What happened
On September 30, 2018, a solo training flight ended in a fatal accident near the Essen/Mühlheim airfield in Germany. The pilot, a 21-year-old student, was operating an Alexander Schleicher ASK 18 glider. Following three successful flights earlier in the afternoon, the pilot commenced a fourth flight. During the final approach, the pilot attempted to execute a sideslip (slip) maneuver.
Witnesses observed the glider enter an uncontrolled state at a low altitude. Specifically, the aircraft appeared to bank sharply to the right while exiting the sideslip, subsequently entering a spin that caused it to disappear behind nearby trees. The glider struck a parking lot approximately 400 meters from the airfield. The impact resulted in the death of the pilot and the total destruction of the aircraft.
The investigation
The BFU investigation focused on the pilot's training records, the aircraft's airworthiness, and the sequence of the maneuver. The investigation found that the ASK 18 was properly registered and maintained, with no technical defects contributing to the crash. Meteorological conditions were favorable, with clear visibility (CAVOK) and light winds.
Investigators examined the student's training history, noting that while the pilot had completed various training stages, the documentation in the training log was inconsistent and incomplete. The investigation also reviewed the oversight provided by the flight instructors and the club's safety management practices.
Findings
The primary cause of the accident was a loss of control during the exit from a sideslip, which led to an upset condition that the pilot could not recover from due to the insufficient altitude.
Contributing factors included:
- The decision to authorize a solo flight on a different aircraft type after a period of inactivity without a prior supervised check flight.
- Inadequate training oversight, as the student's progress was not consistently documented by the various instructors involved.
- The high-risk nature of performing slip maneuvers at low altitudes (the training syllabus specified ending such maneuvers at approximately 50 meters), which leaves minimal margin for error.
- Inconsistent documentation in the training log, which prevented a clear understanding of the pilot's actual proficiency levels.