Garlick UH-1H N85NW

Summary

On 3 June 1997 at about 13:30 local time, a Garlick UH-1H registered N85NW was involved in an accident near Addy, Washington, United States. One person was 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

3 June 1997 at 13:30

Classification

Accident

Location

Addy, Washington, United States

Coordinates

48.3202, -117.9096

Aircraft

Garlick UH-1H

Registration

N85NW

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 133: Rotorcraft Ext. Load

Purpose of flight

Other Work Use

Phase of flight

Not recorded

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

SEA97LA126

Nobody was injured.

The inflight failure of the K-FLEX engine-to-gear box drive shaft and no suitable site in which to make a forced/emergency landing. A factor was the mountainous/hilly terrain.

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

Read the full NTSB narrative

While returning to pick up another log, the pilot heard a high-speed shredding sound' accompanied by high-frequency vibrations. As the noise and vibration increased, the pilot turned downhill and looked for a location where he could make an emergency landing. He then heard a second loud noise, and the rotor RPM immediately began to decay. He stretched his glide over the 130 foot high trees and managed to maneuver the helicopter so that it 'fell into' a switchback on an old dirt logging road. A post accident examination of the K-FLEX drive shaft, which runs between the engine and the transmission, revealed that one of its flex band legs had experienced an inflight fatigue fracture. A review of the records revealed that the shaft had accumulated 459 hours while being used by the United States Army, and had accumulated an additional 432 hours during civilian logging operations.

Quoted verbatim from the NTSB record.