# NTSB SEA91LA128: Enstrom F280C, N5695Y, Baggs, WY, June 7, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 7, 1991, 07:30 local (13:30 UTC)
- Place: Baggs, WY
- Coordinates: 41.029739, -107.649261 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.0297&lon=-107.6493&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report February 8, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41447
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA91LA128
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41447/pdf
- Page: https://openairdocs.org/ntsb/SEA91LA128

## Probable cause

EXHAUST VALVE FAILURE, RESULTING IN A PARTIAL POWER LOSS. CONTRIBUTING FACTORS WERE LOW ALTITUDE AND ROUGH/UNEVEN TERRAIN.

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, maneuvering
  - engine assembly,valve,exhaust - failure,total (cause)
- Forced landing, descent - emergency
  - autorotation - attempted, pilot in command
- Hard landing, landing - flare/touchdown
  - terrain condition - rough/uneven (cause)

## Analysis

THE PILOT OF THE ENSTROM F280C STATED THAT HE HEARD A LOUD NOISE WHILE FLYING AT 50-100 FEET AGL.  HE THEN DESCENDED TO A FORCED LANDING AS THE ENGINE RPM DECREASED.  HE SET THE AIRCRAFT DOWN HARD IN TALL SAGEBRUSH, CAUSING THE DOWNHILL SKID TO COLLAPSE.  AS A RESULT OF THE HARD IMPACT THE MAIN ROTOR BLADES DROOPED AND SHEARED OFF THE TAIL BOOM.  LATER INSPECTION OF THE ENGINE REVEALED THAT THE NUMBER THREE EXHAUST VALVE STEM HAD BROKEN AND THAT PARTS OF THIS VALVE HAD DESTROYED THE TURBOCHARGER AND BOTH SPARK PLUGS IN THE NUMBER THREE CYLINDER.

## Aircraft

- Registration: [N5695Y](https://openairdocs.org/deregistered/N5695Y-2013-04-23), registration cancelled 2013-04-23, S/N 1205 (OpenAirDocs)
- Reported make and model: ENSTROM F280C
- Registry model: [Enstrom Helicopter 280C](https://openairdocs.org/model/enstrom-helicopter-280c) (registry code 3300505) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1205
- Engines: LYCOMING H1O-360-E1AD 205 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: John L. Irwin
- Registered owner: John L. Irwin
- Departed: BAGGS, WY

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 64; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; flight hours: 7,843 total, 949 in this make and model, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 120° at 5 knots
- Visibility: 60 statute miles
- Lowest ceiling: none
- Temperature: -0 °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 19910607030589A](https://openairdocs.org/incident/19910607030589A), Jun 7, 1991: Enstrm 280C, Baggs, WY, Substantial damage. Loud noise low altitude flight. Setdown hard tall weeds. Rotors. Chopped tail. NR3 valve broke destroyed plugs turb

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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