ANC02LA068

NTSB accident investigation · Eurocopter France AS-350-B2 · Denali Park, AK · June 26, 2002

Accident · Minor injuriesLimited investigationFinal report
Date
June 26, 2002, 11:15 local (19:15 UTC)
Place
Denali Park, AK
Injuries
2 minor, 4 uninjured
Damage
Substantial damage
Phase of flight
Takeoff
Aircraft
N197EHEurocopter France AS-350-B2
Weather
Visual (VMC) · Day
Status
Completed · report April 1, 2003
Report
Approved by Office Director
NTSB office
Alaska Regional Office
Parties
Federal Aviation Administration FSDO-03
FAA report
20020626016759A
Case key
55076

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 aircraft control during takeoff, which resulted in dynamic rollover of the helicopter. A contributing factor was the frozen terrain.

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.

Loss of control - on ground/waterTakeoff
Aircraft control - not maintainedPilot in commandCause
Terrain condition - frozenFactor
Roll overTakeoff - aborted
Dynamic rollover - encounteredPilot in command

Analysis

The pilot of the accident helicopter reported that he was attempting to takeoff from a glacier. During takeoff, he discovered the right landing gear skid was frozen to the surface of the glacier, and he decreased the collective control input. As he reduced the collective control input, the right skid broke free from the ice. He said that due to left cyclic input, when the right skid broke free from the ice, a left rolling moment was induced. The helicopter's main rotor blades subsequently contacted the surface of the glacier, and the helicopter rolled onto its right side.

Factual narrative

On June 26, 2002, about 1115 Alaska daylight time, a Eurocopter AS-350-B2 helicopter, N197EH, sustained substantial damage following a loss of control during takeoff from a glacier, about 40 miles east of Denali National Park, Alaska. The helicopter was being operated by Era Aviation, Inc., as a visual flight rules (VFR) on-demand charter flight under Title 14, CFR Part 135, when the accident occurred. The commercial pilot and one passenger received minor injuries; the four other passengers were not injured. Visual meteorological conditions prevailed, and a company VFR flight plan was in effect.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC)on June 26, the pilot said he and the passengers had just completed a 20 minute glacier walk, and returned to the helicopter. He said they were going to depart the glacier as the third helicopter in a flight of three. He said as the first two helicopters passed by, he pulled up on the collective lever, and the left skid lifted up off the ice. He said as the left skid lifted off the ice , it exceeded the height where the right skid should have lifted off. He believed the right skid was frozen to the ice, so he started to reduce the collective input. The pilot said as he reduced the collective input, the right skid broke loose, and the helicopter rolled left. The main rotor blades struck the ice, and the helicopter flipped 180 degrees, coming to rest on its right side.

In a subsequent written statement the operator's vice president of safety said, in part: "The right skid broke free causing the fuselage to "swing" laterally to the left. Due to the amount of cyclic input applied the fuselage moved left allowing the left skid to make contact with the ground providing a left lateral rolling moment. The main rotor blades made contact with the ground which caused the helicopter to pivot up and around the nose, and come to rest on its right side facing downhill."

The transmission was torn loose from its mounts to the fuselage. The tail rotor and engine drive shafts were severed, and the three main rotor blades were destroyed.

Aircraft

Registration
N197EH
Reported as
Eurocopter France AS-350-B2
Category
Helicopter
Serial number
2983
Airframe hours
911
Engine
Turbomeca Arriel 1D1, 746 horsepower, turbo shaft
Damage
Substantial damage
Flight
Part 135
Registered owner
Era Aviation, Inc.
Airworthiness certificate
Standard, Normal
Last inspection
AAIP · June 20, 2002 · 16 hours before
Departed
Denali Park, AK
Destination
Denali Park, 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
29
Injuries
Minor
Certificates
Commercial, Flight instructor
Airplane ratings
Single-engine land
Instrument ratings
Helicopter, Airplane
Medical
Class 1, Valid Medical--no waivers/lim.
Last flight review
May 10, 2002
Seat
Front
Toxicology
Performed
Flight hours
4,039 total · 393 in this make and model · 3,937 as pilot in command · 121 in the last 90 days · 65 in the last 30 days · 3 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
20° at 20 knots, gusting 25
Visibility
10 statute miles
Lowest ceiling
8,000 ft broken
Temperature
37 °F

Docket · 2

The files NTSB released with the investigation on December 10, 2002, on NTSB’s docket system: statements, records, photos and specialists’ reports. 1.1 MB 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.

Other investigations on N197EH · 1

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