What happened
On 7 January 2001, a Bell 206L-1 helicopter, registration N206DD, was conducting a public transport sightseeing flight near the coast of Virgin Gorda in the British Virgin Islands. While flying at approximately 300 feet, the pilot observed a low-pressure warning for the left fuel boost pump. An attempt to reset the circuit breaker failed to resolve the issue, and shortly thereafter, the right fuel boost pump warning light also illuminated.
Despite the cockpit gauge indicating approximately 150 lbs of fuel, the engine ceased operation roughly 15 seconds after the initial warning. The pilot initiated an autorotation from an altitude of about 200 feet, managing to glide the aircraft toward the shoreline. The helicopter landed on the surface of the water in a level attitude. However, despite the deployment of flotation bags, the aircraft rolled onto its right side in shallow water. There were no fatalities and no injuries among the six passengers or the pilot.
The investigation
An investigation was conducted by the AAIB with assistance from the manufacturer and the Canadian Transport Safety Board. Examination of the wreckage and the aircraft's dynamic components revealed no evidence of mechanical issues prior to the impact. However, investigators identified water within the engine nozzle fuel line and the airframe filter.
Crucially, the investigation found significant contamination within the left-side inline fuel transfer filter. This debris consisted of white paint flakes with green primer and fragments of a thin, transparent plastic-like material. While the downstream ejector pumps were clean, the level of debris in the filter was sufficient to suggest that fuel had likely bypassed the screen. The investigation also noted that the airframe fuel filter was only 20% full of liquid, which is atypical under normal operating conditions.
Findings
- The engine failure was caused by the exhaustion of fuel in the main tank.
- Debris in the left-side fuel transfer filter likely obstructed the dual-element jet pump, interrupting the transfer of fuel from the forward tanks to the main tank.
- The presence of paint flakes and plastic fragments indicates that contamination was present in the fuel system prior to the accident.
- Although the fuel gauge indicated remaining fuel, this quantity likely resided in the forward tanks and was not being moved to the main tank due to the filter blockage.