An air-oil separating arrangement in a gas turbine engine having a sump with a rotatable annular wall structure includes an annular section of the sump wall structure having a plurality of circumferentially spaced air metering orifices defined therein, and an air-oil separator having a circular plate attached to the annular section of the sump wall structure and rotatable therewith. The circular plate has a pair of opposite faces and a plurality of separator fins attached to and extending from one face of the plate. The separator fins are circumferentially spaced from one another and extend radially from the center of the plate and define spaces therebetween which are in flow communication with the orifices through the annular section of the sump wall structure. The engine also includes a center vent passage aligned with the center of the separator plate such that when oil particle-laden pressurized air flows from the sump through the metering orifices and radially inwardly through the radial spaces between the separator fins into the center vent passage, the oil particles carried by the air will be impacted by the fins and centrifugally ejected in an outward radial direction back outwardly through the metering orifices and thereby separated from the air flow through the separator and returned to the sump.