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AUTOMATIC FLIGHT MANAGEMENT SYSTEMS 9 - 1

AUTOMATIC FLIGHT MANAGEMENT SYSTEMS

TABLE OF CONTENTS

SUBJECT PAGEFLIGHT MANAGEMENT SYSTEMS.............................................................................................. 3

Overview...................................................................................................................................... 3Flight Management System Outlined........................................................................................... 3

AUTOPILOT FLIGHT DIRECTOR SYSTEM.................................................................................. 3Overview...................................................................................................................................... 3AFDS Mode Control Panel........................................................................................................... 4Flight Control Computers (FCCs) ................................................................................................ 5AFDS Systems............................................................................................................................. 5THRUST Command Modes......................................................................................................... 5ROLL Command Modes .............................................................................................................. 6

PITCH Command Modes............................................................................................................. 6AFDS Command Modes.............................................................................................................. 7Approach Modes.......................................................................................................................... 8Autothrottle................................................................................................................................... 8

FLIGHT MANAGEMENT COMPUTER........................................................................................... 9Overview...................................................................................................................................... 9FMC/CDU..................................................................................................................................... 9AFDS MCP................................................................................................................................. 10MCP Layout ............................................................................................................................... 10Flight Director Switches ............................................................................................................. 10Thrust/Speed Modes.................................................................................................................. 10

Autothrottle Arm Switch ............................................................................................................. 10N1 Switch................................................................................................................................... 11SPD Switch ................................................................................................................................ 11Selector Knob............................................................................................................................. 11C/O Switch................................................................................................................................. 11IAS/Mach Window...................................................................................................................... 11LVL CHG Switch........................................................................................................................ 12Bank Limit Selector .................................................................................................................... 12HDG Selector Knob ................................................................................................................... 12HDG Window ............................................................................................................................. 12HDG SEL Switch........................................................................................................................ 12VNAV Switch.............................................................................................................................. 13VERT SPD Window ................................................................................................................... 13LNAV Switch.............................................................................................................................. 13

V/S Switch.................................................................................................................................. 13ALT Window............................................................................................................................... 14Altitude Selector Knob ............................................................................................................... 14Altitude Intervention Switch........................................................................................................ 14ALT HOLD Switch...................................................................................................................... 14Autopilot FCC Engage CMD Switches ...................................................................................... 14FCC DISENGAGE Bar............................................................................................................... 14APP Switch ................................................................................................................................ 15VOR/LOC Switch ....................................................................................................................... 15

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FLIGHT MANAGEMENT SYSTEMS

Overview: The Flight Management System(FMS) on the 737 is designed to provide fullcontrol of the aircraft in all phases of flight.The Flight Management system is made upof the Autopilot Flight Director System,FMC/CDU, Flight Controls and onboardcomputers.

While it is common to think of these systemsas being separate, it is helpful for thepurpose of understanding how to interactwith the airplane to consider the FlightControls, FMC/CDU and Autopilot ModeControl as an integrated system formanaging the flight path of the aircraft.

As a complete system, the FlightManagement System (FMS) provides forautomated vertical and lateral navigation ofthe aircraft. The system is designed so thatthe crew can interact with the FMS throughthe Flight Controls, the Autopilot FlightDirector Mode Control Panel or theFMC/CDU.

Although the 737 FMS is capable ofmanaging all phases of flight from takeoff totouchdown, the crew is under no obligationto use any of the systems provided. If

desired the airplane can be flown by handwithout using reference to any of theautomated systems. Additionally, the AFDSMode Control Panel can be used to provideFlight Director guidance while hand flying

the airplane, or the FMC/CDU and AFDSMCP can be used in concert with theautopilot to provide fully automated flightcontrol.

Use of the FMS will result in greaterprecision, significantly reduced overalloperating expense, reduced wear and tearon the airframe and significantly reducedpilot workload during critical phases of flight.

Flight Management System Outlined: The737 FMS is made up of the followingsystems:

Radio Navigation Systems (VOR/ADF,

etc) Inertial Reference System

GPS

Air Data Computers

Electronic Flight Instrumentation System(EFIS)

Engine Instrumentation and CrewAlerting System. (EICAS)

Flight Management Computer (FMC)

Autopilot Flight Director System ModeControl Panel (AFDS-MCP)

All of these systems function independently,but are integrated to control the pitch axis,roll axis, yaw axis and acceleration withprecision in all phases of flight.

AUTOPILOT FLIGHT DIRECTOR SYSTEM

Overview: The AFDS integrates functionsof the autopilot system, the flight director

system, and the automatic stabilizer trimsystem in order to provide complete flightregime control. The AFDS is comprised ofthree Flight Control Computers (FCCs) thatoperate in parallel with each other to providehighly precise command and controlcapabilities.

The FCCs, Left and Right, haveindependent power sources and provide

flight control input directly to the flightcontrols through two independent hydraulicsystems. As such, each FCC can beallowed to have full independent control ofall aircraft flight control surfaces, or bothFCCs can be operated in tandem to providefull fail-safe operation for coupledapproaches and autoland.



