1. Flight Test Mishap Red Flag Analysis
Aircraft/Participants
Mishap Synopsis
Cause Summary
Red Flags for Future Testers

2. Airbus A340-600 Aircraft/Participants A340-600 Nine POB
Long-range, twin aisle, high-capacity passenger airliner
Four engines
Three main landing gears (MLG), four wheels each, all equipped with brakes
Braking logics:
With 0º steering angle, all 12 wheels braked by NORMAL hydraulic circuit.
With increasing steering angle, reducing pressure on centre MLG until only 8 wheels braked by NORMAL hydraulics at full steering angle.
With parking brake ON, only 8 wheels braked by ALTERNATE hydraulic circuit.
NORMAL and ALTERNATE hydraulic circuits both available with all engines running.
NORMAL and ALTERNATE hydraulic circuits both produce the same brake pressure.
Nine POB
Cockpit
LH seat: untrained observer from airline
RH seat: trained operator from Airbus
Rear centre seat: untrained operator from Airbus
Cabin
Six further observers from airline and Airbus

3. Airbus A340-600 Mishap Synopsis
November 2007, Toulouse-Blagnac airport, France, day VMC.
Aircraft performing engine run on dry engine run-up bay with surrounding inclined blast walls.
With parking brake on and no chocks, high power applied on all four engines simultaneously.
After a few minutes, aircraft began to move forwards and then rapidly accelerated towards blast wall.
Parking brake released, pedal braking applied, nose wheel steering employed to try and slow and deviate the aircraft.
Engine power reduced as aircraft impacted blast wall.
Aircraft rode over blast wall and snapped in two before coming to a rest.
A total of 15 seconds elapsed before aircraft started to move and the end of the incident.
4 POB with severe injuries and 5 POB with minor injuries.
Aircraft scrapped.

4. Airbus A340-600 Cause Summary
Braking capacity was not sufficient for aircraft weight, run-up area surface condition and engine power setting.
With eight braked wheels (parking brake ON) at start of engine run with 40t of fuel on board, on a dry run-up area the aircraft would not move forward.
With reducing fuel quantity and increasing engine power, the braking performance was no longer sufficient.
Releasing the parking brake and applying pedal braking improved braking performance by 50%, but this advantage was removed when using the nose wheel steering to try and avoid the wall.
The engine power was not reduced as soon as aircraft movement was detected.
The airline observer (left hand seat) was not trained to use the braking and steering controls, or the throttle levers, and did not attempt to do so.
The trained Airbus operator (right hand seat) was fully occupied with commands on the brake pedals, the park brake command and the nose wheel tiller.
The untrained Airbus operator (rear centre seat) reduced the throttles as soon as he realised that the braking and steering actions of his colleague were insufficient, but by that time the aircraft had already impacted the blast wall.

5. Airbus A340-600 Cause Summary
The engine run was performed without chocks
Maintenance manual indicated that any high power engine run should be performed with chocks
However, it was common practice not to use chocks, as it is time-consuming to install them and on occasion they would become stuck due to slight forward motion of the aircraft, leading to a requirement to tow the aircraft off.
The engine run was performed with high power on all four engines
Maintenance manual indicated that any high power engine run on a four-engined aircraft should only be performed on two engines at a time (never all four simultaneously) to avoid high levels of thrust.
The engine run was performed with a lower than usual fuel quantity
The incident engine run was the last of several engine runs which had been performed whilst trying to identify an oil leak on the engines.
As a result, more fuel than usual had been consumed, even if the engine runs had been started with the aircraft above the recommended minimum weight.
Due to the light aircraft weight, a lower thrust setting was sufficient to override the braking system (aircraft skidding despite brake application).

6. Airbus A340-600 Cause Summary
No operations manual existed for non-standard verifications during aircraft delivery process
A standard set of verifications was used, in the form of a checklist.
This checklist did not indicate the possibility to perform a high power engine-run in the event of troubleshooting.
On the other hand it did not exclude it, leaving the operator to make a judgement call and then use experience to decide which maintenance manual procedure to use
There is no legal or regulatory requirement in France for such a manual for aircraft which have not received their individual certificate of airworthiness (i.e. which are still under manufacturer resposnibility)
Perceived pressure to deliver results in short timescale with airline observer on-board
Previous engine runs without chocks had been performed successfully but most likely at higher aircraft weights with reduced total thrust
Upon customer request to verify engine oil leak and at the end of a lengthy ground check, it seemed OK to agree to “one last check”
The operations manual only required the presence of one trained operator in the cockpit during ground checks
There was no possibility for a second trained operator to participate in the immediate analysis of the situation and to perform appropriate remedial action.

7. Airbus A340-600 Red Flags for Future Testers
Time and commercial pressure
Leads to non-respect of published safety recommendations
Can generate impromptu procedures which have not been reviewed
Lack of procedural documentation
Allows for individuals to “make their own way” leading to high variability and no record of what has worked and what has not
Insufficient depth of technical knowledge – could I know more?
In this example, the operator did not recall that applying the nose wheel steering would result in a reduction in the braking performance

8. Airbus A340-600 Best Practice Lessons
Formalise accepted checks in the operations manual and refuse those which are not included.
Ensure that the number of trained personnel in the cockpit is commensurate with the potential risks.
Do not deviate from published maintenance manual procedures.
Do not allow commercial or time pressure to cloud judgement.
Encourage independent review and oversight of operating procedures even if there is no legal or regulatory requirement