Accident Overview
On October 19, 1969, at approximately 11:42 local time, a Piper J3C aircraft registered as HB-OAK was involved in an accident on the grass runway 23 at Geneva-Cointrin Airport. The aircraft was being used for a training flight with an instructor and a student pilot aboard. Both occupants were uninjured, but the aircraft sustained substantial damage and was considered destroyed.
Sequence of Events
The training session aimed to improve the student's circuit work. After an uneventful takeoff and initial pattern, the student extended the downwind leg to give way to an airliner taking off from the main runway. The approach was correct, and the student received a continuous green light signal. However, the aircraft touched down hard about 50 meters past the runway threshold due to excessive speed and insufficient flare, causing it to bounce to an estimated height of 2 to 5 meters.
The instructor took control and applied power to mitigate the pitch oscillation. During the recovery, the left wing suddenly lifted, and the aircraft rolled to the right, reaching a bank angle of about 45 degrees. Despite the instructor's efforts, the aircraft contacted the ground in this oblique attitude. The left landing gear leg broke, and the aircraft slid on its fuselage until it came to a stop in a nose-up position near the taxiway to the aero-club facilities.
Damage
The aircraft suffered damage to the engine mount, the leading edge of the left wing, and the fuselage structure. The left landing gear leg was folded under the fuselage, and the propeller was broken. Neither the instructor nor the student reported any injuries.
Investigation Findings
Post-accident examination revealed no pre-existing mechanical defects in the flight controls or wheel brakes. The stabilizer trim was correct, and weight and center of gravity were within prescribed limits. The instructor held a valid professional pilot license and a provisional instructor permit; the student held a valid student pilot card. The aircraft had valid airworthiness and registration certificates.
The investigation considered two potential contributing factors: an inadvertent elevator input that might have caused a stall and wing drop, and wake turbulence from two jet airliners that had taken off from the main runway approximately 30 to 90 seconds prior. The instructor's reaction to apply power after the bounce was deemed appropriate.
Conclusion
The accident was attributed to a loss of control following a hard landing caused by an incomplete flare and excessive speed, possibly aggravated by wake turbulence from two departing airliners.