What happened
On June 9, 2008, at 8:50 AM, a Tecnam P 2002 Sierra ultralight, identified as 01-WK, departed from Bellegarde aerodrome for a local flight. Shortly after takeoff from runway 19, at an altitude of approximately 100 feet, the engine lost power. The pilot was forced to perform an emergency landing in a nearby field, just a few hundred meters from the end of the runway. Upon impact with the ground, the nose gear collapsed, causing the aircraft to come to rest on its nose. The pilot sustained one injury, and the aircraft was heavily damaged.
The investigation
The investigation focused on the engine's failure to maintain power during the climb. Prior to engine start, the pilot had topped off both fuel tanks. Investigators examined the fuel system and found that the fuel bowls and carburetor float chambers contained very little fuel, indicating that an insufficient quantity of fuel had reached the engine.
While inspections of the tanks and lines showed normal fuel flow, and tests confirmed that both the mechanical and electric fuel pumps were functioning correctly, a critical observation was made regarding the fuel valves. During a test run, the engine operated for approximately 80 seconds at 2,000 rpm after the fuel valves had been closed. Additionally, video footage recorded by the passenger showed the engine running at 5,270 rpm during the takeoff roll.
Findings
- The engine power loss was caused by accidental manipulation of the fuel valves during the pre-flight checks.
- Although the aircraft's manual requires checking that the fuel valves are open before starting the engine, it does not explicitly require a secondary check of their position after the engine is running.
- It is highly probable that the fuel valves were inadvertently closed during the cockpit procedures prior to takeoff.