ANC06TA047

NTSB accident investigation · American Eurocopter AS350 B3 · Nikiski, AK · April 21, 2006

Accident · No injuriesFinal report
Date
April 21, 2006, 01:06 local (09:06 UTC)
Place
Nikiski, AK
Injuries
3 uninjured
Damage
Substantial damage
Phase of flight
Takeoff
Aircraft
N911AAAmerican Eurocopter AS350 B3
Weather
Visual (VMC) · Night
Status
Completed · report April 25, 2007
Report
Approved by Office Director
NTSB office
Alaska Regional Office
Parties
Federal Aviation Administration
FAA report
20060421006519A
Case key
63568

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

The NTSB’s determination of the probable cause, and any contributing factors.

The pilot's failure to maintain adequate altitude/clearance from terrain during an aborted takeoff in whiteout conditions, which resulted in an in-flight collision with terrain. A factor associated with the accident was whiteout conditions.

Analysis

The airline transport certificated pilot was transporting an Alaska State Trooper, and a rescue volunteer with their equipment, to a remote lodge to search for a missing person. The flight was conducted during dark night conditions, and the pilot was using night vision goggles (NVG) to help discern topographical features on the snow-covered terrain. After an uneventful outbound flight to the lodge, the pilot landed the helicopter on a frozen lake adjacent to the lodge. During an hour-long search of the lodge and surrounding outbuildings, snow fell, with a light accumulation on the frozen lake where the accident helicopter was parked. Unable to locate the missing person, the search team boarded the helicopter for the return flight, and the pilot donned his NVGs. Just after takeoff, as the helicopter transitioned from a hover to forward flight, blowing snow from the helicopter's main rotor momentarily reduced the pilot's visibility, and he lost all visual reference with the surface of the frozen lake. While he was attempting to regain a visual reference, the helicopter's tail rotor guard and vertical stabilizer struck the surface of the lake, and he elected to abort the takeoff. The helicopter's skids subsequently struck the surface of the ice, and the helicopter bounced several times before stopping. A postaccident inspection revealed substantial damage to the helicopter's vertical stabilizer, tail boom assembly, and fuselage. The pilot reported that there were no preaccident mechanical anomalies with the helicopter, and that he had not received any formal training in the use of NVG's.

Factual narrative

The factual narrative456 words

On April 21, 2006, about 0106 Alaska daylight time, a high skid-equipped American Eurocopter AS350 B3 helicopter, N911AA, sustained substantial damage during takeoff from a remote area, about 30 miles northwest of Nikiski, Alaska. The helicopter was being operated as a visual flight rules (VFR) government-operated flight under Title 14, CFR Part 91, when the accident occurred. The helicopter was operated by the State of Alaska, Department of Public Safety. The airline transport certificated pilot, and the two passengers, were not injured. Dark night visual meteorological conditions prevailed, and company flight following procedures were in effect. The accident flight originated at the Big River Lakes Lodge about 0106, and was en route to Soldotna, Alaska.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on April 27, the pilot reported that he was transporting an Alaska State Trooper, and a rescue volunteer with their equipment to the Big River Lakes Lodge to search for a missing person. The accident pilot reported that due to dark night conditions and the lack of ground based light sources while flying over unpopulated terrain, he was using a pair of night vision goggles (NVG) to help discern topographical features. He said that after an uneventful outbound flight to the lodge, he landed the helicopter on a frozen lake adjacent to the lodge. The search team subsequently conducted an hour-long search of the lodge and surrounding outbuildings. He said that during the search, snow fell, with a light accumulation of snow on the frozen lake where the accident helicopter was parked.

Unable to locate the missing person, the search team boarded the helicopter for the flight to the Alaska State Trooper's post in Soldotna. Before takeoff, the pilot donned his NVGs. He said that just after takeoff, as the helicopter transitioned from a hover to forward flight, blowing snow from the helicopter's main rotor momentarily reduced his visibility, and he lost all visual reference with the surface of the frozen lake. He reported that while attempting to regain a visual reference, the helicopter's tail rotor guard and vertical stabilizer struck the surface of the lake, and he elected to abort the takeoff and attempt a run-on landing. The helicopter's skids subsequently struck the surface of the ice, and the helicopter bounced several times before stopping. A postaccident inspection revealed substantial damage to the helicopter's vertical stabilizer, tail boom assembly, and fuselage.

The pilot reported that there were no preaccident mechanical anomalies with the helicopter.

During the April 27 telephone conversation with the NTSB IIC, the pilot said that at the time of the accident the State of Alaska Department of Public Safety was not utilizing a formal, or a Federal Aviation Administration (FAA) approved NVG training program.

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.

In flight collision with terrain/waterTakeoff - aborted
Altitude/clearance - not maintainedPilot in commandCause
Weather condition - whiteoutFactor
Weather condition - snow
Light condition - dark night
Inadequate initial trainingCompany/operator management
Terrain condition - snow covered

Aircraft

Registration
N911AA
Reported as
American Eurocopter AS350 B3
Category
Helicopter
Serial number
3611
Airframe hours
967.6
Engine
Turbomeca Arriel 2B, 847 horsepower, turbo shaft
Damage
Substantial damage
Flight
Public aircraft · Part 91
Registered owner
State of Alaska, Department of Public Safety
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · March 1, 2006 · 29.2 hours before
Departed
Nikiski, AK
Destination
Soldotna, 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
Certificates
Commercial, Flight instructor, Airline transport
Airplane ratings
Single-engine land, Single-engine sea, Multi-engine land
Instrument ratings
Helicopter, Airplane
Medical
Class 2, With waivers/limitations
Last flight review
July 1, 2005
Seat
Right
Flight hours
9,000 total · 950 in this make and model · 8,715 as pilot in command · 70 in the last 90 days · 29 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Night
Wind
Calm
Visibility
2 statute miles
Lowest ceiling
800 ft overcast
Temperature
86 °F

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.

Other investigations on N911AA · 1

Matched to the same aircraft by N-number and date.