Incident Overview
On May 13, 2016, during planned workshop maintenance at SOT Warszawa-Babice, a helicopter EC 135 P2+ was undergoing inspection of the fenestron blade pitch control components. According to work order WO/HXR/019/2016 and task MSM/04-25/61/64-3, technicians observed corrosion marks on all sets of metal flex-torsion strips. These strips serve as attachments for the tail rotor blades to the rotating fenestron hub body in the longitudinal plane.
Maintenance Action
All sets of flex-torsion strips were qualified for replacement with new ones. The helicopter remained in scheduled maintenance at the time of reporting.
Probable Cause
The probable cause of the corrosion marks on the metal flex-torsion strip sets was operation of the helicopter in varying environmental conditions.
Preventive Measures
The operator briefed the maintenance personnel of the facility about the incident.
Safety Recommendations
The Polish State Commission for Aircraft Accident Investigation (PKBWL) did not issue any safety recommendations upon completion of the investigation.