# NTSB DEN85LA038: Hughes 369D, N5124X, Spanish Fork, UT, December 8, 1984

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: December 8, 1984, 09:15 local (16:15 UTC)
- Place: Spanish Fork, UT
- Coordinates: 40.019748, -111.550315 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.0197&lon=-111.5503&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16606
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN85LA038
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16606/pdf
- Page: https://openairdocs.org/ntsb/DEN85LA038

## Sequence of events

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

- Loss of engine power(total) - nonmechanical, cruise
  - lubricating system - foreign object (cause)
  - maintenance,service of aircraft/equipment - inattentive (cause)
  - lubricating system - blocked(total)
  - fluid,oil - starvation (cause)
  - turbine assembly,shaft bearing - failure,total
  - compressor assembly - failure,partial
  - lubricating system,oil scavenge pump - overtemperature
- Forced landing, descent - emergency
  - autorotation - performed, pilot in command
- Other gear collapsed, landing
  - terrain condition - snow covered (contributing factor)
  - landing gear,skid assembly - overload
- Roll over, landing

## Analysis

SHORTLY AFTER TAKEOFF PLT FELT SHUTTER IN ACFT AND NOTICED A RISE IN THE TURBINE OUTLET TEMP. PLT HEARD LOW WHINE OF HIGH PITCH NOISE IN ENGINE. ENGINE CHIP DETECTOR LIGHT CAME ON FOLLOWED BY THE ENGINE OUT LIGHT AND HORN AND OIL PRESSURE WARNING LIGHT. AUTOROTATION MADE TO OPENING AT BOTTOM OF CANYON. ON TOUCHDOWN ACFT SLID FORWARD IN 1 FT DEEP SNOW, RT SKID COLLAPSED AND HELICOPTER ROLLED OVER ON ITS RIGHT SIDE. INSPECTION REVEALED EVIDENCE OF OIL STARVATION IN TURBINE AND COMPRESSOR SECTIONS. TURBINE BEARINGS FAILED, GEARBOX BEARINGS BORE EVIDENCE OF HIGH HEAT DISTORTION AND OIL STARVATION WAS EVIDENT IN COMPRESSOR BEARINGS. LUBRICATION SYSTEM COMPONENTS WERE CHECKED AND OPERATED NORMALLY. A 1 1/8 IN DISK OF GASKET LIKE MATERIAL WAS FOUND IN OIL RESERVOIR. DISK WAS SIMILIAR TO THOSE IN CAPS ON QUARTS OF OIL. DISK WAS SAME SIZE AS OPENING TO OIL PUMP AND ENGINE. WHEN PLACED OVER OPENING OIL FLOW FROM TANK TO ENGINE WAS BLOCKED. EXTRA QTS OF OIL OFTEN WERE ON BOARD ACFT SO PLT COULD ASS OIL IF REQUIRED.

## Aircraft

- Registration: N5124X (not matched to a registry record)
- Reported make and model: HUGHES 369D
- Category: Helicopter
- Serial number: 911099D
- Airframe hours: 983
- Engines: ALLISON 250-C20B 375 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 135
- Registered owner: Rocky Mountain Helicopters,
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, October 30, 1984, 79 hours before
- Departed: PUC, PRICE, UT

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 50; commercial; airplane ratings: multi-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 9,725 as pilot in command, 155 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Day
- Wind: calm
- Visibility: 1 statute miles
- Lowest ceiling: 6,000 ft overcast
- Temperature: 32 °F, dew point 30 °F
- Altimeter: 30.00 inHg
- Observed at: PVU, 22 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 19841208065529A](https://openairdocs.org/incident/19841208065529A), Dec 8, 1984: Hughes 369D, Spanish Fork, UT, Substantial damage. Engine quit. On landing, rolled over. Gasket from cap of quart oil container. Found in oil tank, blocked oil flow.

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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