september 14, 2007 1 airborne surveys planning, logistics and safety toronto, canada september 2007...

September 14, 20071 www.iagsa.ca

Airborne Surveys

Planning, Logistics and Safety

Toronto, CanadaSeptember 2007

Exploration 07


Presenters

John Issenman, IAGSA Chief Operating Officer

Stan Medved, Manager Aviation Safety - BHP Billiton, IAGSA Technical Committee Chair and Executive Committee Member


Airborne Surveys – Planning Logistics & Safety

Introduction and Accident Rate Review 09:00-09:10Review of Typical Business Process & Logistics 09:10-09:30Geophysical Goals Versus Aviation Constraints

Fixed Wing Safety Considerations 09:30-10:20Break

Helicopter Safety Considerations 10:40-11:30

Introduction to IAGSA Standards 11:30-12:00Lunch

Sample Survey Flight Specifications & 13:00-14:00Risk AnalysisAccident Case Studies 14:00-14:30

BreakAccident Case Studies (cont) 14:50-15:30

Conclusions 15:30-16:00


Part 1:

Introduction and Accident Rate Review

John Issenman


Why form IAGSA? After a particularly bad year in 1995 (5 aircraft lost;

10 fatalities) several survey companies decided to form the International Airborne Geophysics Safety Association (IAGSA)

Mandate: To develop promote and enhance safety in the

industry Develop standards and recommended safety

practices for survey operations To serve as a repository of safety information

relevant to the industry To educate clients on the relevant safety topics

to assist in writing appropriate contract specifications


What has IAGSA done so far?

Developed “Standards” and “Recommended Practices” for the industry; published in a Safety Policy Manual

Developed a “Recommended Contract Annex” based on the Safety Policy Manual for clients to add to their requirements (more on this later)

Gathered accident and activity data

Gathered safety advisories for sharing among members


What has IAGSA done so far?

Implemented an accreditation program to review Active Member compliance with IAGSA policies

Funded a special project to develop risk analysis tools for high elevation helicopter autorotations

Established website where much of the above information may be obtained www.iagsa.ca


How are we doing?

IAGSA gathers accident and activity data to develop meaningful accident rates

Each Active Member provides annual activity data (i.e. flying hours) for each category of aircraft

In addition, the number of fatal and non-fatal accidents is compiled

These data are used to calculation accident rates normalized to 100,000 flying hours – (convention aviation accident statistics throughout the world)


Accident Rate Review


Accident Rate Review

Airborne Geophysics Survey Industry overall accident rate (fixed and rotary wing) has come down from 11 in 1998 to 2 in 2005

Fatal rate over same time has come down from 6 to 1 per 100,000 hours

North American/European/Australian non-scheduled commercial air services (fixed and rotary) rates are approximately 10 (total) and 1 (fatal) per 100K hours, respectively


Accident Rate Observations

Since IAGSA inception, the accident rates have trended in the right direction

One in two survey accidents result in a fatality compared with one in ten for non airline commercial aviation

Analysis of survey accidents has shown:

the inability to clear high terrain while flying lines is a factor

high proportion of piston engine fixed wing aircraft


End of Part 1:

Introduction and Accident Rate Review

QUESTIONS?


Part 2:

Review of Typical Business Process

John Issenman


Step 1 – Tender Issue

A request for proposals or a tender document is issued to eligible bidders

The RFP specifies, among other things, how the client expects the survey to be flown

It is important that the client know what is “reasonable” to expect

from various aircraft

over differing terrain

with the desired survey equipment


Step 2 – Bid Preparation & Acceptance

A bid is prepared during which the bidder considers:

Suitable types of aircraft for the requested survey data and equipment

Terrain over which the survey it to be done

Specs for flying height, speed and data resolution

Costs

A risk assessment is completed to determine whether the survey can be completed safely as requested or with mitigations applied

If the answer is NO, it will be difficult to submit a conforming bid! (so will someone else bid on it?)


Step 3 – Crew Assembly

Field crew is assembled and mobilized:

One or two geophysicists or logisticians

One or two pilots

Possibly one onboard technician

Probably one Aircraft Maintenance Engineer (AME)

Risk analysis updated based on any amendments to contract and subject to crew input upon arrival on site


Step 4 – Logistics Support

Aircraft availability – Foreign registration of aircraft, aircraft modifications

Air Operator Certificate

Permits

Flight crew licensing

Fuel availability – pre-positioning may be required

Spare parts (aircraft and survey equipment)

Hangar access

Office and personnel accommodation

Security


Step 4 – Data Acquisition

First flights to assess validity of assumptions used in risk analysis (e.g.. determine suitability of digital terrain elevation model used and drape surface generated)

Geophysicists process data gathered daily for quality control.

Pilots fly grid lines and may monitor onboard survey equipment.

Technician or operator may monitor onboard survey equipment.

AME ensures aircraft can fly.

Geophysicist performs quality assurance and preliminary field processing


Step 5 – Data Processing

Most final data processing, cartography, and production of other final products are done at the operator’s main offices; some done in field for QC and to provide preliminary data to client.


End of Part 2:

Review of Typical Business Process

QUESTIONS?


