. Utilizing sen-sor or manually inserted inputs and characteristic constantsassociated with the selected ammunition type, the BCS compen-sates for the effects of range, drift, crosswind, horizontaltarget motion, altitude, air temperature, gun wear, trunnioncant, gunsight parallax and gun jump. Information is processedin analog form and transmitted as output shaft rotations (rep-resenting elevation) to the superelevation actuator and ballis-tics drive and as electrical signals (representing azimuth) todrive the reticle projector of the gunner's periscope and thelaser rangefinder reticle. Elevation and deflection signalsare also transmitted electrically to the stabilization system.The BCS contains self-test circuitry to check computer systemoperation and to pin-point malfunctions to the unit level.

2-13

Figure 2-6 is a functional block diagram of the XM21 BallisticComputer System. The BCS consists of the following primarycomponents:

o Computer Unit

o Gunner's Control Unit

o Commander's Ammunition Selector Control

o Gunner's Ammunition Selector Control

o Cant Unit

o Rate Tachometer

o Output Unit

o Crosswind Sensor

o Reticle Projector

The Computer Unit contains DC power supplies, power distributionand filtering circuits, quadrature suppression, system computa-tional and built-in test electronics and output drive circuitry.The circuitry is mechanized on module type printed circuitboards.

The Gunner's Control Unit facilitates BCS power and lightingcontrol, mode selection, manual data insertion and subsystemfailure indication. A built-in test mode switch in the frontpanel permits selection of computer system test mode, normaloperation mode, or failure indicating lamp test mode. An inter-nal built-in display in the front panel indicates, by means oflights, whether the ballistic computer system is performing_satisfactorily, or, if not, which unit is malfunctioning.Toggle switches are used -t-select manual or automatic range-andcrosswind. Potentiometers allow for manual inputs of:

o Range (20 meter increments)

o Crosswind (5 mph increments)

o Jump (0.1 mil increments)

o Zeroing (0.1 mil increments)

o Altitude (100 meter increments from -200 to 3000 metersfrom mean sea level.

0 Air Temperature (10°F increments from -65°F to 125°F)

2-19- '- -I

r ------- - --------

* -na S1I 5 5 m

~,ii H F4*~ 4)

-3-3

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2.4.3 Stabilization System. The M6OAlE3 incorporates a ratestabilization system, which complements the Weapon System, by in-creasing target acquisition capabilities and accuracy of fireduring periods in which the vehicle is moving. By facilitatingeffective offensive operation 'on the move', the stabilizationsystem reduces vulnerability to enemy fire.

The stabilization system consists of electra-hydraulic compon-ents added to the gun elevation and turret traversing systems(refer to 2.6). The integrated system is designed tooperate in a stabilized mode utilizing the stabilization systemand in a 'power' mode which does not utilize the stabilizationsystem.

The function of the stabilization system is to space-fix (sta-bilize) the gun at a desired angular orientation relative to anearth reference plane. This is accomplished by providing azi-muth and elevation axis stabilization for the turret and gun re-spectively. Stabilization is with respect to external angulardisturbances caused by vehicle motion. Stabilization does notcompensate for changes in target line of sight caused by motion.The commander or gunner must therefore maintain accurate sight-ing with their respective power controls.

The stabilization system consists of a rate sensor package, con-trol selector assembly, electronics control unit, solenoid valve,.traverse servoValve assembly, elevation servovalre assembly,adjustable register assembly, hydraulic filter, anti backlash

cylinder, and stabilization shutoff box.in stabilized operation, the rate sensor package measures angu-lar rates of the gun, turret azimuth, and gun elevation rate.These measured rates are compared with the gunner's (commander's)commanded rates (as determined by the angular position of thegunner's (commander's) handle and measured by the adjustableresistor assembly), and the elevation correction and deflectionsignals generated by the Ballistics Computer. Comparisons areaccomplished by the electronics control unit. Error signalsresulting from these comparisons are shaped according to thecontroller's elevation and azimuth transfer functions and ap-plied as command signals to the servo valves.

Stabilization system power and stabilizer ON/OFF switches arelocated on the control selector assembly. This unit also con-tains null potentiometers for control of stabilization closed-loop balance.

2.5 Power Train

The M60A3 Combat Tank power train is comprised of the enginewith its associated fuel system, cooling system, air-intake andexhaust system, together with the transmission, universal jointand final drives.

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The engine is a twelve cylinder 'V' type, 4 cycle, air-cooleddiesel engine manufactured by Teledyne, Continental Motors,type AVDS-1790-2C (RISE).

Engine system characteristics are as follows:

Maximum Gross Horsepower 750 @ 2400 rpm

Maximum Net Horsepower 642 @ 2400 rpm

Maximum Gross Torque 1770 lb. ft. @ 2000 rpm

Maximum Net Torque 1620 lb. ft. @ 1800 rpm

Engine oil Capacity 22 gallons

Engine controls and indicators include: starter switch, footcontrolled accelerator (throttle) pedal with locking mechanism,tachometer/hour meter, speedometer/odometer, engine oil pres-sure gage, engine oil temperature gage, and a power plant warn-ing light. The power plant warning light illuminates when theengine oil pressure is equal to or less than 13 psi, when theengine oil temperature exceeds 285 degrees F. The hour meterindicates total hours of engine operation. All of these con-trols and indicators are located in the drivers compartment.

The fuel system stores and supplies fuel to the engine, the per-sonnel heater, and the engine air intake manifold heater. Fuelsystem equipment consists of two tanks with a crossfeed mani-fold, electrical fuel pumps located in each tank, mechanicalpurge pump to clear the fuel lines of air, intake manifoldheater for cold weather starting, engine mechanical pump, inte-gral mechanical centrifugal governor controlling the fuel de-livery as a function of engine speed, fuel system filters, in-terlock isolation valve, injector pump which delivers fuel ofhigh pressure to each cylinder and various solenoids and, manualand check valves. Controls and indicators for the fuel systeminclude: a fuel pump shutoff switch, electrical engine fuelshutoff switch, heater master switch, heater HI-LO switch, fuelpurge pump, manifold heater control switch, fuel quantity indi-cator selector switch (left or right), and a mechanical fuelshutoff handle. A fuel quantity gage is also included. Use-able fuel capacity for both tanks is 375 gallons.

The engine air intake system consists of two fender-mounted drytype, top-loading air cleaners, two turbosuperchargers, and airintake manifolds with associated manifold heaters. The systemis identical for both left and right engine cylinder tanks.intake air is drawn from either the crew or engine compartment.The air passes through the inlet hose to the air cleaners. Fil-tered air from the air cleaners enters exhaust-driven turbo-superchargers to compress air into the cylinders through theintake manifold. Manifold heaters are provided for preheatingthe combustion mixture when starting the engine in low ambient

2-22

temperatures. No controls or indicators are provided for theengine air intake system.

The exhaust system has four engine manifolds, one for eachgroup of three cylinders. The engine exhaust passes from theexhaust manifolds to the turbosupercharger, flows around theturbine housing, and through a set of nozzles to drive the tur-bine wheel. The exhaust pipes direct the exhaust toward therear grille doors. Here again, no controls or indicators areprovided for the exhaust system.

The cooling system consists of two axial-flow fans mounted overthe "V" of the engine providing cooling air for the engine andengine and transmission coolers. The cooling system indicatorsconsist of a power plant warning lamp, engine oil temperaturegage, and a transmission oil temperature gage. The power plantwarning lamp will light when either the engine oil pressure islow or the engine oil temperature transmission oil temperatureis hot.

The Detroit Diesel, Allison, GMC CD-850-6A crossdrive transmis-sion is a combination steering, braking and power transmittingunit. The transmission is controlled by means of a steeringcontrol, brake pedal and transmission shift lever installed inthe driver's compartment. There are two forward speed rangeslow (L) and high (H) and one reverse. Steering in neutralcauses the vehicle to pivot in place, with the tracks runningin-opposite directions. The transmission includes a hydraulictorque converter, four planetary gear sets, a steering mechan-ism and an internally operated mechanical braking mechanism.The input parameter to the transmission is engine torque andthe output parameter is transmission torque. Steering controlconsists of a "T"n bar connected to a steering linkage that con-nects to the steer valve shaft assembly on the transmission.Braking control consists of a single pedal actuating a hydraulicmaster cylinder coupled to the two slave cylinders that in turnoperate wet-disk type brakes on the output shafts of the trans-mission. A parking brake feature is incorporated into thetransmission selector lever and slave cylinders. By depressingthe brake pedal while shifting to park (P), a mechanical link-age and cam mechanism causes the slave cylinder to lock in po-sition. To release the brakes, the procedure is reversed. Abrake pressure gage is located on the master cylinder to aid inthe parking brake operation. The transmission system indica-tors include a transmission oil pressure gage, a transmissionoil temperature gage and speedometer/odometer. Transmissionsystem control is a shift lever allowing the driver to shift thetransmission to park (P), neutral (N), low (L), high (H) andreverse (R).

Universal joints are double-journal units that compensate formisalignment of the transmission and final drive. No universalf joint indicators or controls are provided.

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The final drive is a single-stage speed reduction unit. Thefinal drive gear ratio is 5.08:1. Again, there are no finaldrive controls and indicators.

2.6 Vehicle Systems

2.6.1 HydraulicS stem (Table 2-1). Power to operate the tur-ret and ncntr systm is primarily hydraulic. There arethree modes of turret and gun control: non-stabilized powermode, stabilized mode, and manual mode.

Hydraulic power for the systems is stored in a mai accumulatorcharged to 1225 psi. Recharging the accumulator is accomplishedby an electrically operated pump whenever the charge drops be-low 925 psi. A pressure gage is mounted on the accumulatoroutput to maintain a constant pressure to the using-systems.

A POWER switch, located on the Gunner's Gun Control Box Assem-bly, operates a hydraulic power valve spool solenoid. In theenergized position, it allows pressurized oil to flow to thefour-way traversing and elevating spools, commander's overridespool, auxiliary pressure spool, the superelevation actuator,and deck clearance valve.

A POWER ON indicator light is also located on the Gunner's GunControl Box assembly to indicate that hydraulic power is avail-able to operate turret and gun hydraulic systems.

2.6.2 Traversing Gearbox Hydraulic Motor Assembly. The tra-versing-gea-rbox assembly is used to rotate the tank turret. Itis normally hydraulically powered and electrically and mechani-cally controlled. It can also be manually operated using acrank. In the non-stabilized but powered mode, control of theassembly is accomplished by the gunner's power control assemblyhandles. The commander's handles allow the commander overrid-ing control of the system (otherwise the gunner is in control).

The traversing gearbox also contains a magnetic brake operatedby a palm switch on the gunner's or commander' s control handle.The brake is used to prevent turret drift and curtail turretduive motion. (See table 2-2)

In stabilize mode, an additional set of electronics and valvesprovide inputs to the traverse unit. These components tend tomaintain the turret azimuth constant regardless of hull motion.

The manual mode is used during unpowered or fine gun layingoperation. A crank, connected to the traversing mechanism, isnormally locked out but may be operated when the gunner graspsthe crank handle assembly and squeezes the release lever. Aclockwise turn on the crank, located near the gunner's station,causes the turret to rotate right. The reverse rotation causesthe turret to rotate left. The crank will operate the turretat anytime and is not affected by the magnetic brake.

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I

TABLE 2-1 HYDRAULIC SYSTEM DATA

POWER PACK CONTROL ASSEMBLYNet Weight .............................. 189 lb

GUNNER'S CONTROL ASSEMBLYNet Weight .............................. 43.25 lb

RESERVOIRCapaci1ty ................................ 11.25 qtNet Weight .............................. 16.80 lb

ELECTRIC DRIVE MOTORWeight . . ......................... 77.0 lb

Rated Speed (full load) ................. 3,800 rpmRated Power ......................... 0e.. 5 hpRotation (as viewed from drive end) ..... Clockwise

MAIN ACCUMULATOR ASSEMBLYWeight ......... o......................... 72 lbType .............................oo....... Floating Piston

TABLE 2-2 TURRET TRAVERSING SYSTEM DATA

AUTO MODE

Weight ............. . . . . . . . . . . 298 lb

Minimum time for powertraverse of turret 360 ° ................. 15 secMaximum Azimuth TurretAcceleration Rate ....................... 300 mils/sec/secAzimuth Slew Rate ....................... 0.50 to 400 mils/sec

MANUAL MODE

Manual Traverse Range................... 3600 cont. rotationManual Traverse Rate (tank level) ....... 10 mils per hand

crank revolutionManual Traverse Effort.................. Mean force 17 lbs

applied tangentiallyto the hand traversecrank

2-25

A separate mechanical Turret Lock Assembly, located near theloader's seat, can be used during periods of operation whenturret movement is not required. It can not be overpowered byany means.

2.6.3 Gun Elevation Mechanisms. The Gun Elevation actuator ishydraulically powered from the hydraulic system accumulator orby a manual elevation hand pump at the gunner's station. Nor-mal control is through the gunner's control assembly handles or,in the override condition, by the commander's control assemblyhandle. The palm switches on either the gunner's or commander'scontrol handle must be depressed to gain control of the eleva-tion system. In the normal powered mode, hydraulic power fromthe accumulator is provided if the Elev/Trav Power Switch onthe Gunner's Gun Control Box is in the ON position.(Table 2-3)

The manual elevation hand pump can be used in any mode and doesnot require palm switch operation.

In the Gun Stabilized mode, a computer system furnishes elec-trohydraulic signals to the elevation system to maintain con-stant elevation regardless of hull movement. The elevationsystem is also furnished a ballistic correction signal from theballistics computer and superelevation actuator. Elevation isthen corrected for range, type of ammunition, and other effects.

2.6.4 Electrical System. The tank electrical and system powerequipment consists of 6, twelve-volt batteries to maintain the24-vdc system, a 650-amp gear-driven alternator and a solid-state regulator. Output current of the batteries is 300 amps,with a 100-amp/hr capacity rating. Additional related equip-ment includes control switches, power relays, circuit breakers,and a Battery Generator Indicator.

The master (battery) switch energizes a master relay which inturn, provides power from the batteries to the master controlpanel, slip ring assembly, and fire extinguisher control cir-cuit. When the master switch is in the ON position, all elec-trical/electronic equipment can be powered by their individualcontrols, provided the engine is running or the batteries arecharged.

If the master switch is in the OFF position, only the PersonnelHeater and the fire extinguisher system remain operational. AMaster (Battery) Indicator Light on both the Master ControlPanel and the Networks Box assembly monitor the POWER ON status.

A battery-generator indicator is located on the Gage Indicatorpanel. This indicator monitors battery condition when the en-gine is not operating or the alternator charge rate when theengine is operating.

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TABLE 2-3 GUN ELEVATION SYSTEM DATA

Gun Elevating (depession of gun) .......... 100 minimum eachside of vehiclefront centerline to900 of vehiclerear centerline

00 minimum each sidefrom 900 of vehiclerear centerline torear centerline

(elevation of gun) .......... 200 maximum for3600 of turrettraverse

Type of Elevation Mechanism............... HydraulicRate of Power Elevation of Gun(max) ....... 40/sec

Gun Elevation Acceleration Rate ........... 660 mils/sec/sec

Gun Elevation Speed........................ 0.50 to 71 mil/sec

2

I

I

2-27

Circuit breaker protection is provided on the fire extinguisher/fuel cutoff and master relay circuits. These automatic resetCB's are located under the turret platform. Other miscellane-ous CB's are located within the master control panel and inac-cessible to the operator.

Tank exterior lighting consists of standard white light, black-out, and infrared illumination. The headlight group consistsof 2 removable assemblies mounted on the front hull. Each as-sembly has 2 sealed-beam units (white and infrared) and a hoodedblackout drive and blackout marker lamp. A pair of tail lightassemblies exist with standard and blackout capabilities.Both assemblies provide blackout drive marker lamps. The leftlight assembly has a standard drive light and stop light. Theright assembly incorporates only blackout drive and blackoutstop lights.

Lighting controls are located on the master control panel alongwith a HIGH BEAM indicator light. An automotive type foot dim-mer switch is located to the left and below the brake pedal.

Interior lighting consists of a dome light at each crew member'sstation. Dome light assemblies incorporate dimming and selec-table red or white illumination.

2.6.5 Fire Extinguisher System. The primary function of thefixed fire extinguishing systems is to extinguish fires withinthe engine compartment. The system consists of three chargedcylinders, two control head assemblies, three perforated dis-charge tubes, one time-delay valve, one interior and two exter-ior control handles, three deck valves, connecting lines, andfittings.

