# NTSB SEA87LA007: Hughes 500-D, N58239, Seattle, WA, October 10, 1986

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: October 10, 1986, 08:50 local (15:50 UTC)
- Place: Seattle, WA
- Coordinates: 47.440464, -122.279785 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.4405&lon=-122.2798&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report March 10, 1988
- Report: Approved by Office Director
- NTSB case key (mKey): 40552
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA87LA007
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/40552/pdf
- Page: https://openairdocs.org/ntsb/SEA87LA007

## Sequence of events

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

- Loss of engine power, landing
  - throttle/power lever,linkage - loose (contributing factor)
  - preflight planning/preparation - inadequate, pilot in command (cause)
- Hard landing, landing - flare/touchdown

## Analysis

DURING A PRACTICE AUTOROTATION A LOSS OF POWER OCCURRED. THE PILOT ATTEMPTED ENGINE RECOVERY BUT WAS UNABLE TO RESULTING IN A HARD LANDING IN WHICH THE MAIN ROTOR BLADE FLEXED, SEVERING THE TAIL BOOM. THE THROTTLE LINKAGE ON THE PILOTS SIDE WAS FOUND TO HAVE BEEN OUT OF ADJUSTMENT, CAUSING THE ENGINE POWER TO FALL BELOW IDLE.

## Aircraft

- Registration: [N58239](https://openairdocs.org/deregistered/N58239-1995-07-19), registration cancelled 1995-07-19, S/N 1280392D (OpenAirDocs)
- Reported make and model: HUGHES 500-D
- Registry model: [Hughes Helicopters HUGHES 369D](https://openairdocs.org/model/hughes-helicopters-hughes-369d) (registry code 4470706) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1280392D
- Engines: ALLISON 250-C20B 375 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: The Wright Company
- Airworthiness certificate: Standard, Normal
- Departed: BFI, SEATTLE, WA
- Airport: BFI, Boeing Field, runway 31L, 10,000 × 200 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 4,500 total, 1,000 in this make and model, 4,200 as pilot in command, 100 in the last 90 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 360° at 7 knots
- Visibility: 7 statute miles
- Temperature: 61 °F

## 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 19861010048699A](https://openairdocs.org/incident/19861010048699A), Oct 10, 1986: Hughes 369D, Seattle, WA, Substantial damage. The engine lost power during landing and the helicopter landed hard. Right side throttle cable out of adjustment.

## Other investigations on N58239 (1)

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.

- [NTSB SEA90LA135](https://openairdocs.org/ntsb/SEA90LA135), Jul 13, 1990: Hughes 369D (N58239), Toutle, WA, substantial damage. Probable cause: THE PILOT'S IMPROPER PLANNING/DECISION BY OPERATING AND MANEUVERING THE HELIOCPTER IN A REGIME WHERE HE COULD NOT MAINTAIN ROTOR RPM. THE HIGH DENSITY ALTITUDE AND ROUGH TERRAIN WERE RELATED FACTORS.

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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