Event Overview
On March 13, 2016, at SOT Warszawa-Babice, a scheduled hangar maintenance check after 1000 flight hours was being performed on an EC 135 P2+ helicopter, in accordance with work order WO/HXM/008/2016. The total flight time of the helicopter at the time of detection was 1727 flight hours.
Findings
During the inspection of the fenestron blade pitch control components, as per AMM 64-22-00, while cleaning the flexible bundle to verify its condition, a crack was found in one of the flexible metal strips that attach the tail rotor blade to the rotating fenestron hub body in the longitudinal plane. The set of flexible strips was classified for replacement with a new one. The helicopter remained in scheduled maintenance.
Cause
The probable cause of the crack in the flexible metal strip was fatigue wear during operation.
Safety Recommendations
The Polish State Commission for Aircraft Accident Investigation (PKBWL) did not issue any safety recommendations after the investigation.