Abstract: A method for detecting a burner failure in a gas turbine engine that has a combustor and a turbine disposed downstream of the combustor. The combustor has a plurality of burners arranged annularly. The method includes providing a plurality of temperature sensors arranged annularly at an outlet of the turbine; obtaining a plurality of temperature signals from the plurality of temperature sensors; determining a plurality of validated temperature signals from the plurality of temperature signals; determining a temperature focus at least based on the plurality of validated temperature signals; improving the temperature focus such that the temperature focus is within a tolerance range; and performing at least one hazard protection action at least when the temperature focus crosses a predetermined threshold.

Abstract: A blower system for a gas turbine engine comprising: a rotor assembly, an airframe port and a routing-control valve. The rotor assembly is configured to be mechanically coupled to a spool of the gas turbine engine. The airframe port is configured to receive and discharge air to an airframe system. The routing-control valve comprises: a primary channel for bidirectional flow between the rotor assembly and the airframe port; a primary valve member configured to open and close the primary channel; and an auxiliary channel branched from the primary channel. The auxiliary channel is configured to bypass the primary valve member for: a first auxiliary flow from the airframe port to the rotor assembly; or a second auxiliary flow for purging air from the rotor assembly to a discharge port. The blower system is configured to operate in an engine drive mode and in a blower mode.

Abstract: A method of controlling a gas turbine engine. The gas turbine engine has a compressor, a combustor, and a motor configured to drive the compressor. The method has in a first idle mode, controlling combustor fuel flow to maintain compressor rotational speed at or above a predetermined value; and in a second idle mode, controlling the combustor and the motor to drive the compressor to maintain the compressor rotational speed at or above a second predetermined value, lower than the first predetermined value.

Abstract: A burner head for a fuel manifold. The burner head has: a mains fuel injector; a pilot fuel injector; a fuel source; a first isolation valve connected to the fuel source; and a staging valve. The staging valve is connected to the first isolation valve, and the staging valve has a mains fuel conduit connected to the mains fuel injector and a pilot fuel conduit connected to the pilot fuel injector. The first isolation valve and the staging valve are connected in series, such that fuel from the fuel source must pass through the first isolation valve before arriving at the staging valve.

Abstract: A hydraulic stepper motor comprising three hydraulic ports each coupled to a piston that is actuatable between pressurised and depressurised configurations; and a contoured cam surface having at least one peak and trough and arranged to react against the pistons, the cam surface coupled to an output shaft; whereby actuation of one of the pistons moves the cam surface until a trough reacts against one or more pressurised pistons.