ANC99TA090

NTSB accident investigation · Bell 206B · Deadhorse, AK · July 8, 1999

Accident · No injuriesFinal report
Date
July 8, 1999, 12:30 local (20:30 UTC)
Place
Deadhorse, AK
Injuries
4 uninjured
Damage
Substantial damage
Phase of flight
Standing
Aircraft
N47122Bell 206B
Weather
Visual (VMC) · Day
Status
Completed · report November 30, 2000
Report
Approved by Office Director
NTSB office
Alaska Regional Office
FAA report
19990708008519A
Case key
46774

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

A failure of the pilot-in-command to perform an adequate preflight inspection, and remove a rotor blade tie-down strap.

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.

Miscellaneous/otherStanding - starting engine(s)
Starting procedure - initiatedPilot in command
Vertical stabilizer - bent
Rotor blade tie-down(s) - not removedPilot in commandCause
Misc rotorcraft,tail boom - twisted
Aircraft preflight - inadequatePilot in commandCause

Analysis

The pilot for an on-demand helicopter company was beginning a flight that was being operated as a visual flight rules (VFR) U.S. Government flight by the U.S Department of Interior, Bureau of Land Management. The pilot loaded his passengers into the helicopter at a remote biological survey site. He then began an engine start, but a main rotor blade tie-down strap was still attached to one of the rotor blades. As the rotor blades began to turn, the strap struck the upper end of the vertical stabilizer, crushing the leading edge in an aft direction. The helicopter's tail boom was deformed and wrinkled, just forward of the tail rotor gear box.

Factual narrative

On July 8, 1999, about 1230 Alaska daylight time, a Bell 206B helicopter, N47122, sustained substantial damage during engine start-up, about 75 miles southwest of Deadhorse, Alaska. The helicopter was being operated as a visual flight rules (VFR) U.S. Government flight by the U.S Department of Interior, Bureau of Land Management, Fairbanks, Alaska, when the accident occurred. The helicopter, provided by Tundra Copters Inc., Fairbanks, Alaska, was utilized on an on-demand 14 CFR Part 135 flight. The certificated commercial pilot, and the three passengers, were not injured. Visual meteorological conditions prevailed. VFR company flight following procedures were in effect.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on July 8, 1999, the director of operations for Tundra Copters Inc., reported the pilot loaded his passengers into the helicopter at a remote biological survey site. The pilot then began an engine start, but a main rotor blade tie-down strap was still attached to one of the rotor blades. As the rotor blades began to turn, the strap struck the upper end of the vertical stabilizer, crushing the leading edge in an aft direction. The helicopter's tail boom was deformed and wrinkled, just forward of the tail rotor gear box.

Aircraft

Registration
N47122
Reported as
Bell 206B
Category
Helicopter
Serial number
971
Airframe hours
6,274
Engine
Allison C20B, 420 horsepower, turbo shaft
Damage
Substantial damage
Flight
Part 135
Operator
U.S. Bureau Of Land Management
Registered owner
Tundra Copters Inc.
Airworthiness certificate
Standard, Normal
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
Certificates
Flight instructor, Commercial
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 2, Valid Medical--w/ waivers/lim
Seat
Right
Flight hours
6,500 total · 1,100 in this make and model · 6,000 as pilot in command

Weather

Conditions
Visual (VMC) · Day
Wind
40° at 3 knots
Visibility
20 statute miles
Lowest ceiling
None
Temperature
70 °F
Altimeter
29.00 inHg

FAA reports on this event · 1

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