# NTSB SEA86FA039: Hiller-Soloy UH-12E, N40290, Horton, OR, January 16, 1986

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: January 16, 1986, 12:38 local (20:38 UTC)
- Place: Horton, OR
- Coordinates: 44.169036, -123.570198 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=44.1690&lon=-123.5702&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 40264
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA86FA039
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/40264/pdf
- Page: https://openairdocs.org/ntsb/SEA86FA039

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, maneuvering
  - rotor system,main rotor hub grip(sleeve) - fatigue (cause)
  - maintenance,inspection - inadequate, company maintenance personnel (contributing factor)
  - information insufficient, company maintenance personnel (contributing factor)
  - insufficient standards/requirements, faa(organization) (contributing factor)
  - maintenance,recordkeeping - poor, manufacturer (contributing factor)
  - weather condition - gusts (contributing factor)
- Loss of control - in flight, descent - uncontrolled
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

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.

## Aircraft

- Registration: [N40290](https://openairdocs.org/aircraft/N40290), registered now, S/N HA3081, built 1980 (OpenAirDocs)
- Reported make and model: Hiller-Soloy UH-12E
- Registry model: [Hiller UH-12E](https://openairdocs.org/model/hiller-uh-12e) (registry code 4360122) (OpenAirDocs)
- Registry engine: [Allison 250 series](https://openairdocs.org/engine/allison-250-series) (registry code 03014, turbo-prop) (OpenAirDocs)
- Category: Helicopter
- Serial number: HA3081
- Airframe hours: 2288
- Engines: ALLISON 250-020 305 horsepower turbo shaft
- Damage: Destroyed
- Flight: Aerial application, Part 137
- Registered owner: Western Helicopter Services
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: AAIP, December 19, 1985, 28 hours before
- Departed: HORTON, OR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 37; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 4,733 total, 3,100 in this make and model, 4,733 as pilot in command, 120 in the last 90 days, 4 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Day
- Wind: 160° at 19 knots, gusting 23
- Visibility: 2 statute miles
- Lowest ceiling: 1,200 ft broken
- Temperature: 54 °F, dew point 52 °F
- Altimeter: 29.00 inHg
- Observed at: EUG, 10 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19860116000729A](https://openairdocs.org/incident/19860116000729A), Jan 16, 1986: Hiller UH12E, Horton, OR, Destroyed. Main rotor fork failed by fatigue crack at the countersunk hole for the t t pin. Not dye checked as per a d.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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