Part 3 a:

Fixed-wing Safety Considerations In

Airborne Geophysics

Stan Medved


Fixed Wing Safety Considerations

General factors – What are the goals? What Types of aircraft?

Speed – What does it mean for the geophysicist & the pilot?

Climbing and Descending – which is more demanding?

Multi-engine is always safer – isn’t it?


Fixed Wing Safety Considerations - General

Geophysicist’s goal: To obtain the best possible data with available

resources How?

Fly low and slow Increase number / size of sensors Increase sampling rate Improve sensor resolution



Pilot’s goal: To safely fly the task within survey

specifications

How? Operate the aircraft within manufacturers’ and

regulatory limits Use a risk management based approach Regulatory requirements relating to survey

flying are minimal compared with other commercial operations



Aircraft types:

Typical aircraft are smaller single and twin engine piston and turboprop

A few larger aircraft such as the Fugro Dash 7 and CASA 212

With a few exceptions aircraft have not been designed for continuous low level operations

• Performance implications• Affect on structural integrity• Inappropriate limitations

Aircraft need to be modified


Fixed Wing Aircraft Types - Cessna 210


Fixed Wing Aircraft Types - Cessna Caravan


Fixed Wing Aircraft Types - Cessna 404


Fixed Wing Aircraft Types – Air Tractor 402


Fixed Wing Aircraft Types

Smaller aircraft designed to FAR Part 23 standards or equivalent

Airline type aircraft designed to the more rigorous FAR Part 25

This has a significant impact on required and achievable climb performance and system redundancy

Larger aircraft essentially used to provide big EM loop; they are generally too big for other applications


Fixed Wing Aircraft Types - DHC-7


Fixed Wing Aircraft Types – CASA 212


Fixed Wing Aircraft Types – Turbine DC-3


Unmanned Aerial Vehicles

Will become more common

Potential of better performance and safety

Currently payload limited

Large UAVs are more complex than existing manned survey aircraft

Introduces new safety issues


Fixed Wing Safety Considerations - Speed

The speed of an aircraft does not have the same meaning or implications for different people

Geophysicists are concerned with ground speed (GS)

Pilots are primarily concerned with Indicated Airspeed (IAS) followed by True Airspeed (TAS)

What’s the difference?



Indicated Airspeed (IAS) is what the pilot sees on the airspeed indicator.

Calculated by subtracting static air pressure from the total pressure of the airflow (pitot pressure) and dividing by air density

All aircraft reference speeds are quoted in Indicated Air Speed Stall (Vs) Take-off Landing approach (typically 1.3 Vs) Best rate of climb (Vy, Vyse), etc

IAS reference speeds remain unchanged regardless of altitude and temperature



IAS is easy to measure and display to pilot.

IAS only equals true air speed under standard atmospheric conditions i.e. sea level (1013 hPa) & 15C.

As altitude and temperature increase, so does true airspeed for a given IAS.

For example 120 Knots IAS equals a TAS of:

Air Temperature 15C 35C

Sea Level 120 1255000 ft 129 13410,000 ft 139 14415,000 ft 152 156



Ground Speed is simply True Airspeed plus the wind effect.

A practical IAS – TAS – GS example:

Cessna 404 minimum safe/practical airspeed is 130 KIAS

New Mexico survey elevation 6000 ft, air temperature 20C

130 KIAS = 147 KTAS

15 knot tailwind will give a ground speed of 162 knots

Either accept the higher ground speed or choose a different aircraft which can fly safely at a lower IAS.



Some definitions:

Stall speed (Vs) – is the minimum Indicated Airspeed at which the aircraft can generate sufficient lift to continue flying; not related to the function of the engine(s)!

Minimum single engine control speed (Vmc) – is the minimum Indicated Airspeed at which a multi-engine aircraft can be controlled with one engine failed and the other producing maximum thrust



Best single-engine rate of climb speed (Vyse) – is the Indicated Airspeed at which the aircraft will achieve the maximum climb rate with one engine operating at maximum thrust



For higher data resolution, it is often desirable to fly at low speed

Turbulence, high nose up attitude, and turns make consistent flying at minimum flight manual speeds impractical and unsafe

IAGSA has developed a minimum speed standard for fixed wing aircraft which is the greater of:

130% of the clean stall speed (Vs)

110% of the recommended single engine climb speed (Vyse - multi-engine aircraft only)



IAGSA minimum safe speed examples:

C404 120 knots (KIAS)

C208B 82 knots (KIAS)

These are not intended to be used as target survey speeds but are the lowest Indicated Airspeeds that a pilot should ever see while surveying and manoeuvring.



Reasons for not flying slower:

You can fly right down to stall speed, but safety margins are eroded to the point where turbulence or a turn will cause the aircraft to stall. At survey heights recovery is unlikely.

You can fly below single engine control speed as long as both engines are operating – lose one and the aircraft will rapidly depart controlled flight.

You can fly below best single engine climb speed – but in the event of an engine failure, the only way to accelerate to this speed is to descend – in most cases not an option at survey heights.

Aircraft are more difficult to control at low speeds.


Fixed Wing Safety - Climbing and Descending

Pilots generally think in terms of climb and descent rates (metres per minute) whilst geophysicists refer to climb or descent gradients (metres per km).

