Incident Overview
On January 10, 2018, a helicopter EC 135 P2+ crew from the Gdańsk unit conducted a mission to an accident in Dzierzgoń under order No. 12/R3/2018. After completing the mission and landing in Gdańsk, the pilot deactivated the cabin heating and ventilation system. At that moment, the Caution and Advisory Display (CAD) showed a BLEED AIR message, indicating a fault in the heating system. The pilot reported the situation to the Technical Coordination Centre (CKT).
Grounding and Maintenance
The helicopter was immediately grounded. Technical personnel from the Szczecin Maintenance Station (SOT) diagnosed the issue using maintenance documentation (KCO Nos. 081/010 and 081/011). They identified a malfunction of the electrically controlled mixing valve that blends engine bleed air with cabin air. According to MSM 05-60, 6-4 paragraph 15, the valve was replaced with a new one. Following MSM 05-60-00, 6-4 paragraph 12, the crew performed an engine start and conducted a functional check of the heating system on the ground and during a test flight. The helicopter was found to be serviceable and returned to operation.
Cause
The cause of the incident was a malfunction of the mixing valve that mixes air from the engine compressor with cabin air.
Corrective Actions
The operator discussed the incident with all operational personnel of the Polish Medical Air Rescue (LPR). The Polish State Commission on Aircraft Accident Investigation (PKBWL) did not issue any safety recommendations.