In accordance with at least one aspect of this disclosure, there is provided a system for an aircraft engine. In embodiments, the system includes an accessory box and a fuel accessory located in an interior space within the accessory box, where a vent is defined through a wall of the accessory box. In embodiments, the vent includes a plurality of holes or slots in an outer wall of the accessory box for passage of gaseous fuel from the interior space. In embodiments, the vent is configured for passive ventilation of the interior space.

In accordance with at least one aspect of this disclosure, there is provided a system for an aircraft engine. In embodiments, the system includes an accessory box and a fuel accessory located in an interior space within the accessory box, where a vent is defined through a wall of the accessory box. In embodiments, the vent includes a plurality of holes or slots in an outer wall of the accessory box for passage of gaseous fuel from the interior space. In embodiments, the vent is configured for passive ventilation of the interior space.

In accordance with at least one aspect of this disclosure, there is provided a system for an aircraft engine. In embodiments, the system includes an accessory box and a fuel accessory located in an interior space within the accessory box, where a vent is defined through a wall of the accessory box. In embodiments, the vent includes a plurality of holes or slots in an outer wall of the accessory box for passage of gaseous fuel from the interior space. In embodiments, the vent is configured for passive ventilation of the interior space.

Fuel systems of gas turbine engines of aircraft, and associated methods are provided. The fuel systems and methods can permit reverse purging of one or more fuel manifolds of a gas turbine engine to prevent coking in some modes of operation. A fuel system includes first and second fuel manifolds fluidly connectable to a combustor of the gas turbine engine. A valve is operatively disposed between the second fuel manifold and a fuel supply line for controlling fuel supply to the second fuel manifold. A reservoir includes a movable piston disposed therein and dividing the reservoir into a first chamber and a second chamber. The first chamber is fluidly connectable to the fuel supply line or to a fuel purge line via the valve. The second chamber is in fluid communication with the second fuel manifold to receive residual fuel from the second fuel manifold.

This turbine stator vane extends in the radial direction which intersects the flow direction of steam, and includes a pressure surface facing the upstream side in the flow direction, and a suction surface facing the downstream side in the flow direction. A plurality of grooves are formed in at least the pressure surface, the grooves extending outward in the radial direction toward the downstream side. At the periphery of the grooves in the pressure surface, formed is a hydrophilic uneven region having greater hydrophilic properties than the pressure surface. The downstream-side ends of the plurality of grooves are connected to slits for capturing a liquified component of the steam.

An acoustic absorption structure includes: at least one acoustic element which has at least one cavity delimited by at least one enclosure comprising at least one first drainage orifice passing through the enclosure, and a rotational indexing system making it possible to position the acoustic element so that at least one first drainage orifice is positioned in proximity to or at a lowest point of the cavity. An aircraft propulsion assembly including such an acoustic absorption structure is also described.

An oil scavenge system for a gas turbine engine comprising an oil tank and at least one bearing chamber. The oil scavenge system comprises at least one primary scavenge pump, a manifold, a secondary scavenge pump, a deaerator and a filter unit. The at least one primary scavenge pump is configured to pump oil from the at least one bearing chamber to the manifold whilst raising the pressure of the oil from a starting pressure to a first pressure elevated with respect to the starting pressure. The manifold is pressurised to substantially maintain the oil at said first pressure. The secondary scavenge pump is configured to pump oil from the manifold at the first pressure and to raise the pressure of the oil to a second pressure elevated with respect to the first pressure before pumping the oil to the deaerator and through the filter unit to the oil tank.

A diffuser for an oil drainback system drain tube includes a flow chamber configured for attachment to an open end of a drain tube, wherein the flow chamber has a side wall and an end wall, and openings in at least the side wall.

A turbine arrangement comprising a journal having a flange carrying a disc that is attached to the flange with bolts, wherein it includes a stationary circular trough surrounding the flange for collecting oil capable of passing radially between the disc and the flange carrying this disc.

An aircraft engine, has: a shaft rotatable about a central axis and engaged at an end thereof to a rotatable load via splines; a reference tube extending around the shaft and having a first end secured to the shaft and a second end free relative to the shaft for measuring a deformation of the shaft, the reference tube defining at least one tube aperture; an oil nozzle defining an exit flow axis intersecting the at least one tube aperture, the shaft defining at least one shaft aperture through the shaft, an oil flow path extending from the oil nozzle to the splines; and a drain outlet located radially outwardly of an inlet of the at least one shaft aperture for outputting excess oil out of an annular gap defined between the shaft and the reference tube.