Incident Overview
On 2 April 2017, during a pre-flight inspection at Rudniki airfield (designation EPRU), the instructor-pilot of a SZD-50-3 Puchacz glider, registered as SP-3288 and operated by Aeroklub Częstochowski, noticed excessive play and a knocking sound when moving the control stick in the second cockpit. The discovery prompted a detailed examination.
Inspection Findings
After removing the seat pan, deformation of the control stick component was observed. The damage was recorded in the glider's technical log (entry no. 2017/3288/15). The glider was subsequently transported to WIRKK Serwis Szybowcowy Jerzy Biskup for further assessment.
During the workshop inspection, investigators found:
- Twisting and deformation of the upper control tube.
- A pulled-out bushing in the welded joint between the bushing and the upper control tube, at the attachment point of the rear control stick.
- A local crack on the welded joint connecting the bushing to the lower control tube.
Subsequent Examination
On 25 May 2017, a joint inspection of the damaged component was conducted with representatives from SZD Allstar PZL Glider, WIRKK Serwis Szybowcowy Jerzy Biskup, and the Polish State Commission on Aircraft Accident Investigation (PKBWL). The examination concluded:
- The damage resulted from a significant force applied to the control stick when it was in the "pulled back and deflected to the right" position.
- The damage did not compromise flight safety; the glider remained fully controllable throughout.
- The occurrence was isolated, with no previous reports of such damage on this glider type.
Given that the affected component is subject to inspection during 1000-hour checks and routine maintenance (as part of control system continuity checks), the participants deemed no additional inspections necessary for other gliders of the same type.
Cause of the Incident
The incident was caused by the application of a significant force to the control stick under unknown circumstances, with the stick positioned "pulled back and deflected to the right." This force led to the deformation of the upper control tube and the pulling out of the bushing at the welded joint.
Subsequent Actions
No preventive actions were taken by the investigating entity. The commission issued no safety recommendations and provided no commentary.