Abstract: A variable vane control system for controlling the angle of rotation of a circumferential row of variable vanes of a gas turbine engine. The control system includes a mechanical linkage operable to rotate the variable vanes, one or more actuators for operating the linkage and one or more position sensors for detecting the respective actuation positions of the one or more actuators. The control system further includes a linkage position signalling switch for signalling that the mechanical linkage is at a calibration position corresponding to a predetermined rotation angle of the vanes. The control system further includes a controller for controlling the one or more actuators and thereby controlling the angle of rotation of the vanes, based on the detected actuation positions which the controller correlates with vane rotation angle.

Abstract: An engine fuel control system includes a fuel metering valve operable to control the flow of fuel between a supply line and a delivery line. The delivery line is configured to receive fuel from one or more fuel pumps. The engine fuel control system further includes a pressure raising arrangement which receives the fuel flow from the delivery line and raises the fuel pressure therein. The engine fuel control system further includes a pressure sensor arranged to sense the pressure of the fuel in the supply line between the one or more fuel pumps and the fuel metering valve, or to sense the pressure of the fuel in the delivery line between the fuel metering valve and the pressure raising arrangement.

Abstract: A variable vane control system for controlling the angle of rotation of a circumferential row of variable vanes of a gas turbine engine. The control system includes a mechanical linkage operable to rotate the variable vanes, one or more actuators for operating the linkage and one or more position sensors for detecting the respective actuation positions of the one or more actuators. The control system further includes a linkage position signalling switch for signalling that the mechanical linkage is at a calibration position corresponding to a predetermined rotation angle of the vanes. The control system further includes a controller for controlling the one or more actuators and thereby controlling the angle of rotation of the vanes, based on the detected actuation positions which the controller correlates with vane rotation angle.

Abstract: An engine fuel control system includes a fuel metering valve operable to control the flow of fuel between a supply line and a delivery line. The delivery line is configured to receive fuel from one or more fuel pumps. The engine fuel control system further includes a pressure raising arrangement which receives the fuel flow from the delivery line and raises the fuel pressure therein. The engine fuel control system further includes a pressure sensor arranged to sense the pressure of the fuel in the supply line between the one or more fuel pumps and the fuel metering valve, or to sense the pressure of the fuel in the delivery line between the fuel metering valve and the pressure raising arrangement.

Abstract: A tamper-evident seal comprising: a first seal member having an adhesive surface region; a second seal member having a sealing surface region located for adhesion to the adhesive surface region; at least one of the adhesive surface region and the sealing surface region being at least partially coated with a heat-sensitive layer so that when the adhesive surface region is adhered to the sealing surface region the heat-sensitive layer is sealed between the first seal member and the second seal member for providing evidence of thermal tampering.