History of the Flight
The pilot departed Cannes airport at approximately 09:25 for a cross-country flight to Figari. After takeoff, the tower controller instructed the pilot to leave the circuit via reporting point SA2 at 1,000 ft. About ten minutes into the flight, the pilot switched from the main tank to the auxiliary tank for the right engine, after which the right engine operated improperly. Switching back to the main tank restored normal operation. As a precaution, the pilot decided to turn around and return to Cannes, informing the Nice flight information controller of a minor radio issue. At that point, the airplane was approximately 16 NM from the airport. The pilot placed all levers forward (full throttle, full low pitch, full rich) and maintained level flight at 1,000 ft, noting the airplane could not exceed 110 mph (best single-engine rate of climb speed).
Shortly after the U-turn, the airplane began losing altitude. To increase speed toward the blue line, the pilot pushed the stick slightly, gaining a little speed up to 120 mph but continuing to descend. The pilot prepared for a water landing by donning his life jacket and opening the door. He announced to the Cannes tower controller that he was going into the water. The pilot landed on the water off Saint-Honorat Island, evacuated the cockpit, and positioned himself on the wing. He was picked up by a boater on a jet-ski and transferred to a pleasure boat. The airplane sank a few minutes after landing. The airport Rescue and Fire Fighting Service (RFFS) was alerted, and they retrieved the pilot from the pleasure boat at 10:04.
Additional Information
Wreckage and Site
The wreckage remained submerged at a depth of approximately five meters for four days before being raised. Examination of the wreckage revealed no anomaly likely to have contributed to the accident. The rudder trim was near neutral; power controls were at idle, propeller speed controls near full low pitch, and mixture controls at the halfway point. Prolonged exposure to sea water limited engine examination, but no failure was found. Fuel samples from the main and feeder tanks met AVGAS 100LL specifications, while auxiliary tank samples were contaminated with sea water.
Meteorological Conditions
The 09:30 METAR for Cannes reported wind from 010° at 3 kt, CAVOK, and temperature 27 °C.
Pilot Information
The pilot held a Private Pilot Licence (PPL(A)) issued in 2001 with SEP, MEP, and IR/ME ratings. He had approximately 2,830 total flight hours, including 1,510 hours on twin-engine airplanes.
Aircraft Information
N8663Y was a Piper PA30 equipped with six fuel tanks (three per engine): two main tanks (30 US gal each, 27 usable), two auxiliary tanks (15 US gal each), and two wingtip tanks (15 US gal each). The logbook indicated refueling to capacity on 23 July 2021. On 31 July, the pilot's father flew a round trip from Cannes to Figari (2.5 hours) using only main and wingtip tanks. The pilot estimated before the accident flight that the auxiliary tanks were full, main tanks half full, and wingtip tanks empty.
Pilot's Statement
The pilot reported no engine malfunction after switching back to the main tank. He did not attempt to feather the propellers. Just before water impact, he observed propeller speed at 2,400 rpm and fuel flow on one engine at half the value of the other. He did not recall using the rudder pedals during the return.
Conclusions
The investigation was unable to determine what caused the failure of the engine(s), which led to the emergency water landing. Two hypotheses were considered: reduced power on one engine (where lack of feathering would increase drag) or both engines failed. In the latter case, feathering would not have allowed gliding to the airport, making the water landing the only option. The pilot was quickly rescued due to the high concentration of pleasure boats in the area.