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The AFDS takes data from various sensorson the aircraft (AoA, Airspeed, TAT probes,GPS, IRS, etc) and uses the information toprovide pitch and roll cues to the flightdirector system. The flight director system isthen able to display these pitch and rollcommands graphically on the cockpitdisplays.

The crew can follow the flight director cueswhen flying by hand, or can engage theautopilot to follow the pitch/roll cuesprovided by the flight director.

When an autopilot is not active, the crewcan follow the displayed pitch/roll cues bymanipulating the flight controls to match thesteering cues provided by the FlightDirector.

When an autopilot is activated, it issuescommands to the flight controls so as tomaintain control of vertical speed, airspeed,altitude and heading as commanded by theflight director.

AFDS Mode Control Panel: The FlightDirector has many modes for managingpitch, roll and thrust. The crew is able toselect the desired modes for the FlightDirector through the use of the AutopilotFlight Director System Mode Control Panel(AFDS MCP or simply the MCP.) The MCP

is the primary method for directly controllingthe Flight Director.

The MCP is located on the glare shield, andprovides direct control of all Flight Directorfunctions. A common misconception is tothing of this rectangular section of the panelas The Autopilot. Indeed this is not thecase, as the autopilot is itself acomputerized system of control logic andactuators that provide commands to theflight controls. The MCP, on the other hand,does exactly what its name suggests: It

allows the crew to select the MODES thatare used by the FLIGHT DIRECTOR.

Thus: Autopilot Flight Director System ModeControl Panel!

The MCP has lighted function switcheswhich allow the crew to select the modesunder which the AFDS operates.Remember at all times that the Flight

Director provides commands for theAutopilot to control the airplane in threeways:

Pitch

Roll

Thrust

For each of these areas, there is more thana single method that may be specified.

Pitch Modes:Vertical Speed (V/S)Vertical Navigation (VNAV)Speed (SPD)Flight Level Change (FLCH)Altitude Hold (ALT)

Roll Modes:Heading (HDG)Lateral Navigation (LNAV)VOR/Localizer (VOR/LOC)

Thrust Modes:Thrust (N1)Speed (SPD)

LNAV, VNAV, FLCH, V/S, N1 and SPDmode are all available for crew selection, aswell as heading, airspeed, altitude andvertical speed.

In some cases, modes such as FLCH, APP(approach) and SPD will use a combinationof engine power, roll and pitch to achievethe desired results, but it is often easiest toremember that effective use of the MCPmeans the crew will have a mode selectedto manage pitch, roll and thrust individually.

Any active pitch/roll/thrust mode can bedisengaged by selecting a differentpitch/roll/thrust mode on the MCP.

Modes may also be disconnected by

disengaging all operating autopilots anddeselecting the flight director.

If the aircraft is on an approach and LOCand G/S capture has already occurred, thenselecting a different command mode will notdisengage the autopilot. In this situation, theonly method available to disengage theAFDS is to disengage the autopilot anddeselect the flight directors. Pressing the



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TO/GA switch will also disengage theapproach after LOC and G/S capture.

Flight Control Computers (FCCs): Thefunction of the FCCs is to integrate thefunctions of the flight director and theautopilot systems. Each individual FCCprovides control commands directly to itsassociated autopilot control servo. Thisservo operates the flight controls directly.Both autopilot servo systems are poweredusing the left and right hydraulic systems.

If only one autopilot is engaged, it is capableof controlling the pitch and roll axes of flight.In this mode, the yaw damper provides foryaw control when the aircraft receives a rollcommand from the FCC, resulting in fullycoordinated flight.

If both autopilots are engaged and the AFDShas entered approach mode, the FCCscombine to provide redundant pitch, roll andyaw control. Full rudder control ismaintained and will automatically providerunway alignment until touchdown.

In a multiple autopilot approach with acrosswind, the FCCs will use rudder inputand bank angle to slip the aircraft for runwayalignment. The bank angle available islimited and in stronger crosswind conditionsthe FCCs may use a combination of slip and

crab to maintain runway alignment.

If a failure affecting both FCCs occurs duringan approach, an autopilot disconnect willresult. If any failure results in loss of eitherpitch or roll modes, the associated flightdirector command bar will be removed fromthe PFD. In cases where both pitch and rollmode are affected, the flight director will beremoved entirely and replaced with a faultflag.

AFDS Systems: The AFDS, in conjunction

with the FCCs, is capable of providing fullregime, three-dimensional control of theaircraft in all phases of flight. This isaccomplished by issuing commands to theFlight Control Computers that in turn providecontrol commands to the autopilot servos.

The autopilot controls the aircraft in threeseparate regimes:

Thrust Mode

Roll Mode

Pitch Mode

The status of each of these autopilot modesis displayed on the MCP, and on the primary

flight display.

