- Date
- July 9, 2007, 16:10 local (Jul 10, 2007, 00:10 UTC)
- Place
- Skwentna, AK
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N146ETHiller UH-12E
- Weather
- Visual (VMC) · Day
- Status
- Completed · report November 29, 2007
- Report
- Approved by Office Director
- NTSB office
- Alaska Regional Office
- Parties
- Anchorage, FSDO-03
- FAA report
- 20070709014499A
- Case key
- 66158
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
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. Factors contributing to the accident were variable and gusty wind conditions.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
The solo commercial certificated pilot was attempting an off-airport landing on rough/uneven terrain under Title 14, CFR Part 91. The pilot reported that he was attempting a toe-in landing to pickup passengers, and about one foot above the ground he heard a loud bang, and the helicopter yawed to the right. The tail rotor separated from the helicopter, and the helicopter descended uncontrolled, impacting the ground, damaging the tail rotor, tail boom, fuselage, and main rotor system. During a postaccident inspection of the site, the pilot reported finding an area of disturbed snow, where the tail rotor struck the glacier. He described the conditions as wind shifts up to 180 degrees, gusting 10-15 knots, density altitude 7,000 feet, and marginal flat light on a snow-covered 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, and the tail rotor struck a snow bank.
Factual narrative
On July 9, 2007, about 1610 Alaska daylight time, a Hiller UH-12E helicopter, N146ET, sustained substantial damage during an impact with terrain, following a tail rotor strike while attempting to land on a glacier, about 60 miles west of Skwentna, Alaska. The helicopter was being operated by Prism Helicopters, Wasilla, Alaska, as a visual flight rules (VFR) positioning flight under Title 14, CFR Part 91, when the accident occurred. The solo commercial certificated pilot was not injured. Visual meteorological conditions prevailed, and company flight following procedures were in effect.
During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on July 9, the director of operations for the operator said the helicopter was stationed at Terra Camp, which is a mine site west of Skwentna. She said the helicopter left Terra Camp to pickup passengers at a drill-pad site at the 6,000 foot elevation above the camp. According to a passenger waiting at the drill site for the helicopter, she was told that it looked like a gust of wind pushed the tail of the helicopter to the right, and the tail rotor struck a snow bank. She said the tail rotor separated from the helicopter, and the helicopter descended uncontrolled, impacting the ground. She reported damage to the helicopter's tail rotor, tail boom, fuselage, and main rotor system.
In a written statement to the NTSB dated July 9, the pilot wrote that he was attempting a toe-in landing to pickup passengers. He reported that about one foot above the ground he heard a loud bang, and the helicopter yawed to the right. He landed and secured the helicopter. Inspecting the site, he reported he found an area of disturbed snow where the tail rotor must have struck the glacier. In his statement, the pilot described the conditions as wind shifts up to 180 degrees, gusting 10-15 knots, density altitude 7,000 feet, and marginal flat light on a snow-covered glacier.
Aircraft
- Registration
- N146ET
- Reported as
- Hiller UH-12E
- Category
- Helicopter
- Serial number
- HA3046
- Airframe hours
- 5,225
- Engine
- Allison 250C20B, 420 horsepower, turbo shaft
- Damage
- Substantial damage
- Flight
- Positioning · Part 91
- Operator
- Prism Helicopters
- Registered owner
- Dragonfly Air LLC
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · June 1, 2007
- Departed
- Terra Camp, AK
- Flight plan
- Company VFR
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 48
- Injuries
- None
- Certificate
- Commercial
- Instrument ratings
- Helicopter
- Medical
- Class 2, With waivers/limitations
- Last flight review
- May 1, 2007
- Seat
- Left
- Flight hours
- 14,300 total · 560 in this make and model · 13,815 as pilot in command · 200 in the last 90 days · 45 in the last 30 days · 4 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- Variable at 10 knots, gusting 15
- Visibility
- 10 statute miles
- Temperature
- 50 °F
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.