Garlick UH-1H N97NW

Summary

On 12 August 1996 at about 18:30 local time, a Garlick UH-1H registered N97NW was involved in an accident near Coeur D'alene, Idaho, United States. One person was on board and one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

12 August 1996 at 18:30

Classification

Accident

Location

Coeur D'alene, Idaho, United States

Coordinates

47.5897, -116.9096

Aircraft

Garlick UH-1H

Registration

N97NW

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

Route

4TH of Jul Pass → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

SEA96FA187

1 person was seriously injured.

Fatigue fracture of the left forward vertical stabilizer spar, resulting in loss of the vertical stabilizer and tail rotor and subsequent loss of control. A factor was insufficient applicability (by make and model) of an existing FAA airworthiness directive (AD 71-21-02) which mandated repetitive crack inspections in the area of the fracture.

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

Read the full NTSB narrative

The aircraft, originally manufactured by Bell as a military helicopter, had received civil type certification under a different manufacturer. While conducting external load logging operations, the helicopter's vertical fin and tail rotor separated from the tail boom and the helicopter subsequently crashed. Postaccident investigation revealed that the left side of the forward vertical fin spar had a fatigue fracture originating at the first rivet hole above the intersection of the tail boom and the vertical fin. Between March and November 1996, two other similar helicopters (a Bell 205A-1 and a Garlick TH-1L) also crashed during external load operations after their vertical fins separated due to fatigue at the same location on the spar. An existing airworthiness directive (AD) on the Bell 205A-1, AD 71-21-02, contained procedures for checking the fracture area on these aircraft for cracks, but did not apply to any of the aircraft as the 205A-1 which crashed had modifications which exempted it from the AD, and the UH-1H and TH-1L were type-certificated as different make and model aircraft.

Quoted verbatim from the NTSB record.