NTSB Identification: ANC08LA004
14 CFR Part 91: General Aviation
Accident occurred Saturday, October 20, 2007 in Prudhoe Bay, AK
Probable Cause Approval Date: 05/28/2008
Aircraft: BELL 206B, registration: N345TV
Injuries: 1 Serious,1 Minor.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The commercial pilot was cleaning electrical power line insulators using a cleaning apparatus mounted on the helicopter. While cleaning, the pilot said the helicopter was hovering about 60 feet above the ground when the engine lost power. He turned away from the power lines, and the helicopter descended rapidly, impacting the ground, and sustaining substantial damage to the fuselage and rotor system. The helicopter had a 30-foot articulated spray boom mounted on its right side, a 50-gallon water tank inside, and a pressure pump on the left side. The equipment was operated by an onboard boom operator. An examination of the helicopter disclosed that both electric fuel boost pump intakes were clogged with a fibrous material. The electric fuel boost pumps serve as conduits for the engine-driven fuel pump, and if they are clogged, no fuel will reach the engine. Similar fibrous material was found in the airframe fuel filter. At a test facility, the engine was started and run without problems. During a re-examination of the airframe, the fuel tank was cut open, and a triangular-shaped 4" piece of an absorbent pad was found. The contract fueler had routinely been shoving the fuel nozzle through a hole in the plastic packaging of a bundle of absorbent pads, into the edges of the pads, to keep fuel from dripping on the tundra. The fueling process was repeated every 7-8 minutes. Samples of the material taken from the fuel pumps, the piece found in the fuel tank, and an exemplar pad provided by the fuel contractor, were sent to a laboratory for testing. The tests revealed that all the samples were essentially identical. The contamination of the fuel pumps most likely occurred when the fuel nozzle tip cut/captured portions of the absorbent pads when it was placed in the pad bundles, and the cut portions were then pumped into the fuel tanks.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

Fuel starvation due to the blockage of fuel inlet screens, and improper service procedures by ground personnel.

Full narrative available

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