History of the Flight
On 24 February 2021, a Cessna F177RG, registered F-GAAC, departed from Amboise Dierre aerodrome at 14:06 for a return flight to its home base at Étampes Mondésir. The pilot and a passenger were on board. The flight took off after a stopover of approximately one hour and thirty minutes. Five minutes after takeoff, the aircraft reached a maximum altitude of 1,600 ft QNH (height of 1,420 ft). The pilot then descended, flying over Amboise chateau at a height of 650 ft, the lowest point of the path. He followed the Loire River at a reduced speed of around 115 kt, keeping the river on his right.
At 14:16, at a height of 700 ft, the pilot detected engine spluttering. He began troubleshooting, but his actions had no effect, and the engine gradually lost power. Losing altitude and realizing no other option, the pilot directed the aircraft toward an area ahead for an emergency landing. He hesitated between two fields, choosing the shorter field with the clearest approach. He extended the landing gear and flaps and landed with a light tailwind component.
The aircraft contacted the ground without incident, but despite braking, it continued into a ploughed field. After a few meters, the nose wheel collapsed due to rapid deceleration from the change in soil. The pilot struck the sunshield and suffered a superficial forehead injury. The passenger was unharmed.
Site and Aircraft Information
The aircraft came to rest in the middle of a field with zero slope and a clear approach oriented roughly 055°, between a railway track and two roads. The nose gear had ruptured, and one propeller blade was bent; no other damage was found. An estimated 80 to 100 liters of fuel remained in the tanks. The fuel system integrity up to the engine and the operation of the electric fuel pump were checked and found normal.
Additional Examinations
The engine was removed and bench-tested at the École Nationale de l'Aviation Civile (ENAC). The test revealed no malfunctions. However, during removal, the workshop reported that the mechanical fuel pump's supply line was slightly loose. The manufacturer stated that such loosening could introduce air bubbles, potentially causing power loss, but would not result in a complete engine shutdown. No engine test with a loose line was performed for safety reasons. No other factors explaining the power loss were found.
Fuel quality analysis confirmed the fuel was AVGAS 100LL, uncontaminated, and met specifications. It could not explain the power loss.
Aircraft and Pilot Information
The Cessna 177RG is a single-engine, four-seat, high-wing aircraft with retractable gear and a 200 hp Lycoming engine. It was equipped with a transponder and emergency locator transmitter. The flight manual specifies shoulder harnesses; the pilot stated he did not use them, as he considered them only useful in turbulence or mountains.
The 66-year-old pilot held a valid Private Pilot License with SEP rating, with 321 total hours (276 as pilot-in-command, 180 on F-GAAC). He had flown 21 hours in the last six months, all on F-GAAC. He also had gliding experience, including six or seven off-airport landings.
Meteorological Information
Weather conditions at nearby aerodromes: Châteaudun (65 km away) and Tours (33 km away) reported wind from 170° and 180° at 11 kt, respectively, with CAVOK, temperature 19°C, dew point 9°C, QNH 1027 hPa. At flight altitude, a southerly wind of up to 15 kt was reported by Météo-France.
Statements
The pilot stated that the previous day he experienced engine spluttering on approach but landed normally. The maintenance workshop found nothing unusual. He drained the tanks on the morning of the accident and found no water. During the flight, he intended to climb to 2,500 ft but did not before the power loss. He performed quick troubleshooting (electric pump on, fuel selector to LEFT) with no effect. He did not unlatch doors, transmit a radio message, squawk 7700, or activate the ELT due to focus on landing.
The passenger felt the thrust loss, saw the pilot troubleshooting, and was informed of the landing. He considered the chosen field suitable and was not afraid. He was secured only by lap belt and was unaware of shoulder harnesses. He sustained no injuries.
Conclusions
The BEA concluded that the engine lost power for a reason that could not be determined definitively. The investigation did not assign blame or liability.