Accident Overview
The accident occurred when the airplane, while maneuvering for a forced landing following a partial loss of engine power during the takeoff initial climb, collided with the ground. The collision resulted in the destruction of the aircraft.
Witness Observations
A pilot who had taken off immediately after the accident airplane reported hearing the pilot transmit on the common traffic radio frequency: "seven four Victor starting a left turn to return to the airport." A ground witness observed the airplane flying slowly with the engine emitting a very low constant humming sound. Initially, the airplane's wings and nose were level with the horizon. Suddenly, the airplane turned left, the nose went "straight down," and the airplane rapidly descended while reversing course. The airplane ultimately struck the ground in a nose-down attitude.
Maintenance History
The engine had operated approximately 54 hours since receiving a major overhaul. According to logbook records, the pilot performed the last maintenance on the airplane about 3.1 operational hours prior to the accident flight. That maintenance included changing the oil and filter.
Wreckage Examination
During the post-impact wreckage examination, both of the engine's magnetos were found with finger-tight mounting bolts. Evidence indicated that the magnetos had worked back and forth on their mounts through their adjustment range. No other pre-impact mechanical malfunctions or failures were identified. Fuel was present in the pump, lines, and carburetor, and a significant quantity had spilled from the ruptured fuel tanks.