The charged cylinders, fire extinguisher control handles, andrelated components are located to the left of the driver'sseat.

The system operates on a two-shot principal; the first shot dis-charging one cylinder and the second shot the remaining two.The discharged agent is disbursed through the engine compart-ment through the perforated tubing. When the interior controlhandle is actuated, a fuel shutoff solenoid is energized stop-ping fuel flow to the engine.

There is one portable fire extinguisher in the turret, locatedunder the loader's seat.

2.6.6 Personnel Heater, Ventilation System , and Gas Particu-late S stm. The personnel heater is a self-contained unit-loctedon the right side of the driver's compartment. It sup-

plies warm air to the tank interior.

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The heater operates on fuel from the vehicle fuel system bututilizes a separate electrical fuel pump. Heater exhaust ispiped overboard through a hole in the hull roof above theheater unit. Heated air is fan-forced through a manifold andflexible duct to an air deflector in the turret area. Controlof the heater is maintained by a Heater Master switch, a HeaterHI-LO switch, and a Heater ON indicator light all located onthe Master Control Panel in the driver's compartment.

A ventilating blower, located in the ceiling of the left turretbustle, provides approximately five changes of fresh air perminute. An ON-OFF switch, on the ceiling behind the commander'sdome light, controls its operation. The blower is used to purgethe hull interior of noxious gases produced when the guns arefired.

The Gas Particulate System is used to protect crew from breath-ing contaminated air in the event of a CBR attack. Contaminatedair is drawn through a series of filters to remove dust, aero-sols, and poisonous gases. The purified air is deliveredthrough the turret slip-ring assembly to the turret crew sta-tion. Each station has a thermostatically controlled, electricair heater unit for cold weather operation. Crew members at-tach their personal face masks at their own station outlet. Acontrol switch and indicator light are located on the Mastercontrol panel.

2.6.7 Hull-Turret Inflatable Seal. An inflatable seal betweenturret and hull is used to make a water tight compartment ofthe hull/turret interior. During fording operations, a bicycle-type hand pump at the driver's station is operated to inflatethe seat to approximately 14 psi. Also included is a bleedvalve, gage, and manifold to supplement the operation.

2.6.8 Fuel System. See power train description Section 2.5.

2.6.9 Bile um . The Bilge Pump is used to pump water from thecrew are hull during and after fording operations.Control of the pump is achieved by operating a switch on theMaster Control Panel. A light is provided to indicate ON/OFFstatus.

2.7 Crew Station Configuration

A Full Vehicle Crew consists of:

1) Tank Commander (Right Rear Turret)

2) Gunner (Right Front Turret)

3) Loader (Left Rear Turret)

4) Driver (Front Hull)

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The M60A3 tank has 3 major component groups which are discussed

separately. Those are:

1) Hull

2) Turret

3) Cupola

2.7.1 Hull. This portion of the vehicle serves as an enclo-sure for the driver and his controls, a housing for the engineand its support systems, the electrical source, and turret sup-port.

The driver's compartm 'ent, (forward hull) contains ammunitionstorage racks (105mm) located along either side of the seat,vision equipment consisting of three (3) periscopes and a nightvision viewer that he can install in his overhead hatch cover.I A master electrical control panel, gage panel, communicationscontrol panel, and miscellaneous indicating devices provide thedriver with control over the vehicle's electrical and comimuni-U cation systems as well as allowing him to monitor engine per-formance. Primary control devices consist of a "T" bar forsteering, brake pedal, gear shift, and accelerator pedal. Sec-ondary controls include a hand pump for inflating the turretseal, drain valve control levers, fixed fire extinguisher con-trol, emergency fuel shutoff, and purge pump. other equipmentincludes a bilge pump, gas particulate system, personnel heater,escape hatch, etc.

The engine compartment (Rear Hull) houses the engine, aircleaners, fuel tanks, and transmission.

The center hull area contains the batteries that supply theelectrical power for the vehicle.

2.7.2 Turret. This section houses 3 crew members, the mainarmament with its sighting and firing systems, and serves asa structural support for the cupola.

The turret interfaces with the hull through a combination ringgear/ball bearing which allows rotation independent of the hull.A floor suspended from the turret and extending downward intothe hull serves as the supporting member for the fighting crew,their seats, ammuunition storage racks/boxes, equipment storage,power pack, main relay box, electrical slip ring, and othermiscellaneous items. That portion of the turret above thehull supports the main armament, telescope, gunner's periscope,laser range finder, turret traversing controls, ballistic com-puter system and stabilizer control system. Radio equipment,ventilating blower and other items such as dome lights, storageboxes, ammunition boxes, are also located in the turret. Twoseats are available for the commander, one of which is usedwhen his hatch is open, the other when the hatch is closed.The loader and gunner have one seat each.

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2.7.3 Cupola. The cupola serves as a protection device for thecommander as well as providing him with vision devices and aI small caliber automatic weapon.

A combination ring gear/ball bearing joining the cupola andturret allows independent 360 0 rotation. Vision blocks and aI periscope provide the commander with 3600 visibility withoutrotating the cupola. A machine gun, ammunition storage, inter-com/radio controls, firing controls, gun elevation system, tra-versing mechanism and other miscellaneous equipment are alsolocated in and supported by the cupola.

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SECTION IIII 3. TACTICAL ENVIRONMENT ANALYSIS

This section examines the tactical environment in which theM60A3 tank and its crew operates. The extent of scientificanalysis performed by the Link study team on this subject hasbeen limited, primarily by the lack of quantitative and quali-tative data available. The aspects discussed include:

o Geographical and terrain conditions

" Climatic conditions

o Threats and friendly forces

o Tactical information

3.1 Geographical and Terrain Conditions

Terrain has always been the overriding condition determiningthe deployment of armor. In recent wars, both natural and man-made obstacles have dictated the type and extent of armor oper-ation possible. Although some terrain is better suited fortank deployment than others, tanks may be deployed in any partof the world, although numbers may be limited in some areas.

3.1.1 Tactical Considerations. For the tank crew, the ter-rain presents that part of the environment through which thetank and the crew are moved to a position where they can closeon the objective and destroy the enemy. Particular attentionhas been paid in this study to the terrain characteristics ofWestern Europe and the continental United States, since almostall of our armor units are located in these areas. Fortunately,for purposes of training, these two areas are quite similar.Both provide areas comprised principally of gently rollingterrain partially covered with forests, with many rivers andlakes. These areas include sophisticated road networks con-necting all populated areas, and thus high speed approaches toalmost all potential military objectives. The majority of thehighway bridges on the North American and European continentswill support the M60A3 tank. The M60A3 tank has excellentcroascountry mobility since few natural obstacles presenting agradeability of less than sixty (60%) or a water depth of lessthan four (4) feet will stop the tank. Most soils on thesecontinents will support tank traffic although swampland severlylimits mobility. Weather variations in Europe and the contin-ental United States present some problems in tank operations#but temperature extremes generally do not affect armor opera-tion. Visibility has in the past impacted heavily on the crews'ability to move and to acquire and engage targets. Recentbreakthroughs in the state-of-the-art, however, have vastlyreduced this problem. The M60A3 tank with the gunner's andtank commander's thermal viewing systems and the driver's imageintensifier permit near daylight visibility under conditions of

3-1

9 limited visibility such as smoke, fog, haze, and rain.

The tank commander and the driver primarily are concerned withevaluating terrain. The tank commander searches for threats,targets, avenues of approach, fields of fire,and likely firingpositions. He and the driver attempt to predict areas wherethreats might be concealed, areas affording cover, mobility,andI firing stability. Experienced drivers select optimum routesand firing positions with little or no direction from the tankcommander. This leaves the tank commander free to devote hisattention to target acquisition and engagement.

While the M60A3 can negotiate almost any type of terrain foundin the European continent, various types of terrain have theireffects on tank speed, maneuverability and agility. In addition,of course, terrain, cultural and vegetative features vary widelyin their ability to provide cover and concealment. As a result,the driver and tank commander must constantly assess the terrainand its ability to minimize tank visibility from areas of likelythreat location. They must also constantly assess the effectsof the terrain and potential obstacles on the ability of the tankto move to the objective and to maintain its position with re-spect to other elements involved in mutual support. The tankcan cross many obstacles without appreciable effects on speed,while others will slow it significantly, increasing its vulner-ability and limiting its ability to provide support for otherelements. Some terrain surfaces and obstacles will not slowthe tank, but may restrict the ability of the gunner and thetank commander to acquire and engage targets while moving, andthe ability of the gunner to load the main gun and maintain thecoaxial gun in firing condition. The effects of the terrain onthe crew can be profound, until each learns to predict, minimizeand otherwise deal with its effects.

3.1.2 Vehicle Mobility Considerations. The mobility of a landvehicle is a functo of not only the Vehicle characteristicsbut also the geometry of the ground surface and the physicalproperties and state of that surface. The geometry of theground surface depends upon the type of terrain, and for theM60A3, the operating environment is likely to vary from rollinghills and valleys, to flat but uneven ground with gullies,ditches, streams,and rivers. The physical state of the surfacewill vary from that presented by hard paved roads, to that ofunbroken ground with rocks, gravel, sand and dirt, togetherwith assorted vegetation ranging from grass and scattered shrubsto dense foliage and trees. Each of these surfaces can vary asa direct result of climatic conditions, i.e., wet or dry sur- -faces, mud and swampy ground, and more particularly the presenceof snow and ice.

Any vehicle of adequate power to provide the thrust required forpropulsion will move across country only if the characteristicsof the ground surface are such as to sustain the reactionaryforces generated and support the weight of the vehicle.

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Vertical and horizontal reaction forces of the ground involvedin land mobility are called sinkage, traction, and motion re-sistance. Sinkage is a function of ground pressure. Horiz-ontal propelling forces produced by the shearing strength ofthe ground under vehicle action is the maximum thrust the soilcan sustain. A part of this thrust is wasted in overcomingmotion resistance, and the rest, which remains as a usefulforce to accelerate the vehicle, to climb a slope, or to pullloads. These forces are defined in terms of the physicogeome-trical properties of the soil-vehicle system.

The physical properties of the soil can generally be describedin terms of friction and cohesion. Examples of friction typesoils are dry sand and cold "sugar" snow. Sand or frozen snowgrains are loose and move upon each other with ease, particu-larly if the grains are not too coarse. If the grains arepressed against each other, friction develops among them andthey cannot move, thus offering resistance. In this case,thetractive force increases proportionally to the weight of thevehicle. Examples of cohesion type soils are wet clay andsnow. In this case, the tractive force remains constant re-gardless of vehicle weight. This is due to the existence ofcohesive forces which bind soil grains or snow crystals,through capillary action of moisture films and other complexphysical phenomena . Moreover, the tractive force requiredto shear the stickiness of this soil mass is proportional tothe size of the surface area in contact with the ground.

As described above (with respect to onow), the moisture con-tent effects soil characteristics. Therefore, ambient weathercondition is relevant in analyzing soil characteristics inorder to determine vehicle mobility.

it is important to note, at this time, that the vehicle'sspeed is not governed by the power train alone, but also bythe geometry and dynamic properties of the vehicle structure.These factors, in conjunction with the unevenness of the ter-rain surface, produce vehicle vibrations that impact both crewand vehicle, and may be prohibitive for human endurance andcause fatigue stress of the vehicle structure metals if ridingspeeds reach certain limits. The average M60A3 combat tanktactical cruising speed is approximately 10 mph, even thoughthe maximum speed of the vehicle is 30 mph. Cruising speedsapproaching the maximum limit would cause critical pitchingand/or bouncing. Vehicle vibrations depend not only on thecharacteristics of the suspension system but also on theground wave. A sinusoidal profile of the ground can be con-sidered when dealing with the vibration analysis of thevehicle, particularly since it has been found that thereexists a definite pattern of waviness both on highways and invirgin terrain, especially ground of certain geophysical ori-gin. Experience in sand and snow indicates the existence ofthe same irregularity, even though it is not visible at first

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glance. Thus, the adoption of a typical wave based on theavailable limited experience could serve the purpose of anevaluation of vehicle vibrations.

3.2 Climatic Conditions

Althcugh the M60A3 tank can operate in a wide range of climaticconditions, crew tasks can change drastically with changes invisibility and area surface conditions associated with weatherchanges. Changes in visibility, mobility, maneuverability~andagility can have profound effects on crew experience and tankeffectiveness. Tank operations over snow, ice, mud,and hardsurfaces require significantly different responses on the partof the driver, and require different kinds of planning andtactics on the part of the tank comnmander. In addition, theycan have significant effects on the workload of the entire crew.

The entire crew is affected by changes in weather conditionsin anticipating areas of possible threat locations, and in recog-nizing threats and signs of threat activity, especially in lim-ited visibility and in snow. Drivers in particular are affec-ted by rain, fog, snow, and ice in that choices of routes canchange markedly with changes in visibility and surface consis-tency. Fog is a special problem as it greatly reduces theability of the crew to move and to observe. By the same token,it offers a degree of security for movement, especially overfamiliar areas. Thermal sensors do change the tactics employ-ed in fog and other types of limited visibility conditions forboth friendly and hostile elements, but fog does pose specificproblems for armor operations.

Drivers, and tank commanders rarely have opportunities forlearning the way in which the tank operates over snow, ice andmud, particularly in negotiating and crossing slopes. In arm-ored combat, the ultimate success of the tank mission dependslargely on the agility of the tank, which in turn depends onthe ability of the crew members to select routes which are con-sistent with the requirements of the mission, and within thecapabilities of the tank. It is also dependent on the abilityof the driver to exercise control for maximum speed, maneuver-ability, and safety for maximizing firing accuracy, and use ofcover and concealment.

3.3 Threats and Friendly Forces

The primary function of the main battle tank is to support themovement of friendly elements in taking various military obj ec-tives. This function includes the destruction of a variety ofthreats, the most important of which are other tanks, weaponsystems, and emplacements which threaten the tank itself. Manysignificant threats operate on the surface of the battlefield,but helicopter threats are of extreme importance because oftheir ability to make overhead approaches and rapid use of the

cover and concealment afforded by the terrain and by various

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natural and cultural features of the terrain. Ordinarily,tanks destroy threats by direct engagement, using weapons, ortactics and methods of engagement appropriate to the specificthreat and mode of threat deployment. As a result, the tankcrew must be able to discriminate, to the maximum extent pos-sible, among various threat types and modes of threat deploy-ment. Tanks, trucks, personnel, artillery emplacements, heli -copters and ground-attack aircraft require different kinds ofammunition and different kinds of engagement methods. Tankcrews are familiarized with the threats expected to be en-countered in possible future wars, and with the characteristicsof those threats relevant to their detection, identification,review and engagement.

The M60A3 will encounter eight general types of threats, eachhaving significant implications for crew performance..

(1) Tanks - Tanks are the most lethal threat to the M60A3-ecause of their mobility, fire power, and armor pro-

tection. Tanks are generally equipped with high-vel-ocity guns firing chemical and kinetic energy roundswhich can defeat the M60A3. However, the accuracy ofsome threat tanks is degraded at long range by the lackof precise range finding capabilities. Some threattanks are less agile than the M60A3, but the capabili-ties, nunibers,and deployment of these systems maketheir destruction at the longest possible ranges vitalto the success of the M60A3.

(2) Artillery - Mobile artillery systems are less of athreat to tanks than are other tanks, since they lackthe tank's maneuverability. Most mobile artillerypieces do not have rotating turrets, and though they havegreat fire power, they are rarely used for direct fireagainst tanks. They may be used for direct fire def-fense of objectives attacked by the M60A3. Their pos-itions must be predicted from the analysis of the ter-rain, and the tactical situation, and their fields offire avoided whenever possible. Anti-aircraft artil-lery (AAA) tends to be more mobile than indirect firesystems, but AAA rounds fired by these systems are notespecially lethal to the M60A3. The lethality of anti-aircraft artillery systems is in their ability to en-gage and destroy the scout and attack helicopters furn-ishing battlefield intelligence and direct fire supportto the M60A3. Since armed helicopters can engage anddestroy threats which the tank cannot see, systemsthreatening the armed helicopter are direct threatsto the tank itself. In situations where the tank isfaced by a variety of threats, anti-aircraft threatsrate with tanks as priority targets.

