Enstrom F-28C N8617J

Summary

On 17 May 1982 at about 00:30 local time, a Enstrom F-28C registered N8617J, operated by Douglas Duffield, was involved in an accident near Marmath, North Dakota, United States. One person was on board and nobody was injured. The aircraft was substantially damaged. No probable cause statement is available for this record.

Date

17 May 1982 at 00:30

Classification

Accident

Location

Marmath, North Dakota, United States

Coordinates

Not recorded

Aircraft

Enstrom F-28C

Registration

N8617J

Category

Helicopter

Engines

1

Operator

Douglas Duffield

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Baker → Ellis

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

DEN82DA089

Nobody was injured.

The NTSB has not published a probable cause for this record. No probable cause statement is present in the source data.

Nothing about the cause is stated here that is not in the source record.

Read the full NTSB 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.

Quoted verbatim from the NTSB record.