What happened
On 12 August 2021, a Piper PA30, registration N8663Y, departed Cannes airport for a cross-country flight toward Figari. Approximately ten minutes after takeoff, while switching the right engine's fuel supply from the main tank to the auxiliary tank, the pilot experienced an engine malfunction. Although switching back to the main tank temporarily restored normal operation, the pilot decided to perform a precautionary U-turn to return to Cannes.
During the return flight, approximately 16 NM from the airport, the aircraft began to lose altitude. Despite the pilot's attempts to increase speed to the single-engine best rate of climb, the aircraft could not maintain level flight. Realizing a landing was inevitable, the pilot prepared for a ditching by donning a life jacket and opening the cockpit door. The aircraft landed on the water near Saint-Honorat Island. The pilot successfully evacuated the aircraft and was rescued by nearby pleasure boaters and airport emergency services.
The investigation
The investigation focused on the aircraft's wreckage, which was recovered from a depth of five meters after four days submerged. While the rudder trim was found near neutral and power controls were at idle, the prolonged exposure of the engines to seawater prevented a definitive analysis of the mechanical components. Fuel samples from the main and wingtip tanks were found to meet AVGAS 100LL specifications, though auxiliary tank samples were too contaminated with seawater for testing.
Findings
- The investigation could not definitively identify the specific cause of the engine failure.
- The failure of the engine(s) to maintain power led to the inability to maintain level flight and the subsequent loss of altitude.
- If a single engine was producing reduced power, the pilot's failure to feather the propeller likely increased aerodynamic drag, contributing to the loss of performance.
- If both engines failed, the distance from the airport made a return to runway 35 impossible, leaving the water landing as the only viable option.