Accident Overview
On December 6, 2014, at approximately 16:00 local time, a Cessna 172 (registration F-HCPC) operated by an aero club was on a local flight with a pilot and three passengers. During climb to about 2,000 ft, the FADEC red warning lights illuminated and engine power gradually decreased. The pilot attempted to restart the engine without success. He informed the AFIS agent at Cholet-le-Pontreau aerodrome that he was returning to land, but soon realized it would not be possible. At about 500 ft, he selected a field for a forced landing. On short final, the pilot avoided treetops on the path. Upon landing, the aircraft overturned and came to rest inverted. The pilot and passengers evacuated quickly without difficulty.
Pilot Information
The pilot, aged 17, had obtained his PPL(A) three months prior, with about 50 total flight hours on Cessna 152s. He had recently been checked out on the Cessna 172, with two engine failure exercises during that checkout. This was his fourth flight on the Cessna 172. Both fuel tanks were three-quarters full, sufficient for 30-45 minutes. Weather conditions were very favorable. The pilot flew with his parents in the rear seats and a friend in the right front seat. The pilot stated he focused on the chosen field and did not monitor airspeed. On short final, thinking he would hit treetops, he pulled back on the yoke, triggering the stall warning. He did not recall hitting trees. After landing, he ensured all occupants were safe, then returned to the aircraft to turn off the master switch and set the fuel selector to Right. He did not remember the initial fuel selector position. The pilot indicated he was not familiar with the FADEC system and only applied the restart procedures from the checklist. The pilot who flew the previous flight had placed the fuel selector to OFF after that flight.
Aircraft and Engine Details
The Cessna 172 was equipped with a Thielert TAE 125-02-99 diesel engine. The fuel selector has three positions: Left, OFF, and Right. The fuel system includes a reserve supply upstream of the selector, providing about seven minutes of engine operation with the selector in OFF.
Investigation Findings
Examination of the engine revealed no malfunctions; the fuel circuit was continuous from tanks to engine, no contamination was found, and no damage explained the power loss. The engine was tested on a bench and operated nominally. The investigation could not determine the fuel selector position before the accident, but the pilot's action to move it to Right after the accident was noted.
Probable Cause
The investigation suggested that the total loss of engine power likely resulted from fuel starvation due to the fuel selector being in the OFF position, which was not verified before takeoff.