NTSB Identification: ANC03LA038.
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Accident occurred Monday, March 31, 2003 in TYONEK, AK
Probable Cause Approval Date: 09/30/2003
Aircraft: Hughes 369D, registration: N90431
Injuries: 2 Uninjured.

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 certificated helicopter pilot was conducting external load operations in support of seismic operations, and landed a high skid-equipped helicopter in a confined area to pick up a passenger. The landing area had knee to waist level brush. The pilot did not exit the helicopter, but waited until the passenger climbed aboard. The pilot reported that the passenger unknowingly drug a seismic cable over the toe of the left skid as he climbed into the helicopter. As the pilot was lifting the helicopter into a hover, the cable slid aft into the helicopter's external load mirror. The cable severed the mirror from the helicopter, and the mirror was propelled upward, into the main rotor blades. The mirror then struck the vertical stabilizer. A postaccident examination of the rotor system revealed that one rotor blade sustained a dent on the underside of the blade. The director of operations stated that the damaged blade was beyond allowable repair limits, and had to be replaced.

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

The pilot's inadequate visual lookout while lifting into a hover to ensure the helicopter was clear of all objects, which resulted in separation of an external mirror that then struck and damaged a main rotor blade. Factors in the accident were the presence of a seismic cable, and high vegetation around the helicopter's takeoff spot.

Full narrative available

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