Incident Details
On 28 August 2017, the duty crew of the LPR branch in Gliwice received a mission (No. 289/R4/2017) to fly to an accident site in Gierałtowice. The flight to pick up a patient and the transit to the Children's Health Center in Katowice proceeded without incident. During the final approach for landing, the pilot observed a warning on the Cockpit Alert Display (CAD) indicating "XMSN CHIP" – chips in the main gearbox. After landing and shutting down the helicopter, the pilot reported the event to the Technical Coordination Center.
Aircraft and Crew
The helicopter involved was an EC 135 P2+. The crew consisted of a professional helicopter pilot and three other persons, all of whom were uninjured. The aircraft was subsequently grounded.
Cause
The probable cause of the incident was chip accumulation at the bottom of the main gearbox, which separated from the gearbox floor during normal helicopter operation.
Actions Taken
On 28 August 2017, a maintenance technician from the Warsaw Babice Service Station inspected the chip detector and confirmed the presence of chips in category "C". The helicopter was conditionally cleared for operation. The following day, technical personnel performed an inspection, oil filter replacement, and flushing of the main gearbox in accordance with AMM 63-40-00. After a successful pressure test of the gearbox oil system, the helicopter was released for further operation. The incident was discussed with all operational staff of LPR. No safety recommendations were issued by the Polish State Commission for Aircraft Accident Investigation (PKBWL).