(3) Lishtly Armed Vehicles -Additional threats to theM6 0A3 and to the miTsions in which it will be employed

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are vehicles designed to carry troops and to performreconnaissance and fire support functions. They arehighly mobile, but are protected primarily againstanti-personnel weapons such as airburst artillery,small arms and machine gun fire. Some of these vehi-cles carry mortar or anti-tank guided missile systemsand are thus especially important to the M60A3. Theiragility makes them hard to engage but also degradestheir effectiveness as anti-tank weapons. Stationary,they are good, high-priority tank targets; moving,they are most effectively engaged by airborne systemssuch as armed helicopters and fixed-wing attack air-craft.

(4) Fixed Emelacements - Fixed artillery positions usuallyprovide indirect (non line-of-sight) fire support, butmay engage tanks and other assault elements by directfire. Bunkers and other fortified positions also poseserious theats to the M60A3 by firing tube and missilesystems from protected areas. These emplacements, ifthey are well prepared, are hard to locate until theyfire, and must be detected through careful analysis ofthe terrain and the situation. Potential fields offire must be predicted and avoided where possible,especially if the enemy has time to. prepare fixed de-fenses. Bounding over-watch can also be effectivein revealing these threats when the exposed movingelement is engaged.

(5) Personnel - Individual soldiers can be extremelylethal T the M60A3, particularly when equipped withanti-tank guided missiles. Even troops with simpleweapons can be lethal when close to the tank, andconcealed by areas masked from the view of the crew.Mutual support among tanks, artillery, and mechan-ized infantry minimizes the effect of personnelthreats provided effective search and support pro-cedures are followed. Troops firing small arms fromcover can force tanks to close hatches, increasingtheir vulnerability by degrading crew visual contactwith the area, and by enlarging the size of the tank'sblind spots. Troops with grenades and/or explosivecharges can also be significant threats, since theycan damage tank treads, immobilize the turret, andstart fires in the engine compartment if they arepermitted to approach the tank.

Personnel firing anti-tank guided missiles (ATG4) atthe tank must be, currently, in visual contact withthe tank during the missile flight. A crew seeing amissile launch can disrupt the firer's launching per-formance by firing in his area, if they are aware ofthe method of engagement used by ATGM elements. Insome cases the missile is guided from some distance

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to one side of the launcher; firing to the left orright of the launcher can destroy the effect of theATGM.

(6) Mines - When permitted by time and situation, anti-tnmines are placed in areas likely to be used by

the M60A3. Roads, fields and logical routes thatmay be mined must be avoided, unless there is assur-ance that the areas are not mined, or that the mineshave been destroyed. Sometimes obvious routes aremined to channel the tank into less desirable alter-nate routes which are also mined, or sighted in by ar-tillery. When mines are detected, they are neutral-ized by exploding them, or by removing them. whentime permits, the mined area and lanes through thearea are marked by engineers.

(7) Helicopters - Armed helicopters are major primarythreats to the tank. The helicopter can make the sameuse of cover and concealment as the tank, but is in-finitely more flexible in its ability to approach andattack from almost any direction. Helicopters tend tobe channeled by the terrain and the deployment offriendly elements, but their approach is harder topredict than that of ground elements.

The M60A31s best defense against helicopters armedwith anti-tank guided missile systems is in the sup-port of flexible anti-aircraft missile and artillerysystems which, in normal operations, can keep thearmed helicopter away from the main battle area. TheM60A3 can also defend itself from armed helicopterattacks by means of smoke, and with the main gun andthe commander's cupola-mounted machine gun. It mustbe noted however, that anti-helicopter gunnery requiresexceptional skill. Normally, helicopters are exposedonly for very short periods, except during the flightof missiles controlled from the helicopter.

Scout helicopter and other observation aircraft arealso important threats to the M60A3, because they candirect armed helicopters, attack aircraft, artilleryand other tanks in attacking the M60A3. Ideally,these threats will also be neutralized by anti-air-craft artillary support or by attack aircraft, butwill occasionally be engaged by the M60A3. They aresomewhat more difficult to destroy than the attackhelicopter because they tend to operate at greaterslant ranges.

8) Attack Aircraft - Fixed-wing, high performance attackaircraft carryng missiles and bombs are also signi-f icant threats to the M60A3 . Many ground attack de-livery systems require the aircraft to perform a

stabilized dive for an appreciable period of time, _

during which it is vulnerable to anti-aircraft fire.Some systems can be directed by ground or airborneobservers reducing the vulnerability of the deliveryaircraft, making the delivery aircraft, the groundobserver and the airborne observer prime threats tobe engaged by whatever means available. The main gunand the .50 caliber machine gun are the most effec-tive M60A3 systems for engaging attack aircraft, buteffective engagements require very high levels ofcrew skill. The M60A3 primary defense against attackaircraft is in the support of anti-aircraft artilleryand air-to-air weapon systems, coordinated throughthe tactical communications network.

The M60A3 crew will always operate as a part of alarger tactical force consisting of at least one othertank, but most often, with an entire tank platoon, andwith the support of airborne, artillery, infantry andother elements. Most of these elements are not visi-ble to the crew, but interact through the comnmunica-tions net, and through the visible effects of supportweapons in the battle area. Adjacent tanks are fre-quently visible; the position, movement and engage-ment modes being employed by those tanks are crucialto the crew in performing in complete coordination.Ideally, tanks in a section move alternately, withone tank covering the other and providing securityfor it during periods of exposure. At least onetank must be seen by each crew to permit training insection tactics.

Crews are trained to recognize other friendly vehiclesand elements. In the European environment, this in-cludes friendly elements from any allied country. Inmany tank operations, crews will have to distinguishaccurately among threat and friendly forces throughthe discrimination of vehicle silhouettes, modes ofdeployment and employment and through the recognitionof weapon effects. In many tank operations, crewsI can assume that any vehicle to the front is a threat,but each commander must be proficient in distinguish-ing friendly and hostile elements.

3.4 Tactical Information

Information about the mission, deployment of threats, terrain,I weapon and the deployments, availability and capabilities offriendly supporting elements, and systems is available to theMA60A3 crew from a number of sources. The amount and accuracyI of information available at any given time is dependent on thesituation. in general, ground and airborne reconnaissanceelements and other combat units in contact with the threat pro-

vide information which is used in defining the mission and the

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way it is to b- conducted. Tactics, ammunition loads, likelyroutes to the objective, threat types, possible fields of fire,obstacles to movement, available cover and concealment, terrainsurface characteristics and the availability of reconnaissance,engineer, and fire support are all defined to the maximum ex-tent possible prior to a mission, and updated as requiredthroughout the mission.

A great deal of information is provided during oral pre-missionbriefings. The radio is also used heavily, within the limitsimposed by security requirements. The crew itself acquirestactical information during its operations, and reporting ofevents by individual crew members is an important part of thecrew's skill in real-time interaction.

The threat takes many forms: the size of enemy, whether it bean individual tank or a lakge armored force - the compositionof the enemy, whether it be dismounted infantry, tanks, oraircraft - the location of the enemy, whether he is occupyinga dominant portion of the battlefield or is in a very vulnerableposition - whether he is fast-moving and difficult to destroyor is stationary and presents a target which is easy to engage.The sophistication of the enemy with respect to his means ofsupport such as artillery, air, engineers, nuclear and biologi-cal weapons is important. Such general information about theenemy is of vast importance. However, the more detailed inform-ation about the enemy's capabilities available, the better theopportunity to destroy him. Of equal importance is a knowledgeof the enemy's limitations. Do his tanks have power in theirturrets or do they have to be operated manually? Is he capableof firing his tank while on the move, or must he halt? Moredifficult to achieve than a knowledge of the enemy's capabili-ties and limitations is a knowledge of his intentions. Today'spotential enemy has a mechanized army which has us greatly out-numbered in tanks and other mechanized vehicles. He has in histactical doctrine the philosophy of attacking in mass, andclosing on his enemy as rapidly as possible. This concept istaught in the belief that when our forces are closed on rapidly,we will be overrun and become ineffective. To overcome this,tank crews must shoot rapidly. With the proliferation ofanti-tank guided missiles (ATG4) in the hands of individualsoldiers, it becomes even more important that all targets beengaged with increased speed. Since the potential enemy hasthe capability to fight a nuclear, biological or chemical (NBC)battle it is imperative that tank crews conduct training wearingNBC protective equipment. Enemy artillery, mortars and otherindirect fire weapons present a threat to the tank crew inbattle. Although vision, and consequently target acquisition,is impaired, it is most important that the crew be capable ofengaging the enemy with all hatches closed (buttoned up).

The potential enemy in a mid-intensity combat environment iscapable of gaining local air superiority. It is thereforenecessary that tank crews be capable of engaging high performance

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aircraft and helicopters. Air defense support for tank units isusually available to provide some protection from high perform-ance aircraft, but with the proliferation of helicopters on themodern battlefield it is very important that tank crews betrained to identify and engage enemy helicopters. The main gunmay be used to a limited degree against slow moving aircraft,but the commander's M85 machine gun is the principal weaponutilized. All tank commanders must become proficient with thisweapon for engaging enemy helicopters.

Prior to a misoeti vehicle information is essential.The crew must analyze the assets available to help them to per-form their mission. The conduct of pre-comnbat checks by thetank crew should indicate that all systems are ready for combatand that proper ammunition is stowed and loaded as required withthe proper mix of types of ammunition designed to enqaqe anypossible targets. Fuel and lubricant level information to-gether with spare parts availability is also vital knowledge re-quired prior to any tactical operation. The crew should alsohave available to it, any information on the enemy, particul-arly on the type of targets which can be expected. The crewshould also have received all available information on thefriendly situation, such as where the tank will be in the form-ation in relation to other tanks in the platoon, company, orlarger force, what fire support will be available from adjacentor supporting forces such as mortars, artillery, air cavalry,tactical air, nuclear, or other special weapons, and whetherinfantry or engineers will be available to remove mines or other

* obstacles, plus any other type of support either scheduled oron call to assist the tank crew, must be known. Tactical in-formation continually changes, requiring the crew members to

* constantly update their analysis of conditions as this willimpact their ability to effectively operate as a coordinatedtank crew.

other tactical information concerning the location and size ofenemy threats is directly available to the crew members by meansof careful scrutiny and evaluation of the surrounding terrain.While enemy threats will normally use all available cover andconcealment, their presence may be indicated by tell-tale signsof activity that show up as 'movement' or changes in scene con-tent and that are very easily detected by the human eye. Thesesigns may include the movement of foliage, the glint and reflec-tion of sunlight from smooth reflective surfaces, or the pres-ence of smoke or dust clouds. A more thorough analysis of thistype of information is presented in section 4.2 that deals withtarget detection.

To some extent, aural cues will accompany many of the visualcues, especially in the case of close-proximity threat activityand particularly in the case of incoming rounds and small armstire. In many instances the aural cue may be the primary cue inalerting the crew to an immuediate engagement or requirementfor a defensive maneuver, as in the case of an attack by choppersflying NOE missions, or unknown gun emplacements.

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SECTION IV

4. MISSION/CREW TASK/CUE ANALYSIS

The M60A3 tank crew consists of four individuals, working as anintegrated team. Each individual has his own specific tasksand responsibilities within the team. Crew efficiency and theultimate effectiveness of the team as a weapon system dependsas much on the articulation of their individual responsibilitiesas on levels of individual skill. Each member of the crew in-teracts with each other, with his own systems and equipmentIand with the tactical environment in which the tank is employed.Individual skill development depends on interactions with equip-ment at the individual crew stations, but the development ofeven minimal crew skills depends heavily on individual and crewinteractions with the tactical environment.

The tactical environment in which the M60A3 tank is expected tooperate has been analyzed, together with the kinds of missionsin which it is expected to be employed. Environmental informa-tion, important in the development of crew interaction skills,has been identified for possible representation in the crewinteraction simulator. Information about the environment comesto the crew in many ways. The tank comnmander is usually brief-ed prior to a mission, and he has available maps,and occasion-allyphotographs of the mission area. He also maintains con-stant communication by radio, visual signals and personal con-tact with adjacent and supporting elements. In addition,hebriefs the crew on the current situation and keeps them up todate concerning significant changes in the situation and mis-sion.

During the mission, the tank commander and loader maintain vis-ual surveillance of the battle area from their open-hatch posi-tions. when the situation demands, the tank commander operateswith his hatch cracked, to provide a good visual field of view,with good cover from overhead artillery bursts. During theseperiods, the loader may close his hatch, using his unity powerviewing device for area surveillance. The gunner searches theterrain with his perisocpe and with his unity-power window.His field of view is severely limited, but the magnification inhis periscope makes it possible for him to examine areas of pe-tential threat deployment for targets and signs of hostileactivity. He is also able to use his powered optics to assistthe driver in evaluating possible obstacles which the driver

cannot, without magnification, see from his position.The driver's position in the hull provides him with a good viewof the situation to his immediate front, but his field of viewis constrained by the attitude of the tank, the position of thefenders, the front slope, and the turret. Even so, using hisvision blocks, the driver has the capability of examining andevaluating terrain and obstacles within the first hundred meters

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U

or so forward of the tank. He is also capable of seeing somedistance ahead (terrain permitting) and can sometimes detecttargets and signs of activity which the rest of the crew mightmiss. His position is also advantageous in sensing and adjust-ing fire, since he tends to be beneath the obscuration producedby the firing of the main gun. Since the driver's primaryresponsibility is in moving the tank from place to place, inmaintaining as low a silhouette as possible and in keeping theturret as stable as possible for searching, sighting and fir-ing, his primary interest is in the terrain within the firsttwo to three hundred meters to the front. The tactical situa-tion and the mission define what he must do; the area to hisfront dictates how he must do it.

Each member of the crew is aware of the responsibilities ofeach other member of the crew. As a result, each uses his own'position and systems to facilitate the tasks of each other crewmember in optimizing tank performance. Crew members in theturret contribute to tank mobility, agility and concealment byproviding information to the driver, which is difficult for himto acquire by himself. In turn, the driver moves the tank insuch a way as to minimize distractions and disturbances in load-ing, sighting, firing and sensing. Each member of the crew, ineffect, has defined points of contact with the tactical environ-ment, and a different effect on it, but ultimately, each hasthe same objective: the optimization of the tank in its as-signed missions.

Any examination of tank crew missions must recognize that al-though individuals are trained to become a part of the crew andthat a well integrated crew is required in order to operatethe tank, the tank is not employed by itself. All proper tankmissions require that the individual tank be employed as a partof the tank section, the tank platoon, the tank company, etc.Offensive, defensive and retrograde missions are given to tankunits, not individual tank crews. Individual tanks are maneu-Ivered by section leaders or platoon leaders. This directionusually includes the general direction for the tank to move andthe designation of a specific target for the tank crew to en-gage. Whether the tank crew is employed in an offensive or de-fensive operation, it is normally assigned a sector of respon-sibility, usually in an arc of approximately ninety degrees(900). When an offensive mission has been assigned to the tankplatoon, and the platoon is moving in a column formation, eachof the five tanks will be given a sector of surveillance tothe front, right or left flank or to the rear. If the platoonis deployed in a line formation, the three center tanks willbe assigned sectors to the direct front, while the two othertanks will be responsible for protecting each flank if they areboth exposed. Tanks normally fight with infantry as part of acombined arms team, with the primary mission of the tank is todestroy enemy tanks. The missions assigned to tank unitstherefore, are usually oriented toward the destruction of enemyforces rather than upon the seizure or retention of terrain.

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However, tanks may be deployed to assist infantry forces inthe accomplishment of terrain-oriented missions.

4.1 Mission Profiles

Tank missions fall into three basic categories. These are 'of-fensive', 'defensive', and 'retrograde'. Tanks rarely, if ever,operate as individuals and rarely without the support of inf an-try, artillery and airborne elements. Thus the complete tacti-cal environment of the tank includes the terrain, the weather,the mission, threats and other friendly supporting, or support-ed elements. The impact of the environment on the crew changessomewhat with the type of mission, but in all missions, visualinformation is of special importance. For this reason, specialattention has been given in the mission analysis to the crew'suse of visual information in learning effective interactiveskills.

4.2 Target Search and Recognition

The entire M60A3 tank crew is responsible for surveillance,target detection and target recognition. The tank commander isin the best position to detect targets, but when the tank isnot in contact with the enemy, and when contact is not imminent,the loader also has a major responsibility for surveillance.Both the loader and the commander operate with their heads outof the hatches whenever possible, to facilitate the detectionof targets and the recognition of signs of target activity.During periods of contact, the tank commander searches with hishead out of the hatch as long as small arms and artillery firepermit, moving to the "popped" hatch and closed hatch positionsas the situation demands. The loader moves into position forloading, inside the turret when contact becomes likely, relin-quishing his search area to the tank commander. When the crewoperates in a nuclear, biological or chemical warfare environ-ment, each crew member searches through his unity-power ormagnified vision devices. Again, when contact is imminent, theloader must turn over his search area to the tank commander.

