Incident Overview
During cruise flight at 19,000 feet, the pilot of a single-engine airplane reported a loss of cabin pressurization. Shortly thereafter, engine oil pressure was lost, and the engine subsequently experienced a total loss of power. With assistance from air traffic control, the pilot maneuvered the airplane to a position over an airport. However, a low cloud ceiling in the area prevented a successful forced landing. The wreckage was largely consumed by a postcrash fire.
Wreckage Examination
Post-accident examination of the wreckage revealed that the engine crankcase had been breached, primarily above the number 5 and number 6 cylinders. A turbocharger wastegate hose that had been realigned approximately 17 months earlier was found to have rubbed through. Staining on the turbocharger housing was consistent with an oil leak originating from the hose; however, the quantity and rate of the leak could not be determined.
The connecting rods and rod bearings for cylinders 1 through 5 exhibited thermal distress. In contrast, the number 6 connecting rod and bearing did not show such distress. According to the engine manufacturer, the number 6 bearing displayed "no signs of cavitation, oil starvation, thermal distress, or hard particle embedment." The manufacturer also stated that it is not uncommon for the number 6 connecting rod bearing to exhibit little or no damage following an oil starvation event. Examination of the number 6 connecting rod assembly revealed fatigue cracking, characterized as "high stress" fatigue cracking, which suggests that some other event occurred before the connecting rod fractured.