ANC95TA166

NTSB accident investigation · Bell 206B · Glennallen, AK · September 10, 1995

Accident · Serious injuriesFinal report
Date
September 10, 1995, 15:45 local (23:45 UTC)
Place
Glennallen, AK
Injuries
1 serious, 1 minor, 1 uninjured; on the ground: 1 serious
Damage
Destroyed
Phase of flight
Maneuvering
Aircraft
N84TABell 206B
Weather
Visual (VMC) · Day
Status
Completed · report May 9, 1996
Report
Approved by Office Director
NTSB office
Alaska Regional Office
FAA report
19950910028279A
Case key
2751

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 improper in-flight planing/decision and inadequate supervision of the passenger, which allowed the helicopter's lateral center-of-gravity to be exceeded. Factors relating to the accident were: pressure (compelling influence) on the pilot and passenger that was induced by the need to rescue the stranded pilot from a life threatening situation, high winds, and large waves.

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 - in flightHover - in ground effect
Rescue - initiatedPilot in command
Pressure induced by conditions/eventsPilot in commandFactor
Pressure induced by conditions/eventsPassengerFactor
In-flight planning/decision - improperPilot in commandCause
Supervision - inadequatePilot in commandCause
Weather condition - high windFactor
Terrain condition - large wave/swellFactor
Aircraft weight and balance - exceededCause
In flight collision with terrain/waterHover
Terrain condition - water,rough

Analysis

The pilot and passenger of a Bell 206B helicopter, N84TA, overheard radio transmissions about a float equipped Cessna 180A, N94259, that had become inverted on a lake. The helicopter pilot and passenger attempted a rescue of the stranded pilot, who had been sitting on the inverted floats of the airplane for about 5 hours and displayed symptoms of severe hypothermia and shock. A 30 knot wind was producing 3 to 4 feet waves. As the helicopter was hovered next to the airplane, the passenger partially stepped into an external load basket on the right side of the helicopter and began to assist the stranded pilot aboard the helicopter. At about that time, the helicopter began to roll to the right, and the main rotor blades struck the surface of the lake. The helicopter then impacted the lake and sank. The stranded pilot was struck by the helicopter's landing gear skid tube during the crash and received a serious chest injury. The pilot of a third aircraft (float equipped Beaver) observed the events and landed on the lake to rescue all of the participants. (See: ID Number ANC95LA164 for the initial accident involving the Cessna 180.)

Factual narrative

On September 10, 1995, about 1545 Alaska daylight time, a Bell 206B helicopter, N84TA, crashed while conducting a rescue operation on Tazlina Lake, about 20 miles southwest of Glennallen, Alaska. The helicopter was being operated as a visual flight rules (VFR) local area flight under Title 14 CFR Part 91 when the accident occurred. The helicopter, registered to Trans Alaska Helicopters Inc., Anchorage, Alaska, and operated by the U.S. Department of Interior, was destroyed. The certificated commercial pilot received minor injuries. A Bureau of Land Management employee, the sole passenger, was not injured.

A stranded pilot, the subject of the rescue, received serious injuries. Visual meteorological conditions prevailed. The flight originated at the Gulkana airport, Gulkana, Alaska, at 1520.

The operator reported that the helicopter was conducting survey operations and the pilot overheard radio transmissions about a float equipped airplane that had inverted on Tazlina Lake. A military rescue helicopter was reported to have an estimated time of arrival (ETA) at the scene of about 2 hours. The pilot and passenger volunteered to attempt a rescue of the stranded pilot who was reported to be sitting on the inverted floats of the airplane for about 5 hours. The helicopter arrived at the scene and the pilot hovered next to the airplane. The pilot of the airplane displayed symptoms of hypothermia and was unresponsive to the rescuers.

The passenger of the helicopter partially stepped into an external load basket on the right side of the helicopter and attempted to assist the stranded pilot into the right side of the helicopter. This placed a lateral weight change on the right side of the helicopter. The helicopter pilot displaced the cyclic control to the left to maintain a level hover. The helicopter continued tilting to the right and the main rotor blades struck the surface of the lake. The helicopter crashed into the lake and sank.

The two occupants of the helicopter escaped from the helicopter and swam to the stranded pilot who had been thrown into the water. The pilot of a float equipped airplane observed the events and elected to land on the lake. A passenger in the airplane assisted in rescuing the occupants of the helicopter and in getting the stranded pilot onto a float and eventually into the cabin of the airplane. The pilot taxied to the shore of the lake where the military rescue helicopter arrived to transport the victims.

The stranded pilot reported that he was struck by the helicopter's landing gear skid tube during the crash. The pilot's physician reported that he received a bilateral pneumothorax and anterior and posterior rib trauma with flail segments consistent with a heavy crush injury. The initial accident involving the stranded airplane is ANC-95-L-A164.

Aircraft

Registration
N84TA
Reported as
Bell 206B
Category
Helicopter
Serial number
594
Airframe hours
8,118
Engine
Allison 250-C20, 420 horsepower, turbo shaft
Damage
Destroyed
Flight
Public aircraft · Part 91
Operator
U.S. Dept. Of Interior
Registered owner
Trans-Alaska Helicopters Inc.
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · September 6, 1995 · 10 hours before
Departed
GKN · AK

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
35
Certificate
Commercial
Instrument ratings
Helicopter
Medical
Class 2, Valid Medical--no waivers/lim.
Seat
Right
Flight hours
6,500 total · 6,000 as pilot in command · 150 in the last 90 days · 30 in the last 30 days · 5 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
180° at 30 knots
Visibility
30 statute miles
Lowest ceiling
5,500 ft broken
Temperature
50 °F, dew point 45 °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.