Experimental light jet roll accident during maintenance test flight

2 fatalities • Spanish Fork, United States of America • Flight

An experimental light jet crashed during a maintenance test flight after a right-wing roll following liftoff, caused by an improperly reinstalled aileron control component.

What happened

During a local maintenance test flight, an experimental light jet experienced a sudden right-wing roll immediately after departing the runway. Witnesses observed the aircraft bank to approximately 90 degrees, resulting in the right wingtip striking the ground. There were no survivors reported in the crash.

Prior to the flight, maintenance had been performed on the aircraft to stiffen the main landing gear struts. This process involved the removal of the main landing gear, which necessitated the removal of a V-bracket that supports the upper torque tube of the aileron control system. During the reinstallation of this system, the aft upper torque tube bell crank was mounted in an incorrect orientation.

Findings

Investigation of the wreckage revealed that the aileron control system was configured such that control inputs in the cockpit produced movement in the opposite direction of what was intended. The mechanic responsible for the reinstallation mistakenly believed there was only one possible orientation for the bell crank on the torque tube.

While the improper installation caused binding within the control system, this issue was noted during post-maintenance inspections. Rather than correcting the bell crank's position, the mechanic attempted to resolve the binding by disconnecting tie rods and rotating the upper torque tube. This specific adjustment reversed the aileron control direction. Because the aircraft was a proof-of-concept prototype, no formal maintenance documentation existed to guide the procedure. Furthermore, a failure to perform or verify a control surface position check during either the maintenance phase or the preflight inspection prevented the detection of the reversed controls.

Probable cause

The improper installation and subsequent adjustment of the aileron bell crank caused the flight controls to operate in reverse.

Frequently asked questions

What happened in the 2006-07-25 Spectrum FJ33 accident near Spanish Fork, United States of America?

An experimental light jet crashed during a maintenance test flight after a right-wing roll following liftoff, caused by an improperly reinstalled aileron control component.

Were there any fatalities in the 2006-07-25 Spectrum FJ33 accident?

The accident was fatal, resulting in 2 fatalities.

What aircraft was involved and where did it happen?

The accident on 2006-07-25 involved a Spectrum FJ33, registration N322LA, operated by Spectrum Aeronautical, at Spanish Fork, United States of America.

What was the probable cause of the accident?

The improper installation and subsequent adjustment of the aileron bell crank caused the flight controls to operate in reverse.

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