What happened
On the evening of Friday, August 28, 2015, a Piper PA46 350P Malibu Mirage, registration D-ESPE, was at Cannes Mandelieu aerodrome. Following a flight from Switzerland, the pilot was offered refuelling by a ramp agent. During this process, an error occurred where Jet A1 was loaded into the aircraft's tanks instead of the required AVGAS 100LL.
On Monday morning, August 31, the pilot and a passenger departed Cannes Mandelieu for Triengen. During the initial climb, the engine began making unusual noises and the power decreased significantly, causing the aircraft's speed to drop suddenly. The pilot maintained a straight flight path and performed a ditching in the sea. The two persons on board sustained slight injuries, but the aircraft was destroyed.
The investigation
The BEA investigation focused on the sequence of events leading to the incorrect fuel delivery. It was established that the initial fuel order was relayed incorrectly through the stopover management office. During the refuelling process, the operator in charge of the tanker did not verify the aircraft's placards, which clearly indicated "AVGAS ONLY."
Furthermore, the investigator found that the operator had used a smaller diameter nozzle to facilitate the process, a common practice at the aerodrome for certain aircraft, but failed to complete the mandatory grade order confirmation form. The pilot, while performing pre-flight checks, visually inspected the fuel at the tank caps but did not notice the error because the denser Jet A1 had settled at the bottom of the tanks, leaving the AVGAS 100LL on the surface.
Findings
- The primary cause of the engine shutdown was the refuelling with the wrong fuel grade.
- An initial error in the fuel order was passed from the ramp agent to the fuel supplier.
- The refuelling operator failed to follow established procedures, specifically neglecting to check the aircraft's fuel type placards and failing to use the grade order confirmation form when changing nozzles.
- A language barrier between the German-speaking pilot and the French-speaking operator contributed to a misunderstanding regarding fuel pricing, which the pilot mistook for a confirmation of fuel type.
- The pilot's pre-flight fuel check was ineffective because the density difference between the fuels allowed the AVGAS to remain visible at the top of the tanks, masking the Jet A1 below.
- The engine was able to operate normally until the remaining AVGAS in the collector tanks was consumed, at which point the Jet A1 reached the engine.