# NTSB CHI87DER03: Hiller UH-12ET, N135HA, Big Lake, MN, April 3, 1987

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Final report
- Date: April 3, 1987, 15:40 local (21:40 UTC)
- Place: Big Lake, MN
- Coordinates: 45.329784, -93.740158 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.3298&lon=-93.7402&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report October 7, 1988
- Report: Approved by Office Director
- NTSB case key (mKey): 13584
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI87DER03
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/13584/pdf
- Page: https://openairdocs.org/ntsb/CHI87DER03

## Sequence of events

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

- Loss of engine power(total) - nonmechanical, maneuvering
  - fuel system - contamination (cause)
  - preflight planning/preparation - inadequate, pilot in command (cause)
- Forced landing, descent - emergency
  - terrain condition - high obstruction(s) (contributing factor)
- Roll over, landing - flare/touchdown
  - terrain condition - rough/uneven (contributing factor)

## Analysis

AIRCRAFT WAS BEING MANEUVERED FOR LANDING ON A GROUND SUPPORT TRAILER WHEN IT EXPERIENCED A POWER FAILURE. DUE TO HIGH TREES AUTOROTATION WAS MADE TO ADJACENT FIELD. AIRCRAFT LANDED ON ROUGH/UNEVEN TERRAIN AND ROLLED OVER. INVESTIGATION REVEALED CONTAMINATED FUEL SYSTEM. APPROXIMATELY ONE GALLON OF A WHITE MILKY SUBSTANCE WAS DRAINED FROM THE SUMP AND ALL MAJOR COMPONENTS OF THE FUEL SYSTEM WERE CONTAMINATED. THE ORIGIN OF THE CONTAMINATION COULD NOT BE DETERMINED.

## Aircraft

- Registration: [N135HA](https://openairdocs.org/deregistered/N135HA-1995-09-26), registration cancelled 1995-09-26, S/N HA3035 (OpenAirDocs)
- Reported make and model: HILLER UH-12ET
- Registry model: [Hiller UH-12E](https://openairdocs.org/model/hiller-uh-12e) (registry code 4360122) (OpenAirDocs)
- Category: Helicopter
- Serial number: HA3035
- Engines: ALLISON 250-C20B 400 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Hookspray Service Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, November 4, 1986

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 29; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 2,400 total, 530 in this make and model, 2,350 as pilot in command, 3 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 50 °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 19870403008309A](https://openairdocs.org/incident/19870403008309A), Apr 3, 1987: Hiller UH12E, Big Lake, MN, Substantial damage. The engine quit after liftoff. The helicopter rolled over on landing. A white, milky substance found in the fuel.

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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