Extra Flugzeugbau Gmbh EA-300 N102EX accident near Sierra Vista, Arizona

Probable cause

A loss of engine power due to metal debris contamination of the inverted oil system shuttle valve, which resulted in a disruption of oil flow and subsequent oil starvation.

NTSB analysis

The pilot reported that he had flown the airplane about 6 hours with the recently overhauled engine. During the accident flight, he performed touch-and-go landings and then went to an aerobatic area to perform flight maneuvers. During the maneuvers, he noted that the oil pressure was initially 65 to 70 psi, dropped to about 40 psi, and returned to 70 psi when the airplane was in inverted flight. He then did left and right 90-degree inverted turns. As he completed a steep turn, he noticed that the oil pressure was at 0 psi. Before he could react, the engine seized and stopped. The pilot made a successful landing on a road but had to negotiate around a 45-degree left bend; as the airplane rounded the curve, a vehicle traveling in the opposite direction collided with the left wing. Postaccident examination of the engine revealed that the connecting rod near cylinder Nos. 5 and 6 had failed when the engine seized. Further examination found that the shuttle valve, which controlled oil flow while the airplane was in inverted flight, had a triangular shaped shard of metal wedged under the remaining steel ball. This kept the ball from moving its full travel to the shut off position, resulting in a loss of lubrication to the engine.

Text from the NTSB. Open the NTSB docket for WPR10LA454 for the full record.