What happened
On 2 January 2006, a Hughes 369HS helicopter, registration G-LINC, was performing a private flight involving a trip from Sywell Aerodrome to Catthorpe and then to Folkestone Race Course. After spending the day at Folkestone, the pilot commenced the return flight to Sywell. During the flight, the pilot noted the fuel low caution light flickering, which he attributed to fuel movement caused by turbulence.
As the aircraft approached Sywell, the fuel low light became permanently illuminated. The pilot, believing he had approximately 15 minutes of flight time remaining, continued the approach. During the final approach at 400 ft agl, the engine suffered a flame-out. The pilot initiated an autorotation and performed a heavy landing short of the runway threshold. While the occupants escaped without injury, the impact caused the landing skids to splay and the main rotor to strike the tail boom, resulting in its separation.
The investigation
The AAIB investigation established that the helicopter had run out of fuel. The pilot had not physically verified the fuel level after refuelling at the start of the day, relying instead on a gauge that indicated a full tank. Furthermore, the pilot did not perform a fuel burn check during the flight or at the intermediate stop at Folkestone.
Calculations revealed that the pilot's planning was overly simplistic, failing to account for the fuel required for start-up, taxi, and takeoff. While the pilot estimated a fuel burn of 150 lb/hr, the actual consumption rate was higher. The investigation also noted that the pilot did not investigate a discrepancy in the fuel gauge reading at Folkestone, which indicated 200 lb remaining despite his previous calculations.
Findings
- The engine flame-out was caused by fuel exhaustion.
- The pilot's fuel planning was inadequate as it did not include allowances for start-up, taxi, or takeoff.
- A lack of in-flight fuel monitoring, due to the failure to perform a fuel burn check, prevented the pilot from maintaining accurate situational awareness regarding remaining endurance.
- The pilot failed to take appropriate action when the fuel low caution light illuminated, miscalculating the remaining flight time.