Summary
This document revises an earlier proposed airworthiness directive (AD), applicable to certain Airbus Model A319, A320, and A321 series airplanes, that would have required modification of the airplane wiring to separate the electrical inputs sent by the engine interface units (EIU) to certain probe heat computers (PHC). That proposal was prompted by the issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. This new action revises the proposed rule by changing the procedure for testing the modified wiring of the EIU's and PHC's for certain airplanes. The actions specified by this new proposed AD are intended to prevent simultaneous loss of heating to pitot probes 1 and 3, which could result in incorrect airspeed indications to both the pilot's and first officer's airspeed indication systems. Malfunction of these systems could result in reduced controllability of the airplane.