What happened
On April 24, 2000, a student pilot was conducting a winch-assisted training flight in an SZD 30 Pirat glider near Friedersdorf. During the pre-flight preparations, the pilot noticed that the airbrake controls felt heavy. This issue was reported to the flight leader, and a maintenance technician inspected the aircraft. During this inspection, various control connections were disconnected and checked, but no abnormalities or foreign objects were found. Following this check, the aircraft was cleared for flight.
During the takeoff roll on runway 12, the student pilot noticed the aircraft was banking heavily to the left. Attempts to correct this using aileron input were unsuccessful, as the controls failed to respond. Ground personnel also observed the lateral deviation and attempted to provide corrective instructions via radio. The pilot decided to continue the winch launch until the maximum release altitude was reached. After releasing from the winch cable, the pilot notified the airfield of the aileron malfunction.
Despite the loss of lateral control, the pilot managed to maintain a stable, shallow circling pattern using the rudder. The pilot chose not to perform an immediate emergency bail-out but instead attempted to land in a nearby meadow. During the approach, the uncorrectable left bank caused the left wing to strike the ground prematurely. The impact caused the glider to spin violently around its vertical axis before crashing into the ground, resulting in the destruction of the aircraft and one minor injury to the pilot.
The investigation
The BFU investigation focused on why the control surfaces failed to respond during the takeoff phase. Investigators examined the aircraft's control mechanisms and the pre-flight maintenance procedures. The investigation confirmed that all gliders in use had undergone standard pre-flight inspections and that these were properly documented. Upon inspecting the wreckage, investigators discovered that the aileron connection within the fuselage had been left disconnected. The retaining pin for this connection was found loose inside the fuselage.
Findings
- The primary cause of the accident was that the aileron control connection remained disconnected following maintenance/inspection work.
- The student pilot's decision to continue the winch launch to release altitude was appropriate given the circumstances.
- The loss of aileron functionality rendered the aircraft unable to correct a lateral bank during the landing approach, leading to the wing strike.