The area directly above the attitude indicatoris called the Flight Mode Annunciator(FMA) and this provides the crew withimportant information regarding the currentand armed modes for thrust, roll and pitchmodes.

The lower portion of the FMA also displaysthe current status of the AFDS system. TheAFDS status will be blank, indicating that theautopilot is not controlling the aircraft, or itwill say CMD to indicate that the autopilot iscontrolling the airplane in accordance withflight director commands.

THRUST ROLL PITCH

AUTOPILOT FLIGHT DIRECTOR MODEANNUNCIATOR

THRUST Command Modes: Theautothrottle has primary control for allautomated thrust settings. While thrust canbe set manually by the crew, the autothrottleis an efficient and precise method to setengine power.

Thrust modes that may be announced by

the FMA mode annunciator are:

FMC SPD: This indicates that theautothrottle is maintaining speeds ascommanded by the FMC while in VNAVpitch mode. The speed display on the MCPwill be blank but the airspeed cursor on theflight instruments will show the commandedspeed. The Autothrottle will maintain thisspeed by modulating thrust as required



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within engine and aircraft performancelimits.

N1: Thrust setting is based on FMCselected N1 values.

MCP SPD: Speed autothrottle mode. Thrustis set to maintain the speed set in the MCPSpeed window. Rate of climb or descent willbe a result of maintaining desired aircrafttarget speed through the adjustment ofaircraft pitch. Autothrottle will not violatethrust limits or aircraft speed limits.

RETARD: Indicates that the autothrottles arereducing power after LVL CHG or VNAV isengaged for a descent at idle power.

ARM: this mode is displayed on the FMAwhen the Autothrottle has been armed, but

no thrust mode was selected to provide thecontrol logic.

HOLD: Indicates that autothrottle control ofthe thrust levers has been released in orderto prevent thrust lever movement in theevent of an Autothrottle failure. Will beannunciated at 84knots to indicate that theautothrottle has set takeoff power.

GA: Go around thrust mode. Thrust ismodulated to provide a 2000 fpm climb rate.This mode can be terminated by selecting

any other pitch mode.

ROLL Command Modes: The Roll modecommands bank angles so as to result inspecific turn rates or velocity vectors. Theautopilot will attempt to maintain the desiredflight path, which can be dictated by asimple heading bug command setting, or bya complex series of waypoint programmedinto the FMC. At no time will any autopilotroll mode exceed the bank limit selector ormaneuvering speed limits in order to

maintain course. Roll modes which may bedisplayed on the FMA are:

GA: Commands bank angle in order tomaintain ground track during takeoff or goaround maneuver. Ground track will bemaintained based on track disposition attime of engagement. Alternatively, if theTO/GA Heading mode has been activated inthe PMDG Styles menu, GA will command

the aircraft to steer in accordance with theselected heading.

LNAV: Commands bank to follow activeFMC route as displayed on the navigationdisplay. If on ground, LNAV mode will armto engage when passing through 50 feetAGL.

HDG SEL: Commands bank angle tomaintain heading selected in MCP headingwindow.

VOR/LOC: Commands bank to capturelocalizer when intercept track does notexceed +/- 60. Once captured, willcommand bank to maintain localizer.

PITCH Command Modes: Pitch mode

commands aircraft pitch angles to maintaina particular altitude, vertical speed, forwardairspeed or climb/descent path. Pitch modeis nearly always directly linked to actions inthe Thrust mode. Pitch mode inputs cancome from the MCP altitude command knob,the MCP vertical speed knob or the FMCdirectly. When used in conjunction with aThrust mode, Pitch mode is a powerful toolto manage climbs and descents to a highdegree of accuracy. The autopilot will useboth pitch and thrust to maintaincommanded airspeed while navigating a

vertical climb or descent path. Pitch modesthat may be announced on the FMA are:

TO/GA: Commands pitch angle required fortakeoff or go around. On ground, mode isarmed and will command for 8 nose uppitch, followed by required flight directorclimb pitch after ground clearance. OfTO/GA is pressed during approach, willprovide climb attitude guidance for bestclimb rate.

V/S: Maintains vertical speed selected in

MCP V/S window.

ALT ACQ: Indicates that the autopilot ischanging aircraft pitch in order to acquire theMCP or FMC set altitude when transitioningfrom a climb or descent.

ALT HOLD: Commands pitch to maintainaltitude set in MCP altitude window, FMC orwhen ALT HOLD switch is pushed on MCP.



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VNAV PTH: Commands pitch up/down tomaintain selected FMC altitude or FMCcalculated VNAV descent path. Theclimb/descent path is calculated based upondesired altitudes entered into the FMC flightplan. The FMC attempts to use the mostefficient climb and descent angles and willmoderate pitch as necessary in conjunctionwith aircraft speed in order to maintain thosecalculated paths.

VNAV SPD: Commands pitch up/down tomaintain selected airspeed. Duringdescents, VNAV SPD will maintain airspeedbased upon an idle power descent.

