Eurocopter AS-350-B2 N917JT

Summary

On 11 April 2002 at about 22:15 local time, a Eurocopter AS-350-B2 registered N917JT, operated by Evergreen Helicopters of Alaska Inc, was involved in an accident near Valdez, Alaska, United States. 7 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

11 April 2002 at 22:15

Classification

Accident

Location

Valdez, Alaska, United States

Coordinates

61.1833, -145.6167

Aircraft

Eurocopter AS-350-B2

Registration

N917JT

Category

Helicopter

Engines

1

Operator

Evergreen Helicopters of Alaska Inc

Operating rule

Part 135: Air Taxi & Commuter

Phase of flight

Not recorded

Route

Thompson Pass → Tsina Lodge

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ANC02FA029

Nobody was injured.

The pilot's failure to disengage the hydraulic system, and maintain forward airspeed during landing as delineated in the emergency procedures section of the helicopter's operations manual, which resulted in a loss of control while hovering. Factors contributing to the accident were the separation of the hydraulic pump drive belt, and the subsequent lockup of the flight control system.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The pilot of the helicopter was returning to a remote lodge with six skiers aboard. While in cruising flight, the hydraulic pressure warning light on the enunciator panel illuminated, and the aural warning horn sounded, indicating a loss of hydraulic pressure. The pilot confirmed the loss of hydraulic pressure, and slowed the forward airspeed of the helicopter. He cycled the hydraulic cut-off switch on the collective lever by turning the system off momentarily, and then on again. The pilot made a landing pattern and approach to a road, and brought the helicopter to a hover above the road. After coming to a hover the helicopter rolled hard left, and impacted the terrain inverted. According to the helicopter's operator manual, upon loss of hydraulic pressure, the pilot should reduce collective pitch to reduce the airspeed, disengage the collective pitch hydraulic pressure switch, make a flat approach, and land with forward airspeed. An inspection of the helicopter revealed that the hydraulic pump drive belt separated at the point where the belt is bonded together. The separation of the belt resulted in a total loss of hydraulic pressure. The belt is the subject of repeated maintenance inspection and has a life limit of 600 hours of operation. The failed belt had been in operation on the accident helicopter about 419 hours.

Quoted verbatim from the NTSB record.