- Date
- May 16, 1982, 18:30 local (May 17, 1982, 00:30 UTC)
- Place
- Marmath, ND
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Enroute
- Aircraft
- N8617JEnstrom F-28C
- Weather
- Visual (VMC) · Day
- Status
- Completed · report May 16, 1983
- Report
- Approved by Office Director
- FAA report
- 19820516019399A
- Case key
- 71592
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
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
The pilot reported that while he was in flight at about 75 to 80 ft AGL, the engine lost power. During an autorotative landing in an open pasture, a skid dug into the ground and the helicopter rolled over. A subsequent engine teardown revealed evidence that the engine had been operated in an overspeed condition over a prolonged period of time. There was evidence of high valve seating velocities and bouncing, the upper spring seats had been striking the tops of the valve guides, fatigue failure of the keepers had occurred, and subsequently, a valve failed from fatigue.
Aircraft
- Registration
- N8617J
- Reported as
- Enstrom F-28C
- Category
- Helicopter
- Serial number
- 516-2
- Airframe hours
- 483
- Engine
- Lycoming HIO-360-E1BD, 205 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Instructional · Part 91
- Operator
- Douglas Duffield
- Registered owner
- Douglas Duffield
- Departed
- 3U6 · Baker, MT
- Destination
- Ellis, WI
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
- 33
- Certificate
- Student
- Medical
- Class 3, Valid Medical--no waivers/lim.
- Flight hours
- 51 in this make and model
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- Calm
- Visibility
- 25 statute miles
- Temperature
- 135 °F
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.