VNAV ALT: Displayed if VNAV iscommanding pitch to maintain anintermediate altitude during a climb ordescent. For example if final cruise altitude

is FL350 and during a VNAV climb arestriction to FL290 is received, setting29000 in the MCP altitude window will causethe aircraft to level at FL290 and enterVNAV ALT mode. VNAV ALT will bedisplayed only if level off occurred at anintermediate altitude, but VNAV is still theprimary pitch mode for climb/descent.

MCP SPD: A combination of pitch andthrust is used to maintain MCP commandedspeed.

G/S: Commands pitch to maintainglideslope when intercept track does notexceed +/- 40 of front course. Will followglideslope once engaged.

FLARE: Will engage between 60-40 feetAGL. Commands pitch to reduce sink rate.Disengages at touchdown and lowers nosewheel slowly to runway.

AFDS Command Modes: The status of theentire AFDS system is also displayed on the

FMA mode annunciator. This displayprovides the crew with immediate feedbackon the current operating mode of the AFDSsystem. Displayed modes may be any ofthe following:

FD: Any flight director is selected ON whileautopilots are disengaged. Pilot mustmanually follow Flight Director steeringqueues. All modes are available on the

FMC, but the pilot is responsible for usingcontrol inputs to maintain pitch, roll andthrust (if the autothrottle is not engaged.)

CMD: Any autopilot is selected ON and isproperly engaged. The Autopilot iscontrolling pitch and roll modes inaccordance with flight director commands.

CWS P: Pitch is being maintained accordingto Control Wheel Steering logic.

CWS R: Roll is being maintained accordingto Control Wheel Steering logic.

What is Control Wheel Steering?:CWScan be used to control pitch and or roll of theaircraft. CWS provides full control authorityto the pilot and pitch and roll can be

changed by applying pressure to the yoke.When pressure is released, the autopilot willmaintain the pitch and roll attitudeestablished by the control inputs.

CWS Mode can be entered in three ways:

1) Pressing a CWS autopilot engagebutton on the MCP.

2) Application of sustained pressure onthe controls while the autopilot isengaged in CMD mode.

3) Engage the autopilot with no

previously selected pitch/roll modes.

When the AFDS enters CWS mode, CWS Pand/or CWS R will be displayed on the FMCand the current pitch and roll attitude will bemaintained until changed by controlpressures, or selecting an alternate pitch/rollmode on the MCP.



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Approach Modes: The autopilot is capableof flying a fully coupled ILS approach tolanding if desired.

At a minimum, to fly a coupled autopilotapproach, the appropriate ILS frequencymust be entered in the navigation radio andthe proper course selected for the approach.The APP switch on the MCP must bepressed and will initially illuminate.

The aircraft is capable of conducting a fullAutoland with only a single autopilotengaged but this is not considered to beadequate for a safe Autoland.

To engage the second autopilot for a fullycoupled Dual Channel Autoland, the ILSfrequency and course should be set up forthe second navigation radio and the CMD B

autopilot switch should be pressed prior toreaching 800 AGL on the approach.

1CH or SINGLE CH: Will be displayed toindicate localizer capture by one autopilot. Ifonly one navigation radio is tuned to the ILSfrequency, this annunciation will remain forthe entire approach.

In SINGLE CH mode, the aircraft will use rolland yaw to maintain the localizer course forthe approach.

When 2/5 dots below the Glideslope, theAPP switch on the MCP will extinguishesafter localizer and Glideslope are captured.

Once the approach is fully captured, APPmode can be disengaged by:

Pushing the TO/GA switch (click onupper left screw on MCP in thePMDG airplane. In the actualairplane the TOGA switch is locatedon the throttle under your thumb butthat could not be modeled here.)

Disengage the autopilots and turnoff both Flight Director Switches.

Tune the VHF Navigation receiversto a new frequency.

Autothrottle: The autothrottle system usesthe FMCs to directly control throttle input formaximum fuel conservation. The

autothrottle is capable of providing for fullflight throttle management from takeoff torollout.

Whenever engaged, the autothrottle systemwill provide speed limit protection bymodulating thrust to prevent exceeding limitsrelated to flap settings, angle of attack(alpha floor) and maximum structuralspeeds.

The FMC will display the thrust limit for thecurrent regime of flight on the EICASdisplay, and provides commands directly tothe autothrottle so as not to exceed thesethrust limits in any mode of flight.

The autothrottle can accept automatic inputdirectly from the FMC flight plan wheneverVNAV is selected, or manually from the crew

via the MCP.

MCP modes available to the crew forselection include, N1 Thrust (N1), speed(SPD), flight level change (FLCH) andVNAV. The autothrottle will provide speedprotection in all of these modes.

The autothrottle sets thrust by moving boththrottles together simultaneously. Theautothrottle will maintain the relative positionof the throttles, and stop throttle movementat the moment the first throttle reaches the

desired thrust setting. The autothrottle thenadjusts each engine individually to equalizethrust within 8% of N1.

