Hughes OH-6A N61869

Summary

On 20 April 2000 at about 14:15 local time, a Hughes OH-6A registered N61869 was involved in an accident near Green Valley, Arizona, United States. One person was on board and one had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

20 April 2000 at 14:15

Classification

Accident

Location

Green Valley, Arizona, United States

Coordinates

31.8092, -110.9196

Aircraft

Hughes OH-6A

Registration

N61869

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Public Use

Phase of flight

Not recorded

Route

Tucson → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

LAX00TA163

1 person had minor injuries.

Company maintenance personnel's failure to secure an attachment nut to a control link. While maneuvering, the parts separated and resulted in the total cyclic control system failure and impact into rough terrain.

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

Read the full NTSB narrative

While maneuvering about 20 feet above obstacles looking for the footprints of a group of suspected illegal entrants, the U.S. Border Patrol pilot suddenly experienced an unusual vibration in the cyclic control. After the vibration started, the helicopter almost immediately started turning right and descended. The pilot attempted to stop the turn and descent, but to no avail, and he crashed in the rough terrain. The previous day a 300-hour inspection had been completed by Border Patrol mechanics, and it involved a rebuild of the swashplate assembly. During this maintenance, the cyclic control's longitudinal link (part number 369A7608) was removed and replaced at the stationary swashplate. Upon completion of the maintenance, a cotter pin is required to be installed in the link's attachment nut to secure it. The cotter pin, and the respective nut, were observed missing at the accident site. During the recent maintenance, a mechanic had failed to reinstall the cotter pin into the nut, and it backed off during flight. This maintenance oversight-related failure resulted in the pilot's complete loss of cyclic control.

Quoted verbatim from the NTSB record.