# NTSB SEA95LA063: Hiller UH-12C, N222TE, Bonners Ferry, ID, March 7, 1995

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: March 7, 1995, 14:30 local (22:30 UTC)
- Place: Bonners Ferry, ID
- Coordinates: 48.750236, -116.510444 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=48.7502&lon=-116.5104&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report September 24, 1995
- Report: Approved by Office Director
- NTSB case key (mKey): 42120
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA95LA063
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42120/pdf
- Page: https://openairdocs.org/ntsb/SEA95LA063

## Probable cause

ROTOR RPM WAS NOT MAINTAINED. FACTORS TO THE ACCIDENT WERE: INADEQUATE IN FLIGHT PLANNING/DECISION AND SUITABLE TERRAIN WAS NOT AVAILABLE.

## Sequence of events

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

- Loss of control - in flight, maneuvering - turn to reverse direction
  - terrain condition - none suitable (contributing factor)
  - rotor rpm - not maintained, pilot in command (cause)
  - in-flight planning/decision - inadequate, pilot in command (contributing factor)
- Hard landing, landing
- Roll over, landing

## Analysis

THE PILOT REPORTED THAT DURING A STUDENT SOLO INSTRUCTIONAL FLIGHT, HE PERFORMED AN APPROACH TO A PINNACLE AND HELD A HOVER APPROXIMATELY THREE FEET ABOVE THE GROUND. THE PILOT THEN TRANSITIONED TO FORWARD FLIGHT AND STATED THAT THE ROTOR RPM BEGAN TO DECREASE. SUITABLE TERRAIN WAS NOT AVAILABLE, THEREFORE THE PILOT INITIATED A RIGHT 180 DEGREE TURN. DURING THE TURN, THE ROTOR RPM CONTINUED TO DECAY UNTIL TAIL ROTOR AUTHORITY WAS LOST. THE PILOT THEN SIDE SLIPPED THE HELICOPTER TO THE RIVER BANK, WHERE THE HELICOPTER LANDED HARD AND ROLLED ONTO ITS RIGHT SIDE. THE PILOT REPORTED THAT THERE WERE NO MECHANICAL FAILURES OR MALFUNCTIONS WITH THE HELICOPTER AT THE TIME OF THE ACCIDENT.

## Factual narrative

On March 7, 1995, at 1430 Pacific standard time, N222TE, a Hiller UH-12C helicopter, operated by Wilderness Helicopter, Inc., Billings, Montana, impacted terrain while maneuvering near Bonners Ferry, Idaho, and was substantially damaged.  The student pilot, the sole occupant, was not injured.  Visual meteorological conditions prevailed and a flight plan was not filed.  The local instructional flight was conducted under 14 CFR 91.

In a written statement, the pilot reported that he performed an approach to a pinnacle which was approximately 25 feet higher than the surrounding terrain.  The pilot maintained the hover approximately three feet above the ground for 15 to 20 seconds, then transitioned to forward flight.  During the transition, the rotor rpm began to decay.  The pilot stated that he did not feel that he would make his planned departure and began a right 180 degree turn and lowered the collective before flying over the edge of the river.  Approximately 90 degrees into the turn, the rotor rpm decayed enough that tail rotor authority was lost.  The pilot stated that he attempted to side slip the helicopter to a landing spot, however, the helicopter "stalled" just as it reached the edge of a gravel bar.  The helicopter landed hard, breaking the right skid and rolling onto its right side.

The pilot reported that there were no mechanical failures or malfunctions with the helicopter at the time of the accident.

## Aircraft

- Registration: [N222TE](https://openairdocs.org/aircraft/N222TE), registered now, S/N 802, built 1955 (OpenAirDocs)
- Reported make and model: HILLER UH-12C
- Registry model: [Hiller UH-12C](https://openairdocs.org/model/hiller-uh-12c) (registry code 4360116) (OpenAirDocs)
- Registry engine: [Franklin 6A&6V335 series](https://openairdocs.org/engine/franklin-6a-6v335-series) (registry code 27020, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 802
- Engines: FRANKLIN 6V-335-D 210 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Registered owner: Wilderness Helicopter, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, February 20, 1995
- Departed: 65S, ID

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 26; student; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 143 total, 132 in this make and model, 100 as pilot in command, 111 in the last 90 days, 31 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 45° at 5 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 36 °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 19950307003299A](https://openairdocs.org/incident/19950307003299A), Mar 7, 1995: Hiller UH12C, Bonners Ferry, ID, Substantial damage. Practicing pinnicle approach hover. Transition to forward flight lost RPM. Lost tail control. Landed hard. Rolled.

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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