- Date
- July 16, 1990, 10:30 local (16:30 UTC)
- Place
- Ovando, MT
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Maneuvering
- Aircraft
- N439DSSikorsky S-58BT
- Weather
- Visual (VMC) · Day
- Status
- Completed · report December 8, 1992
- Report
- Approved by Office Director
- FAA report
- 19900716026329A
- Case key
- 41241
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
The pilot did not maintain rotor RPM after a compressor assembly blade failure. A related factor was an inadequate autorotation resulting in a hard landing.
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
During an external load logging operation, the pilot had just taken off from refueling and was preparing for another load pick- up when the number one engine lost power and flames were observed shotting out from the exhaust. The pilot tried to fly the helicopter on one engine to a landing area, however, RPM was dropping. The pilot initiated an autorotation which resulted in a hard landing.
Aircraft
- Registration
- N439DS
- Reported as
- Sikorsky S-58BT
- Category
- Helicopter
- Serial number
- 58-658
- Engine
- P&W T400-CP-400, 900 horsepower, turbo shaft
- Damage
- Substantial damage
- Flight
- Other work use · Part 133
- Operator
- Skyline Helicopters
- Departed
- Canyon Creek, MT
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
- 39
- Certificate
- Commercial
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Helicopter, Airplane
- Medical
- Class 2, Valid Medical--no waivers/lim.
- Flight hours
- 6,298 total · 1,248 in this make and model · 6,000 as pilot in command
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- Calm
- Visibility
- 50 statute miles
- Lowest ceiling
- None
- Temperature
- 86 °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.