On May 2, 1987, a Piper PA-11 (registration N38687) operated by Bringham Flying. Service,inc. was involved in an aviation accident near Meade, KS. Investigators recorded the probable cause as: The sticking intake valve on the number three cylinder, which caused an in-flight loss of engine power and a subsequent stall. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An aircraft experienced engine power loss shortly after takeoff, leading to a stall during a turn toward a landing area. The plane impacted the ground and flipped upside down.
What happened
Shortly after departure, the pilot noticed a significant reduction in engine power. While maneuvering the airplane toward a designated landing area, the aircraft entered a stall condition. The impact with the ground occurred to the right of the runway, causing the airframe to flip forward and come to rest in an inverted position.
The investigation
A partial teardown inspection was conducted on the engine to determine the cause of the power loss. The examination revealed that the intake valve on the number three cylinder was sticking, preventing proper fuel-air mixture flow.
Findings
The mechanical failure of the intake valve led directly to the loss of engine power. The subsequent stall during the critical phase of flight prevented recovery before ground contact.
Probable cause
The sticking intake valve on the number three cylinder, which caused an in-flight loss of engine power and a subsequent stall.