SEA87FA106 · Hiller UH-12E
Olympic Air Hiller UH-12E · Accident: abrupt maneuver en route
From S42 · Silverdale, WA to Sanderson Field (SHN)
Event
- NTSB case
- SEA87FA106
- 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
- 1 · 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
Hiller UH-12E
- Aircraft type
- Hiller UH-12
- 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
- N28875
- Operator
- Olympic Air
- Onboard fatalities
- Unknown
- Route
- From S42 · Silverdale, WATo Sanderson Field (SHN), Shelton, WA
- 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
- Abrupt maneuver
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Pilot in command › Rotorcraft flight controls, excessive
- Rotor drive system, main rotor mast(drive shaft) › Failure, total
- Rotor system › Separation
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE PILOT WAS PROPERLY CERTIFICATED FOR THE FLIGHT; HOWEVER, DUE TO OPERATOR INSURANCE RESTRICTIONS, ALL PRIOR COMMERCIAL FLIGHTS HAD REQUIRED THE OWNER/OPERATOR TO ACCOMPANY THIS PILOT, THEREFORE THIS WAS THE PILOT'S FIRST COMMERCIAL FLIGHT AS SOLE PILOT. RETURNING TO BASE AFTER A ROUND-TRIP PASSENGER FLIGHT, HAVING DISEMBARKED PASSENGERS, THE AIRCRAFT WAS OBSERVED PROCEEDING AT HIGH FORWARD SPEED IN STRONG BUT INTERMITTENT WIND CONDITIONS. ALSO, PASSENGERS REMARKED ABOUT TURBULENCE ALONG THIS SAME ROUTE OF FLIGHT EARLIER. INVESTIGATION REVEALED THE MAIN ROTOR SEPARATED IN FLIGHT DUE TO MAST BUMPING, A PHENOMENON ASSOCIATED WITH TEETERING ROTOR SYSTEMS, INDUCED BY EXCEEDING THE NORMAL FLIGHT ENVELOPE FOR THE AIRCRAFT.
Verbatim NTSB analysis from the NTSB dataset
Sources
NTSB record SEA87FA106
- Event ID
- 20001213X31041
- Case number
- SEA87FA106
- 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: 29da46c55ff7b65d0490f340c1594bb20ebdc0deb8a275cc955d060940ff0732; retrieved 2026-09-21T04:07:38.265Z.