Incident Involving an EC 135 P2+ Helicopter in Płock (SP-HXK)

Incident Overview and Operational Context On October 2, 2018, a helicopter crew from the Płock branch of the Air Medical Service (LPR) conducted a HEMS flight to Trzcianka under order number 364/R18/2018. During the flight, the mission was cancelled. While on approach to land at Płock (EPPL), the aircraft was at an altitude of 80 feet and a speed of approximately 20 knots when the pilot's seat shifted longitudinally backward without any input from the pilot. ## Pilot Response and Technical Findings In response to the seat movement, the pilot instinctively pulled the control stick toward themselves and moved both the collective and power levers upward. This action caused the engine torque to exceed the allowable limits. The helicopter landed without further consequences. Following the incident, the Technical Coordination Center was notified. A review of the UMS/PGS system records revealed that the left engine torque reached a maximum of 90.2% for 0.375 seconds, while the right engine torque reached a maximum of 91.4% for 0.500 seconds. According to AMM 05-51-00, 6-8, these exceedances required a Category “D” inspection within five hours of operation. The inspection was completed within the mandated timeframe and yielded a positive result. ## Probable Cause and Safety Actions The probable cause of the incident was identified as contamination accumulated in the area of the seat lock latch, which caused the seat to shift backward. This movement triggered the pilot's reaction on the flight controls, resulting in the exceedance of allowable torque limits. The operator discussed the incident with all LPR operational personnel and reminded pilots to verify the seat lock after every seat adjustment. The State Commission for Aviation Accident Investigation (PKBWL) did not issue any safety recommendations. The investigation was supervised by Mieczysław Wyszogrodzki and concluded on November 20, 2018.