What happened
On June 13, 2004, a Bell 206B helicopter, registration EI-BYJ, was conducting a series of short-duration commercial pleasure flights near Kilanny, County Monaghan. The aircraft was part of a high-frequency operation where passengers boarded and disembarked while the engine and rotors remained running at idle.
During the final scheduled trip of the afternoon, the engine failed approximately two to four minutes after takeoff. The pilot observed a "FUEL PUMP" warning light illuminate shortly before the power loss. To avoid terrain, the pilot executed an autorotation, performing a 180-degree turn to land downwind in a cornfield. While the aircraft sustained significant damage to the tail boom and main gearbox, all four passengers and the pilot exited the aircraft safely without injury.
The investigation
The AAIU investigation examined the fuel system, the pilot's flight logs, and the circumstances surrounding the aircraft's refueling. It was established that the helicopter had undergone a hot refuelling earlier in the day, bringing the fuel level to approximately 53 US gallons. The investigation also reviewed the pilot's recent flying history and the operational environment of the pleasure flight service.
Investigators analyzed the Bell 206B fuel system, noting that the fuel gauge can provide misleading readings due to the longitudinal displacement of the sensors and the aircraft's pitch angle. Furthermore, the investigation looked into the effectiveness of passenger safety briefings and the physical challenges passengers faced when attempting to evacuate the aircraft during the emergency.
Findings
- The primary cause of the engine shutdown was fuel starvation resulting from insufficient fuel in the tank.
- The fuel quantity at the start of the final flight did not meet the minimum requirements mandated by the operator's manual or regulatory authorities.
- The pilot's decision to proceed with the final trip was influenced by potential cumulative fatigue following a long day of flying and a lack of adequate fuel monitoring.
- The passenger safety briefing was ineffective due to high ambient noise levels from the running engine and the physical separation between the crew and passengers.
- Passengers experienced difficulty evacuating the aircraft because they could not easily locate door handles or operate the specialized four-point seat harnesses.
Safety action
Following the investigation, several safety recommendations were issued, including:
- A requirement for operators to revise safety cards to include clear instructions on operating seat harnesses and door handles from within the cabin.
- A recommendation for the IAA to review procedures for high-frequency, high-turnaround helicopter operations to ensure passenger safety briefings are effective.
- A suggestion for EASA to consider requiring independent low-fuel warning lights for helicopters used in commercial operations.