On July 17, 1985, a Cessna 177B (registration N20164) was involved in an aviation accident near Guthrie, OK. Investigators recorded the probable cause as: The pilot's decision to land in trees due to lack of altitude after losing engine power, which resulted from the number four exhaust valve being stuck open due to carbon buildup on the rough surface inside the valve guide. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot lost engine power shortly after takeoff during initial climb. Unable to reach a suitable landing area due to low altitude, the aircraft was directed into trees. Investigation found a stuck exhaust valve caused by carbon buildup.
What happened
The pilot reported losing engine power shortly after takeoff while the aircraft was in the initial climb phase. With insufficient altitude to maneuver toward a more suitable landing area, the pilot elected to direct the aircraft into a wooded area.
The investigation
A mechanical examination of the engine revealed that the number four exhaust valve was stuck in an open position. This failure was attributed to carbon buildup on the rough surface inside the valve guide.
Findings
The loss of engine power during the critical climb phase left the pilot with no viable options for a safe landing. The mechanical failure of the exhaust valve was the primary factor preventing continued flight.
Probable cause
The pilot's decision to land in trees due to lack of altitude after losing engine power, which resulted from the number four exhaust valve being stuck open due to carbon buildup on the rough surface inside the valve guide.
What happened in the 17 Jul 1985 Cessna 177B accident near Guthrie, OK?
A pilot lost engine power shortly after takeoff during initial climb. Unable to reach a suitable landing area due to low altitude, the aircraft was directed into trees. Investigation found a stuck exhaust valve caused by carbon buildup.
What aircraft was involved and where did it happen?
The accident on 17 Jul 1985 involved a Cessna 177B, registration N20164, at Guthrie, OK.
What was the probable cause of the accident?
The pilot's decision to land in trees due to lack of altitude after losing engine power, which resulted from the number four exhaust valve being stuck open due to carbon buildup on the rough surface inside the valve guide.
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