Incident Overview
An instructional flight experienced a sudden engine malfunction shortly after lifting off from a touch-and-go landing. The engine began producing loud, repetitive hammering noises, followed by a complete loss of power. The left-seat occupant, who held a private pilot certificate, transferred control of the aircraft to the certified flight instructor (CFI) in the right seat. Despite the transfer, the aircraft collided with the tops of two oak trees and came to rest in a nose-down attitude against the terrain.
Engine Examination
Following the incident, the engine was removed and disassembled at the manufacturer's facility. Disassembly revealed a catastrophic failure of the number two piston. A subsequent metallurgical examination determined the cause of the failure to be a fatigue fracture that originated at the root of the number two piston ring groove.
Findings
The investigation established that the engine failure was due to the fatigue fracture of the number two piston, specifically emanating from the root of the ring groove. No other contributing factors were identified in the source material. The aircraft and engine details, as well as the precise date, operator, and occupant injuries, were not provided in the official source.