What happened
On February 22, 2016, an EC 135 P2+ helicopter was performing a flight departing from Końskie. During the second minute of the flight, the pilot observed that the needle on the three-pointer analog rotor speed indicator began to fluctuate before eventually coming to a complete stop.
Upon recognizing the instrument failure, the pilot elected to continue the flight and proceed to the base located at EPKA airport. The aircraft landed safely without further incident.
The investigation
The investigation focused on the mechanical cause of the instrument malfunction. Following the event, the helicopter was removed from flight service for inspection. A mechanic identified a faulty main rotor speed sensor. In accordance with the Aircraft Maintenance Manual (AMM 62-41-00), the sensor was replaced with a new unit. Subsequent testing of the main rotor speed indication system was performed, which confirmed that the system was functioning correctly. Following these repairs, the aircraft was returned to service.
Findings
- The primary cause of the incident was the malfunction of the main rotor speed sensor.