All tanks in a unit (section, platoon, company) provide mutualsurveillance and in most combat operations further support isprovided by airborne elements, forward observers and supportinginfantry units. Mutual support is especially important inbuttoned-up operations, because of the severely limited fieldsof view available to each individual crew member.

Targets are rarely detected in combat as distinct, recognizableshapes, because they and the detector make every attempt to re-main concealed and unrecognizable for as long as possible.

Target positions are frequently predicted from intelligence in-formation, and from analysis of the characteristics of the ter-rain. Specific targets are detected by searching suspectedareas for signs of activity. Moving vehicles make heat waves,

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dust and exhaust smoke and, if they move through vegetation,they cause the foliage to move. Surveillance of an area overa period of time can also lead to target detections, where dayto day changes in the terrain are noted. Glint frequentlygives away a position, when sunlight reflects off glass, orother smooth surfaces. Thermal sensors are used during the day,at night, and in periods of limited visibility to reveal heatsources otherwise concealed by smoke, dust, haze, or foliage.

Movement is one of the most significant aids to target loca-tion, and frequently leads to detections, whether it is theactual movement of a vehicle or of foliage in contact with thevehicle. Weapons firing is also an important cue, and can pro-vide information about target type as well as location.

Targets are usually first sensed by observing signs of targetactivity. When a crew member sees a target or a possible tar-get indication, he alerts the entire crew, providing informa-tion about the kind of target or activity seen, its locationand its approximate range. If it is feasible, the gunner willslew the turret to the target area so that he can search withhis periscope or thermal sight, but, depending on the situation(extreme target range, or low probability of target presence),he may continue to search in his own primary sector while thetank crew commander searches the suspected area more closely.The tank commander searches primarily with his binoculars be-cause they permit him to rapidly survey his entire area. Hemay also search the designated area with the thermal sight, therangefinder or the periscope, but this requires him to move in-to the cupola losing visual contact with most of his area ofresponsibility.

Once a target is detected, it must be identified and evaluatedwith respect to its implications for the tank and its mission.At long ranges (beyond 1200 meters or so) some type of poweredoptical instrument is required for positive target identifica-tion, but in many situations, any target detected to the frontcan be considered hostile and subject to engagement. In othersituations, as in the highly fluid battlefield anticipated incentral Europe, the crew will have to take great care in dis-criminating between hostile, U.S., and other friendly vehiclesand elements.

Vehicular targets are recognized by characteristic visual pat-terns which reveal turret, gun, suspension system and otherfeatures. Beyond 1000 meters, most physical characteristicsdifferentiating one tank from another, or one vehicle fromanother, are not distinguishable to the unaided eye even undergood viewing conditions. However, wheeled vehicles can bedistinguished from tracked vehicles at extreme ranges (3,000meters). Haze, target perspective and the use of cover by thetarget changes these capabilities drastically.

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I

4.3 Battle Conditions

The primary mission of the main battle tank is to move towardan objective, supporting the movement of elements responsiblefor taking and occupying the objective. In this mission, thetank detects, engages, destroys or neutralizes threats to themaneuver at as great a range as possible. Since most objec-tives are defended in some degree of depth, the tank must beprepared to find and destroy threats enroute to the objective,by anticipating threat locations and by detecting and evaluat-ing minimal cues to actual threat location and type. The leth-ality of the weapon systems which the M60A3 can be expected toencounter make early detection, acquisition and engagementcrucial, and rapid and accurate crew coordination an absolutenecessity.

Conditions under which the M60A3 operates will place a highworkload, and a high level of stress on each member of the crew.Some battlefield operations will be conducted with the driver's,loader's and tank commander's hatches open, but friendly sup-porting artillery, and fire from hostile ground and airborneelements will make it necessary for the crew to operate, in themost crucial parts of the mission, with hatches closed. Opera-tions are also anticipated in nuclear, biological and chemicalenvironments which will force the crew to operate with hatchesclosed and in protective masks. Closed'hatches will severelylimit visual contact with the battlefield and with adjacentfriendly elements, with protective masks further degrading vis-ual capabilities. Major effects will be on the tank commander

V' and the driver, who must make continuous and complex visualdiscriminations throughout the mission. The driver's perform-ance degradation using vision blocks instead of direct viewingis less than that for the tank commander, since his positionbetween the fenders and beneath the turret significantly limitshis head-up visibility at all times. The tank commander'scupola vision blocks severely constrain his vertical field ofview, and his optical sights limit the size of the area he cansearch readily. All of these conditions force the crew to main-tain visual and radio contact with adjacent units and support-ing elements providing mutual surveillance whenever possible.They also force the crew to respond rapidly and accurately toevents taking place in the battle area.

4.3.1 Engagement Frequency and Duration. As the M60A3 movestoward its objective, it will encounter targets to be engagedand destroyed. The overall situation will determine the typesof threats encountered, their relative lethality,and the meth-ods of engagement chosen. Frequently, objectives are withinvisible range of the line of departure, because the line of de-parture is defined in part by the effective range of the weaponsdefending the objective. As a result, depending on terrain andvisibility, the mission of a given tank may extend for no morethan 2 or 3 miles, with no more than 8 or 10 individual engage-ments. Most engagements will last from a few seconds to a few

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minutes. Those lasting for more than four or five rounds ofmain gun fire urgently require some kind of external support,to allow the tank to maintain its momentum. Once an attack orany armor movement-stops, it must be restarted immediately, orthe entire tactical situation must be revised for defense orfor a retrograde movement.

A tank moving in an attack can expect to encounter a varietyof threats. The crew must be prepared for a variety of engage-ments against armored and lightly armored vehicles, fixed de-fensive emplacements, troops and aircraft. The M60A3 carriesenough ammunition for thirty or forty individual engagementsover a period of several hours, as it moves from one objectiveto another. Crew fatigue resulting from extended operations isan important factor in tank effectiveness and the effects offatigue need to be alleviated through the development of thehighest levels of individual and crew skill possible.

The variety of engagements possible during any given tank mis-sion, and the many methods of engagement available to the crewmake the M60A3 tank the most flexible and adaptable trackedweapons system available. Table 4-1 is a summary of the con-ditions under which the M60A3 may have to fight, and of themethods of threat engagement available to it in performing itsassigned missions. Tables 4-1 through 4-5 list the variety ofengagement situations in which the crew must be proficient.

Table 4-1 combines gunner and tank commander tasks in the em-ployment of tank fire control and weapons systems. Checkmarksindicate specific engagement skills employed against both sta-tionary and moving targets. With the exception of range card

* engagements, each must be accomplished with the tank itself* stationary in both stabilized and unstabilized mode.

Table 4-2 depicts 55 distinct engagement situations. Targetand vehicle motion create 199 situations in which the entirecrew must be proficient in the basic employment of fine controlinstruments, main gun, and coaxial and .50 caliber machineguns.

Table 4-2 is a matrix of target types and weapons to be usedfor successful engagements.

Table 4-3 represents an additional family of skills requiredby the gunner, commander, and loader in allocating weapons totargets, and by the commander in assigning target prioritiesand coordinating sequential or simultaneous threat engagements.

Table 4-3 lists certain required skills for the selection andemployment of available armmunition.

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Each type of round, which has its own characteristics, mustbe understood by crewmen skilled in selecting appropriatetypes of rounds for specific engagement situations. Majorcharacteristics that determine optimum employment of ammuni-tion types are listed in this table. In certain cases, selec-tion of given ammunition for use at a given range limits thecrew to a specific fire control instrument or engagement mode.

Each weapon system is optimally employed within specific rangelimits. When a target appears, the commander must determinespecific weapon(s) allocation based on target type and range.

In addition to their being proficient in the tasks listed inTables 4-1 through 4-5, the crew must be capable of performingthese listed tasks efficiently under various visibility con-ditions (clear days, nights, rain, snow, fog, and smoke asso-ciated with battlefield conditions). The crew must also becapable of operating efficiently in an NBC environment, wearingprotective equipment, for extended periods of time in theclosed-hatch mode.

The variety of engagements in which M60A3 crews must be profi-cient, and the length of time they could be committed to of fen-sive and/or defensive missions requires extensive training inconditions anticipated for M60A3 employment. Few opportunitiesexist for overlearning in individual tank crew tasks, or increw interaction. The development of combat proficiency re-quires extensive Use of synthetic training media for practicingtasks which would otherwise require prohibitive amounts of ter-rain, fuel, targets and ammunition.

4.4 Crew Task Analysis

The M60A3 is manned by a crew of four; each responsible for aset of individual tasks, but more important, each responsiblefor providing inputs needed by each other member of the crewand for responding instantly to the requirements of each. Thetank, its relationships with other friendly elements and thebattlefield environment in which it operates places require-

47-12

merits on the crew not required in other weapons Systems. Theeffectiveness of the tank and its survival on the battlefielddepend more on individual skills and on interaction within thecrew than any other system, largely because many of the crew'smost critical and difficult functions have to be performed invery short time intervals, and under very stressful conditions.The tasks required of combat-ready M60A3 crews were analyzed,to identify the most critical crew interaction skills, so thatconcepts could be developed for a synthetic replacement for thetraining of these skills. Current training systems depend onthe use of the operational tank itself for crew interactiontraining; but the complexity of individual activities, the ef-fect of crew training on the terrain and the cost of fuel, tar-gets, ammunition and other facilities are all prohibitive whenutilized to the degree required for effective crew training.

The primary mission of the M60A3 tank is to attack and destroythreats to the movement of friendly forces on the battlefield.This mission is accomplished by means of movement and fire,using a combination of systems and techniques designed to meetand neutralize a variety of threats under a wide range of cir-cumstances. A 105mm main gun, a 0.50 caliber machine gun and1, or 2, 7.62 millimeter coaxial machine guns provide f ire-power required to successfully engage threats ranging from dis-mounted personnel, to other armored vehicles, and fixed em-placements. The tank's engine, track, and suspension systemsprovide the mobility, agility and maneuverability required tomove rapidly through the battlefield and to take advantage ofavailable cover and concealment. The sighting, ranging, andfire control systems provide for the detection, acquisitionand accurate engagement of threats during daylight and night.The tank's armor protects it and its crew from many of thethreats to its operation. Radio and intercom systems permitthe crew to operate as an integrated unit, and to operate inconcert with other tactical elements on, around and over thebattlefield.

The crew of the M60A3 performs six major functions in employingthe tank in its assigned missions. These include surveillance,movement, target engagement, maintenancevand communication aswell as the tasks required to sustain the tank in operationalreadiness. The efficiency with which these functions are per-formed depends on the crew's level of proficiency in a numberof individual skills and, equally important, is the level atwhich these individual skills have been integrated throughpractice. Each member of the crew must be proficient in thetasks which are unique to his position, but must also be pro-ficient in anticipating the performance of each other memberof the crew in a wide variety of operating situations, and inS performing his own part of each crew function accurately, andat the proper time.

a) Surveillance. Each member of the crew is responsible formaintaining visual surveillance of a specific area. This

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dfa

area of responsibility varies with circumstances, buteach crew member searches for threats, signs of threatactivity, and where possible, maintains visual contactwith other friendly elements. In a defensive position,search areas tend to be fixed. The crew attempts tosearch at the greatest possible range using optical in-struments and binoculars to maximize detection ranges, atthe same time maintaining close-in surveillance to protectthe tank from infiltration and ambush. During movement,changes in the tank's position and attitude dictatechanges in the areas to be searched and in search techni-ques. Each member of the crew identifies terrain areaswhich are more likely to conceal threats and permit themovement of threat elements. In addition, the loader andthe tank commander use their elevated positions in theturret to assist the driver in moving over and among ob-stacles and in using terrain features for cover and con-cealment.

Much of the crew's surveillance activity is oriented to-ward sensing and interpreting signs of activity an thebattlefield. Since each element, whether friendly orhostile, tends to conceal itself to the maximum extentpossible, crews require a high degree of skill in antici-pating those areas where threats could or might be, andin interpreting fleeting indications such as dust, smoke,flash and glint, and the movement of vehicles, other tac-tical elements, and vegetation. The use of magnifiedoptics in the gunner's periscope and in the tank com-mander's sighting and ranging equipment can be used todetermine the sources of these fleeting signs, but thetank commander's binoculars tend to be used heavily be-cause of their flexibility in covering large areas quick-ly, particularly during the movement of the tank.

Once threats, or distinct signs of threat activity aredetected, the crewmexnber making the observation alertsthe rest of the crew and the tank commander decideswhether to engage or evade the threat, issuing appropri-ate commands to the driver, the gunner and the loader.Skilled crews tend to anticipate these commands and pre-pare to act on them, within the limits of their ability.At the same time, each crewmember continues to search hisarea of responsibility while responding to the immediatesituation as defined by the tank commander; alerting therest of the crew to further threats, threat indicationsS and other events that may impact security on mission suc-cess.

b) Movement. During movement, the operation of the tank, itssystems and its crew is a result of a number of comprom-ises among mobility, firepower, armor protection and gen-eral versatility. A primary function of the tank is tomove, using its mobility to find, engage and destroy

4-14

threats to the overall mission which is, in the final an-alysis, to take and hold ground. The tank moves to theground to be held in such a way as to avoid the fields offire of threats and potential threats to its movement,and places itself in advantageous firing positions withrespect to its targets and areas likely to contain threats.

Movement of the tank is the responsibility of the tankcommander. He identifies the objective and, where timeand the situation permit, the route to the objective.The driver is responsible for the mechanics of tank move-ment, under the direction of the tank commander, althoughboth driver and the tank commander really share responsi-bility for the selection of the fastest, most secureroute. However, since the tank commander is also respon-sible for the overall tank security, for coordinatingwith other elements, and for initiating threat engage-ments, the time and attention he can devote to movementis limited. The skilled driver seJfects and negotiatesthe most practical route in a manner that maintains se-curity and optimizes the position of the tank in the eventof an engagement.

The loader and the gunner also play a part in the move-ment of the tank. When the loader is able to ride withhis head out of the hatch, his position above the drivergives him a better view of the terrain between the tankand the objective. While the tank commander searches atlong range with his binoculars, the loader reports ob-stacles, potential fields of fire and features whichcould be used as concealment or cover for the tank. Healso reports signs of close-in threat activity. Sincethe gunner's field of view is limited, his ability tosupport rapid and secure movement of the tank depends onhis skill in using his periscope to examine potentialthreat areas, signs of threat activity and the terrainand obstacles along the route to the objective.

Examination of the terrain between the tank and the ob-jective, the exchange of information among the tank com-mander and the gunner and the information obtained inpremission briefings provide the driver with a perspec-tive of the situation which helps him to anticipate eventswhich require specific movements of the tank for threatengagement, threat evasion or route negotiation. Theability of the driver to anticipate movement requirementsreduces the tank's exposure, optimizes its speed of move-ment, tends to enhance its stability for firing, andmaximizes its rate of fire during engagements. It alsoreduces demands on the attention of the tank commanderand tends to minimize the time to fire the first roundand to increase the accuracy of firing. The degree towhich the driver can anticipate events is largely a

.4-15

matter of practice, but it is also a matter of the way inwhich a particular crew learns to operate with the direc-tion of a particular tank commander.

c) Target Engagement. The M60A3 is equipped with a varietyof primary and secondary systems for detection, acquisi-tion, and engagement of targets in maximum and limitedvisibility. The entire crew is responsible for the de-tection of targets and indications of threat activity,but in most cases, the tank commander is responsible forinitiating and sustaining engagements. Engagements arenormally initiated by a standardized fire command issuedby the tank commander. The fire command contains all ofthe information needed by the rest of the crew to opti-mize the engagement. The target is identified and lo-cated for the gunner, ammunition is designated for theloader, and direction provided to the driver concerningthe position and movement of the tank required before,during and after the engagement. Speed of target acqui-sition and engagement and first-round accuracy are ofprime importance in each target engagement. The indivi-dual skills of the driver in moving into and out of therequired firing position, the skill of the loader in se-lecting, loading, and (perhaps) unloading and clearingthe main gun and coaxial machine gun, the gunner's abil-ity to acquire and identify the target and to make properfire control settings, and the tank commander's skill increw direction, target designation and ranging all con-tribute to the effectiveness of the engagement and thesecurity of the tank. The ability of each member of thecrew to anticipate and prepare for each event signifi-cantly reduces engagement time and increases the overalleffectiveness of the tank.

d) Maintenance. The tank crew is also responsible for per-forming much of the maintenance on the tank and its sys-tems. The crew's primary maintenance responsibility isin performing preoperational checks and recognizing, re-porting, and, where necessary, operating with system mal-functions. It is especially important that the crew re-cognize malfunctions in the weapon and fire control sys-tems. During an engagement, they must be able to recog-nize failures quickly and employ corrective actions and/or backup modes as accurately as possible. The successof an engagement, and of the tank, depends heavily on theability of the crew to operate with less-than-perfectsystems, frequently under adverse and stressful circum-stances.

e) Communication. The tank commander maintains radio andvisual commnunication with adjacent and supporting ele-ments and employs his tank for optimum mutual support.He also communicates with the crew, largely by means ofthe intercom system, providing both specific commands

.4-16

and background information to support close coordinationin each mission phase. Noise, stress, workload, timepressures and changing individual responsibilities demandthat each message be clear, precise and brief. Standard-ized words, phrases and message formats are used withinand among tactical elements to minimize problems in theinterpretation of and response to commands and messages.

