Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Airbus Model A319, A320, and A321 series airplanes. This proposed AD would require modifying the parking brake system to automatically restore the normal parking brake if the parking brake pressure decreases below a certain threshold. This proposed AD is prompted by a report of failure of the parking brake while the airplane was on the holding point of the runway before takeoff, leading to a runway departure. We are proposing this AD to ensure normal braking is available to prevent possible runway departure in the event of failure of the parking brake.