Circumstances
The accident occurred on 5 November 1967 at approximately 1225 local time at the Aéroport de La Chaux-de-Fonds (Les Eplatures). The aircraft, a Piper J3C registered as HB-OGV, was operated by the Société d’aviation de la Gruyères, based in Bulle.
Aircraft and Pilot Information
The pilot, born in 1938, held a student pilot certificate issued on 4 August 1967, valid until 26 July 1969. Flight training began on 25 July 1967 at Gruyères aerodrome. Total flight experience amounted to 34 hours and 48 minutes, with 267 landings, all on the accident aircraft. Of these, 14 hours and 51 minutes (94 landings) were solo. The pilot completed basic training by the end of September 1967. After an unsuccessful first attempt on 7 October, the pilot passed the private pilot license examination on 25 October, but the license had not yet been issued at the time of the accident. No evidence suggested the pilot was unfit to fly that day.
The aircraft was a high-wing, strut-braced monoplane with a tandem two-seat configuration, fixed landing gear, and a tailwheel. It was powered by a Rolls Royce C90-12F engine (90 hp). The maximum takeoff weight was 580 kg; at the time of the accident, weight was approximately 475 kg. The center of gravity was within prescribed limits. The airframe and engine each had 178 hours since the last major overhaul. Examination of the wreckage revealed no evidence suggesting the aircraft was not airworthy at the time of the accident.
Meteorological Conditions
At La Chaux-de-Fonds at the time of the accident, the sky was 6/8 covered at 2000 m. According to the Swiss Meteorological Institute (ISM), wind was gusting from the west-southwest at 20–30 knots. QNH was 996 mb, temperature at ground level was +4°C, and relative humidity was 80%. The aviation forecast issued by the Zurich-Kloten meteorological center, valid from 0600 to 1200 hours, indicated a cold front reaching western Switzerland, with very cloudy to overcast conditions, showers, and a snow level around 1000 m. Wind at 500 m was southwest 12–18 knots; at 1500 m, 240°/25 knots; and at 3000 m, 240°/50 knots. Moderate to severe turbulence was forecast.
Accident Narrative
On the morning of 5 November 1967, the pilot, wishing to make a pleasure flight to La Chaux-de-Fonds, telephoned the Les Eplatures airport from Gruyères to inquire about local weather. Receiving a favorable response—"clear sky and wind 20 km/h along the runway axis"—the pilot decided to proceed and took off at 1030 local time in the Piper HB-OGV. The pilot, flying solo and visiting the Jura region for the first time by aircraft, landed at Les Eplatures without incident at 1109 hours. After landing, the pilot went to the control office to report arrival and noted that the wind speed shown on the anemometer had doubled since the telephone call.
Approximately one hour later, the pilot decided to return to Gruyères and returned to the control office to report departure and file a flight notification form. Consulting the anemometer again, the pilot found the wind direction and strength unchanged since arrival. The pilot then went to the aircraft, boarded, started and warmed the engine, and taxied to the threshold of runway 24. At 1225 hours, the pilot lined up into the wind and gradually applied full power while holding the elevator control full aft. After rolling only 2 to 3 meters, the aircraft was lifted by a gust and became airborne in a three-point attitude. It climbed a few meters while pitching up increasingly, then stalled and dropped onto the left wing. The aircraft struck the ground successively with the left wingtip, nose, landing gear, and right wing before coming to rest in the same direction as takeoff, approximately 35 m from the start of the runway and about 50 m left of the centerline.
Damage
The pilot sustained minor head injuries. The aircraft was damaged to 75% of its value. No ground damage occurred.
Discussion
The pilot, who had not consulted the aviation forecast issued earlier that morning, based the flight on the favorable local conditions at Gruyères and La Chaux-de-Fonds at departure. Although conditions had deteriorated significantly by the time the pilot considered returning, the accident was primarily attributed to an error in the use of flight controls during the initial takeoff phase. By holding the elevator control aft while applying power, the pilot did not account for the relative wind already affecting the wings as the aircraft began to move. According to meteorological data, wind speed was near the stall speed for the wing incidence at the three-point attitude. Consequently, a simple gust caused the aircraft to lift off after only a few meters. With the elevator held aft, the aircraft pitched up abruptly, leading to airflow separation over the wings and loss of control.
Conclusion
The direct cause of the accident was an erroneous use of the elevator control during takeoff in strong headwind.