What happened
On May 24, 2010, a winch-launched recreational flight departed from Elz Airfield. The flight, involving a pilot and one passenger, began without incident despite a crosswind from the right. At an altitude of approximately 50 meters, the pilot requested a reduction in towing speed via radio. Shortly thereafter, at an altitude between 80 and 100 meters, the towline's weak link failed.
Following the break, the pilot initially maintained a straight course, increasing airspeed by pushing the controls forward. The pilot then executed a turn into the wind, followed by a left-hand turn to return to the airfield for a landing on runway 08. During this maneuver, the aircraft overshot the approach path. Witnesses observed the pilot significantly increasing the bank angle to intercept the final approach. This aggressive maneuver caused the airspeed to drop below the minimum required threshold, leading to a stall of the left wing. The Scheibe SF 34 subsequently entered a steep, near-vertical descent into a wooded slope just south of the runway threshold. The impact was high-energy, with the aircraft striking the ground at a longitudinal pitch of 70 to 80 degrees.
The investigation
The BFU examined the wreckage and the winch equipment. The investigation confirmed that all control linkages were intact and no technical defects were found in the aircraft or the winch system. The investigation also reviewed the pilot's credentials, noting that while the pilot held a valid PPL(C) with appropriate ratings, his total flight experience was limited to approximately 80 hours, with only 12 hours logged in this specific aircraft type.
Findings
- The primary cause of the accident was that the minimum flying speed was undershot during the recovery turn, resulting in a wing stall and a spin-like motion.
- The pilot failed to successfully recover from the stall due to the insufficient altitude available.
- The pilot misjudged the prevailing wind conditions and the available altitude for maneuvering.
- The weak link used in the towline (rated at 750 daN) was stronger than the standard blue weak link (600 daN) specified in the flight manual.
- The impact resulted in one fatality (the pilot) and one serious injury (the passenger).