Airworthiness Directives; Airbus

We propose to adopt a new airworthiness directive (AD) for certain Airbus Model A350-941 airplanes. This proposed AD was prompted by the discovery of inadequate corrosion protection in certain areas of the horizontal stabilizer and the rear fuselage cone structure. This proposed AD would require application of sealant and protective treatment on the affected areas of the horizontal stabilizer and the rear fuselage cone structure and, for certain airplanes, modification of the trimmable horizontal stabilizer (THS) torsion box and re- identification of the elevator. We are proposing this AD to address the unsafe condition on these products.