History of the Flight
On 10 July 2022, a Cessna F152 registered F-GMOU departed from Poitiers-Biard airport at 09:05 local time for a circular cross-country flight. The pilot, who held a LAPL(A) obtained on 27 June 2022, had 65 total flight hours and 33 hours on Cessna 152/150. The flight was his first since licensing. The planned route included La Roche-sur-Yon, Les Sables-d'Olonne, La Tranche-sur-Mer, and La Rochelle. The pilot had replenished fuel with 95 litres, providing endurance of 3 hours 30 minutes.
After passing abeam La Tranche-sur-Mer at approximately 10:17, the pilot heard a faint engine misfire. He checked parameters and saw no anomaly. A second misfire occurred shortly thereafter, and he notified La Rochelle-île de Ré air traffic control of engine problems and intention to land. Subsequently, louder misfires at closer intervals were heard; the tachometer oscillated between 2,200 and 2,400 rpm. The pilot adjusted magnetos, richness, and power, but the engine did not respond. The engine then shut down, with the propeller windmilling. The pilot attempted unsuccessfully to restart.
Decision and Ditching
After the engine shutdown, the pilot adopted best glide speed of 60 kt. Believing he was closer to Île de Ré than to La Rochelle airport, he headed toward the island for a forced landing in fields. Realizing he could not reach land, he prepared to ditch, checking for boats in the path. The aircraft contacted the water and tipped forward; the pilot evacuated before it sank vertically. A nearby sailing boat rescued him.
Aircraft and Maintenance
The Cessna F152 (built 1982 by Reims Aviation, Lycoming O-235-L2C engine, 110 hp) had about 925 engine hours. Maximum fuel capacity was 98 litres (6 unusable). The last 100-hour inspection was on 22 June 2022, with 33 hours 50 minutes flown since. Maintenance documents showed no deviations or engine anomalies.
Meteorological Information
Météo-France estimated conditions near Île de Ré at the time: wind 060° at 13 kt, visibility 9 km, clear sky, temperature 25°C, dew point 14°C. Wind at 2,500 ft was 070° at 18 kt. Sea was calm with no swell.
Wreckage Examination
The wreckage was raised on 21 July 2022. Fuel system was continuous; fuel tanks contained fuel-seawater mixture. Estimated remaining fuel at engine shutdown was about 65 litres. Airframe and engine examinations revealed no anomalies. Magnetos and carburettor were removed for further tests.
Carburettor and Magneto Tests
The carburettor, contaminated by seawater, could not be bench-tested. Visual disassembly showed all components in place with nominal settings and no pre-immersion damage. The left magneto was non-functional below 1,500 rpm; the right below 2,000 rpm. The left magneto had a rotor gear tooth offset, making it inoperative below 1,500 rpm but not affecting operation above. Corrosion and oxidation were present but could not be distinguished from immersion effects. After cleaning and adjustment, both magnetos tested nominally. The observed magneto defects did not explain the engine speed drops or shutdown.
Investigation Conclusion
The investigation determined that the cause of the engine misfires and subsequent shutdown could not be identified.
Additional Information
The maximum lift-to-drag ratio of the Cessna 152 is 10 without flaps at 60 kt. With an engine failure at 3,000 ft, the aircraft can cover about 5 NM without wind.