Each member of the crew uses the intercom to report sig-nificant events, including information about threats,threat indications, terrain, obstacles, friendly elementsand weapon effects. Skilled crews make minimum use ofthe intercom, partly by making messages as brief as pos-sible and partly by anticipating the actions and informa-tion needs of the rest of the crew to the maximum extentpossible. Untrained crews make more use of the intercomthan do trained crews. Skilled crews learn to integratewhat is known, seen, and-heard, and to act appropriatelybefore formal commands are issued. This is especiallytrue of the driver, who, in a specific tactical situation,knows when a threat is to be engaged, whether be will berequired to stop, where to stop, or whether he shouldcontinue moving.

f) Readiness. A major part of the crew's responsibility isin maintaining the tank in readiness for action. In ad-dition to performing regular maintenance checks, the crewmust ensure that ammunition and supplies required forcombat operations are stowed according to unit operatingprocedures. Ammunition is stowed in reserve and readyracks according to its anticipated use, with main gun am-munition stowed according to the types of targets ex-pected to be engaged. Part of the checksinvolve checking for the presence, condition,and locationof all relevant ammunition and supplies. In addition,the crew must be prepared to compensate for the failureof various tank, weapon,and fire control systems. Track-ing systems for ranging and target engagement must beable to be used with as little degradation in timing andaccuracy as possible, requiring extensive training in de-graded mode operations.

Figure 4-1 serves to illustrate the complexity of M60A3 missiontasks, the interactive influence on the crew, and the coursesof action available to each crew member in performing the dut-ies required by the mission.

4.4.1 Tank Commander Tasks. The tank commander is responsiblefor controlling and coordinating the performance of the entirecrew, and maintaining contact with adjacent and supportingfriendly elements. The tank commander also has a number of in-dividual systems which he must operate including his rotatingcupola, a thermal (IR) sight, a periscope, a .50 caliber ma-chine gun and a laser rangefinder. The tank commander also op-erates the radio and intercom systems.

4-17

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Figure 4-1 M60A3 Interactive Crew Tasks and Courses of Action

4-18

we- P. MID"

The tank commander's most important individual responsibilityis in detecting threats in time to evade or engage and des-troy them before his own tank is engaged. The tank commanderoperates with his head and shoulders out of his tank as much aspossible. This position permits him to search his entire areaquickly with unaided vision or with his 7-power binoculars.The tank commander's method of search varies with circumstances.When threats are expected in the area, and the terrain and theweather permit long-range visibility, the commander will tendto use his binoculars for searching; when visibility is limitedby the configuration of the terrain or by weather, he may con-centrate on searching with unaided vision. In areas wherethreats may be concealed in vegetation, smoke or fog, he maydrop down into the cupola, using the thermal sight to searchfor thermal signatures indicating the presence of heat emittingthreats.

The tank commander's .50 caliber machine gun is the tank'sprimary defense against aircraft. It is effective against slow-flying helicopters, but is not significant as a defense againsthigh-performance attack aircraft. Its main purpose is in en-gaging personnel targets at intermediate range, and lightlyarmored targets. It is also effective in suppressing fire fromcrew served weapons and anti-tank guided missile systems, with-in its effect-'ve range. The .50 caliber weapon can also beused as a secondary ranging system, since its tracer burns outat known ranges, the range depending on the type of round fired.

The tank commander's most important responsibility is integrat-ing the skills of the four-man crew to move and operate thetank, as a coordinated unit. The tank commander is, typically,an experienced crew member who has served in one or more crewpositions, and has been promoted for his experience and leader-ship ability. He is responsible for the maintenance and opera-tion of his tank, and for the performance of the crew as a tac-tical team. He is also responsible for coordinating withfriendly elemen in his platoon and company, and, to a degree,with other friendly elements supporting his tank, or to whichhis tank must provide support. The tank commander directs hiscrew, and is directed in turn by his platoon leader, who isalso a tank commander. The tank commander who is also a pla-toon leader must direct more of his attention to inter-elementcoordination by way of the radio and by visual means of com-munication, than to directing his own crew.

The tank commander is responsible for the tactical deploymentof the tank, and for operation and maintenance of the tank andits systems. Specifically, he has four major functions,'eachof which ultimately involves the other crew members.

4.4.1.1 Terrain Evaluation. The tank commander's position intho cupola, and responsibilities to the crew and platoon, requirehim to obtain, evaluate, and act on as much information about

4-19

the terrain as possible. Tanks in the defense are attacked byforces moving over the terrain, using it for mobility, cover,concealment and fields of fire. Armed helicopters and scoutsalso use the terrain to attack or to locate the tank, and eachelement uses the terrain to its own best advantage. The com-mander of a tank, in a defensive position, at an assault line,or in an attack~interprets what he sees and knows of the ter-rain to predict the presence of threats, or of the cover, con-cealment and paths of movement available to any threat he mayexpect to encounter. He recognizes terrain surfaces and fea-tures which can channel his own movement or the movement of thethreat, so that when minimal signs of threat activity becomeknown, he can respond effectively. -

Knowledge of, and about the terrain allows the commander (andto a degree, the rest of the crew) to predict likely threatlocations, and to select the most secure and effective routesfor movement toward the objective. The driver and the tankcormander cooperate in route selection and negotiation, byevaluating the ability of terrain, cultural and vegetativefeatures to support, retard, cover or conceal the movement ofthe tank. The driver's proximity to the terrain immediately infront of the tank enables him to evaluate and negotiate sur-faces and obstacles, while the tank commander's elevated posi-tion in the turret and, usually, his more extensive tacticaltraining and experience enable him to evaluate surfaces, fea-tures and obstacles at greater distances, and in closer to theobjective. He is also in a better position to estimate and in-terpret the significance of signs of target activity as theyinfluence the selection of the route and of potential positionsfor effective threat engagement and/or concealment.

As he searches the terrain around the tank, the commandersearches for obstacles to its movement and to the movement ofthe threat he expects to be in the area. He also looks forplaces where threats might be concealed, by noting potentialhiding places and cleared areas affording unobstructed fieldsof fire to threats which could be surveying his route fromthose positions. He also looks for natural channels for hisown movement, to identify areas which might be mined, whichmight be marked for prepared artillery fire, or which might besites for ambush by direct-fire weaponsas he identifies rele-vant features. He also looks for cues to surface consistencyto assist the driver in picking the route affording the bestcombination of cover, speed, and firing position for an exist-ing situation, or for one that is anticipated.

Another aspect of terrain evaluation is relating terrain fea-tures and characteristics to what is known of the deploymentS of other friendly elements. An area in which the tank wouldordinarily be vulnerable could be used as a route or as a fir-ing position, if it and the fields of fire into it are knownto be covered by supporting air or ground elements.

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4.4.1.2 Target Detection and Recognition. Targets are detectedand engaged by the M60A3, to eliminate Ithreats to its own move-ment to the objective and to the presence and movement of otherfriendly elements. Most targets are sited and moved to mini-mize their vulnerability and to maximize their advantage inevading, neutralizing, or destroying friendly elements. Maxi-mum use is made of camouflage, cover, concealment, and suppres-sive and supporting fires, making most targets for the M60A3difficult to find, fix and engage. The tank commander is re-sponsible for maintaining surveillance to maximize the range atwhich targets are detected, identified and evaluated. Unlessthe tank is in contact with hostile elements, the tank commandersearches the area with unaided vision and with his binoculars,riding with his head and shoulders out of the cupola hatch. Inaddition, he assigns a sector of responsibility to the loader,who also operates out of his hatch to the maximum extent pos-sible.

When the tank is engaged, or when it is about to come into con-tact with the enemy, and during friendly artillery preparatoryfire, the tank commander must maintain surveillance with a"popped hatch", whereby his field of view is limited by theoverhead protection of the hatch cover. The commander reliesheavily on adjacent and supporting elements for surveillanceand target detection but ultimately, it is he who must acquirethe threat so that it can be assigned as a target, avoided orassigned a priority for further action. During "popped-hatch"operations, in close engagements or in NBC operations, whenvisibility is severely limited by masks as well as by the fieldsof view available in periscopes and vision blocks, the tankcommander is at a distinct disadvantage in target detection.

Target recognition is the result of a number of kinds of per-ceptual information, including the shape and configuration ofthe target, its behavior and location, and information aboutwhat is expected in the area surveyed. In a fluid battlefield,it is difficult for crews to distinguish among friendly andhostile elements except through the recognition of the distin-guishing shapes of the elements. In less fluid situations,elements to the front can frequently be considered hostile, andthose to the rear, friendly. Airborne elements are especiallydifficult to recognize because of their mobility, and requirethat the crew have good, current intelligence and good communi-cation with other friendly units.

Frequently, targets are detected initially as the crew sensesI smoke, dust, glint, flash, movement or other indications ofpossible threat activity. When such signs are detected, thecommander searches the area with binoculars (if he is out of) the hatch) or with his thermal or optical sights, using the IRsignature and/or optical magnification to examine the area inmore detail. Threats to the M60A3 are difficult to identifyat ranges beyond 1000 meters in good visibility without poweredinstruments, but those ranges are significantly increased whenseven or eight-power instruments are available.

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4.4.1.3 Tactical Decision Making. The tank commander is thetactician of the crew, and perhaps of the section or the pla-toon. He makes decisions concerning the method by which thetank will be employed in its assigned mission, weighing vulner-ability, speed, maneuverability, firepower, support, terrain,and threat factors in selecting and implementing courses ofaction. The tank commander decides which route to take to theobjective, which threats to engage and in which order, themethod of engagement to be used, the firing mode or positionfrom which to fire, and the way in which the tank will operaterelative to other tanks in-the element and platoon. He alsodecides when to request the support of other elements and howto maximize his tank's effectiveness with or without that sup-port.

Tactical decision making involves current information, avail-able through direct or powered viewing and through the inter-pretation of radio messages and other means of communication.It also involves weighing these indications about the presentsituation with information obtained in premission briefings,map study, and, where possible, prior experience with the ter-rain, the enemy and with other friendly elements.

At each point in the tank mission, the tank commander must eval-uate the available information as it relates to his mission,his tank, his crew and their capabilities and limitations.Once targets are detected, they must be evaluated in terms oftype, range, lethality and expected effect on the mission.Decisions must be made to engage or evade targets, or to seekfurther information about them. Where multiple targets arepresented, they must be assigned priority for engagement orevasion depending on their immediate potential as threats tothe mission. Tank commander decisions are the primary influ-ence on the rest of the crew, since these determine where thedriver will drive, when and what the gunner will fire, and howthe loader will perform to assure the availability of the rightammunition at the right time.

4.4.1.4 Target Engagement. The M60A3 is designed to permittarget engagement by the gunner under direction of the tankcommander, so that the tank commander can maintain surveillanceof the battle area, and continue to guide the driver in thenegotiation of routes and firing positions. The M60A3 alsopermits the tank commander to engage targets simultaneously-with the gunner, using his .50 caliber machine gun. When thegunner is incapacitated, or when suppressive machine gun fireI is required in the target area during a main gun engagement,the tank commander may also fire the main gun or coax machinegun from his position. In most instances, the tank commandersupports main gun engagements by providing gross lays in thetarget area (for gunner target acquisition) and by providingrange inputs by way of the laser rangefinder, or secondarymeans.

4-22

The tank commander may also engage targets with his .50 cali-ber machine gun, either to provide suppressive fire, reconnais-sance-by-fire, or simultaneous engagement of targets out of thezone of fire of the main or coax guns. During these periods,the driver and the gunner, to the extent possible, must providethe surveillance required to maintain local security and todetect threats in the battle area.

Engagements are controlled by the tank commander by means ofstandardized fire commands. Each element of the fire commandis set in a fixed relationship to each other element, with wordschosen for brevity and intelligibility under conditions ofstress and noise. Each member of the crew receives informationin the fire command, needed to coordinate his responsibilitieswith those of other crew members. While each tank commanderoptimizes his crew's performance by means of individual tech-niques, the standardization of the fire command assures that nomember of the crew will require more than a bare minimum ofinterpretation in obtaining the information he needs to per-form his job rapidly and accurately.

4.4.1.5 Communications. The tank commander communicates withthe crew over the intercom, and with adjacent and supportingelements by means of radio and visual signals. Radio trans-missions are usually kept to a minimum for security reasons,with most interactions among elements established by standardoperating procedure, or visual signals. Communications amongcommanders are also minimal, especially when the crews are welltrained and carefully briefed.

The tank commander's job is complex, and requires extensivetraining and experience. Following is a list of specific tasksin which the M60A3 tank commander must be proficient.

1) SURVEILLANCE AND TARGET ACQUISITION

o Perform ground and aerial surveillance in assignedsector of search

o Acquire ground targets (day/night)

o Acquire aircraft targets (day/night)

2) ASSISTS IN FIRING ENGAGEMENTS

o Selects firing positions (day/night)o issues fire commands

o Assists gunner when firing main gun engagements

o Assists gunner when firing coaxial machine gun engage-

ment2s

I

o Assists gunner when firing rangecard engagements

o Assists loader when firing loader's weapon system

3) MAIN GUN FIRING ENGAGEMENTS

o Fires main gun battlesight engagements

Using the rangefinder (stationary target/stationarytank)

o Fires main gun battlesight engagements

Using the rangefinder (stationary target/moving tank)

o Fires main gun battlesight engagements

Using the rangefinder (moving target/moving tank)

o Fires main gun battlesight engagements

Using the commander's thermal sight (stationary target/stationary tank)

o Fires main gun battlesight engagements

Using the commander's thermal sight (stationary target/moving tank)

o Fires main gun battlesight engagements

Using the commander's thermal sight (moving target/moving tank)

o Fires main gun precision engagements

Using the rangefinder (stationary target/stationarytank)

o Fires main gun precision engagements

Using the rangefinder (stationary target/moving tank)

o Fires main gun precision engagements

Using the rangefinder (moving target/moving tank)

o Fires main gun precision engagements

Using thermal sight (stationary target/stationary tank)

o Fires main gun precision engagements

Using the commander's thermal might (stationary target/moving tank)

4-24

!

o Fires main gun precision engagements

Using the commander's thermal sight (moving target/moving tank)

4) FIRING ENGAGEMENTS UNDER CONDITIONS OF LIMITED VISIBILITY

o Prepares a sketch rangecard

o Prepares a circular rangecard

o Assists gunner when gunner fires main gun rangecardlay to direct fire

o Assists gunner when gunner fires coax rangecard lay todirect fire

o Assists loader when loader fires his weapon duringconditions of limited visibility

o Fires main gun rangecard lay to direct fire using therangefinder (stationary target/stationary tank)

o Fires main gun rangecard lay to direct fire using therangefinder (moving target/stationary tank)

o Fires main gun rangecard lay to direct fire using thecommander's thermal sight (stationary target/station-ary tank)

o Fires main gun rangecard lay to direct fire using the

commander's thermal sight (stationary target/movingtank)

o Fires coax rangecard lay to direct fire using range-finder (stationary target/stationary tank)

o Fires coax rangecard lay to direct fire using com-mander's thermal sight (stationary target/stationarytank)

o Fires coax rangecard lay to direct fire using com-mander's thermal sight (stationary target/moving tank)

o Fires caliber .50 rangecard lay to direct fire (sta-

tionary target/stationary tank)

o Fires caliber .50 rangecard lay to direct fire (sta-tionary target/moving tank)

o Fires night engagements with artificial illumination

4-25

5) TANK COMMANDERS COAXIAL WEAPONS SYSTEM FIRING ENGAGEMENTS

o Fires coax battlesight engagements using the range-finder (stationary target/stationary tank)

o Fires coax battlesight engagements using the range-finder (stationary target/moving tank)

o Fires coax battlesight engagements using the range-finder (moving target/moving tank)

o Tank commander fires coax battlesight engagements us-ing the commander's thermal sight (moving target/mov-ing tank)

o Tank commander fires coax precision engagements usingthe rangefinder (stationary target/stationary tank)

o Tank commander fires coax precision engagements usingthe rangefinder (stationary target/moving tank)

o Tank commander fires coax precision engagements usingthe rangefinder (moving target/moving tank)

o Tank commander fires coax precision engagements usingthe commander's thermal sight (stationary target/stationary tank)

o Tank commander fires coax precision engagements usingthe commander's thermal sight (stationary target/mov-ing tank)

o Tank commander fires. coax precision engagements usingthe commander's thermal sight (moving target/movingtank)

o Fires coax battlesight engagements using the command-er's thermal sight (stationary target/stationary tank)

o Fires coax battlesight engagements using the com-

mander's thermal sight (stationary target/moving tank)

