What happened
On July 30, 2011, at approximately 10:45 EDT, a Wright B Flyer experimental amateur-built airplane, N453WB, impacted terrain near Springfield, Ohio. The aircraft was conducting a flight test involving stability and performance evaluations under the direction of Wright B Flyer Inc. The flight originated from Springfield-Beckally Municipal Airport (SGH).
During the flight, witnesses observed the engine RPM varying and noted the aircraft flying at a low speed with left and right banking motions. One witness reported seeing the airplane enter a downward spiral. A nearby pilot heard a radio transmission from the crew indicating they were landing in a field five miles north of the airport. The aircraft subsequently struck the ground, resulting in 2 fatal injuries for the two commercial pilots on board.
The investigation
Investigators examined the wreckage and found the top wing displaced forward and the empennage bent downward. While the left fuel tank contained aviation gasoline, the right and header tanks were empty. The engine-driven fuel pump was found torn from its base, though disassembly revealed no pre-impact anomalies in the fuel pump or injection valve.
An examination of the propeller shafts by FAA inspectors revealed that the left propeller shaft tube had separated at its aft weld. Detailed laboratory analysis determined that the weld penetration was incomplete, leaving approximately 25 to 35 percent of the tube thickness unwelded. Visible pores and voids were present in the joint, and the failure was inconsistent with the engineering drawings which required complete weld penetration. Other welds on the aircraft exhibited similar incomplete penetration.
Review of cockpit video from an onboard camera showed the airplane yawing near the end of the recording, at which point both pilots were seen manipulating the controls. The aircraft remained controllable after the yaw occurred.