Aircraft performance charts provide climb rates which vary with density altitude.

Typical survey aircraft can achieve a maximum cruise climb rate of 1000 fpm at 120 KIAS.

As survey elevation increases TAS increases and achievable rate of climb decreases.



An Example:

At sea level 120 KIAS and rate of climb (ROC) of 1000 feet per minute (fpm) results in a climb gradient of 8.3% (i.e. 83 metres per km)

At 5000 feet 120 KIAS equals 129 KTAS and ROC will typically decrease to 900 fpm. Climb gradient reduces to 7.0%

Add a 15 knot tailwind and climb gradient decreases to 6.25%



Desirable to have the aircraft maintain constant height over the ground

In practice the maximum sustainable climb gradients are between 5 and 10% (slower airplane; steeper gradient)

Landing approach gradients are typically 3 - 3.5%

Anything above 4% is considered steep for a landing approach – and the aircraft is configured to achieve a good descent rate gradient (slow, flaps out, landing gear down, low power setting)



Survey flying, depending on terrain, necessitates frequent climbs and descents.

We don’t reconfigure the aircraft (landing gear and flaps down) to increase drag to optimise descent gradients on survey

Reluctant to reduce power too aggressively only to reapply for the subsequent climb; speed builds up when descending and limits descent gradient

Achievable descent gradients tend to be shallower than climb gradients!!!

Difficult to calculate accurate descent gradients due to lack of performance chart data – obtained by experience and testing



Want to climb and descend at same gradient in order to achieve consistent heights at intersections;

Generate a “drape” surface



Over such steep terrain we “drape” the surface to match the aircraft’s performance; descent performance is usually the limiting factor

The quality of the “drape” depends on the accuracy of the digital elevation data used – much of it is still insufficient for this purpose

Pilots need to be ready for errors in drape and have some performance margin available as shown in the following example:


Fixed Wing Safety - Climbing and DescendingLegend

Blue:

source terrain data

Green:

actual terrain

Magenta:

drape surface

Red:

actual flight profile

Vertical interval:

200 metres each

Horizontal distance:

Approx 20 km

High due to terrain “off-line”Terrain not modelled but real!Aircraft needs margin to climbabove then recapture drape


Fixed Wing Safety - Single Engine Vs Twin Engine

“Twin engine aircraft are safer than single engine aircraft”

Based on the premise if an engine fails the aircraft can return to an airport on the remaining engine


Failure Rates for Turbine and Piston Engines

Actual figure for all Pratt & Whitney PT6 engines in SE aircraft * = 1 in 300,000 hrs (i.e. probability 3 x 10 -6)

Commonly accepted figure for piston engines = 1 in 20,000 hours (i.e. probability 5 x 10 -5)

Therefore the piston engine is about 15 times more likely to fail than the turbine engine

The likelihood of BOTH engines failing on a piston twin is the product of the probabilities for each engine or 1 in 400,000,000 hours (i.e. probability 2.5 x 10 -9)* Report JAA/SE-IMC/AASG/6 Issue 2, 6 August 2001. “Power Loss Events on Single-Engine

Turboprops: Phase of Flight”.



FAR Part 23 Certification requirements for a twin engine aircraft:

In still air at 5000 feet density altitude an aircraft must be able to achieve a one engine inoperative climb gradient of 1.5% subject to:

• Maximum weight• Landing gear retracted• Flaps in the most favourable position• Propeller feathered• Maximum continuous power on the operating

engine• 5 degrees angle of bank towards the operative

engine• At OEI best rate of climb speed



At 5000 feet, air temperature of 20°C and maximum weight, a Cessna 400 series aircraft will achieve:

OEI climb rate of 150 fpm at 108 KIAS (about 1% gradient!)

If the propeller isn’t feathered, the aircraft descends at 250 fpm

There will be loss of altitude during the transition to single engine flight

At typical survey heights, there may be insufficient margin to enable the aircraft to climb away

Flight manual performance figures represent best case scenarios and do not account for any degradation due to survey equipment



The twin engine aircraft will provide the presumed safety advantage when operating offshore, or over relatively flat terrain at low elevations and temperatures

High elevations and/or temperatures may well exceed the single engine ceiling

Even modest terrain gradient may exceed the single engine climb gradient



Why are performance figures so marginal?

For the original design operating environment (stable cruise flight at >5000ft), resulting single engine climb performance is sufficient for the majority of cases

Aircraft used in survey were not designed to operate continuously in a low-level (<500ft) environment



Comments on One Engine Inoperative (OEI) Performance

Loss of one engine will result in ~ 80% reduction in performance;

Performance may be further degraded by installed survey equipment;

Many surveys are conducted at density altitudes that exceed the single engine ceiling of the aircraft;

Loss of power may be experienced at a low energy point (i.e. low airspeed and height above the ground) so technique must be perfect;

If survey drape parameters have been selected on the basis of twin engine climb gradient then the OEI climb gradient will be less than terrain gradient.



