Kaman K-1200 accident near Dexter, Oregon, March 12, 2006
On March 12, 2006 at about 7:00 pm local time, a Kaman K-1200 (helicopter), registered N133KA, was substantially damaged in an accident near Dexter, Oregon. It was an external-load flight under external-load helicopter rules (Part 133). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's failure to identify the overspeed of the helicopter's main rotors due to a turbine governor malfunction, and his failure to take the appropriate actions described in the Flight Manual's emergency procedures section. Factors include the malfunction (partial bypass) of a lubricating system filter screen, which led to the partial blockage of an oil supply orifice, resulting in the failure of the splines on the power turbine governor speed input shaft, and ultimately to the loss of the governor's ability to correctly control fuel input to the engine. Additional factors include no suitable landing terrain and tree stumps in the area the pilot elected to land in.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 12, 2006 · about 7:00 pm local time
- Place
- Dexter, Oregon · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Kaman K-1200
- Registration
- N133KA · no longer on the register · serial 0005
- Damage
- Substantial damage
- Flight
- External-load flight · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
While approaching the collection point with a load of logs, the helicopter's power turbine and rotor system experienced a steady-state overspeed due to the failure of the splines on the shaft that provides turbine speed input to the turbine governor. Without this input, the governor erroneously sensed a turbine underspeed, and therefore provided fuel in excess of that required to maintain the correct speed. The splines failed due to a significant reduction in the flow of lubricating oil resulting from the partial blockage of an oil filter outflow orifice. The outflow orifice became partially blocked because the oil filter screen was aligned in its housing in a manner that allowed some contaminants to bypass it. Although the Kaman K-1200 Flight Manual contains an emergency procedure that allows for the pilot to take manual (non-governed) control of the fuel input to the engine in the event of a governor failure, the pilot did not perform the procedure because he was not able to correctly identify the cause of the sequence of events.
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: airline transport pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 16,300 hours in all; 760 in this make and model; 250 in the last 90 days; 70 in the last 30 days; 15,100 as pilot in command
- Last flight review: May 1, 2005
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: ctr
- Injury: minor injuries
The aircraft
- Airframe total time: 12,675 hours
- Last inspection: approved inspection programme, March 1, 2006; 13 hours since
- Maximum gross weight: 12,000 lb
- Seats: 1
- Landing gear: fixed
- Engine: Lycoming T-53-17A-1 (turboshaft); 0 hours total
The flight
- Departed from: Dexter OR at 6:40 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 36°F (2°C), dew point 0°F (-18°C)
- Altimeter: 30.04 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.
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.