SEA86FA039 · Hiller-Soloy UH-12E
Hiller-Soloy UH-12E · Accident: airframe, component or system failure while maneuvering
From HORTON, OR to an unrecorded destination
Event
- NTSB case
- SEA86FA039
- 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
- Instrument Meteorological Cond
Hiller-Soloy UH-12E
- Aircraft type
- Hiller Soloy 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
- N40290
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From HORTON, 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 137: Agricultural
- 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
- Destroyed
Cause areas
- Rotor system, main rotor hub grip(sleeve) › Fatigue
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE FORK CONNECTING THE ROTORCRAFT'S BLUE BLADE TO THE MAIN ROTOR HUB SEPARATED AFTER A LONG TERM FATIGUE CRACK HAD SPREAD THROUGH MORE THAN 60% OF THE FORK CIRCUMFERENCE. THE OPERATOR FAILED TO CARRY OUT THE APPROPRIATE INSPECTION OF THE FORK UNIT AS DELINEATED IN THE FAA AIRWORTHINESS DIRECTIVE DUE IN PART TO CONFUSION OVER THE WORDING OF THE AD COUPLED WITH THE MISPERCEPTION THAT THE FORK REQUIRED ONLY A VISUAL INSPECTION RATHER THAN A DYE PENETRANT CHECK. THE MISPERCEPTION OF THE TYPE OF INSPECTION WAS BORN OUT OF A BELIEF THAT THE ORIGINAL BLADE FORK WITH ITS TEN THOUSAND SERIES SERIAL NUMBER REQUIRED ONLY A VISUAL CHECK. THE INSTALLED BLADE FORK SERIAL NUMBER WAS NO LONGER EVIDENT ON THE PART AND MANUFACTURER RECORDS HAD BEEN LOST THUS PREVENTING THE OPERATOR FROM VERIFYING THE SERIAL NUMBER AND INSTITUTING THE NECESSARY INSPECTION. STRONG GUSTY WINDS EXISTED AT THE ACCIDENT SITE ASSOCIATED WITH FRONTAL PASSAGE AT THE TIME OF THE ACCIDENT.
Verbatim NTSB analysis from the NTSB dataset
Sources
NTSB record SEA86FA039
- Event ID
- 20010110X00259
- Case number
- SEA86FA039
- 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: b945c4c0831eb77eb4215e49dac6b4bdd1c06ff66c2b506e28cae97c33c137ad; retrieved 2026-09-21T04:42:12.624Z.