# NTSB SEA83FA065: Fairchild Hiller FH-1100, N26631, Longview, WA, March 18, 1983

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Field investigation · Final report
- Date: March 18, 1983, 15:10 local (23:10 UTC)
- Place: Longview, WA
- Coordinates: 46.190799, -123.050476 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=46.1908&lon=-123.0505&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 39603
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA83FA065
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/39603/pdf
- Page: https://openairdocs.org/ntsb/SEA83FA065

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise
  - rotor drive system,main gearbox/transmission - fatigue (cause)
  - rotor drive system,main gearbox/transmission - failure,partial (cause)
  - rotor drive system,main gearbox/transmission - corroded (contributing factor)
- Loss of control - in flight, cruise
  - aircraft handling - not possible, pilot in command (contributing factor)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

SEVERAL PERSONS SAW THE HELICOPTER FLYING AT A CRUISING ALTITUDE OF ABOUT 200 TO 300 FT, THEN ENTER A LOOP TYPE OF MANEUVER. THEY LOST SIGHT OF THE HELICOPTER NEAR THE BOTTOM OF THE MANEUVER BEFORE IT CRASHED. THE PLT RECEIVED SERIOUS HEAD INJURIES & COULD NOT RECALL WHAT HAD HAPPENED. AN EXAM OF THE AIRFRAME REVEALED THAT THE TRANSMISSION & MAIN ROTOR HUB ASSY HAD REMAINED PARTIALLY ATTACHED TO THE AIRFRAME THRU THE LEFT & RIGHT LONGITUDINAL TRANSMISSION STRUTS. BOTH THE LEFT & RIGHT VERTICAL AS WELL AS BOTH LEFT & RIGHT LATERAL TRANSMISSION STRUTS HAD SEPARATED NEAR THEIR ATTACH POINTS. A METALLURGICAL EXAM OF THESE PARTS REVEALED THAT FITTING ASSEMBLY, PN 24-61022-6 HAD FAILED AT A FATIGUE CRACK. ADDITIONALLY, CORROSION WAS FOUND WITHIN THE LEFT VERTICAL & LATERAL (ADJUSTABLE) TRANSMISSION STRUTS. PREIMPACT CONTINUITY OF THE CYCLIC PITCH CONTROL WAS VERIFIED.

## Aircraft

- Registration: N26631 (not matched to a registry record)
- Reported make and model: Fairchild Hiller FH-1100
- Category: Helicopter
- Serial number: 225
- Airframe hours: 1725
- Engines: ALLISON 250-C18B 317 horsepower turbo shaft
- Damage: Destroyed
- Flight: Personal, Part 91
- Registered owner: Archie Radakovich
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, March 15, 1983, 1 hours before
- Departed: NONE, LONGVIEW, WA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 69; commercial; airplane ratings: single-engine land, single-engine sea; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 5,443 total, 14 in this make and model, 3 in the last 90 days, 2 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 350° at 4 knots
- Visibility: 55 statute miles
- Lowest ceiling: none
- Temperature: 63 °F, dew point 28 °F
- Altimeter: 29.00 inHg
- Observed at: TDO, 21 nm away

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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