Any throttle can be moved while theautothrottle is engaged, however theautothrottle will return the throttle to itscommanded position once it is released.

When the autothrottle mode HOLD isannounced on the PFD, the autothrottleservo is disconnected to preventuncommanded movement of the

autothrottle. The HOLD mode engagesautomatically when the aircraft acceleratesabove 65 knots during the takeoff. HOLDcan also engage in flight in VNAV and FLCHmodes if autothrottle movement isoverridden or stopped manually.

The autothrottle will disconnect in anysituation where a fault is detected in theengaged autothrottle mode, or if any reverse



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thrust lever is raised to reverse idle. Theautothrottle should be disengaged if oneengine fails in flight, or if both FMCs fail.

If the autothrottle is armed in flight, butdisengaged, it will automatically re-engage ifany pitch or autothrottle mode is selected onthe MCP.

Flap limit speeds, angle of attack, andairplane configuration limit speeds are

monitored by the AFDS and the FMCs in allpitch and autothrottle modes except V/Smode. If an overspeed is anticipated, eitherthe FMC will adjust pitch or the autothrottlewill adjust thrust to prevent exceeding aspeed limitation. The FMC may announceDRAG REQUIRED if it is determined thatpitch adjustment is the only method toprevent an overspeed condition.

FLIGHT MANAGEMENT COMPUTER

Overview: The 737 carries twoindependent FMCs which run in parallel to

each other in order to maximize accuracy,and eliminate errors.

The FMCs contain a database of navigationaids, waypoints, airports, airways, runways,SIDS, STARS, company route informationand aircraft performance data.

The FMCs are loaded by ground personnel,and the databases are updated every twentyeight days.

During flight, the FMC will monitor the

database for a combination of VOR andVOR/DME stations at high angles ofintercept to the route of intended flight.During the flight, the FMC will autotune theVHF navigation equipment to provide updateand verification of current aircraft position,and to provide position, radial and DME datato the crew for navigation purposes.

The FMCs will use this method of monitoringcurrent aircraft positioning as well as GPSposition data and IRS computed positiondata.

In the absence of reliable VOR tuning andGPS signal, the system will obtain anaverage position as computed by the InertialReference System. (IRS Not modeled in thisPMDG version.)

The FMCs use the navigation database andaircraft performance information stored innon-volatile memory to provide complete

lateral and vertical navigation. This isaccomplished by interfacing with and

providing commands to the AFDS andautothrottle systems.

The FMCs will use route, weather andaircraft performance data to operate theaircraft in the most economical fashion forany given flight regime based upon crewinstructions.

FMC/CDU: The FMC/CDU is the tool thecrew uses to interface with the FMC. TheCDU also provides a means for the FMC todisplay information for crew use.

The FMC will display information related tothe flight on the EFIS monitors, as well asthrough a series of FMC/CDU menus knownas pages.

A CDU line containing small boxes is asignal to the crew that information must beentered for proper FMC operation. A linecontaining dashes indicates information thatis optional for entry, but which will providefor more accurate FMC operation.

The FMC/CDUs are very specific aboutallowing correct data entry into the datafields. The FMC/CDU will not acceptillogical references, or references which arenot usable given the capabilities of the FMC.

The FMC/CDU provides a MENU key whichallows the crew to select either the FMCfunctions of the FMC/CDU, or access to theACARS capabilities of the FMC.



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AFDS MODE CONTROL PANEL

AFDS MCP: The AFDS Mode ControlPanel is located on the glare shield. This isone of the principle means used by the crewto communicate with and control the AFDSduring most phases of flight. The MCPcontains switches to select and arm theautopilots as well as various pitch, roll and

axis modes of the AFDS. In addition, theMCP allows the crew to override an FMCcommanded mode, or manually selectheading, speed, altitude and vertical speedas desired.

MCP Layout: The MCP layout is designedto allow for an intuitive interface between thecrew and the AFDS. Similar functions onthe MCP are clustered together in order toseparate dissimilar functions.

Flight Director Switches: Located oneither end of the MCP, the Flight Directorswitches enable or disable the display offlight director command bars on the PFD.

The flight directors display information asreported by the left or right Flight ControlComputer respectively. The autopilot willonly accept commands from one FlightDirector at a time. The current MASTERFlight Director is identified by an illuminatedMA above the flight director switch.

Thrust/Speed Modes: All of the AFDSmodes which use speed intervention andspeed protection are clustered around theIAS/Mach speed selector knob.

Autothrottle Arm Switch: When selectedON, this switch arms the autothrottle formode engagement. The autothrottle willengage when any of the following speed

intervention/vertical navigation modes areengaged:

FLCH

VNAV

TO/GA

N1

SPD

If the flight director is selected OFF and theautothrottle is armed, the autothrottle willrevert to the SPD mode until flight directorsare rearmed, or unless N1 mode is manually

selected.

If VNAV is already engaged at the time theA/T ARM switch is selected ON, theautothrottle will engage in the appropriatemode for the regime of flight.



