# NTSB SEA90LA116: Enstrom F28C, N51729, Camas, WA, June 7, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 6, 1990, 17:30 local (Jun 7, 1990, 00:30 UTC)
- Place: Camas, WA
- Coordinates: 45.640892, -122.369194 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.6409&lon=-122.3692&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report October 20, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 41224
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA90LA116
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41224/pdf
- Page: https://openairdocs.org/ntsb/SEA90LA116

## Probable cause

THE FAILURE OF A SPRAG CLUTCH IN THE ROTOR-DRIVE MECHANISM, AT AN ALTITUDE AND POSITION THAT PRECLUDED OR LIMITED THE POSSIBILITY OF A SUCCESSFUL OUTCOME.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, takeoff - initial climb
  - rotor drive system,freewheeling sprag unit - failure,total (cause)
- Forced landing, descent - emergency
  - autorotation - performed, pilot in command
  - altitude - inadequate (contributing factor)
- Hard landing, landing - flare/touchdown

## Analysis

THE OWNER OF THE ENSTROM HELICOPTER, WHICH WAS OUT OF ANNUAL INSPECTION LIMITATIONS, ELECTED TO FLY IT OFF A TRAILER IN ORDER TO REPOSITION IT FOR MAINTENANCE PRIOR TO A FERRY FLIGHT. AT ABOUT FIFTY FEET, HE HEARD A LOUD NOISE, THE ENGINE SPEED INCREASED, AND THE ENGINE BECAME DISENGAGED FROM THE ROTOR DRIVE SYSTEM. AN AUTOROTATION WAS MADE, BUT THE HELICOPTER SUSTAINED SUBSTANTIAL DAMAGE. THE OWNER STATED HE BELIEVED THAT THE SPRAG CLUTCH FAILED.

## Aircraft

- Registration: [N51729](https://openairdocs.org/deregistered/N51729-2013-04-01), registration cancelled 2013-04-01, S/N 420, built 1978 (OpenAirDocs)
- Reported make and model: ENSTROM F28C
- Registry model: [Enstrom F-28C](https://openairdocs.org/model/enstrom-f-28c) (registry code 3300407) (OpenAirDocs)
- Registry engine: [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series) (registry code 41524, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 420
- Airframe hours: 795
- Engines: LYCOMING HIO-360-E1AD 205 horsepower reciprocating
- Damage: Substantial damage
- Flight: Positioning, Part 91
- Registered owner: Darrell R. Jones
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, August 29, 1988

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; airline transport, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 2,520 total, 715 in this make and model, 2,230 as pilot in command, 22 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 64 °F, dew point -0 °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 19900606040269A](https://openairdocs.org/incident/19900606040269A), Jun 6, 1990: Enstrm F28C, Camas, WA, Substantial damage. Lifted off dolly to position other side of fence. Sprague clutch broke disengaging engine to rotors. Crash landed.

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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