Kaman K-600 (HH-43B) N286M

Summary

On 21 May 2002 at about 00:45 local time, a Kaman K-600 (HH-43B) registered N286M was involved in an incident near Cocolalla, Idaho, United States. One person was on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

21 May 2002 at 00:45

Classification

Incident

Location

Cocolalla, Idaho, United States

Coordinates

48.0786, -116.6303

Aircraft

Kaman K-600 (HH-43B)

Registration

N286M

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

Cocolalla → Unknown

Aircraft damage

Not recorded

Weather

VMC

Light

Day

NTSB number

SEA02IA096

Nobody was injured.

The reverse installation of the RPM compensator assembly control box bolts resulting in the threaded end of the bolt impinging on a clevis and jamming the collective during climb. A contributing factor was the lack of adequate documentation provided by the technical order instruction for installation of the compensator.

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

Read the full NTSB narrative

The pilot of the Kaman K-600 (HH-43) rotorcraft began to reduce collective to stop the climb and bring the hook into position for another log pickup when the collective effectively jammed at a high power setting forcing the rotorcraft into a climb. The pilot was able to utilize an alternative means of reducing power and, after flight testing the rotorcraft successfully, landed without damage or injury. Post-incident examination revealed that the four hex head bolts that secure the RPM compensator assembly control box into the cabin ceiling had been installed in reverse; such that each bolt head was at the top of the control box with each threaded bolt end extruding downward through the control box bolt retaining ears. This allowed the clevis of the compensator telescopic unit, linked to the collective, to jam against the extended bolt end. The maintenance instructions contained in the Technical Order (T.O.) for the HH-43 were found to contain no instructions relating to the proper orientation of the bolts at installation.

Quoted verbatim from the NTSB record.