# NTSB LAX89LA141: Hughes 369D, N5108E, Vallejo, CA, March 31, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: March 30, 1989, 17:25 local (Mar 31, 1989, 01:25 UTC)
- Place: Vallejo, CA
- Coordinates: 38.089279, -122.24913 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.0893&lon=-122.2491&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report June 22, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 26362
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX89LA141
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26362/pdf
- Page: https://openairdocs.org/ntsb/LAX89LA141

## Probable cause

FATIGUE FAILURE OF A DEFECTIVE PC TUBE ASSEMBLY RESULTING IN A LOSS OF ENGINE POWER. A CONTRIBUTING FACTOR WAS THE UNSUITABLE TERRAIN.

## 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, climb - to cruise
  - fuel system,pc line - fatigue (cause)
  - material defect, manufacturer (cause)
- Forced landing, landing - flare/touchdown
  - autorotation - performed, pilot in command
- On ground/water encounter with terrain/water, landing - flare/touchdown
  - terrain condition - rough/uneven
  - terrain condition - none suitable

## Analysis

DURING AN AIR TAXI CARGO FLIGHT ENGINE POWER WAS SUDDENLY LOST & THE PILOT AUTOROTATED TO A LANDING ON A WET MARSH. AS THE AIRCRAFT CAME TO REST THE MAIN ROTORS SEVERED THE TAIL BOOM. EXAM OF THE ENGINE REVEALED THAT THE PC TUBE ASSEMBLY, P/N 6848471, HAD FAILED AT THE SCROLL FITTING FERRULE, & THIS BROKEN LINE CONDITION PRODUCED AN IMMEDIATE LOSS OF ENGINE POWER. THE PC TUBE HAD A TOTAL OF 11.8 HOURS OF USE SINCE BEING INSTALLED/MANUFACTURED. A METALLURGICAL FAILURE ANALYSIS REVEALED THAT THE PC TUBE HAD FAILED IN FATIGUE.

## Aircraft

- Registration: [N5108E](https://openairdocs.org/aircraft/N5108E), registered now, S/N 811075D, built 1981 (OpenAirDocs)
- Reported make and model: HUGHES 369D
- Registry model: [Hughes Helicopters HUGHES 369D](https://openairdocs.org/model/hughes-helicopters-hughes-369d) (registry code 4470706) (OpenAirDocs)
- Registry engine: [Allison 250-C20 series](https://openairdocs.org/engine/allison-250-c20-series) (registry code 03020, turbo-prop) (OpenAirDocs)
- Category: Helicopter
- Serial number: 811075D
- Airframe hours: 1697
- Engines: ALLISON C250-C20B 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 135
- Operator: Helinet, Inc., doing business as Helinet Aviation Services
- Registered owner: R.S. Aviation Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, March 20, 1989, 12 hours before
- Departed: 056, NOVATO, CA
- Destination: CCR, CONCORD, CA
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 32; flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 5,017 total, 284 in this make and model, 4,933 as pilot in command, 187 in the last 90 days, 84 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 30 statute miles
- Lowest ceiling: none
- Temperature: 70 °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 19890330005139A](https://openairdocs.org/incident/19890330005139A), Mar 30, 1989: Hughes 369D, Vallejo, CA, Substantial damage. Engine quit on climbout autorotated to a hard landing. Main rotors chopped tail. Fuel pressure control tube cracked

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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