A mechanic writes, “The upper rudder pivot bolt backed out of its self-locking nutplate at the upper (hinge--) while in flight...” “(The) rudder was ripped from the lower bell crank control, and departed the aircraft. The aircraft landed without incident. The rudder was recovered (found), and its upper pivot bolt was retained in the rudder cap. The bolt could be inserted in the nutplate with light, finger pressure only, and removed the same way.

The nutplate was worn and had lost its locking ability. At installation of a factory new rudder assembly, a drilled AN bolt was used to include a cotter key below the nutplate.” Provided part numbers are: rudder 0431001-29; nutplate NAS 682A3. (See last April’s Alerts for a similar event.)

Part Total Time: Unknown.