SEA95LA063

NTSB accident investigation · Hiller UH-12C · Bonners Ferry, ID · March 7, 1995

Accident · No injuriesLimited investigationFinal report
Date
March 7, 1995, 14:30 local (22:30 UTC)
Place
Bonners Ferry, ID
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N222TEHiller UH-12C
Weather
Visual (VMC) · Day
Status
Completed · report September 24, 1995
Report
Approved by Office Director
FAA report
19950307003299A
Case key
42120

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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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

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Loss of control - in flightManeuvering - turn to reverse direction
Terrain condition - none suitableFactor
Rotor rpm - not maintainedPilot in commandCause
In-flight planning/decision - inadequatePilot in commandFactor
Hard landingLanding
Roll overLanding

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
Reported as
Hiller UH-12C
Category
Helicopter
Serial number
802
Engine
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

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
26
Certificate
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.