Airworthiness Directives; Airbus SAS Airplanes

We propose to adopt a new airworthiness directive (AD) for all Airbus SAS Model A330-200 Freighter, -200 and -300 series airplanes; and Airbus SAS Model A340-200, -300, -500, and -600 series airplanes. This proposed AD was prompted by reports of depressurization of hydraulic reservoirs caused by air leakage from the pressure relief valve (PRV) of the hydraulic reservoir (HR) due to the extrusion of the O-ring seal from certain HR PRVs. This proposed AD would require identifying the part number of the HR, and replacing and re-identifying affected HR PRVs. We are proposing this AD to address the unsafe condition on these products.