# NTSB LAX89DVM02: Hiller UH-12E, N169HA, Salinas, CA, April 26, 1989

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Final report
- Date: April 26, 1989, 11:00 local (19:00 UTC)
- Place: Salinas, CA
- Location: 36.6902° N, 121.6338° W: Placed by OpenAirDocs: center of Salinas, CA, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=36.6902&lon=-121.6338&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report May 22, 1990
- Report: Approved by Office Director
- NTSB case key (mKey): 26174
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX89DVM02
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26174/pdf
- Page: https://openairdocs.org/ntsb/LAX89DVM02

## Probable cause

THE SEPARATION OF THE TORSION COUPLING IN THE MAIN ROTOR DRIVE SYSTEM.

## Sequence of events

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

- Airframe/component/system failure/malfunction, maneuvering - aerial application
  - rotor drive system - separation (cause)
- Forced landing, descent - emergency
- Hard landing, landing - flare/touchdown
  - terrain condition - open field
  - misc rotorcraft,tail boom - sheared

## Analysis

DURING AN AERIAL APPLICATION FLIGHT, THE ENGINE RPM INCREASED AND THE ROTOR RPM DECREASED. THE PILOT AUTOROTATED TO AN OPEN FIELD WHERE AFTER TOUCHDOWN, THE MAIN ROTOR BLADES SEVERED THE TAIL BOOM. INSPECTION OF THE ENGINE REVEALED THAT THE TORSION COUPLING WAS SEPARATED IN THE MAIN ROTOR DRIVE SYSTEM.

## Aircraft

- Registration: [N169HA](https://openairdocs.org/deregistered/N169HA-2012-08-10), registration cancelled 2012-08-10, S/N HA3069, built 1977 (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: HA 3069
- Airframe hours: 4109
- Engines: LYCOMING VO-540-C2A 305 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Registered owner: Helicair Ag Inc
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: 100 hour, March 17, 1989, 21 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 35; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 7,576 total, 1,500 in this make and model, 104 in the last 90 days, 38 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 290° at 5 knots
- Visibility: 40 statute miles
- Lowest ceiling: none
- Temperature: 59 °F
- Altimeter: 30.00 inHg
- Observed at: SNS, 5 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 19890426010059A](https://openairdocs.org/incident/19890426010059A), Apr 26, 1989: Hiller UH12E, Salinas, CA, Substantial damage. RPM increase and rotor decay on swath run. Sudden stop in lettuce field cut off tailboom. Torsion coupling failed.

## Other investigations on N169HA (2)

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.

- [NTSB LAX86FVM06](https://openairdocs.org/ntsb/LAX86FVM06), Aug 12, 1986: Hiller UH21E (N169HA), Salinas, CA, substantial damage
- [NTSB LAX81FVA28](https://openairdocs.org/ntsb/LAX81FVA28), Mar 11, 1981: Hiller Acft UH12E (N169HA), Huron, CA, substantial damage

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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