SEA01LA061

NTSB accident investigation · Eurocopter AS-350 B2 Ecureuil · Mazama, WA · March 11, 2001

Accident · Minor injuriesLimited investigationFinal report
Date
March 11, 2001, 09:00 local (17:00 UTC)
Place
Mazama, WA
Injuries
2 minor, 4 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N189EHEurocopter AS-350 B2 Ecureuil
Weather
Visual (VMC) · Day
Status
Completed · report July 30, 2001
Report
Approved by Office Director
Parties
FAA-FSDO
FAA report
20010311005609A
Case key
51900

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 pilot's failure to maintain aircraft control. Snow covered terrain, high and variable wind conditions, and failure of attaining the proper touchdown point were factors.

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/waterLanding
Aircraft control - not maintainedPilot in commandCause
Terrain condition - snow coveredFactor
Weather condition - variable windFactor
Proper touchdown point - not attainedPilot in commandFactor
Weather condition - high windFactor
Roll overLanding

Analysis

The pilot approached the remote snow covered mountain site into the wind. During the descent at about 50 feet, the wind increased and shifted. The helicopter began to descend rapidly, and the pilot increased power in an attempt to arrest the rate of descent. Shortly thereafter, the low rotor rpm horn sounded and the helicopter touched down just past the normal landing site with sufficient force and forward speed to prevent him from holding it on the landing site. The pilot applied forward cyclic in an attempt to prevent the helicopter from falling off a 30 foot drop. Due to the low rotor rpm and the inability to maintain altitude, the pilot elected to land the helicopter in a large open snowfield. During the landing, the helicopter settled in the snow and the main rotors contacted the ground. The helicopter subsequently rolled over. The weather at the accident site was reported as high overcast. The wind direction was not indicated, however, the wind velocity was reported at 15-20 knots. No mechanical failures or malfunctions were reported.

Factual narrative

On March 11, 2001, about 0900 Pacific standard time, an Eurocopter AS 350 B2 Ecureuil, N189EH, registered to and operated by Era Aviation Inc. as a 14 CFR Part 135 on demand air taxi service, rolled over after landing on a remote snow covered mountain site on Silverstar Mountain located seven miles west southwest of Mazama, Washington. Visual meteorological conditions prevailed at the time and a company visual flight rules flight plan was in effect. The helicopter was substantially damaged and the commercial pilot and three passengers were not injured. The two remaining passengers received minor injuries. The flight originated from Mazama Heliski Lodge about 15 minutes prior to the accident.

In a written statement prepared by Era Aviation's Vice-President - Safety, the purpose of the flight was to drop off skiers at a prepared mountain ridge landing site. The landing site was a small ridge on a large rock outcrop on the north side of the mountain. The area had been leveled and four 4-foot high stakes had been placed in the snow with flags attached to act as wind indicators. The pilot had approached the site into the prevailing winds. During the descent at about 50 feet, the wind increased and shifted to the left side. The helicopter began to descend rapidly, and the pilot increased power in an attempt to arrest the rate of descent. Shortly thereafter the low rotor rpm horn sounded and the helicopter touched down just past the normal landing site with "enough force and forward speed to prevent the pilot from holding it on the intended landing site, so he added forward cyclic in an attempt to prevent it from falling of[f] a 30 foot drop." Due to the low rotor rpm, and the inability to maintain altitude, the pilot elected to land the helicopter in a large open snowfield. During the landing, the helicopter settled into the snow and the main rotors contacted the ground. The helicopter subsequently rolled over.

The weather at the accident site was reported as high overcast. The wind direction was not indicated, however, the wind velocity was reported at 15-20 knots.

No mechanical failures or malfunctions were reported.

Aircraft

Registration
N189EH
Reported as
Eurocopter AS-350 B2 Ecureuil
Category
Helicopter
Serial number
2956
Airframe hours
1,745
Engine
Turbomeca Arriel/1D1, 740 horsepower, turbo shaft
Damage
Substantial damage
Flight
Part 135
Registered owner
Era Aviation, Inc.
Airworthiness certificate
Standard, Normal
Last inspection
AAIP · February 23, 2001 · 1,703 hours before
Departed
Mazama, WA
Destination
Mazama, WA
Flight plan
Company VFR

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
46
Injuries
None
Certificates
Commercial, Flight instructor
Airplane ratings
Single-engine land
Instrument ratings
Airplane, Helicopter
Medical
Class 2, Valid Medical--no waivers/lim.
Last flight review
November 30, 2000
Seat
Right
Flight hours
6,328 total · 1,286 in this make and model · 4,953 as pilot in command · 110 in the last 90 days · 71 in the last 30 days · 4 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
20 knots
Visibility
10 statute miles
Temperature
14 °F

FAA reports on this event · 1

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