- Date
- April 30, 2013, 16:30 local (May 1, 2013, 00:30 UTC)
- Place
- Anaktuvuk Pass, AK
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N1171Bell Helicopter Textron 206L-1
- Defining event
- Landing-flare/touchdown: Dynamic rollover
- Weather
- Instrument (IMC) · Day
- Status
- Completed · report July 29, 2013
- Report
- Approved by Office Director
- NTSB office
- Alaska Regional Office
- Parties
- Federal Aviation Administration
- FAA report
- 20130430006769A
- Case key
- 86822
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 lateral control while hovering over an area of snow-covered terrain, in flat light conditions, which resulted in a dynamic rollover.
Findings · 3
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
The commercial helicopter pilot reported that while flying over an area of flat and featureless, snow-covered terrain, deteriorating weather conditions with low ceilings, light snow, and flat light conditions reduced his visibility, so he elected to make a precautionary landing to wait for improved visibility. He said that while attempting to land, blowing snow from the main rotor downwash reduced his ability to discern topographical features on the snow-covered terrain. During touchdown, the helicopter drifted to the left, the left skid struck the snow-covered terrain, and the helicopter rolled onto its left side. The helicopter sustained substantial damage to the rotor system, tail boom, and fuselage. The operator reported that there were no preaccident mechanical malfunctions or anomalies that would have precluded normal operation.
Factual narrative
The commercial helicopter pilot reported that while flying over an area of flat and featureless, snow-covered terrain, deteriorating weather conditions with low ceilings, light snow, and flat light conditions reduced his visibility, so he elected to make a precautionary landing to wait for improving visibility. He said that while attempting to land, blowing snow from the main rotor downwash reduced his ability to discern topographical features on the snow-covered terrain. During touchdown, the helicopter drifted to the left, the left skid struck the snow-covered terrain, and the helicopter rolled onto its left side. The helicopter sustained substantial damage to the rotor system, tail boom, and fuselage. The operator reported that there were no preaccident mechanical malfunctions or anomalies that would have precluded normal operation.
Aircraft
- Registration
- N1171
- Reported as
- Bell Helicopter Textron 206L-1
- Category
- Helicopter
- Serial number
- 45234
- Airframe hours
- 29,902
- Engine
- Rolls Royce C30P, 650 horsepower, turbo shaft
- Damage
- Substantial damage
- Flight
- Part 135
- Operator
- Pathfinder Aviation
- Registered owner
- Gm Leasing Co LLC
- Airworthiness certificate
- Standard, Normal
- Last inspection
- 100 hour · February 1, 2013
- Departed
- Kuparik River, AK
- Destination
- PAUM · Umiat, 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
- 51
- Injuries
- None
- Certificate
- Commercial
- Medical
- Class 2, Without waivers/limitations
- Last flight review
- March 26, 2013
- Seat
- Right
- Flight hours
- 7,350 total · 4,670 in this make and model · 7,300 as pilot in command · 40 in the last 90 days · 40 in the last 30 days · 3 in the last 24 hours
Weather
- Conditions
- Instrument (IMC) · Day
- Wind
- 210° at 10 knots
- Visibility
- 1 statute miles
- Temperature
- 19 °F
Docket · 2
The files NTSB released with the investigation on June 3, 2013, on NTSB’s docket system: statements, records, photos and specialists’ reports. 702 KB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.