Abstract: A clearance control apparatus for controlling the clearance between a rotary assembly (17) and a casing (24) surrounding the rotary assembly (17) is disclosed. The clearance control apparatus comprises a temperature measuring device (34) to measure the temperature of a radially outer portion of the rotary assembly and a cooling arrangement (28) to cool the casing (24). A control system (36) is associated with the temperature measuring device (34) and the cooling arrangement (28) to control the extent of cooling of the casing (24). The extent of cooling is dependent upon the temperature of the aforesaid portion.

Abstract: A gas turbine engine fuel metering valve is configured to move within an operating position range having a first end position for establishing a first fuel flow rate, a second end position for establishing a second fuel flow rate, and an intermediate position located between the first and second end positions for establishing a third fuel flow rate. The first and second fuel flow rates are either both higher than or both lower than the third fuel flow rate.