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N1 Switch: If current mode is FLCH, SPD,VNAV SPD, VNAV PTH, VNAV ALT orTO/GA, pressing the N1 switch changes thethrust limit to the CLB thrust setting. Thissetting will be displayed on the EICAS. Thisdoes not affect the autothrottle mode, butchanges the thrust limit allowed.

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If any other mode is currently selected,pressing N1 will advance thrust to thecurrently displayed thrust limit.

SPD Switch: If pressed, the autothrottle isengaged in speed mode. SPD will beannunciated on the FMA and the throttle willcontrol thrust to maintain the IAS/Machdisplayed in the IAS/Mach MCP window.SPD mode will not exceed minimum ormaximum speed limits.

Selector Knob: Changes the valuedisplayed in the IAS/Mach window andupdates the command speed bug on thePFD.

Left click will change single digits. Rightclick will change tens unit.

If VNAV mode is engaged, the window willusually be blanked because the speed inputand control commands are being managedby the FMC. If VNAV mode is active andthe SPD INTV (Speed Intervention) knob ispushed then the MCP Speed window willdisplay the FMC commanded speed so thatadjustments can be made.

Pressing SPD INTV will return speed controlto the FMC as described in the flight plan.

If the autothrottle is operating in FLCH, SPDor TO/GA mode, the display will not beblanked.

SPD is inactive if in FLCH, VNAV or TO/GAmode.

C/O Switch: The Change Over switchallows the crew to manually select anreading in Knots or Mach.

IAS/Mach Window: Indicates current orselected VNAV speed unless VNAV isalready engaged. PFD command airspeedbug is manipulated using this setting.Indicator will be blank when VNAV mode isengaged. When VNAV is engaged, speedand speed bugs are placed under control ofthe FMC.

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LVL CHG Switch: Pressing the LVL CHGswitch will disengage any other active pitchmode. Level Change integrates AFDS pitchcontrol and autothrottle thrust control toeffect an altitude change.

If the IAS/Mach indicator is blank: Indicatorwill un-blank and display the FMC targetspeed. If the FMC target speed is invalid,then LVL CHG will use the existing airspeed.

If the IAS/Mach indicator is not blank:Command speed for the climb will remain asdisplayed.

The Autothrottle will advance the throttles tothe selected thrust for climbing, or reducesto idle if a descent is being effected.

AFDS will use pitch control to control speedafter climb/descent thrust is set by theAutothrottle, resulting in the best rate ofclimb or descent.

When MCP altitude is reached, the pitchmode changes to altitude hold and ALT is

displayed on the PFD. The autothrottleholds the commanded speed and SPDmode is engaged.

Bank Limit Selector: Allows the crew tomanually set a bank limit for the aircraft.This switch is normally left at 30 degrees butmay be selected lower as desired.

Within Microsoft Flight Simulator, the clickarea for the bank angle selector is locatedaround the click area for the heading bug. Ifyou accidentally alter the bank limit modewhen attempting to change heading, simplymove the mouse to the opposite side of theheading bug and click again. This will bringthe bank limit switch back to 30 degrees.

If you notice during flight that your airplaneis only turning slightly, this might be a culpritarea to examine!

HDG Selector Knob: Allows magneticheading to be selected in the HDG window.Heading mode will disarm if the aircraftcaptures an ILS on LOC mode.

HDG Window: Indicates magnetic headingselected using heading selector knob.

HDG SEL Switch: Engages heading holdmanually. When pressed, AFDS willmaintain current heading. If bank angleexceeds 15 degrees, AFDS will maintainheading at time the wings roll level.



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VNAV Switch: Pressing the VNAV switcharms or engages the vertical navigationmode of the AFDS, and transfers pitch andspeed modes of the AFDS and autothrottleto the FMC.

VNAV mode gives control of the pitch modeto the FMC and causes the AFDS to fly avertical profile as it is described in the FMCflightplan and updated or modified by thecrew.

If VNAV is engaged, VNAV mode appears ingreen on the PFD.

VNAV mode will not engage (but will arm) ifthe FMC Performance Initialization page isincomplete.

VNAV mode is disengaged by any of thefollowing:

Engaging TO/GA, LVL CHG, SPD, V/S,ALT, or G/S pitch modes. Or if VNAV switchis pushed a second time before VNAVengagement.

VERT SPD Window: Displays currentvertical speed at time V/S speed is pushed.Displays selected vertical speed as selectedusing V/S knob. Range is 6000 fpm to+6000 fpm.

LNAV Switch: Pressing LNAV switch armsor engages the lateral navigation mode ofthe AFDS, and transfers roll and yaw(heading) control to the FMC.

LNAV will engage as long as the aircraft isabove 50 AGL and within 2.5 miles of theplanned track. If the aircraft is outside ofthese parameters, LNAV mode will arm andengage when the aircraft moves within theseparameters (e.g.- after takeoff).

