SEA83FA135 · Enstrom 280C
Enstrom 280C · Accident: airframe, component or system failure en route
From King County International Airport - Boeing Field (BFI) to an unrecorded destination
Event
- NTSB case
- SEA83FA135
- 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
Enstrom 280C
- Aircraft type
- Enstrom 280
- 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
- N652H
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From King County International Airport - Boeing Field (BFI), Seattle, WATo 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 91: General Aviation
- 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
- En route · cruise
- 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
- Other maintenance personnel › Maintenance, lubrication, inadequate
- Rotor drive system, tail rotor gearbox(90 deg) › Other
- Rotor drive system, tail rotor gearbox(90 deg) › Worn
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
DURING A TRAFFIC REPORTING FLT FOR A RADIO STATION, THE PLT NOTED THE ONSET OF A SEVERE VIBRATION WHICH HE FELT THROUGH THE ANTITORQUE PEDALS. HE STATED THAT WITHIN SECONDS, THE HELICOPTER LOST DIRECTIONAL CONTROL & BEGAN A RAPID, UNCONTROLLED SPIN TO THE RIGHT. REPORTEDLY, THE HELICOPTER TUMBLED OUT OF CONTROL FOR A TIME. HOWEVER, THE PLT WAS ABLE TO REGAIN PARTIAL CONTROL AS IT ROLLED THRU A RELATIVELY UPRIGHT ATTITUDE. BEFORE CRASHING, THE RATE OF DESCENT WAS SLOWED WITH FULL COLLECTIVE & A ROTATING IMPACT OCCURRED IN A HORIZONTAL ATTITUDE. AN INVESTIGATION REVEALED THE TAIL ROTOR DRIVE SHAFT SPLINE COUPLING, PN 28-13609, HAD BECOME WORN. THE TEETH OF THE COUPLING WERE WORN AWAY & THERE WAS IRON OXIDE & CARBONIZED LUBRICANT WITHIN THE COUPLING. THE SPLINED MALE END OF THE COUPLING WOULD ROTATE WITHIN THE SPLINED FEMALE HOUSING. IT HAD ACCUMULATED 149.1 HRS SINCE LUBRICATED. THE LUBRICATION CHART & CHECK SHEET (PAGES MM-3-5 & MM-3-6 OF THE MAINTENANCE MANUAL) SHOW THAT THE COUPLING SHOULD BE LUBED AT 100 HR INTERVALS
Verbatim NTSB analysis from the NTSB dataset
Sources
NTSB record SEA83FA135
- Event ID
- 20001214X43526
- Case number
- SEA83FA135
- 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: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1983-06-28.
- API snapshot SHA-256: 2831a5ca7e3e06fa64d4d7c6bdc2fbce0e43f208f6d0be9f84215a5a132b188e; retrieved 2026-09-22T02:36:36.320Z.