- Date
- August 19, 1990, 18:00 local (Aug 20, 1990, 00:00 UTC)
- Place
- Meeteetse, WY
- Injuries
- 3 serious, 4 minor
- Damage
- Destroyed
- Phase of flight
- Enroute
- Aircraft
- N83776Aerospatiale SA316B
- Weather
- Visual (VMC) · Day
- Status
- Completed · report December 14, 1992
- Report
- Approved by Office Director
- FAA report
- 19900819034069A
- Case key
- 17844
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
A main rotor head blade dampener failure. A factor in the accident was the subsequent failure of a blade restraining cable.
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.
Analysis
Approximately 2 minutes into the flight, the pilot experienced a slight 1 to 1 vibration through the cyclic. This type vibration is associated with main rotor dampers and the pilot 'stirred' the cyclic in an effort to purge air out of the blade dampers. This eliminated the problem, however, it recurred and could not be eliminated. The vibration increased to the point of loss of control. An emergency landing was attempted with touchdown occurring at about 60 knots. The helicopter came to rest inverted and was largely consumed by post-impact fire. Metallurgical analysis on a failed blade restraining cable revealed a catastrophic failure in a low cycle fatigue mode consistent with a secondary cause, and due to short term vibrations. In addition to fatigue, there was evidence of plastic deformation due to vibratory loads from the damper systems. Fire damage prevented additional failure analysis.
Aircraft
- Registration
- N83776
- Reported as
- Aerospatiale SA316B
- Category
- Helicopter
- Serial number
- 1827
- Engine
- Turbomeca 316B, 600 horsepower, turbo shaft
- Damage
- Destroyed
- Fire
- On-Ground
- Flight
- Part 135
- Operator
- Rocky Mountain Helicopter
- Registered owner
- Unknown
- Destination
- NONE
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
- 42
- Certificates
- Commercial, Airline transport, Flight instructor
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Airplane, Helicopter
- Medical
- Class 1, Valid Medical--w/ waivers/lim
- Flight hours
- 6,635 total · 500 in this make and model · 5,000 as pilot in command · 50 in the last 30 days · 5 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 240° at 10 knots
- Visibility
- 7 statute miles
- Lowest ceiling
- 6,000 ft overcast
- Temperature
- -0 °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.