What happened
On August 2, 2018, a Piper PA28-181, registration F-GKEC, was performing a navigation flight from Île d’Yeu to Lyon Bron. During the descent toward the destination, the pilot contacted Lyon Bron air traffic control and was informed that the runway was temporarily unavailable due to an aircraft obstruction. Believing the aircraft had sufficient fuel to wait or divert, the pilot planned a diversion to Villefrante Tarare.
Shortly after, the engine began to sputter. The pilot declared a "MAYDAY," reporting that the engine was stopping due to fuel exhaustion. While attempting to locate a suitable field for an emergency landing, the pilot decided to turn back toward Lyon Bron. During this maneuver, the aircraft entered a stall, as evidenced by the audible stall warning during final radio communications. The aircraft subsequently struck the wall of a warehouse and came to rest on its roof, resulting in the destruction of the aircraft and two slight injuries to the pilot and passenger.
The investigation
The BEA investigation focused on the fuel management and flight planning preceding the accident. Investigators examined the aircraft's fuel system and found that the fuel selector was set to the right tank, but the engine was not delivering power. Notably, the fuel gauge for the left tank was marked "INOP" (inoperative), and the pilot had been managing fuel levels by switching tanks every 30 minutes rather than using visual inspections.
Analysis of the flight logs and previous legs of the journey revealed significant discrepancies. The pilot had used erroneous flight time calculations from previous legs, which led to an incorrect estimation of the hourly fuel consumption. Furthermore, the investigation found that the engine settings during previous flight segments had likely caused higher-than-expected fuel consumption due to higher power settings and climb profiles.
Findings
- The primary cause of the engine failure was fuel exhaustion.
- The pilot proceeded with the flight without verifying the actual quantity of fuel on board during the pre-flight inspection.
- Erroneous flight time calculations from previous legs led to a significant overestimation of the remaining fuel endurance.
- Higher engine power settings during previous flight segments resulted in a higher fuel burn rate than the pilot had calculated.
- The pilot's decision to divert to another airfield without knowing the true fuel state contributed to the fuel depletion.
- The pilot's limited experience with this specific aircraft type likely led to an incorrect estimation of the aircraft's glide ratio during the emergency.