AD FAA-2018-0704

We are adopting 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 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 AD requires replacing affected PRVs and re- identifying affected HRs. We are issuing this AD to address the unsafe condition on these products.