LNAV mode will be displayed in greed onthe PFD if LNAV mode is engaged.

If LNAV arms, but the aircraft is not on anintercept heading to planned track, the FMCscratch pad will show the text NOT ONINTERCEPT HEADING, and the previouslyarmed roll mode will remain active.

LNAV mode is disengaged by any of thefollowing:

Selecting HDG SEL modes.At localizer capture.If LNAV switch is pushed a second timebefore LNAV engagement.

V/S Switch: engages V/S mode. AFDS willmaintain V/S set in V/S window. V/S doesnot provide speed protection in the climb ordescent.



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ALT Window: Displays altitude as selectedusing the altitude selector knob. Displayedaltitude is target altitude for all AFDS, FMSand altitude alert functions. AFDS and FMCwill not allow a climb or descent through thedisplayed altitude. If altitude has beencaptured, AFDS and FMC will not allow theaircraft to depart from displayed altitudeunless a pitch mode has been selected.

Altitude Selector Knob: Allows selectionof altitude in the ALT window.

If at cruise, and within 50nm of the Top OfDescent point, selecting a lower altitude inthe MCP altitude window, then pressing theMCP ALT knob causes the DES NOWfeature to become active, and the AFDS willinitiate a 1,250 ft/min descent rate untilintercepting the VNAV calculated descentpath, at which point it will enter the VNAVdescent path.

Altitude Intervention Switch: The ALTINTV button can be pressed to the followingeffect:

During a climb or descent, pushing the ALTINTV button will delete the next waypointaltitude constraint between the airplane andthe altitude displayed in the ALT window.(For example: during a step descent,pressing the altitude selection knob willdelete the next level off point in the FMCflight plan, provided it is above the MCPaltitude displayed in the ALT window.)

If climbing, and no waypoint related altituderestrictions exist, pressing the ALT INTVbutton will transfer the MCP ALT value tothe FMC and overwrite the FMC altitude.The aircraft will level at the MCP altitude.

When pushed during cruise, the ALTwindow value will be transferred to the FMCflightplan and the new altitude becomes the

cruise altitude. If in VNAV ALT or VNAVPTH modes, VNAV will automatically initiatethe required climb or descent.

ALT HOLD Switch: Manually engagesaltitude hold mode. AFDS will capture andhold the altitude as indicated at the time theswitch is pushed.

Autopilot FCC Engage CMD Switches:Pressing switch engages associated FCCand places it in CMD mode. If both flightdirector switches are off, autopilot willengage in CWS Roll and CWS Pitch mode.

FCC DISENGAGE Bar: Pulling down forcesall autopilots to disengage, or prevents themfrom being activated.



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APP Switch: Arms or engages the AFDS tocapture and track the localizer and glideslope. LOC and G/S are armed (displayedin white on PFD) only prior to actual captureof localizer and glideslope. AFDS cancapture localizer or glideslope in any order,and upon capture each will display in greento show that LOC and G/S modes are bothactive.

LOC capture can occur when aircraft track iswithin 120 degrees of the front course, G/Scapture can occur when the intercept trackangle is within 80 degrees of the localizercourse.

Once LOC and G/S are captured, the APPswitch will extinguish, indicating that the onlyway to disengage the APP mode is to followthe steps outlined earlier in this chapter.

APP mode can be terminated prior tolocalizer or glide slope capture by pushing

the APP switch a second time, or byselecting LOC, LNAV or VNAV modes tooverride APP mode.

APP mode will also disengage if localizer iscaptured and different roll mode is selected.If the glideslope only has been captured,selection of a different pitch mode willdisengage the APP mode.

If TO/GA is selected, or the flight directorsare selected OFF at any time, APP modewill disengage.

VOR/LOC Switch: Arms or engages theAFDS to capture and track the localizer.LOC is armed only (displayed in white onPFD) prior to actual localizer capture. Thecurrent AFDS roll mode will remain activeuntil localizer capture. LOC display willchange to green when LOC mode becomesactive upon localizer capture.

LOC mode can be disengaged by pressingthe LOC switch a second time prior to LOCcapture, or by selecting the flight directorsOFF, or engaging the TO/GA mode.

It is generally important not to set theairplane up to violate your clearance limitwhile being vectored for an approach.When ATC instructs you to Intercept theLocalizer for Runway X pressing VOR/LOCwill intercept the localizer.

When cleared for the approach, pressingAPP will allow the aircraft to intercept anddescend via the Glideslope.



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TCAS II Version 7

Overview: PMDG has partnered with LeeHetherington, a veteran PMDG Beta tester,to bring you a TCAS II Version 7 logic

engine that provides real world TCASposition and resolution advisory informationprecisely as displayed to airline pilots flyingthe 737NG.

Written by Lee, the TCAS II Version 7 logicengine will be made available by him formany other applications, but we are proud topresent his work integrated into the existingPMDG airplane to provide a TCASsimulation truly worthy of the phrase, AsReal as it Gets!

