Methods and systems for operating an engine coupled to a fuel system having at least one fuel manifold configured to supply fuel to a combustor of the engine are described. The method comprises, when the engine is active, supplying fuel to the combustor by supplying gaseous fuel from a gaseous fuel supply to the at least one fuel manifold, and when the engine is inactive, purging the at least one fuel manifold by supplying inert gas from an inert gas supply to the at least one fuel manifold.

According to an aspect, a gas turbine engine includes a turbine section with a turbine case and a plurality of turbine blades within the turbine case. The gas turbine engine also includes an active clearance control system with an active clearance control cooling air supply, a valve pneumatically coupled to the active clearance control cooling air supply, and a controller. The controller is configured to determine an active cooling control schedule adjustment based on a condition of the gas turbine engine, operate the active clearance control system according to an active cooling control schedule as modified by the active cooling control schedule adjustment, apply a decay function to the active cooling control schedule adjustment to reduce an effect on the active cooling control schedule adjustment, and resume operating the active clearance control system according to the active cooling control schedule based on an active cooling control condition being met.

A control system for turbine systems configured to provide accurate interpretations of detected particle accumulation, improve performance of turbine systems, and/or minimize costs due to downtime and maintenance are disclosed. The control system may build an intelligent model of fluid flow based on measured data provided by a sensor in a fluid flow path of the turbine system. The intelligent model consults a filter efficiency framework and determines an impact value that quantifies an operational efficiency of the turbine system and may identify a location of possible leakage, estimate a total amount of ingress of particles, identify components of the turbine system that may be operating in a diminished capacity, estimate a risk of damage to components of the turbine system, and/or recommend mitigation actions.

A system includes a gas turbine system including a compressor, a combustor, a turbine, and an exhaust section. The system also includes multiple sensors coupled to components of the gas turbine system. The system further includes a controller communicatively coupled to the gas turbine system and the multiple sensors and configured to control operations of the gas turbine system, wherein the controller is configured to calculate a surrogate value for turbine exit Mach number based on the feedback from the multiple sensors and to utilize the surrogate value to derive a control action for the gas turbine system.

An aircraft electrical power generation system includes an AC generator having a rotor including a plurality of electromagnetic rotor-windings and stator including plurality of electrical stator-windings. The rotor mechanically coupled to a shaft of a gas turbine engine by transmission-system. The generator includes a frequency controller, a torque sensor determining a torque on the transmission-system by the generator and controller to operate the system in first and second modes. In first mode, the power output frequency of the generator controlled by the frequency controller within limits, and reduced idle signal going to a turbine engine controller. In second mode, the power output frequency of the generator not controlled by the frequency controller and increased idle signal going to the turbine engine controller. The controller operates the system in first mode when the torque is below a limit, and in second mode when the torque is above a limit.

A control system for an aircraft hybrid propulsion system comprising a gas turbine engine coupled to an electric generator, a propulsor coupled to an electric motor, and an electrical storage device coupled to the motor and the generator. The control system configured to operate the propulsion system in a first descent mode and a second descent mode. In the first descent mode, the gas turbine engine is operated at a first engine power level and the generator is operated at a first generator power level. In the second descent mode, the gas turbine engine is operated at a second engine power level, higher than the first engine power level, and the generator is operated at a second generator power level, higher than the first generator power level. Electric power generated by the electric generator during operation in the second descent mode is stored in the electrical storage device.

Disclosed is a throttle quadrant arrangement having a throttle lever which is independently mechanically connected to different Rotary Variable Differential Transformers (RVDTs). A friction lever selectively creates and releases friction from the throttle lever to enable it to be selectively positioned. The system is configured such that the mechanical connections existing between the throttle lever and the RVDTs are shielded from the friction created by the friction lever.

The present disclosure concerns the communication between electronic systems in an aircraft subassembly such as a propulsion unit. This communication is at least partially carried out by light signals transmitted through at least one interior volume of the sub-assembly, this interior volume defining an optical channel. To this end, at least one of these systems includes an emitter arranged to emit a light signal and modulate it depending on data to be transmitted generated by this system, and at least one other of these systems includes at least one receiver capable of receiving this light signal.

A control system for an aircraft hybrid propulsion system comprising a gas turbine engine coupled to an electric generator, a propulsor coupled to an electric motor, and an electrical storage device coupled to the motor and the generator. The control system configured to operate the propulsion system in a first descent mode and a second descent mode. In the first descent mode, the gas turbine engine is operated at a first engine power level and the generator is operated at a first generator power level. In the second descent mode, the gas turbine engine is operated at a second engine power level, higher than the first engine power level, and the generator is operated at a second generator power level, higher than the first generator power level. Electric power generated by the electric generator during operation in the second descent mode is stored in the electrical storage device.

A gas turbine engine has a fan rotor delivering air into a bypass duct defined between an outer fan case and an outer interior housing. The fan rotor also delivers air into a compressor section, a combustor, a turbine section. A chamber is defined between the outer interior housing and an inner housing. The inner housing contains the compressor section, the combustor and the turbine section. A first conduit taps hot compressed air to be cooled and passes the air to at least one heat exchanger. The air is cooled in the heat exchanger and returned to a return conduit. The return conduit passes the cooled air to at least one of the turbine section and the compressor section. The heat exchanger has a core exhaust plane. The turbine section has at least a first and a downstream second rotor blade row, with the core exhaust plane located downstream of a center plane of the second blade row.