What happened
On September 8, 2002, a PZL-Bielsko SZD-51-1 glider, registration PH-933, departed from Lemelerveld airfield for a local solo training session. The pilot intended to practice steep turns within a designated training area located northeast of the airfield. After reaching an altitude of approximately 400 meters, the pilot began performing a series of left and right turns.
During these maneuvers, the aircraft descended to an altitude of roughly 300 meters and entered an uncontrolled, spinning flight pattern. The pilot attempted to use the rudder to recover the aircraft, but the glider remained in an unstable attitude, rotating around its longitudinal axis. An observer on the ground noted that the aircraft's movement resembled a falling leaf. As the aircraft approached the ground, the nose pitched down and the descent rate increased. Although the pilot managed to level the wings slightly just before impact, the heavy damage to the aircraft was unavoidable. The pilot sustained two broken vertebrae during the crash.
The investigation
The investigation focused on the pilot's training status and the aircraft's stability. At the time of the accident, the pilot was flying under the responsibility of an instructor but did not possess a formal certificate of competence. While the pilot had been briefed twice earlier that day, they had failed to report to the instructor for a specific briefing prior to this particular flight. Although weather conditions were stable, the investigation noted that the intended maneuvers should have been discussed with the instructor.
Furthermore, the investigation examined the aircraft's center of gravity. The pilot's weight, approximately 60 to 62 kg, placed the center of gravity near the rear limit of the allowable range (the pilot's weight must be between 55 kg and 110 kg). This rearward weight distribution inherently reduces the aircraft's stability around the lateral axis.
Findings
- The aircraft entered an unstable flight state that the pilot had not previously practiced with an instructor.
- The rearward center of gravity caused by the pilot's low weight contributed to decreased longitudinal stability.
- The pilot failed to conduct a pre-flight briefing with the instructor regarding the specific training objectives for the flight.