A gas turbine engine comprising a fan section, a compressor, a combustor and a turbine, includes a nacelle having an inner nacelle surface defining an inlet duct designed to reduce an inlet duct area of the inlet duct to increase acoustic attenuation. A series of central deflectors 40 are positioned at intervals along the length of the tank and another series of side deflectors 46 are mounted at intervals along the upwardly extending side walls 16 and 18 of the tank. Passageways have an entry end and an exit end and fasteners extend into the passageways for retention therein prior to securement of the vent to the structure.