6) TANK COMMANDER WEAPON SYSTEM ENGAGEMENTS

o Fires caliber .50 ground battlesight engagements(stationary target/stationary tank)

o Fires caliber .50 ground battlesight engagements(stationary target/moving tank)

o Fires caliber .50 ground battlesight engagements(moving target/moving tank)

4-26

-* . r ________----______-___________-

o Fires caliber .50 air engagements at low performanceaircraft (moving stationary tank)

o Fires caliber .50 air engagements at high performanceaircraft (moving, stationary tank)

7) EMPLOYMENT OF THE MACHINE GUN SYSTEMS

o Uses the tank machine guns under special conditions(ranging, designated targets, firing through cover,incendiary effects, and ricochet fire)

o Re-engages targets

o Performs reconnaissance by fire

o Uses suppressive fire techniques

o Initiates fire commands

o Issues subsequent fire commands

o Engages area targets with commander's weapon usingthe "Z" pattern

o Uses range estimate techniques (tracer burnout)

8) SMOKE GRENADE LAUNCHERS

o Activates smoke grenade launchers

o Operates grenade launchers

MISCELLANEOUS TASKS

1) BORESIGHTING THE TANK

o Prepare tank for boresighting

o Coordinates crew efforts in boresighting of the tank

2) ZEROING THE TANK

o Zero tank main gun

o Zero .50 caliber MG_

o Zero coaxial weapon system

f o Zero loader's weapon

4-27

I

3) LASER RANGEFINDER

o Install safety filter on receiver/transmitter unit

o Perform LRF self-test

o Boresight LRF sight

o Perform target range input (laser)

o Perform target range input (manual)

o Place rangefinder into operation and range accurately

o Perform rangefinder checks

4) COMMANDER'S PERISCOPE M36EI

o Conduct before-operations maintenance checks and ser-vices on periscope M36E1

o Install M36E1 periscope image intensifier elbow, visi-ble light elbow, and body assembly

o Remove M36E1 periscope image intensifier elbow, visi-ble light elbow, and body assembly

o Conduct after-operations maintenance checks and ser-vices on periscope M36E1

5) TANK THERMAL SIGHT (TTS)

j o Inspect tank thermal sight

o Prepare TTS for operation

( o Perform TTS system test

6) TURRET POWER OPERATION

o Operation of gun elevating and turret traversing sys-tem in stabilized and non-stabilized mode

o Place turret into power operation

f 7) AUXILIARY EQUIPMENT

o Perform night binocular checks

o Use hand-held night vision devices

4-28

8) NBC EQUIPMENT

o Performs gas particulate check

o Performs all crew duties while wearing NBC protectiveequipment and clothing

9) LAND NAVIGATION SYSTEM

o Places land navigation system into operation

" Performs land navigation using the reference heading

o Readout information

10) COMMUNICATIONS

o Operate tank radio

o Perform operational checks on tank radios

o Uses correct radiotelephone procedures

4.4.2 Loader Tasks. The loader's primary task is to load themain tank gun. His also responsible for loading and main-taining the coaxial machine gun and for surveillance of thebattle area, when he can be spared from his primary responsi-bilities.

In some respects, the loader's job is the most demanding, es-pecially in the M60A3 as it fires on the move, in the stabil-ized mode. The loader must select the correct ammunition fromthe ready-rack, loading it into the breech of the main gun asit moves in elevation with respect to the turret floor. Evenin stationary engagements, the loader must be careful to avoidfinger contact with the breechblock. He must also avoid beingstruck by the breech as it recoils; he must avoid the hot,empty shell casing as it is automatically ejected and droppedto the turret floor. When more than one round is fired in anengagement, the loader must be able to maximize the rate offire so as to destroy or neutralize the target before it canreturn fire. At the same time, he must maintain his balancein a moving environment, with an accumulation of shell casingson the floor of the turret.

When firing the coaxial machinegun, the loader must keep trackI of the rate at which ammunition is expended, so that he can re-load the ammunition box before it is empty. ordinarily thegunner reloads the machine gun ammunition between engagements,but he must be proficient enough to do it rapidly, and on themove if necessary.

The loader is also responsible for detecting, diagnosing andclearing malfunctions in the main gun and the coaxial machinegun.

( 4-29

Malfunction procedures with the main gun are relatively fixedand straightforward, but coax failures can be more complicated.A coax stoppage may be the result of a bad round, a dirty orbent round, an electrical malfunction, or a change in head-space due to wear. The loader must recognize, primarily bymeans of aural cues, what produces the stoppage so that he canemploy immediate remedial action.

Between engagements, and when an engagement is not imminent,the loader searches an assigned area to ensure local securityand to detect threats as far away as possible. Ordinarily, theloader does not use the tank's binoculars, but he may occa-sionally share them with the tank commander. For combat, andin combat-ready units, loaders tend to acquire binoculars notin the normal TO&E. In certain terrain, of course, binocularsare of little advantage, but in the central European environ-ment, they are essential in searching areas within the crew'sfield of view, since threats could be located within view atwell beyond 3000 meters. During closed-hatch operations, whenthe tank is receiving fire, or in an NBC environment, the load-er maintains surveillance using his unity-power vision block,which he mounts in his hatch cover. The vision block providesa severely limited field of view, but can be useful in survey-ing the loader's sector of responsibility.

The M60A3 may be equipped with a 7.62mm, machine gun to be usedby the loader. When the loader is not involved in main gunloading, the 7.62 is particularly effective against hostiletroops equipped with ATGM's when hard targets are not being.engaged. When fired with other 7.62's and .50 caliber gunsfrom supporting elements, the 7.62 can be effective againstslow-flying aircraft and helicopters by disrupting the air-craft's ability to bring accurate fire against the tank(s).

The loader's tasks include the following:

SURVEILLANCE

" Maintain surveillance of the loader's search sector, us-ing unaided vision or loader's periscope

" Report threats and signs of possible threat activity tothe tank commander

o Provide guidance in obstacle clearance to driver

COMM4UNICATIONS

o Prepare tank radio for operation

o Operate vehicular intercommunications equipment

o Prepare combat vehicle crewman's helmet (CVC) for opera-tionL

o Perform operator maintenance on radios and accessories

MAIN GUN WEAPON SYSTEM

o Load 105mm round

o Unload 105mm round

o Perform Emergency Closing of Main Gun Breech

o Service and Check Main Gun Ammunition

o Store Main Rounds in the Tank

o Set Range Fuse Settings on Beehive Ammunition

o Determine Corrective Action Required by Replenisher Tape

o Load Ammunition (Load a Basic Load Using a Unit Load Plan)

o Disassemble the Breech Block

o Remove the Main Gun Breech Block Group

o Assemble Breech Block

o Adjust Variable Breech Operating Cam

o Perform Emergency Closing of Main Gun Breech

o Clean and Lubricate the Breech Block, Cannon Bore andBore Evacuator of the Tank after Operations

o Perform Main Gun Prepare-to-Fire Procedures from theLoader's Position

o Identify Main Gun Ammunition

o Remove Main Gun Rounds from Ready Rack

o Load Main Gun Rounds into Ready Rack

o Loads Main Gun Rounds into Tubular Ammunition Racks(Bustle)

o Extract a Fired 105mm Cartridge Case

o Perform Failure to Load Procedures

o Perform Failure to Extract Procedures

o Unloads Main Gun Rounds from Tubular Ammunition Racks

(Bustle)

4-31

o Perform Failure to Fire Procedures (Misfire)

o Operate Turret Ventilator Blower System

o Place Main Gun Safety Switch in Safe Position

o Select and Load the Announced Ammunition Under Low Am-bient Light Conditions

o Perform Tactical Safe-to-Fire Procedures During Main *unEngagements

o Perform Tactical Safe-to-Fire Procedures During CoaxialWeapon Engagement

o Removes Expended 105mm Cartridge Cases From the Turret

LOADER'S WEAPON SYSTEM

o Stow Weapon System

o Unstow Weapon System

o Prepare Weapon System for Operation

o Fire Weapon System

o Disassemble and Assemble Loader's Weapon System

o Inspect and Maintain Loader's Weapon System

o Check Operation of Loader's Weapon System

o Mount Loader's Weapon System in Tank

o Remove Loader's Weapon System from Tank

o Boresight Loader's Weapon System

o Load and Unload Loader's Weapon System

o Clear Loader's Weapon System

o Troubleshoot Loader's Weapon System Using Table 3-6,DEP 9-2350-253-10

COAXIAL WEAPON SYSTEM

o Disassemble and Assemble MAG-58 MG

o Inspect and Maintain MAG-58 MG

o Check Operation of MAG-58 MG

4-32

,-A091 422 SINGER CO BINGHAMTON NY LINK DIV FG 19/3,DESIGN DEFINITION STUDY REPORT. FULL CREW INTERACTION SIMULATOR--JUN 78 N461339-77-C-0185

UNCLASSIFIED LR-895-VOL-I NAVTRAEQUIPC-77-C-185-000 NL

I IEEEIIII

I I2

2.111 112-

111 11112.L ___

MICROCOPY RESOLUTION TEST CHART

NATIONAL HURI AU (01 'ANDARM 1]96 A

o Mount MAG-58 MG in a Tank

o Remove MAG-58 MG from a Tank

o Boresight MAG-58 MG

o Load MAG-58 MG

o Unload and Clear MAG-58 MG

0 Troubleshoot MAG-58 MG Using Table 3-6, DEP 9-2350-253-10

o Service and Check Coaxial MG Ammunition

o Stow MG Ammunition

o Remove Expended Cartridge Cases from the Turret

MISCELLANEOUS

o Prepare Tank for Boresighting

o Load and Unload Smoke Grenade Launcher

o Perform Smoke Grenade Launcher Misfire Procedures

o Install and Remove M37 Periscope

o Operate Stabilization Emergency Shut-Off Switch

o Perform Loader Checks Prior to Placing Turret in PowerOperation

4.4.3 Gunner Tasks. The gunner in the M60A3 is responsiblefor the accuracy with which the main gun is fired. The restI of the crew assists the gunner by positioning the tank (driver),providing a functioning loaded gun (loader), and by layingthe gunner' s sights in the immediate vicinity of the targetfor rapid target acquisition in the gunner's sights (tank com-mander). After the gun is fired, all crew members observe theeffect of the round, to provide the gunner with informationto adjust his fire for further effect, or prepare for the ac-quisition of another target.

The gunner's job is to make the necessary settings in the bal-I listic computer to apply appropriate sight elevation to thegun, to acquire the target in his sight as quickly as possible,to track the target if it moves, and to adjust fire in case ofI a miss or when the first round does not have the required ef-fect. When the primary sighting system is not available dueto malfunction or damage, the gunner must use the telescope,using alternate ranging techniques as supplied by the tankcommnander, or by the gunner himself.

When firing on moving targets, the gunner applies lead, usingthe lead lines on his aiming reticle or by using the lead-computing function of th4e _fire co6ntrol system.U

The gunner's magnified optics and his position in the turretgive him an advantage over the loader and the driver in targetdetection, especially at long ranges. His limited field ofview almost requires that some other crew member guide himwhen searching the terrain through his periscope. Between en-gagements or during maneuvers to contact, the gunner slewsthe turret to provide coverage of his search sector at inter-mediate to long ranges (1500-3000 m or more) depending on theterrain.

During maneuvers, the gunner employs his magnified optics toassist the driver by examining the terrain to determine surfacebearing capabilities. He (the gunner) also examines obstacleswhich are too far away, or out of the driver's field of view.The tank commander may also perform these tasks, although henormally concentrates on long-range search for threat indica-tions.

The gunner's performance in discriminating targets is facili-

place the-target in his field of view, describes the target and,when necessary, identifies it for the gunner by some prominentfeature in the area. When the tank commander's workload istoo high to permit this level of communication, the gunnermakes the necessary discriminations on his own initiative.

A major problem lies in the preparation of range cards for in-direct fire and for direct fire during periods of limited visi-bility. Range card firing requires that the gunner sight onlikely target areas from a fixed position, using a fixed ref-erance near the tank as an aiming point. The range card isprepared on a circular grid, or as a sketch of the terrain inwhich azimuths and elevations are noted, between the aimingpoint and features within the target area.

Range cards are passed from one tank to another, as the relieftank is moved into position with respect to the aiming point.Typically, gunners have difficulty in visualizing azimuth re-lationships within the target area, the aiming stake, the gunand the azimuth indicator.

When direct firing from a range card, the crew observes thetarget area to determine weapon effects. At night, if illum-I I ination from flare. or searchlights is available, the gunneradjusts his sight into the target. Where illumination is notavailable, he and the other crew members use the illuminationI provided by the round fired in adjusting subsequent rounds,

-*....

I

The gunner operates in both unlimited and limited visibility,using optical and thermal sighting equipment. Even in day-light, or with good nighttime illumination, he may use thermaland optical sights together, using the IR signature to locateconcealed targets. Weapon effects and battlefield illuminantsmake it difficult for the gunner to maintain his night visioncapability, but where illumination is minimal, the gunner pre-serves his night vision sensitivity by closing his eyes as hefires, opening them in time to sense weapon effect for the ad-justment of subsequent rounds. The basic tasks required ofthe gunner are as follows:

TARGET ACQUISITION

o Recognize Target Indications, Shape, Color and/or Land-marks Defining Target Location as indicated by Tank Com-mander

AMMUNITION SELECTION

o Selects Ammunition for Specific Target Types and IndexesAmmunition in Ballistic Computer

MAIN GUN FIRING ENGAGEMENTS

o Fires Battlesight Engagements Using the Gunner's Peri-scope (Stationary Target/Stationary Tank)

o Fires Battlesight Engagements Using the Gunner's Peri-scope (Stationary Target/Moving Tank)

o Fires Battlesight Engagements Using the Gunner's Peri-scope (Moving Target/Moving Tank)

o Fires Battlesight Engagements Using the Gunner's ThermalSight (Stationary Target/Stationary Tank)

o Fires Battlesight Engagements Using the Gunner's ThermalSight (Stationary Target/Moving Tank)

o Fires Battlesight Engagements Using the Gunner's ThermalSight (Moving Target/Moving Tank)

o Fires Battlesight Engagements Using the Gunner's Tele-scope (Stationary Target/Stationary Tank)

o Fires Battlesight Engagements Using the Gunner's Tele-scope (Stationary Target/Moving Tank)

o Fires Battlesight Engagements Using the Gunner's Tele-scope (Moving Target/Moving Tank)

o Fires Precision Engagements Using the Gunner's Peri-scope (Stationary Target/Stationary Tank)

