What happened
On the evening of 23 September 2006, a Eurocopter AS350 helicopter, registration G-JESI, was performing a private charter flight from the K Club in County Kildare to Adare, County Limerick. Earlier that day, the aircraft had undergone "hot refuelling"—a process where the engine remains running and rotors continue to turn—at a landing site during the Ryder Cup event. During this process, the pilot noted that the fuel gauge appeared stuck at 20%, despite being told by the refueller that 302 litres had been added.
Following the refuelling, the aircraft remained parked until 18:30 hrs, when four passengers boarded for the flight. At approximately 19:35 hrs, the helicopter was forced to land in a field near Dunkerrin, County Offaly, due to a critical lack of fuel. Upon inspection of the aircraft the following morning, only 6.5 litres of fuel were recovered from the tank. There were no injuries and no damage to the aircraft.
The investigation
The AAIU examined the refuelling procedures and the fuel accounting systems used by the provider. The investigation found that while the helicopter's fuel gauge and warning lights functioned correctly during subsequent tests, the actual fuel level was significantly lower than the pilot believed. The investigation also scrutinized the refuelling provider's records, noting that the manual nature of the fuel dockets and anomalies in the accounting system made it impossible to audit exactly how much fuel had been dispensed at the K Club that day.
Findings
- The primary cause of the low fuel situation was a discrepancy between the recorded fuel uplift and the actual fuel delivered.
- The pilot's belief that the fuel gauge was unreliable led to a reliance on a manual docket rather than a verified gauge reading.
- The refuelling provider's operations manual and exposition did not include provisions for hot refuelling.
- The fuel accounting system relied on manually written dockets, which lacked the precision of meter-generated prints.
- There was ambiguity regarding whether certain Irish Aviation Authority (IAA) regulations for fuel installations applied to mobile refuelling units.
Safety action
The AAIU issued several interim safety recommendations to the IAA, including requirements for clearer regulations regarding mobile refuelling, the necessity of including hot refuelling procedures in both provider and operator manuals, and the implementation of meter-generated dockets to ensure accurate fuel tracking.