France

Emergency landing due to fuel exhaustion following a flight of five hours and 15 minutes.

The landing distance of the airplane on a wet runway as defined in the Airplane Flight Manual (AFM) performance tables are not compatible with the length of runway available at La Môle Aaerodrome. When preparing the flight, the pilot used the flight record provided by the operator ProAir to determine landing performance. Landing distance on a wet runway presented in the file increased that on a dry runway by 15%. The 15% increase on a wet runway can only be used in conjunction with the increase of 60% imposed in commercial operation, otherwise it may be inappropriate. The value resulting from the calculation was, in this case, wrong and less than the value indicated in the aircraft flight manual. The pilot probably did not use the EFB application for the calculation of performance or the flight manual to verify this value. The pilot thus undertook the flight on the basis of erroneous performance values, without realizing that he could not land at this aerodrome if the runway was wet. In addition, during the final approach, the speed of the aircraft was greater than the speed approach reference and the approach slope was also greater than the nominal slope, which resulted in an increase in the landing distance. During the landing roll, the aircraft exited the runway longitudinally at a speed of 41 kt. The pilot failed to stop the aircraft until it does not violently collide with obstacles at the end of the track.
Contributing factors:
- The operator's use of the same operations manual for two different types of operations;
- The absence in the operations manual of a calculation method, coefficient and safety margin for the calculation of performance in non-commercial transport;
- Lack of knowledge by the pilot and the operator of the method of calculation of landing performance in non-commercial transport;
- The lack of indication in the operations manual that the landing performances at La Môle aerodrome are limiting in case of a wet or contaminated runway.

The rudder control broke in flight, causing a significant alteration of the aircraft yaw controllability. This failure considerably increased the pilot's workload and stress. In these conditions, it became difficult for him to keep the airplane aligned with the runway centreline upon landing. Monitoring the alignment of the aircraft was done to the detriment of the speed. It is very likely that the oscillations during the final step resulted from a stall of the aircraft at low speed.

The engine failure was the result of an incorrect refueling, due to an intake initial order probably incorrect that the incomplete application of procedures by the operator in charge of refueling and the lack of attention of the pilot did not allow recovery. The quantity of 100LL present in the feeders and the pipes allowed the taxiing and the take-off run, without the pilot noticing any anomaly. Once this quantity of 100LL consumed, the JET A1 present in the lower part of the tanks fed the engine and caused the power decrease.
Contributed to the accident:
- Coordination between the aerodrome operator and its subcontractors during the fuel order taken by the ramp agent, who does not encourage the operator in charge of refueling to confirm the type of fuel in a service carried out under strong time constraints,
- A usual practice for refueling certain types of helicopters, whose reservoir ports are not compatible with the dimensions of the standard refueling nozzles, which trivialize the change of nozzle for the refueling of JET A1, occasionally leading to the filling of order confirmation vouchers, thus reducing the effectiveness of the manifest safety for the operator through the presence of keying devices specific to each fuel,
- The ineffectiveness of the fuel type check item of the pre-flight procedure.

The collision with the ground was due to the deliberate and planned action of the copilot who decided to commit suicide while alone in the cockpit. The process for medical certification of pilots, in particular self-reporting in case of decrease in medical fitness between two periodic medical evaluations, did not succeed in preventing the copilot, who was experiencing mental disorder with psychotic symptoms, from exercising the privilege of his licence. The following factors may have contributed to the failure of this principle:
-The copilot’s probable fear of losing his ability to fly as a professional pilot if he had reported his decrease in medical fitness to an AME,
-The potential financial consequences generated by the lack of specific insurance covering the risks of loss of income in case of unfitness to fly,
- The lack of clear guidelines in German regulations on when a threat to public safety outweighs the requirements of medical confidentiality.
Security requirements led to cockpit doors designed to resist forcible intrusion by unauthorized persons. This made it impossible to enter the flight compartment before the aircraft impacted the terrain in the French Alps.

Due to the absence of any flight data recorder, investigations were unable to determine with certainty the exact cause and circumstances of the accident.