Fuel control system for a gas turbine engine

摘要

A fuel control system for a gas turbine engine, comprises a main metering valve 18 for controlling fuel supply to the engine during a first mode of operation. A back-up metering valve 3 is provided in series with the main metering valve 18 for controlling fuel supply to the engine during a second mode of operation. The back-up metering valve 3 is arranged to track the main metering valve 18 during the first mode of operation. A changeover means 16 is provided for bypassing the back-up metering valve 3 during the first mode of operation and for connecting the back-up metering valve 3 with the main metering valve 18 during the second mode of operation.