# NTSB SEA90LA121: Hiller UH-12D, N62431, Walla Walla, WA, July 4, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 4, 1990, 07:15 local (14:15 UTC)
- Place: Walla Walla, WA
- Coordinates: 46.109523, -118.299392 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=46.1095&lon=-118.2994&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report December 15, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 41229
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA90LA121
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41229/pdf
- Page: https://openairdocs.org/ntsb/SEA90LA121

## Probable cause

A LOSS OF ENGINE POWER FOR UNDETERMINED REASONS.

## Sequence of events

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

- Loss of engine power, maneuvering - aerial application
  - reason for occurrence undetermined (cause)
- Forced landing, descent - emergency
  - autorotation - performed, pilot in command
- In flight collision with terrain/water, landing - flare/touchdown
  - terrain condition - crop

## Analysis

THE HELICOPTER WAS SUBSTANTIALLY DAMAGED DURING A FORCED LANDING, WHEN THE SKIDS CAUGHT IN PEA VINES OF THE CROP THE PILOT WAS SPRAYING. HE STATED THAT THE ENGINE SUSTAINED A SUDDEN POWER LOSS. DURING A POST-ACCIDENT CHECK, THE ENGINE STARTED NORMALLY AND RAN TO 3200 RPM.

## Aircraft

- Registration: N62431 (not matched to a registry record)
- Reported make and model: HILLER UH-12D
- Category: Helicopter
- Serial number: 956
- Airframe hours: 9084
- Engines: LYCOMING VO-435-A1C 250 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Registered owner: Blue Mountain Aviation
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, January 10, 1990, 44 hours before
- Departed: ALW, WALLA WALLA, WA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 44; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 5,060 total, 400 in this make and model, 250 in the last 90 days, 80 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 210° at 3 knots
- Visibility: 25 statute miles
- Temperature: 61 °F, dew point -0 °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 19900704025329A](https://openairdocs.org/incident/19900704025329A), Jul 4, 1990: Hiller UH12D, Walla Walla, WA, Substantial damage. Lost power. Autorotated into pea vines. Skid caught vines caused upset landing. Carb did not meet type data sheets.

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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