-4- it

o Fires Precision Engagements Using the Gunner's Peri-scope (Stationary Target/Moving Tank)

o Fires Precision Engagements Using the Gunner's Peri-scope (Moving Target/Moving Tank)

o Fires Precision Engagements Using the Gunner's ThermalSight (Stationary Target/Stationary Tank)

o Fires Precision Engagements Using the Gunner's ThermalSight (Stationary Target/Moving Tank)

o Fires Precision Engagements Using the Gunner's ThermalSight (Moving Target/moving Tank)

o Fires Precision Engagements Using the Gunner's Telescope(Stationary Target/Stationary Tank)

o Fires Precision Engagements Using the Gunner's Telescope(Stationary Target/Moving Tank)

o Fires Precision Engagements Using the Gunner's Telescope(Moving Target/Moving Tank)

o Apply Immediate Action in case of Main Gun Failure toFire

o Uses Gunner's Standard Adjustment Technique

o Set Tank Battlesights

o Employ Misfire Procedures

o Uses Target Form Technique

o Employs MIL Change Techniqueo Employs Range Change Technique

o Applies Relay Technique

o identify A Proper Sight Picture and use all Sight Reticles

o Employs Burst On Target Method of Fire Adjustment

o Performs Fire Adjustments Based on TC's Subsequent FireI Commands

o Perform Prepare-To-Fire Checkso Sense Rounds

o Performs Ranging Machine Gun Adjustments

4-36L

I

o Checks Status of Replenisher Before, During and AfterFiring Main GunI

COAXIAL WEAPONS SYSTEM ENGAGEMENTS

o Fires Battlesight Engagements Using the Gunner's Peri-scope (Stationary Target/Stationary Tank)

o Fires Battlesight Engagements Using the Gunner's Peri-scope (Stationary Target/Moving Target

o Fires Battlesight Engagements Using the Gunner's Peri-scope (Moving Target/Moving Tank)

o Fires Battlesight Engagements Using the Gunner's ThermalSight (Stationary Target/Stationary Tank)

o Fires Battlesight Engagements Using the Gunner's ThermalSight (Stationary Target/Moving Tank)

o Fires Battlesight Engagements Using the Gunner's ThermalSight (Moving Target/Moving Tank)

o Fires Battlesight Engagements Using the Gunner's Tele-scope (Stationary Target/Stationary Tank)

o Fires Battlesight Engagements Using the Gunner's Tele-scope (Stationary Target/Moving Tank)

o Fires Battlesight Engagements Using the Gunner's Tele-scope (Moving Target/Moving Tank)

o Fires Precision Engagements Using the Gunner's ThermalSight (Stationary Target/Stationary Tank)

o Fires Precision Engagements Using the Gunner's ThermalSight (Stationary Target/Moving Tank)

o Fires Precision Engagements Using the Gunner's ThermalSight (Moving Target/Moving Tank)

o Fires Precision Engagements Using the Gunner's Telescope(Stationary Target/Stationary Tank)

o Fires Precision Engagements Using the Gunner's Telescope(Stationary Target/Moving Tank)

O Fires Precision Engagements Using the Gunner's Telescope(Moving Target/Moving Tank)

o Employs the "Z" Firing Pattern Against Area Targets

m

ASSISTS TK COMMANDER IN FIRING ENGAGEMENTS

o Assists Tank Commander when Commander Fires Main Gun En-gagements

o Assists Tank Commander When Commander Fires Coaxial Wea-pon Engagements

o Assists Tank Commander when Commander Fires Commander'sWeapon Engagements

o Assists Tank Commander when Commander Fires Rangecard

Lay to direct Fire Engagements

FIRING ENGAGEMENTS UNDER CONDITIONS OF LIMITED VISIBILITY

o Prepare a Sketch Rangecard

o Prepare a circular Rangecard

o Prepare Azimuth Indicator for Operation

o Operate Azimuth Indicator

o Operate Elevation Quadrant

o Operate Gunner's Quadrant

o Gunner Fires Main Gun Rangecard Lay to Direct Fire

o Using the Gunner's Periscope (Striking/Missing Target)

o Gunner Fires Coax Rangecard Lay to Direct Fire using theTelescope (Stationary Target/Moving Target)

o Gunner Fires Main Gun Rangecard Lay to Direct Fire usingthe Gunner's Thermal Sight (Stationary Target/StationaryTank)

o Gunner Fires Main Gun Rangecard Lay to Direct Fire usingthe Gunner's Thermal Sight (Moving Target/Stationary Tank)

o Gunner Fires Main Gun Engagements Employing RangecardFiring Data

o Gunner Fires Coaxial Weapon Engagements Employing Range-card Firing Data

o Employs Area to Point Firing Patterns when Firing from aRangecard

o Prepare Tank for Firing an Artillery

4-38

!

o Prepare the Tank for Firing After Moving into a Preparedand Marked Firing Position

o Perform Slippage and Accuracy Check

SENSE AND ADJUST INDIRECT FIRES

o Requests Supporting Fires (Air, Artillery)

o Sense Supporting Fires

o Adjusts Supporting Fires

TURRET OPERATIONS

o Place Turret in Manual Operation

o Perform a Zero-Pressure Check (Hydraulic Power Pack)

o Place Turret into Power Operation

o Place Turret in Stabilized Operation

o Operate Gun Elevating and Turret Traversing System inStabilized Mode

o Place Stabilizer in Standby Mode

o Position Gun Tube in Cradle in response to Signals

o Track targets smoothly

o Perform Stabilization Check

o Perform Manual Elevation Check

o Adjust and Control Gun Reticle Lights

BORESIGHTING THE TANK

o Prepare Tank for Boresighting

o Complete Boresight Procedures

ZEROING THE TANK

o Perform Main Gun Prepare-to-Fire Checks

o Zero Tank Main Gun

" I

"" " - ] J Ji illd41 /i ° I ill li4 • H

COAXIAL WEAPONS SYSTEM

o Boresight MAG-58 Mounted on a Tank

o Zero MAG-58 MG

MISCELLANEOUS

GUNNER'S TELESCOPE

o Prepare Gunner's Telescope for Operation

o Boresight Gunner's Telescope

o Select Correct Ammunition Reticle

M35EI GUNNER'S PERISCOPE

o Perform Before-Operations Maintenance Checks and Servicesand Prepare M35E1 for Operation

o Install M35E1 Periscope Image Intensifier Elbow, VisibleLight Elbow and Body Assembly

o Remove M35EI Periscope Image Intensification Elbow, Visi-ble Light Elbow, and Body Assembly

o Perform After-Operation Maintenance Checks and Serviceson Periscope M35E1

o Boresight M35E1 Gunner's Periscope

o Perform Sight Purging Check (Prepare to Final Check)

LASER RANGEFINDER

o Perform LRF Self-Test

o Perform LRF Malfunction Detection Test

o Perform LRF Range Test

o Perform Target Range Input (Laser)

o Perform Target Range Input (Manual)

o Perform Rangefinder Checks

MUZZLE REFERENCE SYSTEM

o Activate Muzzle Reference System

o Manually Operate Muzzle Reference System

4-40

I

TANK THERMAL SIGHT

o Install TTS*

o Remove TTS*

o Inspect Tank Thermal Sight

o Prepare Tank Thermal Sight for Operation

o Perform TTS System Test

o Boresight TTS

XM 21 COMPUTER

o Perform XM 21 Computer Self-Test Procedures

o Perform XM 21 Computer Elevation Channel Check

o Perform Computer Check

o Perform Superelevation Check

o Place XM 21 Computer into Operation

4.4.4 Tank Driver Tasks. The driver moves the vehicle fromone place to another over a variety of terrain surfaces-alwaysconscious of the tactical environment in which he operates,and aware that he might encounter threats at any time. Thenovice driver takes detailed direction from the tank commander,who helps him to select the best route for speed, agility, con-cealment, stabilization of the turret for sighting and firing,and to coordinate movement with adjacent and supporting ele-ments. The tank commander, based on his experience as a crew-man, also provides guidance on the best way to approach obsta-cles and marginal terrain surfaces, and helps the driver tominimize stress on the track and suspension system. He alsoprovides direction in the selection of positions from which tofire, where as much of the tank is concealed, or protected,as possible.

The skilled driver constantly searches the area to his front,to anticipate changes in the situation requiring changes inhis performance. He also associates specific terrain surfacesand obstacles with the capabilities and limitations of thetank and with the probable effects on the tank and the per-formance of the rest of the crew when these surfaces and ob-stacles are to be negotiated. The driver also searches thearea for threats and signs of threat activity. He evaluates

*Assumes TTS Not Permanently Installed

4-41-

what he sees in the area between himself and the objective andits ability to conceal and impede, or support the movement ofpossible threats, and his own tank. A skilled driver requiresI minimal direction from the tank commander, anticipating theneeds of the crew through his interpretation of what he seesand learns about the mission, the tactical situation, and the

mission environment.

The driver's job requires extensive training and experience inmoving the tank over various types of terrain, and operatingthe tank in the battlefield environment to maximize total crewperformance within its assigned missions. The experienceddriver is skilled in both the operation of the tank within itsoperating limits, and providing the crew with the best possibleplatform for target acquisition, engagement and destruction,while minimizing its vulnerability to a wide variety of battle-field threats.

During basic driving training, the driver learns to operate thetank's driving controls to start, stop and steer the tank bothforward and backward. By negotiating surfaces and obstacleswithin the capabilities of the tank, he learns to associatethe tank's performance with various conditions it could en-counter on the battlefield. in the central European environ-ment, the tank can negotiate almost any terrain it is likelyto encounter, but there are obstacles and surface characteris-tics beyond its capacity. Even those which it can negotiatehave specific effects on the tank and crew performance, andrequire the driver to learn to anticipate these effects.

The driver, like the rest of the crew, learns to operate inlimited visibility, using unaided vision and his night drivingdisplay. He also learns to drive with the hatch closed, usinghis three vision blocks for driving reference. Opportunitiesfor learning driver skills, especially in negotiating difficultterrain and obstacles, are rare. Useful terrain for drivertraining at the BAT level is very limited. Where opportunitiesdo exist in unit training, they tend not to be used as heavilyas they might due to resultant maintenance problems. Thedriver should learn how to avoid losing a track, for example,by being exposed to the sounds, vibrations, and control reac-tions associated with track stress. To expose him to theseeffects in the real world, however, is expensive and may not beJustified by the proficiency it would develop.

The driver's tactical responsibilities are more stringent thanthose involved in simply moving the tank from place to place.The driver is ultimately responsible for how often, how longand how clearly the tank is seen from various threat positionsI along its route. He is responsible for providing the gunner,loader, and the tank coimmander with a stable platform for sight-ing, loading, and firing. He is responsible for detecting tar-gets, threats and threat indications and for sensing the ef-fects of rounds fired by the gunner and the tank commuander.

-42

I

Like the tank commander, the driver looks ahead as far as hecan, so that he can anticipate events as much in advance aspossible. He looks for covered and concealed routes to theobjective and examines the terrain for surface characteristicswhich could impede or stop the movement of the tank, or whichcould impose undue stresses on the crew or on the tank itself.He also looks for terrain features, buildings, vegetation andterrain surfaces having implications for the deployment, move-ment and concealment of enemy elements which could threatenhis own tank. As he moves the tank to the objective, he avoidsobvious fields of fire, and searches each possible threat posi-tion for signs of threat presence or activity. Tanks, artil-lery, personnel carriers and even dismounted troops are allpotential threats. Where time permits, the driver alerts thecrew to any threats he detects, and responds to driving com-mands from the tank commander. Where time is short, the drivertakes evasive action without direction, alerting the crew tothe nature, location and approximate range of the threat as hemoves to a covered or concealed position.

The driver also avoids areas which might be mined or whichmight be sighted-in for indirect artillery fire. This requiresthat he evaluate available visual information and tactical in-formation available in premission briefings and during themission, primarily over the radio net. I

When engagements are expected, the driver searches for the bestplace to position the tank in case a fire command is issued.Ideally, he tries to place the tank in a position where onlythe gun and periscope windows are exposed, and where he canmove quickly and unobtrusively to an alternate position forsubsequent firing. When the turret is operated in the stabil-ized mode, the driver looks for a surface which will facilitatemovement during firing, with a minimum of disturbances to thecrew in the turret.

Frequently, of course, the driver does not have any good choicesavailable to him in minimizing vulnerability and in maximizingoverall effectiveness. In these situations he must evaluatethe relative importance of turret stability, cover and conceal-ment, speed, agility and waiting to sense and adjust the roundsfired. Normally the tank commander assists in these tradeoffs.Occasionally, tank commander participation is not available andthe driver is required to make decisions to which the rest ofthe crew must adjust.

The driver has a profound effect on the performance of the en-tire crew. His choice of route and position can determinewhether the objective and areas of possible threat deploymentI can be seen from the turret, and whether accurate fire can bebrought against targets in the battle area. Driver performancecan also significantly determine the vulnerability of the tank.If he drives or stops the tank in an exposed position, he couldbe engaged before the threat is apparent. If he moves the tank

74-

through concealment, but causes movement in the trees or othervegetation, he can be readily detected and engaged. If heleaves tracks into an area of concealment, he may also becomeI vulnerable to weapons able to penetrate that concealment.Driving the tank through terrain which will not support it, orbetween obstacles too close to permit passage can stronglyI effect the vulnerability of the tank and degrade the perform-ance and the security of other friendly elements.

The driver's performance effects the gunner, the loader and theI tank commander, and conversely the gunner, loader and tank com-mander influence and performance of the driver. The driver isin a position to view terrain to his immediate front, and withsevere limits, the area beyond his fenders. The other membersof the crew, higher up in the tank, provide information to thedriver about surfaces, distances, threats and threat indicationswhich he cannot see. While this is largely the responsibilityof the tank commander, the loader and the gunner provide infor-mation When it is available, when it seems appropriate, whenthe tank commander is occupied with target acquisition, commun-ications or engagements, or when his (tank commander's) viewof the driver's area of responsibility is obscured. In tankoperations, it is sometimes necessary for the loader to dismountto examine the terrain along the route for load-bearing capa-bility, mines, or vulnerability from areas from which it mightbe obscured. Airborne or surface reconnaissance elements canalso supply some of this information, or it can be supplied byadjacent elements able to view the area in question.

Although the most critical driver skills relate to tacticalmaneuvers around the battlefield, in the day and in periods oflimited visibility, driver skill is also important in road

* marches, where the driver must maintain position in the forma-tion. This is not difficult during periods of unlimited visi-bility, but requires a high degree of skill at night, and infog, rain and snow. Tactical movements frequently take placeduring periods of poor visibility to take advantage of avail-able concealment. As a result, driver skill in adverse condi-tions is not only hard to develop, but is also critical in the

missions of the tank.

The driver is also responsible for crew-level maintenance of amajor part of the tank and its systems. The driver's specifictasks include:

BEFORE-OPERATION MAINTENANCE CHECKS & SERVICE

o Before-Cperation Maintenance Checks & Services on TankInstruments, Gages & Warning Lights (Engine Running/Engine Of f)

o Before-Operation Maintenance Checks & Services on Hydrau-lic Brake System

4-44

0 Before-operation Maintenance Checks & Services, Checks&Services on SernAccelerator, Transmission & Brake

Controls

o Before-Operation Maintenance Checks & Services on the M27Periscope

o Perform Before-operation Checks & Services on the TankDrain Valves

o Perform Before-Operation Maintenance Checks & Services onDrivers Thermal Viewer

o After-Operation Maintenance Checks & Services on Driver'sThermal Viewer

o Place Turret into Power Operation

o Remove and Install the M27 Periscope

o Remove and Install Driver's Thermal Viewer

o Place the Driver's Thermal Viewer into Operation

PERFORM DURING OPERATION MAINTENANCE CHECKS & SERVICES

o Perform During.-Operations Maintenance Checks & Services,Maintenance Checks & On Steering, Accelerator, Shift &Brake Controls

o Perform Main Gun Prepare-to-Fire Procedures from theDriver's Position

o Monitor Tank Instruments, Gages and Warning Lights

MAINTAINS & OPERATES COMMUNICATION EQUIPMENT

o Performs Operator Maintenance on Tank External Phone

j o Place a Tank External Phone into operation

o operate Vehicular Intercommnunications Equipment

o Prepare Combat Vehicle Crewi'man's Helmet (CVC) for operation

) o Perform Operator Maintenance on Communication Equipment

AFTER-OPERATIONS MAINTENANCE CHECKS & SERVICES

o After-operations Maintenance Checks & Services on TankInstruments, Gages & Warning Lights (Engine Running)

o Performs After-Operation Maintenance Checks & Serviceson Basic Issue Items

4-45K

TARGET ACQUISITION

o Acquire Ground Targets (Day)

o Recognize and Identify Threat Weapons from Front, Sideand Hull Down Views

o Recognize and Identify Friendly Weapons from Front, Sideand Hull Down Views

o Acquire Ground and Airborne Targets and Report Them to TC

o Recognize Smoke, Glint, Dust, Flash and Movement Cues toPossible Threat Activity

o Detect Concealed Personnel, Vehicle, Aircraft and WeaponThreats

0 Discriminate Among Hostile and Friendly Elements

o Discriminate Among Target Types; Discriminate Among Ar-mored, Lightly Armored and Area Targets

o Make Acquisition Reports

o Recognize the Most Vulnerable Areas of Threat Tanks

o Acquire Targets and Rank Them, the Most Dangerous TargetFirst

TANK OPERATION PROCEDURES & DRIVING PERFORMANCE

o Start and Stop Tank Engine

o Start Tank Engine by Towing

o Start Tank Engine by Auxiliary Power-Slave Start

o Operate Tank in Neutral Steer

o Drive Tank Over Varied Terrain with Driver's Hatch in theOpen/Closed Position

o Operate Tank Across a Water Obstacle

o Respond to Ground Guide Signals While Driving a Tank0 Accelerate, Decelerate, and Brake Smoothly

o Maintain Correct Speeds

o Use Driver's Night vision Equipment

o Drive Tank Using the Land Navigation System

i-46

o Negotiate a Narrow Shallow Ditch

o Negotiate Over Slight to High Elevations

o Move Through a Small Stream or Water Hole

o Negotiate a Wide Shallow Ditch

o Drive Following Correct Road March Procedures

o Drive Through Wooded Areas

o Climb Tank Over a Short, Steep Elevation

c Move Through a Narrow Defile

o Move Across a Narrow Bridge

o move into and out of Restricted Areas (Motor Pools, Assem-bly Areas, Narrow Trails)

o Cross Vertical or Near Vertical Obstacles

o Approach, Ford, and Exit Correctly from Streams

0 Ascend and Descend a Steep Hill

o Cross Deep Ditches or Gullies

o Drive Over Soft Marsh Areas

o Perform all Driving Tasks in the Closed Hatch Mode

o Drive Tank on Varied Road Surfaces (Pavement, Gravel,Dirt, Etc.)

