Summary
This document proposes to adopt a new airworthiness directive (AD) that would apply to certain Robert E. Rust (R.E. Rust) Models DeHavilland DH.C1 Chipmunk 21, 22, and 22A airplanes. This proposed AD would require you to check the airplane logbook to determine whether certain modifications have been incorporated on the airplane and incorporate the modifications that have not already been accomplished. This proposed AD is the result of the manufacturer performing a design study on the structural integrity of certain parts and reports of service failure of other parts installed on the affected airplanes. The actions specified by this proposed AD are intended to prevent reduced structural integrity in the primary structure of the airplane, which could result in failure of the rudder torque tube, elevator fasteners, and the vertical fin rear spar, or jamming or damage to the elevator. Such failures could lead to loss of control of the airplane.