Kaman K-600 (HH-43B) incident near Cocolalla, Idaho, May 21, 2002
On May 21, 2002, a Kaman K-600 (HH-43B) (helicopter), registered N286M, was involved in an incident near Cocolalla, Idaho. It was an other work-use flight under external-load helicopter rules (Part 133). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 21, 2002
- Place
- Cocolalla, Idaho · map
- Type
- Incident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Kaman K-600 (HH-43B)
- Registration
- N286M · registry record · serial 110
- Damage
- Not recorded
- Flight
- Other work-use flight · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; rotorcraft: helicopter
- Flight time: 16,000 hours in all; 1,000 in this make and model; 300 in the last 90 days; 100 in the last 30 days; 15,000 as pilot in command
- Last flight review: July 22, 2002
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
- Injury: no injuries
The aircraft
- Last inspection: continuous airworthiness programme, May 20, 2002; 4 hours since
- Maximum gross weight: 9,150 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming T53-L-11 (turboshaft); 0 hours total
The flight
- Departed from: Cocolalla ID at 10:45 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 240° at 11 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 4,400 ft; a few clouds at 3,800 ft
- Temperature: 54°F (12°C), dew point 43°F (6°C)
- Altimeter: 29.79 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N286M the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.