Summary
A twin-engine airplane initiated an instrument flight while loaded approximately 800 pounds beyond its certificated maximum gross takeoff weight. Shortly after climbing to its assigned altitude of 7,000 feet above mean sea level, the pilot radioed an air traffic controller stating, "...we have an engine problem." The nature of the problem was not elaborated in subsequent transmissions. After the pilot's final radio call, eyewitnesses on the ground reported observing the aircraft in a counterclockwise flat spin.
Examination
An on-scene inspection of the wreckage revealed that the left engine had sustained a mechanical failure. Continuity of flight, engine, fuel, and propeller controls was confirmed. Investigators found an oil film on the left engine nacelle, the inboard half of the left wing, the left side of the fuselage, and the horizontal stabilizer and elevator. The left engine crankcase had fractured near the number 2 cylinder. Fracture surface analysis indicated that the failure originated from fatigue, which had propagated approximately 7 inches from its starting point. Additionally, the connecting rod for the number 2 cylinder had separated from the crankshaft journal.
Maintenance History
Maintenance records documented that the engine had a crankcase crack that was not covered by any FAA Airworthiness Directive or engine manufacturer specifications. The maintenance personnel had informed the pilot about this existing crack. Inspection of the hangar floor where the aircraft was stored revealed a fresh pool of oil beneath the area corresponding to the left engine position. Oil-based tire impressions from the left main landing gear tire led from the oil pool to the ramp outside the hangar.
Pilot Experience
According to the pilot's logbook, he had received 4 hours of multi-engine flight instruction during a single session on one day. The following day, he logged 10 hours of multi-engine instruction across two sessions. He obtained his multi-engine rating on the third day. Prior to these entries, the logbook contained six other flight instruction entries annotated as "X Country IFR."
Probable Cause
The source does not explicitly state a probable cause for the accident.