Accident Summary
While in cruise flight at 10,000 feet above ground level, the engine lost power. The pilot subsequently performed a forced landing with the landing gear retracted into a field.
Maintenance History
According to records, the engine experienced a propeller strike on February 19, 2003. It was removed and sent to Certified Engines Unlimited for special inspection, with a total time since major overhaul (TTSMOH) of 509.2 hours. The engine was reinstalled on the airplane on March 21, 2003, and returned to service.
On May 13, 2003, the engine was again removed and sent to Certified Engines Unlimited due to a crankshaft counterweight failure at a TTSMOH of 535.1 hours. The counterweights were replaced, and the engine was reinstalled on June 12, 2003.
Catastrophic Failure and Examination
On October 7, 2003, during cruise flight, the airplane experienced a catastrophic engine failure at a TTSMOH of 734.1 hours. Examination at TCM revealed the crankshaft was fractured through the number one connecting rod journal forward fillet radius and the upper counterweight hanger blade. The rear upper crankshaft counterweight was detached from its hanger blade. One plate and snap-ring on each side of the counterweight were forced from their installed positions by mechanical action of the pins. The counterweight plates of this counterweight were bowed outward relative to their installed positions. One of the snap-rings was fractured in two pieces, and both snap-rings that were not in place showed signs of being forced from their retaining grooves in the counterweight. The remaining rear counterweight exhibited severe mechanical damage but remained intact on the hanger blade. The forward set of counterweights, pins, plates, and snap-rings were intact and undamaged, with free and unrestricted movement on the hanger blades.