Airworthiness Directives; Airbus Model A320 and A321 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A320 and A321 series airplanes, that requires a revision to the Airplane Flight Manual (AFM) to include procedures for the flightcrew to follow in the event of radio altimeter height malfunction. This amendment also requires replacement of certain radio altimeter antennas with improved antennas, at which time the AFM revision will no longer be required. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent output of erroneous radio altimeter height information to the flightcrew and autopilot, which could result in reduced ability of the flightcrew to cope with adverse operating conditions.