Airworthiness Directives; Airbus Airplanes

We are adopting a new airworthiness directive (AD) for certain Airbus Model A319, A320, and A321 series airplanes. This AD was prompted by investigations that revealed that the cover seal of the brake dual distribution valve (BDDV) was damaged and did not ensure efficient sealing. This AD requires modifying the BDDVs having certain part numbers; modifying the drain hose of the BDDV; checking for the presence of water, ice, and hydraulic fluid; re-identifying the BDDV; and doing related investigative and corrective actions if necessary. We are issuing this AD to prevent damage to the BDDV, which could lead to water ingestion in the BDDV and freezing of the BDDV in flight, possibly resulting in loss of braking system function after landing.