Summary
On 12 June 2017, an incident involving a helicopter EC135P2+ operated by Lotnicze Pogotowie Ratunkowe (Polish Medical Air Rescue) occurred in Rogoźno, Poland. The helicopter lost its fuel cap during a medical transport mission. The crew returned to base without the cap and landed without further incident.
Circumstances
After returning from a medical transport mission, the crew began restoring operational readiness. Simultaneously, technical personnel from the Szczecin maintenance base were replacing IBF dust filters. The pilot started refueling the helicopter while a mechanic, who was removing the filters, positioned a ladder that blocked the fuel filler area. After completing fueling, the pilot moved the hose, collected documents from the cabin, and left without performing any other checks.
At 14:45, the crew received a HEMS mission from the Poznań dispatch center for a medical emergency near Rogoźno. The helicopter departed at 14:48. Upon landing, the HEMS crew member noticed that the flap above the fuel filler was open, the access door was unlatched, and the fuel cap was missing. The on-board physician determined that hospital transport was unnecessary. The pilot calculated fuel consumption relative to flight time and decided to return to base (EPPO) without the fuel cap, without notifying the operations center or technical coordination. The landing was uneventful.
Findings
The investigation identified the following circumstances:
- Simultaneous refueling by the pilot and maintenance work by technical personnel, which violated procedures in the Aviation Fuel Quality Control and Refueling Instruction.
- The pilot did not inspect the cabin and helicopter surroundings after maintenance was completed.
- The HEMS crew member boarded the helicopter before the HEMS flight without conducting a pre-flight inspection of the aircraft.
- The manufacturer did not secure the fuel cap with a lanyard attached to the airframe.
Probable Cause
The probable cause of the incident, involving the loss of the helicopter's fuel cap during flight, was the improper execution of the refueling procedure by the pilot, as described in the Aviation Fuel Quality Control and Refueling Instruction.
Contributing Factors
- Technical personnel from the Szczecin maintenance base performing maintenance on the helicopter (replacing IBF filters) while operational readiness was being restored.
- The HEMS crew member failing to perform a thorough pre-flight inspection of the aircraft before departure.
Corrective Actions
The operator briefed operational and technical personnel on procedures related to refueling and aircraft maintenance, pre-flight checks by HEMS crews, and the actions required of the aircraft commander following an incident. Personnel were reminded of the necessity to perform a thorough inspection of the helicopter and its surroundings after any maintenance task.