What happened
The flight involved a student pilot and an instructor (CFI) conducting practice maneuvers at a local airfield. The pair were executing touch-and-go landings, a common training exercise where the aircraft touches the runway but does not come to a full stop before taking off again.
During the takeoff roll of the fourth touch-and-go attempt, the left engine lost power while the aircraft was climbing through approximately 200 feet above ground level. The instructor immediately assumed control of the aircraft. At roughly the same moment, the student observed oil leaking from the left engine compartment.
The instructor feathered the propeller on the inoperative engine. At that time, the aircraft was vibrating and indicated an airspeed of 100 mph. To maintain the best single-engine rate of climb speed, the instructor lowered the nose. However, at this speed, the aircraft began to descend rather than climb.
The instructor continued flying over rough terrain toward nearby power lines. Upon realizing the aircraft would not be able to clear the obstacles or continue flight, he turned toward the most suitable terrain available and executed a crash landing.
The investigation
A post-accident examination of the left engine revealed a broken oil cooler line. Despite this damage, four quarts of oil remained in the system. Investigators found no evidence that the loss of oil had caused the engine failure.
Further inspection showed that the spark plugs were heavily sooted, indicating an extremely rich fuel mixture. Rough spots were also found on the carburetor float chamber needle valve. This condition reportedly could have allowed the valve to stick open, leading to the rich mixture and subsequent engine malfunction.