A fuel system comprises a supply unit (10) operable to deliver a metered supply of fuel to a supply manifold (14), a staging valve (16) operable to control the supply of fuel from the supply manifold (14) to a pilot outlet (60a, 60b) and a main outlet (54)...

An aircraft fuel pumping arrangement (10) comprises a first fuel pump (20), an electrically powered motor (22) operable to drive the first fuel pump (20) to deliver fuel to an outlet, a second fuel pump (24), a gas driven turbine (28) operable to drive the...

A fuel staging system is described which comprises a staging valve 28 operable to divide a metered fuel supply between a pilot delivery line 18 and a mains delivery line 16, and a recirculation valve 54 connected to the mains delivery line 16 and operable ...

A method of controlling the operation of a fuel metering unit of the type incorporating a metering valve (12) and a temperature sensor (30) is disclosed, the method comprising the steps of: sensing a change in temperature; using the sensed change in temper...

A fuel control system comprises a metering valve (10) operable to control the flow of fuel between a supply line (12) and a delivery line (14), a spill valve (16) operable to control fuel flow within the supply line (12), a pressure raising valve (24) conn...

A fuel metering unit (FMU) comprising a metering valve (28) operable to control the supply of fuel to a delivery chamber (58) of a pressure raising valve (PRV) (52), the PRV (52) including a valve member (54) movable under the influence of the pressure wit...