Synopsis
On Sunday, 29 May 1977, at 10:30 UTC, an AS 202/15 Bravo aircraft, registration HB-HFC, crashed near the village of Collonges in the commune of Péron, France. The aircraft was destroyed and all three occupants sustained fatal injuries.
Flight History
The pilot, a 52-year-old Swiss private pilot, departed from Geneva-Cointrin Airport at 10:16 UTC with two passengers for a sightseeing flight over the Jura Mountains. The aircraft was rented from the Motor Fluggruppe Genf of the Aero-Club of Switzerland. After leaving the Cointrin control frequency at 10:19, the aircraft flew southwest, passing north of Logras, then turned right to align with the ridge of the Jura Mountains heading northeast towards the Reculet. Near the village of Péron, the pilot turned right towards the valley to overfly a friend's house at a location called Sous-le-Rutet. The pilot descended with reduced engine power. At low altitude, he executed a turn of more than 180° to observe the house, bringing the aircraft facing a higher ridge with an average elevation of 1100 m, which was above the aircraft's altitude. According to a witness who could read the registration, the aircraft was flying very low over the treetops. As the pilot began a right turn towards lower terrain and applied power to climb, the aircraft abruptly entered a left autorotation and crashed vertically after one and a half turns of a spin. The aircraft disintegrated upon impact with trees and the ground.
Injuries and Damage
The three occupants—the pilot and two passengers—were fatally injured. The aircraft was totally destroyed. Impact damage included severed branches and damaged fir trees.
Aircraft Information
The aircraft was an AS 202/15 Bravo, serial number 022, manufactured by Flug- und Fahrzeugwerke AG. It was registered to the Aero-Club of Switzerland, Geneva section, and had a valid certificate of airworthiness for VFR day operations. The total airframe time was 356.69 hours. The engine was a Lycoming O-320-E2A, producing 150 hp, with a total operating time of 356.69 hours. The fixed-pitch metal propeller showed evidence of rotation and power at impact. The aircraft's estimated takeoff weight was 975 kg, slightly below the maximum of 1000 kg, and the center of gravity was within limits.
Pilot Information
The pilot held a private pilot license valid until 6 October 1977. He had a total of 399 flight hours, with 13.21 hours in the previous 12 months and 2.25 hours in the previous 3 months. He had only 2.48 hours on the AS 202/15 type, and his most recent flight on that type, lasting 0.21 hours, was 18 months prior. The pilot had previous experience in gliding and aerobatics, but the extent was not specified. The club's chief pilot considered him to have good experience.
Meteorological Conditions
The METAR for Geneva at 10:20 UTC reported wind from 060° at 7 knots, visibility greater than 10 km, 1/8 cumulus at 1800 m, temperature 20°C, dew point 6°C, and QNH 1018 hPa. The general weather situation indicated good visibility, variable winds below 5 knots, and the zero-degree isotherm at 2300 m. A pilot of an air police aircraft reported significant downdrafts along the relief, and ground observers noted a downdraft at the Rutey location that directed smoke towards the plain. The temperature at Geneva was 8°C above standard. At the aircraft's altitude of about 1500 m during the ridge flight, the actual temperature was estimated to be either around standard (5°C) or between 13°C and 14°C, depending on the calculation method. Carburetor icing was considered unlikely due to the temperatures.
Probable Cause
The accident was the consequence of the aircraft impacting the mountain slope after a loss of speed. The probable cause is to be found in the flight maneuvers carried out at dangerously low altitude.