A USAF accident investigation board has determined that a failure in the rudder operating mechanism caused the crash of a T-38 aircraft on a training mission 12 miles north of Edwards AFB, CA, on May 21, 2009. The report states the failure was most likely due to maintenance issues.

USAF Maj. Mark Paul Graziano, a student pilot from the USAF Test Pilot School, died as a result of that accident. His student navigator, USAF Maj. Lee Vincent Jones, sustained serious injuries.

The report said there is "clear and convincing evidence that the cause of this mishap was a failure of the rudder operating mechanism, which disconnected the flight controls from the rudder actuators and caused the rudder to deflect 30 degrees left. This hardover rudder induced an uncontrollable yaw and a resulting roll, causing the aircraft to depart controlled flight. This condition is unrecoverable in the T-38."

The report identified two potential causes for the failure of the rudder operating mechanism. The first is a structural fatigue failure or structural break in a critical component or bolt, the second a maintenance error in which a nut or cotter pin did not properly secure a bolt connecting two critical components. Citing two historical cases of rudder failure, the report concluded that maintenance error was the more likely cause of the rudder failure.

The report stated that "insufficient supervisory oversight and a lack of discipline of the training process" was a factor. Significant discrepancies were noted regarding maintenance procedures and documentation of training. The report said, "In the vast majority of cases, the aircraft maintenance mechanic had likely received appropriate training in the past (almost all civilian employees interviewed testified to having prior military service, most in the Air Force as upper level maintenance mechanics). However, lack of documentation in the training process made verification impossible."