During the airplane’s initial climb in crosswind conditions, the engine experienced a partial loss of power, and the airplane entered an aerodynamic stall.
The pilot attempted to lower the nose of the Globe GC1B, but with insufficient altitude, the plane hit a ditch parallel to the runway at the airport in Wellington, Florida, which resulted in substantial damage to the fuselage and both wings.
The pilot sustained serious injuries, while a passenger sustained minor injuries.
Examination of the airplane revealed that the engine’s No. 3 cylinder had low compression, and the No. 3 intake valve had hardened carbon deposit buildup on its stem.
After the valve was cleaned and reinstalled, the engine compression returned to the normal range.
It is likely that, during the initial climb, the intake valve stuck intermittently due to the carbon deposit buildup, which resulted in the partial loss of engine power and the airplane’s inability to climb.
Probable cause: The partial loss of engine power during the initial climb due to a sticking intake valve on the No. 3 cylinder.
This August 2018 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.