TCAS is a vital aviation safety tool, andwhile traditional MSFS based TCASsimulations have served primarily as aircraftposition radar, Lee has teamed with PMDGto bring a TCAS II simulation that willprovide Conflict Resolution Advisoryinformation precisely as is done on theaircraft.

What TCAS II Does: TCAS II usestransponder encoded information to predictthe closest point of contact for aircraftoperating in the surrounding area. If it isapparent that the flight path of two aircraftwill conflict, advisory information is providedto the crew in order to direct aircraft awayfrom each other.

By integrating Lees behavior model, wehave been able to provide realistic real timeTCAS information to the navigation displayin the PMDG 737 cockpit. Resolutionadvisories are displayed in the format ofavoidance boxes and vertical speedcommands on the PFD and the VSI.Additionally we have provided aural calloutsthat are given to crews in order to maximize

the effectiveness of escape proceduresduring a resolution advisory.

TCAS Display: Traffic information isdisplayed on the navigation display of thePMDG 737. To ensure TCAS is working,you can select TEST on the Transpondermode switch, and a test format will be

shown on the navigation display, along withthe advisory information, TCAS System TestOKAY.

TCAS range can be adjusted using the NDRange knob on the EFIS MCP. Maximumrange for TCAS information is 40nm.

Traffic information displayed on the ND willbe displayed using one of four graphic iconsto identify the threat level of displayed traffic.

General Traffic not considered to bea conflict.

Proximate traffic within 6nm and +/-1200ft vertically but not conflicting.

Traffic Advisory:Potential ThreatTraffic. Traffic Traffic aural warning.

Resolution Advisory: Accompaniedby pitch guidance to resolve traffic conflict.

TCAS Operation: TCAS is marvelous in itssimplicity. To receive the collision protection

of TCAS, simply test the system prior totakeoff, and place the Transponder Modeselector in the TA/RA switch position toreceive Traffic Advisories and ResolutionAdvisories.



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Above/Normal/Below: For effective trafficdetection, it is important to manage theTCAS bias. There are three bias modes.Above, Normal and Below. The switchposition should reflect the current area ofinterest. If you are climbing, select ABOVE.During level flight select NORMAL. Duringdescent select BELOW.

ABS/REL: There are two ways that TCAScan provide you with altitude information ondisplayed traffic. Absolute altitude andRelative altitude. Setting this switch to ABSwill show you the current Mode S reportedaltitude encode for each detected target.REL will display the approximate verticalseparation between your current altitude andthe target aircraft altitude. REL is generallyconsidered a better setting as the RELinformation makes it easier to determinewhether traffic is above or below and bywhat distance.

Altitude information is displayed along witheach traffic symbol, along with an arrow toindicate whether the conflicting traffic isclimbing or descending.

General Traffic: On the 737NG, TCAS isconfigured to suppress the display of alltraffic except for TA and RA qualifying traffic.(Yellow or Red). In principle, this wouldmean that you should never see conflictingtraffic on TCAS.

Not all TCAS installations offer GeneralTraffic Suppression, however and GeneralTraffic information can be useful formaintaining good situational awareness.We have defaulted the TCAS setup to

display General Traffic. For perfect realism,you can uncheck the Show All Non-Threatening Traffic box under TCAS on theVARIOUS page of the PMDG Styles menu.

Traffic Advisory (TA): A Traffic Advisoryshould be taken seriously, as it will be thefirst indication of a potential resolutionadvisory. A Traffic Advisory will beaccompanied by the aural warning Traffic!Traffic! The Navigation Display will showthe conflict traffic in yellow. This will help toquickly identify the correct relative locationand altitude to begin searching.

Resolution Advisory (RA): A resolutionadvisory is considered to be an aircraftemergency. A resolution advisory will bedisplayed on TCAS in red, along with anaural command to climb or descend.Resolution advisories are designed toprovide maximum vertical spacing betweentwo aircraft that are in conflict with oneanother. The success of an RA dependsupon immediate and decisive action by thecrew in accordance with the instructionsprovided by the RA.

RA instructions are based upon anexpectation that within 2.5 seconds of anRA, the crew will perform a +/-0.25Gmaneuver in accordance with the RAinstructions.

On the Vertical Speed indicator, an RA willtrigger two color bands

Red: Conflict AreaGreen: Target Pitch Zone



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The aural warning will give initial instructionsfor the RA, and the crew should adjust pitchto enter the green band on the VSI. Notethat as the RA develops, it may change thelocation of the green band in order toincrease or decrease the needed verticalspeed to reflect greater or lower separationof conflicting traffic.

A similar Conflict Box is displayed on theattitude indicator to provide unambiguousguidance to the crew during an RA.

This Conflict Box is displayed in red andmatches safe green band displayed on theVertical Speed Indicator.

When TCAS has determined that bothaircraft are clear of one another, the ConflictBox and colored pitch bands on the Vertical

Speed will be removed, along with the auraladvisory, Clear of Conflict.


09 afds system

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