Comments on Pilot Workload

At the point of engine failure the aircraft will yaw rapidly, airspeed will begin to decrease and/or aircraft will begin descending;

Pilot must maintain speed above minimum single engine control speed, increase operating engine to maximum power, feather the correct propeller, apply 5 degrees of bank and keep the aircraft correctly balanced, and attain best rate of climb speed;

Failure to achieve any of the above will reduce climb performance; even optimum performance may not be sufficient to clear rising terrain; turning away will also reduce climb



Comments on Pilot Workload (cont)

A decision to carry out a forced landing may be necessary.

Training and practice for handling an engine failure in a multi-engine aircraft is essential to achieving satisfactory performance

Such training is itself a hazardous activity especially if conducted at survey flying height

Frequent training in a simulator is the best way to maintain competence; there are few simulators available for the class of aircraft used in the industry



Examples of where survey aircraft should have been able to maintain altitude with one engine inoperative

Aircraft Type Country Year Remarks

C404 South Africa 1991 Fatal – Loss of airspeed while setting up after engine failure

Aero Commander Australia 1994 Fatal – Fuel system mismanagement led to

engine failure and loss of control

C404 Zimbabwe 1995 Non fatal – forced landing after aircraft unable to maintain altitude on one engine

Islander Brazil 1996 Non fatal – loss of aircraft, unable to maintain altitude on one engine

Navajo Indonesia 1998 Fatal – engine failure implicated

Cessna 404 Mozambique 2004 Fatal – engine failure implicated



As of mid 2007 no survey industry losses of single-engine turbine aircraft attributable to the engine

Provided maintenance and pilot training are done well, there is no reason not to use piston twin engine aircraft but in practice turbines have demonstrated far greater reliability

The principal reason for difficulty after engine failure with a twin is the combination of pilot workload and poor single engine performance (especially true for piston engine aircraft)



Single Engine (FAR Part 23) Certification

Stall speed not to exceed 61 KIAS

• Based on the expectation that an off-airport forced landing will be survivable at touchdown speeds

• There is no such limitation for twin engine aircraft – typical stall speeds are ~ 80 KIAS except for STOL aircraft

In the event of an engine failure, there is a clear course of action.

On the other hand, a forced landing may be into hostile terrain


Fixed Wing Safety Considerations Summary

Fixed wing (and helicopter) performance limitations need to be considered when determining specifications such as ground speeds and drape parameters

Prevailing winds and temperatures have a significant impact on ground speed and climb (and descent) gradients

Specifying a twin engine aircraft does not automatically provide a higher safety standard unless all the conditions are met to enable a return to base on one engine

If a forced landing is the result following an engine failure, it is less likely to be survivable in a twin engine aircraft than in a single engine aircraft


End of Part 3 a:

Fixed Wing Safety Considerations

QUESTIONS?


BREAK!


Part 3 b:

Helicopter Safety Considerations

In

Airborne Geophysics

John Issenman



Safety considerations for fixed wing aircraft apply equally to helicopters (eg. IAS – TAS, single vs. twin, min safe speeds)

Many projects in mountainous areas require use of helicopters at high elevations

Can deliver better survey data because they can fly slower and climb steeper; therefore contour steep terrain more successfully than fixed wing

Usually light, single engine models such as Eurocopter AS 350 series are chosen but some twins also used


Helicopter Pros and Cons

PROS: Slower flight for greater data resolution Ability to fly steeper gradients

CONS: Lower productivity due to lower speed and endurance Higher operating costs Unique additional hazards AS 350 Ecurieul (Squirrel) or ASTAR


Helicopter Autorotations

In the event of an engine failure, a helicopter can perform an autorotation to land safely

Successful autorotation is limited to certain combinations of height above ground (h) and speed (v)

Pilot is provided with a chart of the H-V avoid area within which an autorotation may not be successful



Typical H-V avoid area chart - Robinson R-22.

Pilot to “avoid operation in shaded area”.

Note effect of increasing density altitude (combination of altitude with high temperature).

Hover at 400 feet

50 Knots & 200 feet

Hover at 10 feet

Hover at 625 feet


Helicopter Autorotations Pilot procedure in event of engine failure(AS350)

Lower collective pitch control (left hand) to prevent loss of rotor speed

Establish 65 knots using cyclic control (right hand) Turn into wind At 65 ft (20 m) flare to nose up attitude At 20-25 ft (6-8 m) and constant attitude apply collective pitch to

reduce sink rate Resume level attitude, cancel sideslip, touch down Notes say to expect 1800 ft/min descent at 65 knots

That’s 10 seconds from 300 feet!!

That’s why we want to minimize time spent in “avoid area”


Medium Helicopter with EM Bird – Bell 205/212

Photo reminds us that the pilot in this situation would also have to drop the “bird” whilst executing the auto rotation


Good Training – Good Outcome


Helicopter Safety Considerations – HOGE

IAGSA recommends that “Hover-out-of-ground-effect” (HOGE) capability should be the performance benchmark for helicopters

A helicopter can hover “in-ground-effect” (HIGE) at a higher weight than when far above the ground

To be in ground effect requires that the helicopter be no more than about half a rotor diameter above a level solid surface

Operating with HOGE capability means the pilot has some extra margin for downdrafts, or unexpected circumstances (like the unexpected terrain shown earlier!)


