Abstract: An aircraft engine having a fan or propeller stage mounted to a planetary gearing system through a planetary gearing output drive shaft is provided with a lubricant system having a seal with lubricant delivery chamber for receiving a lubricant and a sealing surface sealing against a rotatable shaft, the rotatable shaft has a hollow interior and an opening in registration with the delivery chamber. The lubricant system has a lubricant pump in fluidical communication with and downstream of the opening.

Abstract: A booster assembly for a gas turbine engine having a first rotor assembly comprising a low pressure turbine drivingly connected to a fan via a first shaft and a second rotor assembly comprising a second turbine drivingly connected to a high pressure compressor via a second shaft. The booster assembly comprises a further compressor arranged to be disposed about said common axis between the fan and high-pressure compressor in a direction of flow and a gearing having first and second input rotors and an output rotor. The first input rotor is arranged to be driven by the first rotor assembly and the second input rotor is arranged to be driven by the second rotor assembly such that the output rotor drives the further compressor in dependence upon the difference in rotational speed between the first and second rotor assemblies.