Method of controlling the operation of a fuel metering unit and such a unit

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 temperature to derive a fast temperature correction factor (36c); using the sensed change in temperature to derive a slow temperature correction factor (38c); using the fast and slow temperature correction factors (36c, 38c) in combination with a fuel demand (34a) to determine a metering valve position; and moving the metering valve (12) to the determined metering valve position.