A de-aerator for an oil system of a gas turbine engine, comprising: a body extending between a first axial end and a second axial end opposite the first axial end, the body having at least one sidewall that extends between the first axial end and the second axial end, and a base panel connected to the at least one sidewall at the second axial end, wherein the base panel and the at least one sidewall define an internal cavity of the body; a cover panel connected to the body at the first axial end; a fluid inlet in communication with the body at the first axial end, the fluid inlet having an internal flow passage configured to direct fluid tangentially into the internal cavity; a helical fluid passage disposed within the internal cavity having an entry end and an exit end, the entry end disposed to receive fluid from the fluid inlet, the helical fluid passage having a plurality of circumferential turns that collectively axially descend toward the second axial end of the body, wherein the circumferential turns each include one or more air passages disposed radially inward providing a gas path to a central region disposed radially inside of the helical fluid passage; at least one partition disposed within the internal cavity in a plane that is substantially perpendicular to a central axis of the de-aerator, at or below the exit end of the helical fluid passage, and spaced above the base panel of the de-aerator wherein the at least one partition has an upper surface, a lower surface, a thickness extending between the upper surface and the lower surface; and at least one fluid outlet disposed adjacent the base panel, the at least one fluid outlet configured to permit liquid passage from the internal cavity of the body to outside the body, characterised in that the at least one partition has a plurality of apertures extending through the partition between the upper surface and the lower surface. a body extending between a first axial end and a second axial end opposite the first axial end, the body having at least one sidewall that extends between the first axial end and the second axial end, and a base panel connected to the at least one sidewall at the second axial end, wherein the base panel and the at least one sidewall define an internal cavity of the body; a cover panel connected to the body at the first axial end; a fluid inlet in communication with the body at the first axial end, the fluid inlet having an internal flow passage configured to direct fluid tangentially into the internal cavity; a helical fluid passage disposed within the internal cavity having an entry end and an exit end, the entry end disposed to receive fluid from the fluid inlet, the helical fluid passage having a plurality of circumferential turns that collectively axially descend toward the second axial end of the body, wherein the circumferential turns each include one or more air passages disposed radially inward providing a gas path to a central region disposed radially inside of the helical fluid passage; at least one partition disposed within the internal cavity in a plane that is substantially perpendicular to a central axis of the de-aerator, at or below the exit end of the helical fluid passage, and spaced above the base panel of the de-aerator wherein the at least one partition has an upper surface, a lower surface, a thickness extending between the upper surface and the lower surface; and at least one fluid outlet disposed adjacent the base panel, the at least one fluid outlet configured to permit liquid passage from the internal cavity of the body to outside the body, characterised in that the at least one partition has a plurality of apertures extending through the partition between the upper surface and the lower surface.