Western UH-1H N205GL

Summary

On 7 February 2001 at about 21:00 local time, a Western UH-1H registered N205GL was involved in an accident near Darby, Montana, United States. One person was on board and one died. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

7 February 2001 at 21:00

Classification

Accident

Location

Darby, Montana, United States

Coordinates

45.7791, -114.2392

Aircraft

Western UH-1H

Registration

N205GL

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

Darby → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

SEA01LA046

1 person died.

Inflight loss of a tail rotor pitch change link-to-blade grip attach bolt, resulting partial loss of tail rotor control, and subsequent entanglement of the helicopter's external load cable with a tree during emergency descent. Factors included the pilot's retention of external load equipment, and the tree in which the external load cable became entangled.

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

Read the full NTSB narrative

The pilot was on the last half of his first external load of the afternoon when he reported over the radio, " tail rotor failure, look out landing" (referring to the log landing crew.) The pilot released his logs from the lower hook, but retained his 150-foot line. He flew over the log landing to regain airspeed, but the helicopter's long line then snagged a tree on the far side of the landing, causing the aircraft to roll left and pitch nose down. The aircraft impacted the ground 250 feet from the snagged tree, nose low, with between 100 and 130 degrees of left roll, landing on the top left crew door post. During post-accident examination, one of the pitch links on the tail rotor hub was found disconnected from the pitch horn on the tail rotor grip. The attaching bolt, nut, cotter key and washers associated with the disconnected tail rotor pitch link were missing and were not located. No other evidence of inflight malfunction of the tail rotor drive train or tail rotor control system was noted. Examination of the tail rotor pitch change links and blade grip horns at the NTSB Materials Laboratory disclosed evidence of a complete loss of the pitch change link-to-blade grip horn attach bolt before ground impact, as a result of either its nut backing off inflight or of the bolt itself fracturing inflight.

Quoted verbatim from the NTSB record.