Helicopter Safety Considerations – HOGE

HOGE ceiling is 8500 feet HOGE at 8,500

HOGE at 10,750HOGE at 9,500

At max weight of 2250 kg (4960 lb) and 20˚C

Example: AS350 – B3

Can safely work at higher elevations by limiting to lower temperatures or reducing weight

200 kg lighter at 20˚C

Same weight at 10˚C



Twin Engine Helicopters

Most cannot land in a confined area vertically with one engine inoperative (OEI)

Maximum altitude with OEI tends to be low

• Bell 412EP OEI service ceiling:

Max weight – 5400 ft

Mid weight – 8400 ft

At moderate to high elevation surveys failure of one engine will result in a forced landing



Other Helicopter Specific Considerations

Dynamic roll over

Ground resonance

Run on landing – tail rotor failures

The landing area (size, surface, obstacles) has a significant impact

Settling with power

Wire strikes

Towed bird strikes

Tail rotor strikes


Helicopter Safety Considerations - Summary

Helicopters offer advantages because of slower speed and steeper gradients

Can operate away from airfields but the landing area needs to be carefully considered

Minimum survey speed to remain outside the H-V avoid area

Operate at weights that give a HOGE capability

Autorotative landings happen very quickly

There is no manufacturer data available to determine successful autorotation parameters at high elevations

Twin engine helicopters are unlikely to remain airborne following an engine failure at moderate to high survey elevations


End of Part 3 b:


QUESTIONS?


Part 5:

Introduction to IAGSA Standards

John Issenman



Standards and Recommended Practices described in Safety Policy Manual with background information

Based on ICAO format

Also written in the form of a contractual clauses in the IAGSA Contract Annex for suggested use by those writing specifications.

The international oil industry through the Association of Oil and Gas Producers has adopted IAGSA Recommended Practices



All Active Members agree to substantially comply with these and must demonstrate this as a condition of Accreditation

An Active Member who does not comply with one or more Standards, makes a declaration in the form of a “Notification of Difference”



Examples of some standards Definitions Flying height to be determined after risk analysis

following a recommended format Minimum speed for fixed wing aircraft Use of helmets Pilot training syllabus Equipment required for over water and offshore

surveys Helicopter performance benchmarks Helicopter avoid area recommendation


IAGSA STANDARDS AND RECOMMENDED PRACTICESEXAMPLES

Training and equipment for over water and offshore flight: exposure suits; life vests; egress practice

Helmets & appropriate clothing;survey flight training syllabus

Towed “birds” and refuelling from drums operations


End of Part 5:


QUESTIONS?


LUNCH


Part 6:

Sample Survey Flight Specifications andTypical Risk Analyses

Stan Medved


Sample Survey Flight Specifications andTypical Risk Analyses

Fixed Wing C208 vs C404 Helicopter


Risk Analysis - General

IAGSA provides a standard format for fixed wing and helicopter risk analyses that each operator may use as-is or customize to suit

Risk Analysis is necessarily a subjective process but a consistent format will provide for a good basis for comparisons

We cannot explicitly quantify the risk; too many variables with unknown probabilities but…..

We CAN effectively compare acceptability of risk for one aircraft type to another and propose mitigations for anticipated hazards whose risk level is unacceptable



Note that airborne geophysics hazards are often unlike those for air transport operation

For example: Controlled Flight Into Terrain (CFIT) is one of the major causes of aircraft accidents in both airline and airborne geophysics operations; but for different reasons

Mitigating strategies applicable to airline operations are often incompatible with airborne geophysics: airlines use EGPWS to combat CFIT but this equipment is totally useless for low level airborne geophysics



Start by gathering all information relevant to the survey being analyzed (i.e. survey location, terrain, surface cover, line lengths, prevailing weather, etc.)

Specific data for each aircraft Type being analyzed must also be included

IAGSA form provides guidance on what information is required



Client Resource Company Contact Name Client Contact

Survey Title Big Survey Start Date Mid July

Location A hot desert Est. End Date Mid Sept

Aircraft Operator Contact Name

Total Size (lkm) 75,842 Proposed Aircraft Types

Cessna C208BCessna C404No. of Blocks 3

Remarks (list any general comments regarding this risk analysis):

This analysis has considered both the Cessna 208B and the Cessna 404.

Target ground speed will be 130 knots.



Block Name 1 2 3

Survey Type Aeromagnetic

Terrain Clearance 150 m

TraverseLines

Direction 360˚ T

Spacing 1,000 m

Average Length 104 km 111 km 118 km

Total Trav. line length (lkm) 20,105 lkm 18,359 lkm 21,927 lkm

Control Lines

Direction 90˚ T

Spacing 4,000 m

Average Length 139 km 156 km 185 km

Total Control line length (lkm) 5,179 lkm 4,715 lkm 5,557lkm

Total line kilometers this Block (lkm) 75,852

Fixed Height, Drape or Contour? Drape

If DrapePlanned Gradient (ft/nm) 250 ft/nm

Manual / Auto Guidance? Auto Guidance



Weather

Prevailing wind Direction

Avg. wind speed (knots)

Mean min temp (C)

Mean max temp (C)

Remarks / Source

Elevation (Feet MSL)

Minimum

Median (this value is required)

Maximum

Fuel Supplier Name

Fuel Storage / Delivery method(tanker, buried tanks, bladder, drums?)

