What happened
On October 19, 2014, a Cessna 206F, registration F-GDAA, was conducting parachute jump operations departing from Oyonnax Arbent aerodrome. During the ninth flight of the day, while descending at 1,500 ft toward runway 21, the pilot observed an alarm on the engine monitoring device (EDM 700) indicating rising cylinder and exhaust gas temperatures. Upon attempting to adjust the mixture and power, the pilot found that the engine was no longer delivering power.
After switching to the opposite fuel tank, there was no change in engine performance. Realizing the aircraft could not reach the aerodrome and facing an approaching hillside, the pilot attempted an emergency landing in a nearby field. During the landing roll, the nose gear collapsed, causing the aircraft to pivot and capsize onto its back, resulting in the destruction of the aircraft.
The investigation
The investigation focused on the fuel system and the pilot's refueling procedures. Investigators found the right fuel tank was empty, while the left tank contained between 15 and 20 liters of fuel. While the fuel filters and injectors showed no mechanical defects, the fuel strainer and distributor were found to have fuel levels below the required operating threshold.
Analysis of the flight logs revealed that the pilot's refueling strategy had deviated from the previous day's pattern. Although the pilot used a manual gauge to check levels, this gauge was not specific to the aircraft and lacked a proper conversion table. The investigation also examined the pilot's consumption estimates, noting that while the pilot typically budgeted 30 liters per flight, the actual refueling amounts on the day of the accident (70 and 80 liters) were insufficient to cover the cumulative flight time and delays caused by air traffic control holds.
Findings
- The engine failure was caused by fuel exhaustion in the selected tank.
- The engine was at idle during the descent, making the early symptoms of fuel starvation—such as power loss or engine stumbling—difficult for the pilot to detect.
- The pilot misidentified the temperature alarms as a potential sensor failure or mechanical issue rather than a symptom of a lean air-fuel mixture caused by low fuel.
- The use of an improper manual fuel gauge without a corresponding conversion table contributed to inaccurate fuel level readings.
- A failure to adhere to the established refueling strategy led to insufficient fuel reserves for the day's operations.