France

The accident was the result of the combination of the following factors:
- The pilot initiated the descent too late, causing the aircraft to approach well above the glide,
- The pilot continued the approach with an unstabilized airplane nor in speed nor on the glide,
- The airplane landed halfway down the runway, reducing the landing distance available,
- The speed upon touchdown was recorded at 119 knots, 30 knots above the recommended speed in the flight manual,
- The braking coefficient was considered as medium because of a wet runway surface,
- The airplane suffered an aquaplaning effect when the pilot initiated the braking procedure.

The exact cause of the loss of power on the left engine could not be determined. The pilot, concentrating on monitoring the approach parameters, did not immediately realize the left engine malfunction. He noticed that the aircraft's rate of descent was too high to follow the standard approach slope. The pilot first attempted to go around and reconfigured the aircraft to do so by retracting the landing gear and flaps. In spite of these actions, the pilot noticed that the power delivered by the aircraft's engines did not allow him to recover the plane and understood, by being aware of the action of his right foot on the rudder pedal, that the power delivered by the left engine was abnormally low. Given the low height of the plane at the time of this observation, the pilot decided to land in the country. Contributing to the high rate of descent after the occurrence of the left engine malfunction was the fact that the drags were extended at the time the engine power decreased and the fact that the left propeller probably windmilling until the landing.

The following findings were identified:
- GASC (Groupement d’avions de la sécurité civile) has a small resource of Tracker pilots;
- Without a co-pilot, the pilot is deprived of the usual cross-checking of piloting decisions and actions;
- The pilot has little experience on established firefighting missions. He has never carried out a mission of this nature in a single-pilot aircraft;
- Certain limitations of the flight envelope are unknown to pilots, particularly at high weight and in steep turns;
- Pilots have little knowledge of the aerological phenomena associated with certain fires, and the associated turbulence;
- With the implementation of the Tracker withdrawal, pilots are concerned about their future within the GASC;
- Fatigued from sustained activity, the pilot had a false understanding of the situation;
- The pilot suffered from overconfidence;
- The pilot did not perceive the terrain. He flew a little low as he approached the hill ;
- He adopted a trajectory very close to the flame front and did not anticipate the risk of turbulence;
- Focused on a dwelling to protect, he did not detect the inappropriate altitude of his plane and maintained a strong bank;
- The left wing underwent a local stall causing a steep left bank, which caused the pilot to recover the aircraft too low in relation to the height of the trees, which he had a false idea of.

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.