What happened
On August 21, 2009, a Scheibe SF 25 C motor glider departed from Juist airfield (EDWJ) for a training flight. The flight was being conducted by a flight instructor accompanied by a 17-year-old student participating in a "Pinch-Hitter" training course.
During the approach to grass runway 26 at approximately 17:06 local time, the instructor throttled the engine to idle to demonstrate the effect of the spoilers. During this maneuver, the aircraft lost altitude. The instructor attempted to retract the spoilers and increase engine power to recover; however, no increase in power was achieved. Consequently, the left wing of the aircraft struck a dune approximately 250 meters before the runway threshold. The impact caused the left wing to break, and the aircraft subsequently struck the ground, resulting in the collapse of the main landing gear and the separation of the left wing.
The investigation
The BFU investigation examined the aircraft, the flight conditions, and the sequence of events. The investigation confirmed that the accident occurred in visual meteorological conditions (VMC) with winds between 10 and 15 knots. The aircraft, which had a total time in service of 1,771 hours, had undergone its 100-hour maintenance inspection recently, in July 2009.
Investigators examined the wreckage and found no technical defects in the aircraft. While a FLARM flight recorder was on board, the BFU was unable to retrieve flight path data because the external SD card was missing at the time of the investigation.
Findings
- The primary cause of the accident was the loss of engine power following the reduction of thrust to idle during the spoiler demonstration.
- The aircraft struck a dune approximately five meters in height, leading to the structural failure of the left wing and the landing gear.
- There were no technical malfunctions identified in the Scheibe SF 25 C prior to the impact.
- The accident resulted in one person slightly injured and heavy damage to the aircraft.