Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to all Airbus Model A319, A320, and A321 series airplanes. That AD currently requires identification of the part number and serial number of the parking brake operated valve (PBOV); and, if necessary, inspection of the PBOV, including a functional check of the PBOV, and follow-on and corrective actions. That AD also provides for an optional terminating action for the requirements of that AD. This new action would mandate the optional terminating action, which would terminate the inspection requirements of the previous AD. The actions specified by the proposed AD are intended to prevent leakage of hydraulic fluid from the PBOV, which could cause the loss of the parking brake accumulator, and render the alternate braking system and the parking/emergency braking system inoperative, as well as the loss of function of the yellow hydraulic system (which provides all or part of the hydraulics for the elevator, rudder, aileron, flaps, stabilizer, yaw damper, pitch and yaw feel systems and autopilot, and certain spoilers).