What happened
On May 31, 2014, a Schleicher ASW 28-18E glider with a retractable engine departed Agathazell via aero-tow for a cross-country flight. During the flight, the pilot encountered deteriorating thermal conditions, leading to the decision to release water ballast near Biberach. To maintain altitude, the pilot utilized the retractable engine for approximately ten minutes near Leutkirch and for another 15 minutes near the Blender region.
As the pilot was unable to clear the region despite the engine's use, an emergency landing was initiated. After the engine was shut down, the pilot was unable to secure the propeller or retract the engine mechanism. While attempting to fly over a power line to reach a suitable landing field, the aircraft struck the line, causing the glider to crash near Wagenbülar.
The investigation
The BFU investigation focused on the sequence of events leading to the impact and the mechanical state of the aircraft. Investigators examined the wreckage, which was found with the fuselage broken, the wings detached from the fuselage, and the tailplane torn off. The investigation confirmed that the cockpit area sustained only minor damage and that the pilot, who was able to exit the aircraft independently, sustained one serious injury.
Findings
- The primary cause of the accident was the inability to secure the propeller after engine shutdown, which prevented the retractable engine from being stowed.
- The investigation determined that the propeller stopper Bowden cable had slipped out of its guide and was non-functional.
- The collision with the 8.20-meter-high power line mast was the immediate cause of the aircraft's impact with the ground.
- Meteorological conditions at the time were reported as good visibility (CAVOK) with gusty winds between 15 and 20 knots.