SEA00FA015 · Kaman K-1200
Mountain West Helicopters Kaman K-1200 · Accident: total loss of engine power (mechanical failure) during initial climb
From ID to an unrecorded destination
Event
- NTSB case
- SEA00FA015
- 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
- 0
- 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
- N164KA
- Operator
- Mountain West Helicopters
- Onboard fatalities
- Unknown
- Route
- From IDTo 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
- Initial climb
- 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
- Total loss of engine power (mechanical 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
- Rotor drive system, engine to transmission drive › Separation
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
Shortly after departure, during the initial climb, the helicopter experienced a sudden loss of power and the pilot initiated a forced landing to a nearby road. Post-accident inspection of the transmission assembly revealed that the splined engine adaptor was fractured due to a torsional overstress imposed on the transmission by the engine. It was determined that the adaptor fracture was secondary to another failure further along in the drive train or transmission. Further examination revealed that the helicopter's freewheeling sprag clutch assembly (located at the drive shaft input to the main transmission) exhibited signs of significant wear to include smearing, non-uniform surface wear and cam deformation. Damage or dragging in this assembly could account for the overstress fracture of the adaptor.
Probable cause
Failure of the splined engine adaptor as a result of torsional overstress. Factors include a worn freewheeling clutch assembly.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA00FA015
- Event ID
- 20001212X20172
- Case number
- SEA00FA015
- 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. 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: 75f011f43832e7f8a7fb193c0c943b178bb4af572b6b6499d9a93a59c559a052; retrieved 2026-09-22T13:44:49.874Z.