# NTSB DEN83FA224: Hughes 369D (500), N8693F, Provo, UT, September 30, 1983

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Field investigation · Final report
- Date: September 30, 1983, 10:00 local (17:00 UTC)
- Place: Provo, UT
- Coordinates: 40.219486, -111.690216 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.2195&lon=-111.6902&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16005
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN83FA224
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16005/pdf
- Page: https://openairdocs.org/ntsb/DEN83FA224

## 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, maneuvering
  - fuel system,line fitting - loose (cause)
  - maintenance,100-hour inspection - inadequate (cause)
  - fuel system,line - leak (cause)
  - fluid,fuel - starvation (cause)
- Forced landing, landing
  - autorotation - performed, pilot in command
- Nose down, landing
  - terrain condition - soft (contributing factor)
  - terrain condition - wet (contributing factor)

## Analysis

THE HELICOPTER WAS ON A TEST FLT TO TRACK & BALANCE THE MAIN ROTOR SYSTEM & TO COMPLETE A 100 HR INSPECTION. PRIOR TO THE FLT, AN OCCASIONAL FLICKER OF THE FUEL FILTER LIGHT WAS NOTED, BUT IT WAS THOUGHT TO BE A WIRING PROBLEM. AFTER TAKING OFF, THE FUEL FILTER LIGHT FLICKERED ON A FEW MORE TIMES, BUT NEVER ILLUMINATED STEADILY. AFTER LESS THAN A MINUTE OF FLYING TIME, THE PLT FELT 2 QUICK 'JERKS' (YAWS). HE START A 180 DEG TURN TO LAND. AFTER 90 DEG OF TURN, THE N2 DECREASED TO 95%, THEN SURGED TO 105%, THEN THE ENG QUIT RUNNING. THE PLT INITIATED AN AUTOROTATION, BUT DURING LANDING ON SOFT, WET TERRAIN, THE HELICOPTER ROCKED FORWARD & THE MAIN ROTOR STRUCK THE TAIL BOOM. AN EXAM OF THE HELICOPTER REVEALED A 'B' NUT ON 1 OF 2 DIFFERENTIAL PRESSURE LINES (CONNECTED TO THE FUEL FILTER DIFFERENTIAL PRESSURE SWITCH) WAS LOOSE. DURING THE EXAM, THE 'B' NUT SEPARATED FROM ITS ATTACH POINT BY A 1/2 TURN USING FINGER PRESSURE.

## Aircraft

- Registration: N8693F (not matched to a registry record)
- Reported make and model: HUGHES 369D (500)
- Category: Helicopter
- Serial number: 180252D
- Airframe hours: 3183
- Engines: ALLISON 250-C20B 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 91
- Registered owner: Rocky Mountain Helicopter, Inc
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, September 30, 1983, 0 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 40; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 10,500 total, 500 in this make and model, 200 in the last 90 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 45 statute miles
- Lowest ceiling: 12,000 ft broken
- Temperature: 57 °F, dew point 48 °F
- Altimeter: 29.00 inHg
- Observed at: PVU, 2 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 19830930052869A](https://openairdocs.org/incident/19830930052869A), Sep 30, 1983: Hughes 369D, Provo, UT, Substantial damage. Engine quit on a maintenance test flight. Severed tail boom onlanding. Loose b nut on fuel line ingested air.

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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