# NTSB LAX90LA171: Hughes 369E, N5217N, Firebaugh, CA, May 11, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: May 10, 1990, 18:00 local (May 11, 1990, 01:00 UTC)
- Place: Firebaugh, CA
- Coordinates: 36.850002, -120.540664 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=36.8500&lon=-120.5407&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 November 23, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 26800
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX90LA171
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26800/pdf
- Page: https://openairdocs.org/ntsb/LAX90LA171

## Probable cause

FAILURE BY COMPANY MAINTENANCE TO PERFORM A MANDATORY COMPRESSOR SECTION INSPECTION THAT RESULTED IN THE UNDETECTED EROSION OF THE COMPRESSOR VANES AND ENGINE FAILURE. CONTRIBUTING TO THE ACCIDENT WAS THE FAILURE OF THE PILOT TO MAINTAIN ADEQUATE MAIN ROTOR RPM AT CRITICAL ALTITUDE.

## 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
  - maintenance,inspection - not performed, company maintenance personnel (cause)
  - compressor assembly,stator vane - eroded (contributing factor)
  - compressor assembly,stator vane - failure,partial (contributing factor)
  - compressor assembly,stator vane - fractured (contributing factor)
- Forced landing, descent - emergency
  - autorotation - initiated, pilot in command
  - rotor rpm - inadequate, pilot in command (contributing factor)
- Hard landing, landing - flare/touchdown

## Analysis

THE HELICOPTER LOST ENG POWER AND LANDED HARD. THE PLT REPORTED HE HAD JUST COMPLETED RELEASING AN EXTERNAL LOAD. THE HELICOPTER WAS ABOUT 125 FEET AGL IN A CLIMBING LEFT TURN WHEN THE PLT HEARD A LOUD BANG. THE PLT ENTERED AUTOROTATION. THE PLT NOTED THAT THE MAIN ROTOR RPM WAS LOW AND WAS UNABLE TO REGAIN ANY MAIN ROTOR RPM BEFORE THE LANDING FLAIR. AT TOUCHDOWN, THE MAIN ROTOR BLADES FLEXED DOWNWARD AND SEVERED THE TAILBOOM. THE THIRD STAGE COMPRESSOR HAD FAILED, DAMAGING THE REMAINING STAGES OF THE COMPRESSOR. THE COMPRESSOR CASE PLASTIC WAS ERODED. THE ENG HAD UNDERGONE MAJOR MAINTENANCE AT 1,774.5 HOURS WHICH REQUIRED THE REMOVAL OF THE TURBINE SECTION. THERE WAS NO EVIDENCE IN THE ENG LOGBOOKS OF THE COMPRESSOR SECTION BEING INSPECTED AT 1,750 HOURS AS REQUIRED BY THE MANUFACTURER. THE ENGINE MAINTENANCE MANUAL WARNS EROSION WILL CAUSE DAMAGE TO COMPRESSOR BLADES AND VANES.

## Aircraft

- Registration: [N5217N](https://openairdocs.org/deregistered/N5217N-1996-06-26), registration cancelled 1996-06-26, S/N 0134E (OpenAirDocs)
- Reported make and model: HUGHES 369E
- Registry model: [Mcdonnell Douglas Helicopter 369E](https://openairdocs.org/model/mcdonnell-douglas-helicopter-369e) (registry code 3027369) (OpenAirDocs)
- Category: Helicopter
- Serial number: 0134E
- Airframe hours: 1854
- Engines: ALLISON 250 C20B 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Other work use, Part 133
- Registered owner: Rogers Helicopters
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, January 5, 1990, 95 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 55; commercial; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 7,372 total, 1,045 in this make and model, 7,007 as pilot in command, 63 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 290° at 4 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 70 °F, dew point 46 °F
- Altimeter: 29.00 inHg
- Observed at: FAT, 37 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 19900510015639A](https://openairdocs.org/incident/19900510015639A), May 10, 1990: Hughes 369E, Firebaugh, CA, Substantial damage. Compressor section failed after placing load. Dropped line. Autorotated to hard landing. Rotors chopped tailboom.

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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