Accident Sequence
The pilot was approximately 30 nautical miles from the intended destination when the oil pressure gauge indicated maximum pressure. After the pilot reduced the throttle, the oil pressure appeared to return to normal. Shortly afterward, the oil pressure dropped to zero and the oil temperature began to rise. The pilot attempted to land on a road but could not maintain directional control on short final due to a crosswind. He then turned the airplane into the wind and executed a forced landing in a desert field. During the landing, the main landing gear separated from the aircraft.
Post-Accident Examination
A post-accident inspection revealed that the main crankshaft seal had been extruded outward, causing oil to be pumped out during the flight. Approximately 1.5 quarts of oil were drained from the engine prior to its teardown. On January 24, 2005, an engine manufacturer's representative examined the engine crankcase, crankshaft nose seal, and breather tube. The seal bore exhibited witness marks indicating that the seal had occupied the bore properly. Corresponding witness marks on the crankshaft where the seal had been in contact showed that the seal had been positioned correctly.
Breather Tube Configuration
The engine breather tube extended from the firewall area to the trailing edge of the right main landing gear strut, a length inconsistent with the standard tube. The tube did not have a whistle slot. The airplane was originally a show airplane, and the breather tube was designed to prevent oil and moisture from draining onto the aircraft. However, due to its nonstandard design, the end of the tube was susceptible to icing. An edition of the Lycoming Flyer stated that under very cold conditions, moisture may freeze and continue to build up ice until the tube is completely blocked. It noted that it is normal practice for airframe manufacturers to provide a means of preventing freeze-up, such as insulation, placement in a hot area, an electric heater, or a whistle slot. When a breather tube with a whistle slot is replaced, the new tube must be of the same design.