Fuel Filtration / Quality Control

Flight Following Primary Comm Method

Alternate method (if applicable)

Planned Communication Time interval

Add other relevant general information including airport data


Risk Analysis – Terrain information

Terrain Gradient (m/km) % of Block Surface % of Block

Flat (< 10) 30 Water 0

Gentle (11-50) 60 Desert 90

Undulating (51-150) 10 Scrub 10

Steep (>150) 0 Pastoral 0

Total (must be100) 100 Wooded 0 Tree height n/a

Planned drape gradient

ft/nm 250 Jungle 0 Canopy height n/a

m/km 41 Total 100


Risk Analysis – Other HazardsHazards None Few Moderate Many Remarks

Power lines X

Towers/Masts X

Known bird Activity X

Known aircraft activity X

Urban areas X

Farm houses X

Airstrips X

Blasting areas X

Restricted/Danger areas X R - 51

Politically sensitive areas X Border 5 km


Risk Analysis – Aircraft Data

This section allows for entry of data describing:

the maintenance status of the aircraft (ie. will any major components require replacement during the survey)

weight and balance based on the survey equipment and crew complement plus any special safety equipment required (life raft; emergency water rations)

fuel required, including reserve fuel based on IAGSA standards

Maximum planned flight endurance


Risk Analysis – Climb Performance Data

Aircraft Type C404 Titan

Flight Manual Performance

KCAS KTAS G/S

Gear / Flap

Start Survey wt.

8,173 Configuration

Stall Speed 83 89 99 Up / up

Survey Speed 140 150 160 Up / up

All engines climb speed 120 128 138 Up / up

OEI climb speed (ME aircraft) 109 117 127 Up / up

Climb rates FpmClimb gradient

Compare thesegradients with

ft/nm m/km the planned

All engines climb rate 780 339 55.8 drape gradient

OEI climb rate (ME aircraft) 170 80 13.17 (if applicable)

Planned drape gradient 250 41



Identify the applicable HAZARDS (IAGSA standard RA form assists with this)

Estimate and rank the severity of the consequences should the hazard be encountered

Estimate and rank the exposure to the hazard or likelihood that it will be encountered

Rate the “Risk factor” as the product of the severity and the exposure/likelihood

Decide on the acceptability of the calculated risk factor


Risk Analysis – One Engine Inoperative Risk Matrix

Using a risk matrix the OEI scenario is to be considered. This is an assessment of the risk relating to the requirement to execute a forced landing or ditching in a twin-engine aircraft in the event of an engine failure

The terrain and performance data from the general section are required to complete this analysis

First assign the severity rating of the consequences of a ditching or forced landing

Next assign the likelihood rating that such an outcome would occur



SEVERITY 5 - Assigned when there is no forced landing or ditching area

available. Survey site is completely wooded or over jungle. Any attempt to conduct a forced landing will probably not be survivable.

4 - Assigned when the aircraft is considered to be able to execute a survivable forced landing or ditching for some (25%) of the survey area.

3 - Assigned when the aircraft is considered to be able to execute a survivable forced landing or ditching for about half of the survey area.

2 - Assigned when the aircraft is considered to be able to execute a survivable forced landing or ditching for most (75%) of the survey area.

1 - Assigned when the complete survey area is suitable for survivable forced landing or ditching scenario



LIKELIHOOD

5 - Assigned when the gradient of the terrain or drape exceeds the maximum climb gradient of the aircraft in normal two engine operation and precludes a controlled descent to lower altitudes at which sustained OEI flight can be achieved.

4 - Assigned when the gradient of the terrain or drape exceeds the maximum climb gradient of the aircraft in single engine climb configuration for the complete survey area and precludes a controlled descent to lower altitudes at which sustained OEI flight can be achieved.



LIKELIHOOD (Con’t)

3 - Assigned when the gradient of the terrain or drape exceeds the maximum climb gradient of the aircraft in single engine climb configuration and descent to altitudes at which sustained OEI flight can be achieved is not possible for more than 50% of the survey area.

2 - Assigned when the maximum gradient of the terrain or drape is less than the maximum climb gradient of the aircraft in single engine operation calculated at the mean survey weight and temperature or it is possible to descend to altitudes at which sustained OEI flight is achievable.

1 - Assigned when the maximum gradient of the terrain is less than the maximum climb gradient of the aircraft in single engine operation calculated at the start survey weight and maximum projected temperature.



Note that the numerical value has only “relative” meaning (i.e. Risk factor of “4” is not twice as risky as “2” only “greater than”)

LIKELIHOOD SEVERITY

5 4 3 2 1

5 25 20 15 10 5

4 20 16 12 8 4

3 15 12 9 6 3

2 10 8 6 4 2

1 5 4 3 2 1

Enter the resulting severity and likelihood ratings into the risk matrix to calculate a “risk factor”


Risk Analysis - Use of The Risk Matrix

The matrix is presented below, complete with suggested methods of reducing risk factors. The following index is then to be used to determine the risk management required for the proposed survey.

RISK FACTOR SURVEY CONDITIONS

16-25 Survey not to proceed as currently planned. Consultation between Aviation Manager, Field Operations Manager and Chief Pilot/Senior Field Pilot required to significantly amend plans.

