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NTSB Report
May 17, 1982 · Enstrom F-28C · N8617J
Marmath, ND
Overview
Report Status
Preliminary report
Event Type
Accident
Date
May 17, 1982
Injury Outcomes
No injuries (1 uninjured)
Location
Marmath, ND
Aircraft
Enstrom F-28C
Tail Number
N8617J
Operator
Douglas Duffield
Injuries
None
Aircraft Damage
Substantial
NTSB Number
DEN82DA089
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.
Full Narrative
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.
Flight
Event TypeAccident
Event Time19:30 CDT
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftEnstrom F-28C
Tail NumberN8617J
Aircraft CategoryHeli
DamageSubstantial
OperatorDouglas Duffield
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · HIO-360-E1BD · Reciprocating · 205
Seats3
People & Injuries
Injury SummaryNo injuries (1 uninjured)
Fatal0
Serious0
Minor0
Uninjured1
Total1
Crew 1Age 33 · Third Class
Conditions
ConditionsVMC
LightDaylight
WindCalm
Visibility25 sm
CeilingNone
Temperature / Dew Point14 C / 0 C
Altimeter0