Incident Overview
A pilot conducting a local banner-towing flight decided to return to the airport after 45 minutes. While en route, the pilot advanced the throttle to initiate a climb but received no response from the engine. The engine began losing power, and smoke appeared from under the cowling. The oil temperature gauge approached the red line, and the RPM gauge decreased, though the oil pressure remained constant at 80 psi.
Emergency Landing
The pilot performed an emergency landing in a field. After touchdown, the airplane struck a tree with its right wing.
Engine Examination
Post-incident examination of the engine revealed a hole burned through the top of the #3 cylinder, consistent with detonation. Advisory Circular AC65-12A notes that detonation can burn a hole completely through a piston.