Incident Details
During the climb after takeoff, the engine began to run rough and subsequently lost power. According to the pilot, he turned on the boost pump, and the engine quit. He then turned the pump off, causing the engine to surge momentarily before quitting again. The forced landing resulted in the airplane striking trees and coming to rest on a street.
Examination Findings
A postaccident examination of the engine revealed corrosion in the left magneto. The corrosion was indicative of moisture contamination of the magneto, which may have resulted in a loss of power. Additionally, the engine-driven fuel pump pressure was set high, which would have resulted in a rich mixture when the boost pump was activated.
The engine was equipped with pressure-type Slick Electro Model 6224 magnetos. A service bulletin, applicable to another aircraft manufacturer, had been issued by the magneto manufacturer to inspect the pressurized magnetos every 100 hours for evidence of moisture contamination. The same information was contained in the magneto maintenance and overhaul manual.
Maintenance History
The airplane was maintained under an annual inspection program with no intervening 100-hour inspections. A total of 159 hours of flight time had been accumulated since the last annual inspection.