Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Airbus Model A319, A320, A321, A330, and A340 series airplanes. This proposal would require revising the Airplane Flight Manual to provide the flight crew with certain instructions associated with the Global Positioning System (GPS). This proposal also would require modification of the Global Positioning System Signal Unit (GPSSU) of the satellite navigational system. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to prevent position and altitude errors due to bad oscillator warm-up characteristics of the GPSSU, which could result in navigational errors that may exceed 0.5 nautical mile.