What happened
On July 29, 1986, a female student pilot attempted her first solo flight in a Cessna F152 HB-CNS at Grenchen Airport. The aircraft was operated by the Flugsportgruppe Grenchen. Prior to this event, the student had completed her initial training with Instructor X and a brief period with Instructor Y between late June and early July 1986.
On the day of the accident, the student had just completed three dual-control landings with Instructor X, all of which were described as perfect. She was cleared for solo operations. The takeoff from Runway 25, climb-out, and entry into the downwind leg proceeded normally. However, when she reported on the radio at the end of the downwind leg, there were communication difficulties; she failed to answer a query from the control tower.
As she turned onto the base leg, two other aircraft were present: one on final approach and another further out on the approach path. The student became distracted by these traffic conflicts. While maneuvering for final approach at approximately 1,900 feet QNH (500 feet above ground), she spotted one aircraft taxiing off the runway and the other shortly before landing. Her focus shifted entirely to the traffic situation, leading her to consider a go-around but ultimately causing her to neglect basic flight control.
She reduced power significantly, causing the aircraft to descend rapidly below the normal glide path. It was not until she was approximately 6 meters (20 feet) above the ground and 150 meters from the runway threshold that she realized she was too low. She applied full power abruptly. Although the engine responded normally, the aircraft had already descended too far. It struck a cornfield near the runway entrance at a shallow angle and came to a stop with a nose-high attitude due to nose gear collapse.
The pilot sustained head injuries. The aircraft suffered substantial damage. No fire occurred. The student was not wearing shoulder harnesses during the flight, nor had she done so during previous training flights with Instructor X.
The investigation
The Swiss Transportation Safety Investigation Board (SUST) examined the circumstances surrounding the accident. Key findings included:
- The student pilot held the necessary qualifications for her first solo flight.
- The aircraft was airworthy, with weight and balance within limits. It had recently passed its 100-hour inspection.
- Weather conditions were clear with good visibility (25 km), scattered clouds at 4,000 feet, and light winds from the southwest.
- The student had a total of 18 hours of flight time, all in the accident aircraft type. During the last 90 days, she had logged 15.52 hours.
- Instructor Y, who had trained her previously, noted that she struggled with stabilizing approaches and coordinating pitch and power with one hand. He recommended approximately 30 more flights before soloing, a recommendation that was not followed by Instructor X.
- There was a lack of coordination between the two instructors regarding the student's readiness for solo flight.
Findings
The accident was caused by an approach below the normal glide path and an inadvertent loss of elevator control at low altitude. Contributing factors included:
- Insufficient training level: The student was not adequately prepared for her first solo flight, lacking experience in stabilizing approaches and managing power/pitch coordination.
- Distraction: The presence of other aircraft on approach distracted the pilot, leading to a loss of situational awareness regarding her own altitude and airspeed.
- Poor instructor coordination: There was inadequate communication between Instructor X and Instructor Y regarding the student's progress. Instructor X may have authorized the solo flight based solely on total flight hours rather than specific competency assessments recommended by Instructor Y.
- Improper use of safety equipment: The pilot was not wearing shoulder harnesses, which increased the risk of injury to her head during the impact.
Safety action
The investigation highlighted critical issues in flight training coordination and the assessment of student readiness for solo operations. The lack of communication between instructors regarding a student's specific skill deficits (such as stabilizing approaches) allowed an underprepared pilot to attempt a solo flight. This case underscores the necessity for rigorous handover protocols between flight instructors and strict adherence to safety equipment usage during all phases of training.