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Aviation Accident

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NTSB Identification: ANC99LA140
The docket is stored in the Docket Management System (DMS). Please contact Records Management Division
Accident occurred Friday, September 10, 1999 in JUNEAU, AK
Probable Cause Approval Date: 08/10/2000
Aircraft: Eurocopter AS-350B-2, registration: N6052C
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 helicopter pilot, with one passenger aboard, was conducting a search for an overdue company helicopter. While searching the upper portion of a glacial ice field, deteriorating weather conditions required the pilot to alter his search route. He said that he slowed the helicopter to 15 knots and attempted to use a mountain range on the right side of the helicopter for visual reference. He said: 'Visibility in front was enough to see all the way to the top of the Herbert (greater than three miles). The ceiling sloped down to the east 45 degrees with a height at the ridge of approximately 700 feet.' The pilot added that just seconds before the impact, he thought the helicopter was at least 500 feet above the surface. He said that 'flat light conditions' made it very difficult to see the topographical features of the ice field below. The helicopter struck the snow-covered ice field, slid about 75 feet, and the helicopter rolled over to the right. The helicopter sustained substantial damage to the fuselage, tail boom, and rotor system. After the accident, the pilot radioed for another company helicopter to pick them up. A second company helicopter, N6099Y, landed at the accident site, boarded the uninjured pilot and passenger, and continued the search. During the search, N6099Y also collided with the snow-covered ice field. See ANC99FA139, and ANC99LA141. The accident pilot did not possess an instrument rating, and the helicopter was not equipped with a radar altimeter.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
  • The pilot's failure to maintain altitude/clearance. Factors associated with the accident were flat light conditions, snow-covered terrain, and self-induced pressure to continue the search.