An electrical power system architecture and method for allocating power includes a power distribution bus configured to receive power generated by a first engine having a first generator and a second generator, a first set of electrical buses connected with the power distribution bus and associated with the first engine, and a second set of electrical buses configured to selectively connect with the power distribution bus.

According to an aspect, a ground-based health test of a fuel pump of a fuel control system of a gas turbine engine is initiated. A starter speed of the gas turbine engine is determined while the ground-based health test is in progress. Fuel flow is initiated from the fuel pump to an ignition system of the gas turbine engine with the starter speed set below a nominal ground-based engine starting speed. A parameter of the gas turbine engine is monitored to verify light-off. A health status of the fuel pump is determined based on the starter speed at which light-off is achieved.

According to an aspect, a ground-based health test of a fuel pump of a fuel control system of a gas turbine engine is initiated. A starter speed of the gas turbine engine is determined while the ground-based health test is in progress. Fuel flow is initiated from the fuel pump to an ignition system of the gas turbine engine with the starter speed set below a nominal ground-based engine starting speed. A parameter of the gas turbine engine is monitored to verify light-off. A health status of the fuel pump is determined based on the starter speed at which light-off is achieved.

A fuel assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a fuel valve that meters flow of fluid between a combustor and a fuel supply, and a controller in communication with the fuel assembly. The controller is programmed to receive data corresponding to a present rotational speed of a gas turbine engine component and data corresponding to at least one present flight condition, and is programmed to cause a flow rate from the fuel valve to change in response to determining that a rate of change in an acceleration rate relating to the present rotational speed meets at least one predetermined threshold. At least one predetermined threshold relates to an engine light-off event of the combustor and is based upon the at least one present flight condition.

A method of controlling at least a part of a start-up or re-light process of a gas turbine engine, the method comprising: controlling rotation of a low pressure compressor using a first electrical machine to increase angular velocity of the low pressure compressor; and controlling rotation of a high pressure compressor using a second electrical machine to restrict angular velocity of the high pressure compressor while the angular velocity of the low pressure compressor is increased.

The invention relates to a combustion chamber for a turbomachine. The combustion chamber comprises at least one spark plug, at least one fuel injector of a first type of injector that is located facing the spark plug, and at least one fuel injector of a second type. Each fuel injector comprises a mobile sealing member that is configured to open when the fuel pressure exceeds an opening threshold. The opening threshold of the mobile sealing member of the injector of the first type is strictly less than the opening threshold of the mobile sealing member of the injector of the second type.

The invention relates to a combustion chamber for a turbomachine. The combustion chamber comprises at least one spark plug, at least one fuel injector of a first type of injector that is located facing the spark plug, and at least one fuel injector of a second type. Each fuel injector comprises a mobile sealing member that is configured to open when the fuel pressure exceeds an opening threshold. The opening threshold of the mobile sealing member of the injector of the first type is strictly less than the opening threshold of the mobile sealing member of the injector of the second type.

A method is provided for operating an aircraft system. During this method, an engine is operated using first fuel provided by a first fuel source. A fuel supply for the engine is switched between the first fuel source and a second fuel source, where the switching of the fuel supply includes shutting down the engine during aircraft flight. The engine is operated using second fuel provided by the second fuel source.

Systems and methods for shutting down a gas turbine engine in response to a severe mechanical failure include determining a rate of change of one or more process conditions. If the rate of change of the one or more process conditions exceeds a respective predetermined failure threshold, a potential severe mechanical failure of the gas turbine engine may be determined. Steps may be taken to confirm the potential severe mechanical failure of the gas turbine engine. In response, an engine restart is prevented.

Systems and methods for shutting down a gas turbine engine in response to a severe mechanical failure include determining a rate of change of one or more process conditions. If the rate of change of the one or more process conditions exceeds a respective predetermined failure threshold, a potential severe mechanical failure of the gas turbine engine may be determined. Steps may be taken to confirm the potential severe mechanical failure of the gas turbine engine. In response, an engine restart is prevented.