What happened
On June 8, 2023, a Tomark SRO Viper SD4 microlight, registration 69AHM, was performing a cross-country flight departing from Montceau-les-Mines – Pouilloux aerodrome. After a brief stop at the airfield, the pilot and one passenger departed from runway 09.
During the initial climb, at an altitude between 150 and 200 feet, the aircraft's engine shut down. Witnesses observed the aircraft veer slightly to the right before the pilot attempted a left-hand turn, likely in an effort to return to the runway. During this maneuver, the aircraft entered a stall-spin, pitched down sharply, and struck the ground at high speed. The impact was followed by a fire that caused significant damage to the aircraft's nose and center section. The two fatalities were the pilot and the passenger.
The investigation
The BEA investigation focused on the mechanical state of the aircraft and the fuel system configuration. Investigators examined the wreckage and found that the fuel selector was in the OFF position. This selector requires a two-step process—raising a vertical pin before turning—to reach the closed position. Testing by a flight instructor demonstrated that if the selector is set to OFF, the engine can continue to run for approximately two to three minutes using residual fuel in the system before failing.
Investigators also reviewed the pilot's training and the aircraft's maintenance history. The aircraft had undergone a 100-hour inspection earlier that year and had a total of 622 flight hours. The pilot, a 19-year-old with 28 hours of flight time on this type, was described by his instructor as a conscientious student who had been trained in engine-failure procedures.
Findings
- The primary cause of the engine shutdown was that the fuel selector was left in the OFF position prior to takeoff.
- It is believed the pilot failed to open the fuel supply during pre-flight checks, likely having closed it at the end of the previous flight.
- The engine continued to operate briefly using only the residual fuel remaining in the lines and system, eventually starving the engine of fuel during the climb.
- The pilot's decision to attempt a turn back toward the runway, rather than continuing straight ahead on the extended runway axis, contributed to the loss of control and the subsequent stall.