SEA06LA065 · Kaman K-1200
Kaman K-1200 · Accident: airframe, component or system failure while maneuvering
From Dexter, OR to an unrecorded destination
Event
- NTSB case
- SEA06LA065
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Kaman K-1200
- Aircraft type
- Kaman K-1200
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N133KA
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Dexter, ORTo not recorded
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 133: Rotorcraft Ext. Load
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Maneuvering
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Airframe, component or system failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Pilot in command › Emergency procedure, not followed
- Pilot in command › Rotor RPM, not identified
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
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.
Probable cause
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.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA06LA065
- Event ID
- 20060327X00352
- Case number
- SEA06LA065
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: e2b3abe8d6e0f35e0f7858853137ced4468b9974b931a5990b09fe4c5f04c5f1; retrieved 2026-09-21T18:48:55.045Z.