9-15 Survey may proceed upon approval by Aviation Manager and/or Chief Pilot of amendments to current plan or other factors that mitigate identified risks.

1-8 Survey may proceed as currently planned.


Risk Analysis - Mitigation

The likelihood of a forced landing as a result of engine failure can be reduced by the following:

Aircraft Selection - consider other aircraft types or categories (i.e. helicopter) if the performance characteristics are not suitable for the survey.

Aircraft Payload - By reducing the weight (i.e. fuel loading) of an aircraft the performance can be optimized.

Temperature Considerations - Planning of the survey for the coolest periods (daily and/or seasonal) may be necessary to optimize performance.

Maintenance Considerations - Engine Trend Monitoring, Fuel Quality Control and S.O.A.P. Sampling.


Risk Analysis - Mitigation

Where likelihood cannot be reduced, perhaps severity of forced landing event can be as follows:

Aircraft Selection - single engine aircraft and helicopters do not require areas as large as twin-engine fixed wing aircraft for successful forced landing and the landing speeds are lower

Height of Survey and Drape Parameters - Increasing the height of the survey can improve the probability of maintaining flight after experiencing an engine failure; will give a pilot greater reaction time to configure the aircraft, climb away from the ground, or turn towards lower ground. A similar result may be achieved by reducing the maximum allowable gradients used for the drape.

Protective Equipment - Consider adding more protective gear for crew members (helmet, 4-5 point harness, ditching and survival gear, etc.)


Risk Analysis – Which Aircraft

We’ve seen that the piston multi engine C404 is a low risk

The turbine single engine C208B is also a low risk – given the high probability of a successful forced landing over most of the area and the high reliability of its engine

The difference is that the C404 will have a survey ground speed of 160 knots whilst the C208B can achieve a ground speed as low as 120 knots

Survey specification calls for 130 knots which can be achieved by the C208B


Risk Analysis – Helicopter


Risk Analysis – Helicopter Autorotation Risk Matrix

Severity 5 - Assigned when there is high probability of critical

or fatal injury following an autorotation attempt at any altitude.

4 - Probability of surviving, without critical injury, an autorotation attempt at any altitude is unlikely.

3 - Probability of surviving, without a serious or critical injury, an autorotation attempt at any altitude, is poor.

2 - Probability of surviving, without serious or critical injury, an autorotation attempt at any altitude is fair.

1 - Probability of surviving, without critical injury, an unsuccessful autorotation attempt is good.



Likelihood 5 - Assigned when more than 75% of the survey area

would be flown in the avoid area of the Height vs. Velocity chart.

4 - Assigned when most, 50 - 75%, of the survey area would be flown in the avoid area of the Height vs. Velocity chart.

3 - Assigned when 25 - 50%of the survey area would be flown in the avoid area of the Height vs. Velocity chart.

2 - Assigned when less than 25% of the survey area would be flown in the avoid area of the Height vs. Velocity chart.

1 - Assigned when the helicopter would be flown outside of the avoid area on the Height vs. Velocity chart for the entire survey area.



Mitigations include more rigorous AR training for pilots; more rigorous maintenance standards (HUMS)

LIKELIHOOD SEVERITY

5 4 3 2 1

5 25 20 15 10 5

4 20 16 12 8 4

3 15 12 9 6 3

2 10 8 6 4 2

1 5 4 3 2 1

Enter the resulting severity and likelihood ratings into the risk matrix as in previous fixed wing example


Risk Analysis – Helicopter Risk Matrices

Other Risk matrices for: HOGE performance Hazards of executing a forced landing with power

(due to weather or other factors)

For airplanes and helicopters also consider hazards that are independent of aircraft class and number of engines


Risky Behaviour


End of Part 6:

Sample Survey Flight Specifications and

Typical Risk Analyses

QUESTIONS?


Part 7:

Accident Case Studies

Stan Medved


Survey Accident Case Studies

Two survey accidents will be examined and how planning and appropriate controls may have prevented them:

May 1997, Cessna 210N – Emerald, Australia

November 1994, Aero Commander 680F – Cloncurry, Australia


Cessna 210N - Background

Single engine Cessna 210N conducting survey west of Emerald, Australia in the Drummond Range area

One pilot and one operator on board

Planned height of 80m

East – West lines

Early morning departure for an expected ~ 5 hour flight

Generally open flat terrain except crossing Drummond Range (400m above surrounding terrain) with a number of narrow valleys

One line over rugged terrain needed to be reflown



Aircraft departed at 6.38am

No radio communications planned or made with Company or ATC Flight Service

When the aircraft did not return by 11.30am as expected, the Company reported the aircraft as overdue.

