Flight and Incident
The pilot reported conducting a preflight inspection and engine run-up before takeoff. After departure, while climbing through 1,000 feet, he heard a knocking sound from the engine and observed low oil pressure on the cockpit gauge. Within 60 seconds, the engine seized, and the airplane began losing altitude. The pilot turned toward an open field but collided with trees 40 yards short of the field. The airplane came to rest in a wooded area in a nose-low, right-wing-low attitude.
Post-Accident Examination
Examination of the airframe revealed that the right wing was partially separated at the root, and the left wing was displaced aft. The horizontal stabilizer was separated from the empennage assembly. Oil residue was found on external oil hoses, the starter, and the underside of the fuselage. Additionally, oil was observed on the airstrip apron where the preflight run-up had been conducted.
Engine and Oil Cooler Examination
The oil cooler had two cracks in its first segment, adjacent to the joint between the first and second segments, and in line with one of the oil ports. The NTSB Materials Laboratory examined the cracks and found that the exterior portion of the crack was damaged, apparently from contact with the mating face of the crack. Fracture features on the undamaged portions consisted of ductile dimples, indicative of overstress fracture.