What happened
On July 27, 1967, a student pilot was conducting a local flight in a Rhönlerche II glider, registration HB-721, at Grenchen Airport. After being released from a tow near Bettlach, the pilot noted a significant loss of lift and decided to return to the airfield.
As the pilot approached the airport, they observed a Piper aircraft on final approach. To avoid a perceived collision, the student pilot abandoned the planned approach to runway 07 and began a series of turns. The pilot initially attempted to land with a tailwind on the glider runway, but upon noticing a tow plane preparing for takeoff, changed course again. While attempting a final turn to land perpendicular to the runway, the aircraft's airspeed dropped critically. At an altitude of approximately 6 to 7 meters, the glider stalled, causing the right wing to drop and the aircraft to strike the ground.
The investigation
The investigation was based on written reports from the pilot and flight instructor, as well as an interview with the student pilot. Because the damage to the aircraft had been repaired prior to the investigation, the inquiry focused on analyzing the flight sequence and the pilot's decision-making process. The investigation also reviewed the pilot's training progress and flight experience, noting that the student was in the midst of a flight training course.
Findings
- The student pilot's initial decision to return to the airfield due to a lack of thermals was correct.
- The pilot was distracted by the presence of a Piper aircraft, failing to realize that the other aircraft was landing on a different runway at a much lower altitude.
- The pilot failed to observe the right-of-way rules that would have allowed for a standard approach to runway 07.
- The decision to attempt a tailwind landing was unnecessary and driven by recent training exercises involving cable-break simulations.
- The pilot initiated a turn at an insufficient airspeed and altitude, leading to a loss of lift and the subsequent stall.
- The pilot's ability to act calmly and deliberately was compromised by the complexity of the maneuvers and the presence of other traffic.