What happened
On Sunday, January 21, 2001, a Piper PA 18-150 Super Cub, registration F-GNMD, was conducting a navigation flight consisting of several legs between Toulouse Lasbordes, Ste Léocadie, and St Girons. While returning to Toulouse Lasbordes, the pilot contacted the control tower at 17:56. At 18:00, while flying at 1,200 feet and preparing to turn left for the base leg to runway 16, the pilot reported that the engine had stopped.
In an attempt to restore power, the pilot switched fuel from the right tank to the left tank and engaged the starter twice, but the engine failed to restart. Realizing the aircraft could not reach the runway, the pilot executed a forced landing in a field. During the landing roll, the aircraft struck a pylon and overturned. There were no fatalities among the single occupant, though the aircraft sustained light damage.
The investigation
The investigation focused on the fuel system and the pilot's flight planning. Post-incident examination of the aircraft revealed that the right fuel tank was empty, while the left tank still contained fuel. The engine and starter were found to be in functional condition, though ground tests indicated that the engine required approximately 12 seconds of cranking to restart following a fuel starvation event.
Review of the aircraft logbook showed the flight sequence for the day: a 45-minute flight from Lasbordes to Lasbordes, followed by a 65-minute leg to Ste Léocadie, a 75-minute leg to St Girons, and a final 43-minute leg toward the destination. The pilot had calculated an estimated remaining endurance of 3 hours and 25 minutes at the start of the day and had performed checks at each stage.
Findings
- The engine failure was caused by fuel exhaustion.
- The pilot's flight preparation and fuel management were insufficient.
- Before the final 43-minute leg, the estimated remaining endurance, based on manufacturer consumption rates and actual flight times, was approximately 55 minutes.
- The flight ended shortly after sunset, which was scheduled for 17:49.