What happened
On May 13, 2016, during a scheduled maintenance procedure at the SOT Warsaw-Babice airfield, an inspection was conducted on an EC135 P2+ helicopter. The maintenance task involved examining the control elements of the fenestron blade pitch. During this inspection, technicians identified traces of corrosion on all sets of the metal spring bands. These specific components serve as the attachment mechanism for the tail rotor blades to the rotating fenestron hub body within the longitudinal plane.
The investigation
The investigation focused on the condition of the metal spring bands found during the routine service. The PKBWL established that the corrosion was present across all sets of the identified hardware. As a result of these findings, all affected spring band sets were classified for immediate replacement with new components. The aircraft remained grounded under scheduled maintenance following the discovery.
Findings
- The presence of corrosion on the metal spring bands was likely caused by the operation of the helicopter in variable environmental conditions.
- No injuries or fatalities were reported as the event was a maintenance-related incident rather than an in-flight occurrence.