What happened
On July 10, 2010, a Cessna U 206 G Stationair, registration F-GCCE, was conducting parachute jump operations at Lorient aerodrome. During the climb to 1,400 meters for the third jump of the morning, the pilot noticed a decrease in engine power. After switching to the right fuel tank, the engine returned to normal power, and the pilot declared a 'Pan, Pan, Pan' emergency via radio before deciding to continue the climb to FL100 to complete the mission.
Following the completion of the jump, while on final approach for runway 25, the engine lost power again. The pilot attempted to switch to the left tank and activate the auxiliary pump; however, the engine only ran for a few seconds before failing completely. The pilot attempted an emergency landing approximately 50 and 500 meters short of the runway threshold, resulting in the aircraft impacting a grove of trees. The aircraft was destroyed.
The investigation
The investigation focused on the fuel management practices used during the flight operations. It was determined that the aircraft's owner utilized a specific fuel management strategy: placing the required fuel for scheduled rotations in one tank while maintaining a reserve of approximately 40 liters in the other. For the morning's operations, the right tank had been partially drained.
Prior to the first flight, the pilot estimated the fuel levels using a graduated wooden rule, calculating approximately 100 liters in the left tank and just over 30 liters in the right tank. While the flight logs recorded precise flight durations, the pilot's fuel tracking was flawed. Instead of calculating consumption based on the actual hourly rate of one liter per minute, the pilot subtracted a flat rate of 30 liters per rotation, as instructed by the owner.
Findings
- The primary cause of the accident was an erroneous estimation of the amount of fuel consumed.
- A significant contributing factor was the time pressure exerted on the pilot. Following a delay in the first rotation due to air traffic, the jump organizer pressured the pilot to accelerate the schedule to meet a tight 40-minute turnaround window. This pressure likely influenced the pilot's decision to continue the climb despite the initial engine power fluctuation.