Methods and systems for starting an engine are provided. A cold-start request to start the engine in a first operating condition associated with a predetermined engine temperature range is obtained. In response to obtaining the cold-start request, an amount of boost fuel to provide to the engine is determined, based on at least one second operating condition of the engine. The engine is started by supplementing a baseline fuel flow to the engine with the amount of boost fuel.

A method of delivering fuel to an engine during operation of the engine, that includes, sensing the speed of sound in the fuel, determining a density or property of the fuel, and based on that density or fuel property adjusting the flow rate of the fuel. Further, an established fuel profile or determined energy density value can also be used to adjust the flow rate of the fuel.

A method of delivering fuel to an engine during operation of the engine, that includes, sensing the speed of sound in the fuel, determining a density or property of the fuel, and based on that density or fuel property adjusting the flow rate of the fuel. Further, an established fuel profile or determined energy density value can also be used to adjust the flow rate of the fuel.

Methods, systems, and assemblies for operating an aircraft having a turboprop engine are described. The method comprises obtaining a measured torque of the turboprop engine from a mechanical torque piston measurement system and displaying the measured torque in a cockpit of the aircraft. During operation of the turboprop engine, a torque measurement saturation condition of the torque piston measurement system is monitored to detect when the torque piston measurement system is outside of an operating range. A synthesized torque of the turboprop engine is determined based on one or more actual engine operating parameters of the turboprop engine. In response to detecting that the torque piston measurement system is outside of the operating range, the synthesized torque is displayed in the cockpit of the aircraft.

A pump system for a gas turbine engine including a first pump connected to a fluid flow demand line for delivering fluid to a fluid flow demand and a second pump connected, in parallel to the first pump, to the fluid flow demand line and supplementing fluid to the actuation or burner system based on the fluid flow demand. A pressure regulating valve (PRV) is fluidly connected to the flow demand line for bypassing flow to a pump inlet pressure of the first pump and second pump, and controlling a modulated pressure flow signal to a bypass valve, wherein the bypass valve is in fluid communication with the second pump and the PRV for receiving modulated pressure from the PRV and regulating delivery of fluid from the second pump to a bypass flow line.

A pump system for a gas turbine engine including a first pump connected to a fluid flow demand line for delivering fluid to a fluid flow demand and a second pump connected, in parallel to the first pump, to the fluid flow demand line and supplementing fluid to the actuation or burner system based on the fluid flow demand. A pressure regulating valve (PRV) is fluidly connected to the flow demand line for bypassing flow to a pump inlet pressure of the first pump and second pump, and controlling a modulated pressure flow signal to a bypass valve, wherein the bypass valve is in fluid communication with the second pump and the PRV for receiving modulated pressure from the PRV and regulating delivery of fluid from the second pump to a bypass flow line.

A control device includes a load fuel quantity calculation unit, an allowable fuel quantity calculation unit, a flow rate low value selection unit, a basic drive quantity calculation unit, a fuel deviation calculation unit, and a correction unit. The load fuel quantity calculation unit determines a load fuel quantity based on a required output. The allowable fuel quantity calculation unit determines an allowable fuel quantity to protect a gas turbine. The flow rate low value selection unit selects a minimum fuel quantity from among the determined fuel quantities. The basic drive quantity calculation unit determines a basic drive quantity of an air intake quantity regulator. The fuel deviation calculation unit determines a fuel deviation between the allowable fuel quantity and the minimum fuel quantity. The correction value calculation unit determines a correction value corresponding to the fuel deviation which is then used to correct the basic drive quantity.

An exemplary aircraft includes a turbine engine having a gas generator spool and a power spool, the power spool operational to drive a rotor, a first generator coupled to the gas generator spool, and a controller operable to increase a load on the gas generator spool when the gas generator spool is on a speed limit thereby increasing a speed limit margin in order to increase power available from the turbine engine.

Methods and systems for controlling a bleed-off valve of a gas turbine engine are described. The method comprises maintaining a first bleed-off valve associated with a first compressor of the gas turbine engine at least partially open upon detection of an unintended engine disturbance causing a drop in pressure of a combustion chamber of the engine; monitoring a rotor acceleration of the first compressor; and controlling closure of the first bleed-off valve when the rotor acceleration of the first compressor reaches a first threshold for a first duration.

Methods and systems for controlling a bleed-off valve of a gas turbine engine are described. The method comprises maintaining a first bleed-off valve associated with a first compressor of the gas turbine engine at least partially open upon detection of an unintended engine disturbance causing a drop in pressure of a combustion chamber of the engine; monitoring a rotor acceleration of the first compressor; and controlling closure of the first bleed-off valve when the rotor acceleration of the first compressor reaches a first threshold for a first duration.