What happened
On 29 October 2001, a Cessna F177RG, registration G-AYPI, departed Guernsey for a planned day trip to Dinard. After completing standard pre-flight inspections and receiving clearance to fly below 3000 feet, the pilot leveled the aircraft at 2000 feet. Approximately 12 nautical miles from Guernsey, the engine began to backfire and developed a rough running condition.
As the pilot attempted to contact Jersey Approach, the engine performance deteriorated further, making it impossible to maintain altitude. Having already turned back toward Guernsey Airport, the pilot declared a MAYDAY and prepared for an emergency ditching. The pilot released the door catches, secured a life jacket, and positioned the life raft.
The aircraft struck the sea surface in a level attitude with flaps extended to 30°. The impact caused the aircraft to stop abruptly and pitch forward, resulting in the left wing dipping into the water. As the cabin flooded, the pilot was initially unable to open the doors but eventually managed to kick the door open and escape the submerged aircraft. The pilot remained in the water for approximately 15 minutes before being assisted by a local fisherman and subsequently rescued by emergency services. The pilot sustained minor injuries.
The investigation
Investigators reviewed the aircraft's maintenance records and engine log books. The records indicated that regular maintenance had been performed, including a 50-hour check in August 2001. However, the engine logs revealed two separate instances of high oil consumption earlier that year.
In February 2001, repairs were made to the number four cylinder after a snapped piston ring and stuck oil control ring were discovered. In July 2001, the number three cylinder was removed, honed, and cleaned due to carbon contamination and compression issues. The wreckage of the aircraft was not recovered.