Airworthiness Directives; McDonnell Douglas Model DC-9-14, DC-9-15, and DC-9-15F Airplanes; Model DC-9-20, -30, -40, and -50 Series Airplanes; and Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), MD-88, and MD-90-30 Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas airplane models, that requires inspection of the captain's and first officer's seat locking pins for minimum engagement with the detent holes in the seat tracks; inspection of the seat lockpins for excessive wear; and corrective actions, if necessary. This action is necessary to prevent uncommanded seat movement during takeoff and/or landing, which could result in interference with the operation of the airplane and consequent temporary loss of control of the airplane. This action is intended to address the identified unsafe condition.