Search initiated and three days later the wreckage was located in the survey area with no survivors

Aircraft had impacted trees in a steep turn (85 – 90 deg) coming to rest 30m below the ridge top

Emergency locator transmitters destroyed on impact


Cessna 210N - Conditions

Prior to the accident the aircraft was flying on an easterly heading

Sun was relatively low on the horizon

Broken layer of cloud between 2000 and 3000 ft (close to level of high terrain) - visibility beneath the cloud layer was good

Moderate wind, however severe mechanical turbulence was reported in the area at low level

No evidence of any airframe or engine abnormality or birdstrike



No evidence of any physiological condition affecting either crewmember

Pilot had moderate levels of experience (1,445 hrs total and 450 on survey in Cessna 210N)

No regulatory requirements for specific survey low level flying training for pilots

Survey operators approval required company pilots to have completed a general low flying course

No record of the pilot having undergone this training



Company provided some guidance on low level operations but no information on escape manoeuvres or operations in restricted areas

Company advocated trading airspeed for height technique to climb over rising terrain


Cessna 210N - Findings

Wind conditions were conducive to severe mechanical turbulence

Data quality in the accident area was poor the previous day flown in similar conditions

Sun glare and cloud may have affected pilot’s visibility

Pilot had not received appropriate low flying training for the environment

Company guidance was inadequate for the operating environment

Failure of ELTs resulted in a very large search area


Aero Commander 680F – November 1994


Aero Commander 680F - Background

Aeromagnetic survey, 80m height, 140 knots, ~ 5hr duration

Aircraft departed between 7.00 and 7.30am with pilot and operator on board

No radio communications planned or made with Company or ATC Flight Service

When the aircraft did not return by 12.30pm as expected, a field crew member started making calls to see if the aircraft had landed elsewhere

Formal SAR action initiated at 8.45pm


Aero Commander 680F - Conditions

Aircraft wreckage found next morning

Aircraft was 3.4% above maximum takeoff weight

Calculated best single engine rate of climb was 160 ft/min

Weather conditions were good – clear skies and light winds, 37C

Aircraft was out of control at impact (120 deg bank and 35 deg nose down)

At time of impact right engine was operating at full power, left engine shutdown and propeller feathered


Aero Commander 680F - Conditions

No mechanical abnormalities in airframe, both engines and propellers

Left engine fuel selector valve: Centre and Outboard tanks in closed position

Right engine fuel selector valve: Centre tank open; Outboard tank closed


Aero Commander 680F - Pilot

Pilot was experienced in survey operations

Pilot had 710 hours in Aero Commander 500 series aircraft but had only flown the 680F model once, the day before and had not flown any other Aero Commander series aircraft in the preceding four months

Pilot had received a verbal briefing from another company pilot on the differences in the fuel system between the 500 series and 680F Aero Commander models

Pilot had left the hotel at 5.00am and did not have breakfast


Aero Commander 680F – Fuel System

The Aero Commander’s fuel system has a number of fuel tanks that need to be manually selected and managed

Attention is needed to ensure that as the outboard tank gets close to empty the centre tank is selected before the engine is starved of fuel

Company pilots used different procedures for managing fuel usage

The fuel tanks, fuel usage rates and fuel selector panel differ between the 500 series and 680F

The outboard tanks empty in ~60 minutes in the 500 series and ~20 minutes in the 680F (left tank 3 – 5 minutes quicker than the right tank)


Aero Commander 680F – Fuel System

Fuel Selector Panels – located on the overhead console

680F

500 Series


Aero Commander 680F – Hypothesis

The pilot’s only flight in the 680F was 2 hours long and not long enough to need to use the outboard fuel tanks

During the flight both outboard tanks were selected feeding their respective engines

After about 20 minutes the left engine began to run roughly and the pilot reached up to the overhead panel and instinctively selected what he thought was the Centre tank, instead he switched the fuel off

The pilot assuming an engine failure secured the failed engine and began to turn away from the survey area and towards Cloncurry


Aero Commander 680F – Hypothesis

3 – 5 minutes later the right engine began to surge and then run rough due to air entering the fuel line to the engine

The resultant power loss on the one operating engine would have caused a rapid reduction in speed and climb rate

Realising his error the pilot selected the correct Centre fuel tank position which restored fuel flow to the right engine

However with the aircraft at very low speed (below Vmc) the sudden restoration of power on one engine caused the aircraft to go out of control


Aero Commander 680F – Findings

The pilot was unfamiliar with the fuel system on the Aero Commander 680F

The company did not provide sufficient training on the differences

The briefing provided to the pilot was done in a hotel room without reference to aircraft manuals or the aircraft itself

Company pilots used different fuel management techniques

The pilot had not eaten since the evening meal the day before the accident


Aero Commander 680F – Findings

The pilot would have been subjected to significant heat stress

The aircraft was overloaded

The Company’s emergency response plan was inadequate

Pilot incapacitation or birdstrike were ruled out by the investigating agency as likely causes


Accident Case Studies

Both involved failures in a number of controls or defences culminating in the accident

We use the risk assessment process to understand the hazards, assess the risk and ensure that we have effective controls in place


Part 8:

Conclusions

Stan Medved & John Issenman


Conclusions

Airborne geophysical survey is a relatively high risk activity

The nature of the activity provides little margin

Through detailed planning and understanding of the risks and controls available we can make it as safe as routine charter flying

It takes a cooperative approach involving both the survey provider and client commissioning the surveys

The controls developed and implemented have proven to be effective

Whilst these risk controls increase cost they also allow surveys to be carried out more efficiently


How Quickly Things Go South


Exploration 07

More information at:

www.iagsa.ca

Questions?

september 14, 2007 1 airborne surveys planning, logistics and safety toronto, canada september 2007...

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