What happened
On May 26, 2002, a student pilot was conducting a solo 50-km triangular cross-country flight near Stüde-Bernsteinsee, Germany, to verify flight proficiency for a private pilot license. After successfully utilizing thermals and reaching an altitude of approximately 1,080 meters, the flight took an unusual turn near the first waypoint.
An eyewitness in another glider observed the Schleicher ASK 23 exiting a thermal field at a very high speed. The aircraft exhibited extreme wing oscillations, indicating it was subjected to intense positive and negative loads while maintaining a steep flight path. Barograph data confirmed an abrupt loss of 200 meters in altitude, followed by erratic fluctuations and high rates of climb and descent.
At an altitude of approximately 100 to 200 meters, the cockpit canopy was jettisoned via the emergency release mechanism. The aircraft completed two left-hand circles before the pilot attempted to exit the glider using a manual parachute. However, the deployment was incomplete, and the pilot struck the ground at low altitude, resulting in fatal injuries.
The glider continued on an uncontrolled path, eventually coming to rest upside down approximately two meters above the ground, wedged against a garage and conservatory roof. The impact caused significant damage to the aircraft, including a broken right wing.
The investigation
The BFU investigation examined the aircraft, flight data, and witness testimonies. The Schleering ASK 23 was found to be in excellent maintenance condition, with no technical defects identified that could explain the flight profile. The investigation also reviewed the pilot's medical status, finding no evidence of impairment or alcohol consumption.
Investigators analyzed the barograph, which recorded the extreme vertical accelerations and the unusual flight path. They also examined the parachute, noting that while the release handle had been pulled, the low altitude prevented the canopy from fully inflating. The investigation also noted that the radio battery was missing from its compartment and could not be located at the crash site.
Findings
- The pilot was capable of action during the final flight phase, as evidenced by the manual jettisoning of the canopy and the activation of the parachute.
- The altitude at the time of parachute deployment was insufficient for the emergency device to fully deploy and inflate.
- The cause of the highly unusual and extreme flight maneuvers, characterized by intense vertical loads and rapid altitude changes, could not be determined.
- There were no technical failures found in the aircraft's airworthiness or mechanical systems that would account for the loss of control.