o Drive Tank on Varied Soil Compositions (Muddy, Sand, SoftDirt, Etc.)

o Drive Tank Under Black-out Drive Conditions

o Drive Tank Following Night Flashlight Signals

o Drive Tank Following Groundguide Arm and Hand Signals

o Move Tank over Moderately Uneven Terrain and Among Widely'I Spaced Obstacles

0 Become Familiar with Acceleration, Deceleration and Turn-ing Characteristics

o Negotiate Slopes

o Move Tank Up, Down and Across Slopes at Maximum SafeSpeed

o Recognize Response in Acceleration and Steering to VariousSlopes and Surfaces

o Negotiate Obstacles

o Recognize Logs, Ditches, Walls, Trees, Brush; NegotiateObstacles

o Recognize Response of Tank to Movement Over and ThroughObstacles

o Recognize Obstacles that cannot be Negotiated

o Negotiate Various Terrain Surfaces

o Negotiate Hard, Soft, Sandy, Icy, Muddy, Swamp, Snow Sur-faces

o Recognize Response of Tank on Each Surface

o Operate Tank in Limited Visibility Over Various Surfacesand Among Various Obstacles

o Operate Tank in Fog, Rain, Smoke and Darkness by DirectVisual Reference

o Recognize Surface and Obstacle Characteristics in LimitedVisibility

o Interpret Infra-Red and Night Vision System Images in mov-ing Tank Over and Among Various Surfaces and Obstacles

o Recognize Images with Respect to Obstacle and Surface Ef-fects on Tank Movement

o Back Tank with Guidance from Commander

o Control Speed to Minimize Stopping Distance; RecognizeEffects of Reverse movement and Turning in Visual Scene

TERRAIN APPRECIATION

o Recognize Areas of Possible Threat Deployment; EvaluateI Cover and Concealment Available in Battle Area; CorrelateBriefing and Communications Information with Terrain Char-acteristics; Evaluate Signs of Current or Past Threat

Activity.

Ax

o Recognize Possible Avenues of Approach and Fields of Firefor Potential Threats; Evaluate Load-Bearing Characteris-tics of Terrain, Evaluate Obstacles, Evaluate Terrain andI Cultural Features Available for Threat Concealment; Cor-relate Information about Threat Objectives with Character-istics of the Battle Area.

o Recognize Possible Routes to the Objective. EvaluateLoadbearing, Obstacle Quality of Terrain; Recognize Areasof Cover and Concealment; Correlate Terrain Characteris-tics with Deployment of Threat and Friendly Elements; Se-lect Routes and Engagement Procedures for Optimum Utili-zation of Support Elements and Minimum vulnerability fromPossible or Indicated Hostile Areas.

TACTICAL DRIVING

o Select Routes for Movement Capable of Supporting Tank,Containing Maximum Cover and Concealment; Select Routewith Obstacles within Capability of the Tank. CompareTerrain Surfaces, Obstacles and Features with Known TankCapabilities and with Major Elements of the Tactical Sit-uation; Recognize Landmarks Defining the Objective andthe Designated Route and Recognize Cues to the Deploymentof Friendly and Hostile Elements.

o Select Areas Affording Covered or Concealed Firing Posi-tions; Identify Areas Along Route Affording Smooth Routesfor Stable Firing; Maintain Surveillance of Area AlongRoute; Prepare to Move into Covered or Concealed Positionfor Firing.

o Identify Secure Exit Routes from Firing Positions; BaseSelection of Exits on the Tactical Situation and on theCondition of the Terrain at that Time.

o Detect and Report Targets, Signs of Target Activity.

o Modify Route to Maintain Security with Respect to SensedThreats, Threat Activity, within Limits established byTank Commander.

o Maintain Turret Stability within Practical Limits duringmovement, Turning, Stopping.

DRIVING PERFORMANCE DURING TACTICAL MANEUVERS & FIRING ENGAGE-14ENTS

o Perform Evasive Maneuvers Upon Enemy Contacto Move Vehicle into Defilade Firing Position upon Enemy

Contact

o Perform Correct Driving Procedures during Main Gun Engage-ments (Stationary Target/Stationary Tank)

o Perform Correct Driving Procedures During Main Gun Engage-ments (Stationary Target/Stationary Tank)

o Perform Correct Driving Procedures During Main Gun Engage-ments (Moving Target/Moving Tank)

o Perform Correct Driving Procedures During Coax Engagements(Stationary Target/Stationary Tank)

o Perform Correct Driving Procedures During Coax Engagements -

(Stationary Target/Moving Tank)

o Perform Correct Driving Procedures During Coax Engagements(Moving Target/Moving Tank)

o Perform Correct Driving Procedures During Caliber .50Engagements (Stationary Target/Stationary Tank)

o Perform Correct Driving Procedures During Caliber .50Engagements (Stationary Target/Moving Tank)

o Perform Correct Driving Procedures During Caliber .50Engagements (Moving Target/Moving Tank)

o Perform Correct Driving Procedures When Tank CommanderEmploys the Smoke Grenade Launchers

o Empioy Correct Driving Procedures when Loader Fires theLoaders Weapon (Stationary Target/Stationary Tank)

o Employ Correct Driving Procedures when Loader Fires theLoader' s Weapon (Stationary Target/Moving Tank)

o Employ Correct Driving Procedures when Loader Fires theLoaders Weapon (Moving Target/Moving Tank)

o Move Into Prepared Night Firing Positions

o Select a Route Providing a Stable Firing Platform for Fir-ing in the Stabilized Mode

o Sense Rounds

o Select Firing Positions

o Move Tank into Hull-Down Positions

o Move Tank into Turret-Down Positions

4.4.5 Crew Interactive Tasks. Most operational tasks performedby the crew of the M60A3 are interactive; each individual action isdependent to some degree on the performance of some other crewmember, and each action has some effect on the rest of the crew.For these reasons, each crew member learns enough about the jobof each other member to permit him to anticipate the effectsof each person's actions on his own tasks, and to anticipatethe ways in which his tasks affect the rest of the crew.

The most intimate crew interactions occur between the tank com-mander and the gunner, and between the tank commander and thedriver, as the tank is used to engage and destroy targets, andas it is moved around the battle area. Much of the activity inthe tank is organized around a standardized fire command format.The fire command provides precise information to each member ofthe crew which permits him to do his job rapidly, accurately,and in the proper relationship to the job of each other memberof the crew.

When the tank commander makes the initial fire command, healerts the crewmember who will have to act, usually the gunner.The initial fire command also alerts the driver to the fact thatan engagement is imminent. Immediately after the alert, thetank commander identifies the ammunition and/or weapon to beemployed and he describes the target, its direction and range.When main gun ammunition is identified, the loader searches theready rack for the proper round, removes and loads it, announc-ing "up" to the gunner, who has indexed the ammunition in theballistic computer. At the same time, as the tank commander&nnounces the target type and location, he slews the turret tobring the target into the gunner's field of view. The driver'sresponsibility is to locate the target, or its general direction,and steer the tank to a position where its visibility from thetarget is minimized, while the target still remains visiblefrom the crew positions in the turret.

As the tank commander slews the turret toward the target, heuses the laser range finder to supply an accurate range inputto the computer, unless his range estimate indicates that thetarget can be engaged with the battlesight setting. As theround is loaded, the gunner lays his crosshairs on it and fires;the loader prepares to load a subsequent round, and the rest ofthe crew watches to sense and adjust fire as required for targeteffect. At the same time, the driver prepares to move the tankto a new firing position, or to continue maneuvers toward theobjective.

Tables 4-6 through 4-9 present typical crew interactive tasksfor four types of engagements, and the manner in which theseprocedures are integrated for rapid and accurate performance.The tables are organized to illustrate sequences of actionsalong a time line. In actual practice, any crewmember can in-itiate an engagement, if he sees a target or a good indicationof target presence; Tables 4-6 through 4-9 assume that the tankcommnander initiates the engagement.

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Except in range card firing, the crew's goal is to obtain afirst-round hit in as short a time as possible, and, if thefirst round misses, to obtain a hit by adjusting fire. Thecrew also attempts to fire the first round as rapidly as possi-ble, not only to obtain a first-round hit, but, if possibleto spoil the aim of the threat.

A great deal of armor crew training is intended to standardizeindividual and crew performance so that essential procedurescan be performed with little or no conscious thought. Since notwo combat engagements are expected to be alike, there is alsoemphasis on training crews to recognize essential differencesin missions and engagements so that procedures can be selectedto meet those differences which are critical for mission suc-cess. Although each member of the crew responds to the direc-tion of the tank commander, each is responsible for taking theinitiative, as required to enhance the effectiveness and/or thesecurity of the tank and its supporting elements. The driveris in the most critical position to sense and respond to criti-cal variations in the tactical situation, since it is he whohas the most immediate control over movement and position, andthus the exposure and vulnerability of the tank. Ordinarily,the driver expects to receive a command telling him when andwhere to drive for the gunner or the tank commander to fire.He expects to remain stationary until the fire mission is com-plete. The skilled driver tends to stop before the command isgiven, and to select a position which optimizes security andtarget acquisition. He also tends to move out when he sees thatthe target has been destroyed, or when he detects another threat

preparing to engage his tank.

The gunner and the loader cani also help to maximize tank effec-tiveness by taking the initiative, but primarily they alert thecrew to threats or possible threats. They can also providevaluable guidance to the driver in the selection and negotia-tion of his route to the objective, but their workload and theirlimited visual contact with the terrain make this difficult.The gunner's periscope is sometimes used in evaluating terrainsurfaces and obstacles at a distance. Even the coax can beused by the tank commander or the gunner to evaluate terrainsurface characteristics for the driver. The impact of 7.62mmammunition can sometimes indicate whether the surface is softor hard as rounds will ricochet or throw up dust from hard sur-faces, and show little or no impact at all in soft surfaces.

Each member of the crew learns something of the job of eachI other member so that coordination can be accurate and timely.Each crew member also, learns to do the job of other crewmembers

a so that each can substitute for the other if necessary. In comn-bat, it is not unusual for a tank to operate with three crew-members instead of four. Tank commanders riding in the openhatch are especially vulnerable. If the tank commander is hit,

he is usually replaced by the gunner, since the gunner is usu- _

ally the most experienced of the three other crewmembers. Also,

4-6

the gunner can operate from the tank commander's position inmuch the same way he would operate at his own station. opera-ting with a three-man crew degrades tank performance by makingit necessary for the main gun to be fired from the tank com-mander's position. When the rangefinder is out of order andthe main gun is fired at targets beyond battlesight range, thegunner should use the telescope but it can be used only fromthe gunner's station. If the gun is fired from the telescope,the crew loses the advantage of surveillance from the tank com-mander's cupola. Specific circumstances dictate the most ef-fective course of action, and may result in the loader firingfrom the gunner's position which, of course, means that he mustmove out of the seat to reload for sustained fire. This can beeffective when the tank must move between rounds, and when thetarget, such as a fortification, cannot return effective anti-tank fire between rounds.

4.6 Utilization of Tactical Information

The M60A3 crew needs as much information as is available con-cerning the situation in which they are involved at any giventime. Specifically, they need to know the enemy, terrain,weather, and support available to them in their mission. Tac-tical information is obtained by direct (and IR) viewing of thebattlefield, communications with scout elements and advancedcombat elements, aerial photographs, premission briefings, andobservation of threat activities prior to and during the mis-s ion.

The mission is usually defined in terms of the objective, routesavailable to the objective, and the objective's defenses. Themission description also defines the manner in which the tankis to maneuver with other tanks and friendly elements, maintain-ing security and mobility while applying fire to the objectiveand to hostile elements encountered enroute. Ordinarily, tankattacks involve at least platoon-size units, generally in two-I tank elements. One tank in an element moves from one positionto another while the other tank supplies covering fire. Defen-sive missions require similar cooperation, but movement islimited to that required to optimize firing and defensive posi-tions as the threat approaches.

Information about the enemy is vital to the success of the tankI mission because it defines weapons, ammunition, and tacticsrequired, and it helps to define the ways in which enemy forcesmay be deployed and moved. If a tank encounter is anticipated,I the crew knows that the terrain over which they could move mustbe carefully searched. When aircraft are expected to be en-countered, the tank commander knows that he must divide his at-tention to engage with his .50 caliber weapon and that he mustconstantly search for different kinds of cover than is neededfor security from ground forces.

44.5

Terrain and the weather conditions have profound effects onM60A3 crew operation, by determining routes which can and can-not be taken, the speed with which the tank can move and itsmaneuverability and agility. These factors also influence thecrew's range of visibility and determine its vulnerability toambush and surprise. Terrain and weather also effect the tankI by defining the positions and routes various threat elementscan employ. Careful study of the terrain can tell the crewwhere threats could be hiding, and where their weapons could beI sighted so that these areas can be avoided, and searched morecarefully for subtle signs of threat activity. Rain, snow, andice can effect both the M60A3 and the threat, further channel-ing and slowing movement.

Snow, rain and fog can be used to advantage, in making movementsmore secure than they might otherwise have been, although theydo require special route negotiation and battlefield surveil-lance skills on the part of the crew.

Support information is extremely important to the tank crew.The tank, by definition, almost always operates in support ofsome other element, whether it is another tank or infantryelements. ordinarily, the tank itself isalso supported byother elements, either directly or indirectly. The types andamount of support available strongly influence the way in whichthe tank performs its mission. Artillery can neutralize threatswhich are inaccessible or invulnerable to the tank's weapons.Artillery can also prevent dismounted troops from attacking thetank with ATGM's and other anti-tank weapons, although anti-I personnel artillery fire can also force the tank to be operatedwith hatches closed or propped. Air support can greatly reducethe effectiveness of armored threats to the M60A3 by engagingtanks and other heavy weapons. By the same token, anti-aircraftartillery can reduce the effects of enemy air-to-ground anti-tank systems.

The most elementary type of support available to the tank isother tanks in the same or adjacent units. Mutual support amongtanks in a maneuver element or in a platoon involves radio andstandard operating procedure (SOP), in addition to extensivevisual contact with the other elements and with the effects of

their weapons.Tactical information is used in the identification of possiblethreat areas capable of supporting the movement of various kindsof threats. It is used to identify safe, fast routes for move-ment, to determine the amount and type of ammunition to becarried and its arrangement in the ready-rack. Tactical infor-mation is also used to estimate the speed of movement, maneuversmost likely to be effective, and the types of intelligence andfire support to be expected during a mission, Tanks operating

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without support are extremely vulnerable, and must move cauti-ously, making extensive use of cover and concealment. Tanks op-

i erating with mechanized infantry can move more quickly with lessconcern for close-in threats. Tanks with air support can concen-trate on targets requiring sustained fire, leaving many lightly

- armored and point targets for the armored helicopter in strikeaircraft. Air support also means more accurate, and longer rangetarget acquisitions which greatly enhance the ability of the tankto accomplish its mission, and to maintain its own security.