# NTSB ANC94LA064: Hiller FH1100, N746FH, Tyonek, AK, June 4, 1994

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 3, 1994, 20:30 local (Jun 4, 1994, 04:30 UTC)
- Place: Tyonek, AK
- Coordinates: 61.080879, -151.160934 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=61.0809&lon=-151.1609&mi=10
- Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 4 uninjured
- Status: Completed, report April 25, 1995
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 2508
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC94LA064
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/2508/pdf
- Page: https://openairdocs.org/ntsb/ANC94LA064

## Probable cause

THE PILOT'S SELECTION OF UNSUITABLE TERRAIN FOR LANDING WHICH RESULTED IN A DYNAMIC ROLLOVER. A FACTOR WAS THE SOFT LANDING AREA SELECTED.

## Sequence of events

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

- Roll over, standing - idling rotors
  - terrain condition - soft (contributing factor)
  - unsuitable terrain or takeoff/landing/taxi area - selected, pilot in command (cause)
  - dynamic rollover - encountered, pilot in command

## Analysis

THE PILOT STATED HE LANDED ON THE RIVER BANK, AND AFTER REDUCING COLLECTIVE TO FLAT PITCH, THE RIVER BANK 'SLOUGHED OFF' UNDER THE RIGHT SKID, AND THE HELICOPTER ROLLED OVER ONTO ITS RIGHT SIDE INTO THE THEODORE RIVER. HE STATED HE HAD ALREADY REDUCED POWER AND WAS UNABLE TO CORRECT FOR THE ROLL RATE DUE TO DYNAMIC ROLLOVER.

## Factual narrative

On June 3, 1994, at 2030 Alaska daylight time, a Hiller FH- 1100 helicopter, N746FH, rolled onto its side, into the water after landing on a river bank located on the Theodore River near Beluga, Alaska.  The personal flight was conducted under 14 CFR 91 in visual meteorological conditions.  The flight departed from Lake Hood with a stop at Alexander Creek.  No flight plan was filed.  The Pilot-in-Command and all three passengers were uninjured and the aircraft was substantially damaged.

According to the Pilot-in-Command, he reduced collective to flat pitch after landing on the river bank and the river bank "sloughed off" under the right skid.  He stated the helicopter rolled onto its side and he did not have enough control to counter the roll.

## Aircraft

- Registration: [N746FH](https://openairdocs.org/deregistered/N746FH-2003-10-30), registration cancelled 2003-10-30, S/N 72, built 1967 (OpenAirDocs)
- Reported make and model: HILLER FH1100
- Registry model: [Fairchild Hiller FH-1100](https://openairdocs.org/model/fairchild-hiller-fh-1100) (registry code 3376502) (OpenAirDocs)
- Registry engine: [Allison 250 SER 250HP](https://openairdocs.org/engine/allison-250-ser-250hp) (registry code 03002, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 72
- Airframe hours: 5827
- Engines: Allison 250-C18 317 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Dodge, Earl
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, May 3, 1994, 7 hours before
- Departed: ALEXANDER CR, AK

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 68; commercial; airplane ratings: multi-engine land, single-engine land, single-engine sea, multi-engine sea; instrument ratings: airplane; medical: class 3, valid medical--no waivers/lim.; seat: right; flight hours: 34,886 total, 660 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 90 statute miles
- Lowest ceiling: none

## 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 19940603013909A](https://openairdocs.org/incident/19940603013909A), Jun 3, 1994: Hiller FH1100, Tyonek, AK, Substantial damage. Landed on river bank. River bank sloughed off under right skid. Helicopter then rolled into river.

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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