1970 Piper J3C HB-OFV accident at Grenchen Airport

Investigation and aircraft details The Swiss Federal Aircraft Accident Investigation Commission opened an investigation on 28 May 1970 into the accident involving Piper J3C HB-OFV at Grenchen Airport. The aircraft was owned and operated by Regionalflugplatz JuraGrenchen AG, Grenchen. It was powered by a Continental A 65 engine rated at 65 hp and fitted with a Sensenich 72 C 42 wooden propeller. The aircraft had 5,120.22 flight hours and 8,059 landings, and its last 1,000-hour inspection was completed on 6 May 1970 at 5,103 hours. ## Personnel and conditions The pilot was a student pilot born in 1922, holding a student pilot certificate issued on 4 May 1970 and valid until 15 March 1971. Training began in the second half of April 1970 in Grenchen. By the time of the accident, the student had 13 hours of dual instruction with 85 landings and 20 minutes of solo flight with 3 landings. The flight instructor, born in 1931, held a private pilot license and a motor flight instructor qualification, with 1,742 hours and 4,956 landings. During the accident, the instructor was on the runway. Grenchen Airport is at 430 m above sea level and has three grass runways oriented 07/25. Runway 07 was in use; it was 530 m long and 30 m wide, with some unevenness. Weather conditions included a bise situation, wind from 100° at 8 knots, visibility of 20 km, and the sun at an elevation of 025° and azimuth of 275°. ## Flight sequence and accident On the morning of 28 May 1970, the student completed six dual flights and the first two solo flights. In the afternoon, at 1713 local time, the student made another dual control flight and then a solo flight, which was unremarkable. At 1732, the student started the fourth solo flight. After takeoff roll, the aircraft, with its tail in a horizontal position, veered slightly to the right. The student corrected with left rudder, after which the still-slow aircraft lifted off and flew left-banked 45° to the left over the runway edge. Outside the runway, the left wingtip touched the ground. The resulting braking caused the aircraft to stall; the propeller struck the ground, and the aircraft came to rest upside down. ## Damage and findings The pilot was uninjured. The aircraft was damaged, with damage estimated at about 40 percent of its value. There were no third-party damages. The investigation concluded that the student overcorrected the slight right veer with the left rudder. At the same time or immediately after the correction, an unintended lift-off occurred, possibly caused by a ground unevenness. The inexperienced and older student pilot was not able to handle the situation and did not take steps to return the aircraft to a normal flight attitude. The accident was attributed to the inappropriate correction during the veer and the student's subsequent passive behavior.