Casualties unknown

2007-07-10: Hiller UH-12E (N146ET) — Prism Helicopters — Skwentna, AK

Skwentna, AK, US

On July 10, 2007, a Hiller UH-12E (registration N146ET) operated by Prism Helicopters was involved in an aviation accident near Skwentna, AK. Investigators recorded the probable cause as: The pilot's failure to maintain clearance from a glacier, which resulted in a tail rotor strike during landing, and damage to the helicopter during an emergency descent/landing on rough/uneven terrain. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 2 related events involving the same aircraft type or operator are linked below.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

A solo commercial pilot attempting an off-airport landing on a glacier experienced a tail rotor separation after a loud bang, resulting in uncontrolled descent and damage.

Accident Details

The accident involved a solo commercial certificated pilot conducting an off-airport landing on rough, uneven terrain under Title 14, CFR Part 91. The pilot reported attempting a toe-in landing to pick up passengers. Approximately one foot above the ground, he heard a loud bang, and the helicopter yawed to the right. The tail rotor separated from the helicopter, leading to an uncontrolled descent and impact with the ground. The impact damaged the tail rotor, tail boom, fuselage, and main rotor system.

Postaccident Findings

During a postaccident inspection of the site, the pilot reported finding an area of disturbed snow where the tail rotor struck the glacier. A passenger waiting to be picked up reported that it looked like a gust of wind pushed the tail of the helicopter to the right, causing the tail rotor to strike a snow bank.

Weather and Environmental Conditions

The pilot described the conditions at the time of the accident as wind shifts up to 180 degrees, gusting 10-15 knots, a density altitude of 7,000 feet, and marginal flat light on a snow-covered glacier.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20070711X00901. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.