What happened
During the engine run-up prior to departure, the crew discovered that the engine would quit when the right magneto was selected. Despite this discovery, the decision was made to proceed with the flight. During the takeoff of the Cessna (type not specified in source), a passenger noted that the climb attitude appeared normal.
As the aircraft reached approximately 200 feet above the trees, the Certified Flight Instructor (CFI) instructed the private pilot to monitor the airspeed and maintain a straight heading. The CFI then took control of the flight controls and banked the airplane to the right. During this maneuver, the passenger observed a barn and subsequently recalled the aircraft colliding with a power line.
The investigation
Upon examination of the aircraft, investigators found that the right magneto sparked only sporadically when tested. Additionally, a review of the pilot-operating handbook revealed no specific procedures for operating the aircraft while the magnetos switch was in the both position.