# NTSB LAX90DUJ03: Hiller UH-12E, N689SB, Yuma, AZ, October 11, 1989

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Final report
- Date: October 10, 1989, 19:27 local (Oct 11, 1989, 02:27 UTC)
- Place: Yuma, AZ
- Coordinates: 32.67937, -114.659225 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=32.6794&lon=-114.6592&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report July 22, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 26542
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX90DUJ03
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26542/pdf
- Page: https://openairdocs.org/ntsb/LAX90DUJ03

## Probable cause

THE PILOT MISJUDGED THE FLARE ALTITUDE. CONTRIBUTING TO THIS ACCIDENT WAS THE FAILURE OF THE ENGINE TORSIONAL COUPLING WHICH ULTIMATELY CAUSED THE TOTAL LOSS OF POWER.

## 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 - aerial application
  - engine assembly,mount - separation (contributing factor)
- Forced landing, descent - emergency
  - autorotation - performed, pilot in command
- In flight collision with terrain/water, landing - flare/touchdown
  - emergency procedure - improper, pilot in command (cause)
  - flare - misjudged, pilot in command (cause)

## Analysis

THE PILOT COMPLETED AN AERIAL APPLICATION OPERATION AT ABOUT 200 FT AGL WHEN HE NOTICED THE ENGINE RPM DECAYING. HE PROCEEDED TO AN OPEN AREA TO EXECUTE A PRECAUTIONARY LANDING. UPON ARRIVING OVER THE OPEN AREA AT ABOUT 100 FT AGL, THE ENGINE SUSTAINED A TOTAL LOSS OF POWER. THE PLT IMMEDIATELY EXECUTED AN AUTOROTATION, BUT FLARED TOO HIGH CAUSING THE TAIL ROTOR ASSEMBLY TO STRIKE THE GROUND. A WRECKAGE EXAM DSCLSD THAT THE ENGINE TORSIONAL COUPLING RUBBER MOUNTS HAD SEPARATED. THIS CONDITION CAUSED AN OVERSPEED WHICH ULTIMATELY SHUT DOWN THE ENGINE.

## Aircraft

- Registration: [N689SB](https://openairdocs.org/deregistered/N689SB-2013-05-02), registration cancelled 2013-05-02, S/N 1475 (OpenAirDocs)
- Reported make and model: HILLER UH-12E
- Registry model: [Hiller UH-12E](https://openairdocs.org/model/hiller-uh-12e) (registry code 4360122) (OpenAirDocs)
- Registry engine: [Lycoming VO-540 series](https://openairdocs.org/engine/lycoming-vo-540-series) (registry code 41534, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1475
- Engines: LYCOMING VO-540 305 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: West Farm Air Inc.
- Registered owner: James P. Smith
- Airworthiness certificate: Special, Restricted (Special); Standard, Utility
- Last inspection: 100 hour, September 21, 1989, 56 hours before
- Departed: SOMERTON, AZ

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; commercial, flight instructor; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 12,900 total, 3,900 in this make and model, 12,400 as pilot in command, 120 in the last 90 days, 68 in the last 30 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night/dark
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 75 °F, dew point -0 °F
- Altimeter: 29.00 inHg

## 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 19891010039579A](https://openairdocs.org/incident/19891010039579A), Oct 10, 1989: Hiller UH12E, Yuma, AZ, Substantial damage. Torsional coupling failed during ag operation. Brief autorotation to impact.

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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