What happened
While approximately 30 nautical miles from the destination, the pilot of the aircraft noticed the oil pressure needle pegged at the high side of the indicator. After closing the throttle, the oil pressure initially appeared to return to normal; however, the pressure subsequently dropped to zero and the oil temperature began to rise.
The pilot attempted to land on a road, but during short final, a crosswind prevented the maintenance of directional control and alignment with the roadway. To compensate, the pilot turned the aircraft into the wind and performed a forced landing in a desert field. The impact caused the main landing gear to shear from the airplane. There were no fatalities reported.
The investigation
Post-accident examination of the engine revealed that the main crankshaft seal had been extruded outward, causing oil to be pumped out during flight. Approximately 1.5 quarts of oil were drained from the engine prior to teardown. An examination conducted on January 24, 2005, by an engine manufacturer's representative found that witness marks on the seal bore and crankshaft indicated the seal had been properly positioned.
Investigators noted that the engine breather tube, which extended from the firewall area to the trailing edge of the right main landing gear strut, was inconsistent with standard length. Furthermore, the breather tube lacked a required whistle slot. The aircraft had previously served as a show airplane; while the original design intended for the breather tube to drain in a manner that prevented oil and moisture from contacting the airframe, the nonstandard modification left the end of the tube susceptible to icing.