What happened
On July 31, 2017, a mechanic discovered various structural damages to an SZD 9-bis Bocian glider at the Warsaw Babice (EPBC) aerodrome. The damage was noted while the aircraft was being moved out of a hangar. The identified issues included a broken vertical reinforcement of the second rib on the right wing, cracks in the internal fuselage skin, and damage to the left wingtip mounting and skin. Additionally, damage was found to the fuselage structure beneath the horizontal stabilizer and a crack was identified on the lower rudder suspension bracket.
These damages had not been previously recorded in the aircraft's technical logbook (PDT). Following the discovery, the glider was withdrawn from service and sent to a certified organization for repairs.
The investigation
The investigation, conducted by the operator, attempted to determine how the damage occurred. Review of security camera footage covering the area in front of the hangar was inconclusive, as the camera did not capture the specific movement of gliders in and out of the hangar itself. Interviews with mechanics and flight managers were also conducted, but no witnesses were available to identify the moment the damage occurred. Because the technical logbook showed no prior entries for defects, it was concluded that the aircraft had been returned in functional condition after its last flight.
Findings
- The specific cause of the structural damage could not be determined.
- There was a lack of continuous monitoring coverage for the hangar area.
- The investigation noted a failure by the operator to identify the safety risk posed by the failure of personnel to report the incident at the time it occurred.
Safety action
- Pilots of the user's aero club were informed of the incident during standardization training.
- The subject of the incident will be discussed at a Flight Safety Conference.
- New monitoring equipment, including a thermal imaging camera, will be installed in the glider hangar to prevent similar unrecorded incidents in the future.