Methods and systems for detecting and responding to an engine disturbance are described. The method comprises monitoring a rate of change of a combustor pressure of an engine, detecting an engine disturbance when the rate of change of the combustor pressure falls below an event detection threshold, initiating an engine recovery sequence in response to detecting the engine disturbance, confirming a surge event when the rate of change of the combustor pressure increases above a surge confirmation threshold within a flameout confirmation time period after having crossed the event detection threshold, applying a surge recovery sequence in response to confirming the surge event, confirming a flameout event when the flameout confirmation time period expires and the rate of change of the combustor pressure remains below the surge confirmation threshold after having crossed the event detection threshold, and applying a flameout recovery sequence in response to confirming the flameout event.

A system and method for adaptively controlling a cooldown cycle of an auxiliary power unit (APU) that is operating and rotating at a rotational speed includes reducing the rotational speed of the APU to a predetermined cooldown speed magnitude that ensures combustor inlet temperature has reached a predetermined temperature value, determining, based on one or more of operational parameters of the APU, when a lean blowout of the APU is either imminent or has occurred, and when a lean blowout is imminent or has occurred, varying one or more parameters associated with the shutdown/cooldown cycle.

Systems and methods for controlling fuel flow to an engine during start are provided. Fuel is caused to be injected into a combustor of the engine according to a first fuel schedule defining a minimum fuel flow limit required to achieve light-off of the engine, the minimum fuel flow limit set at an initial value. Following light-off of the engine, at least one operating parameter of the engine is monitored. Based on the at least one operating parameter, occurrence of flameout in the engine is detected. In response to detecting occurrence of flameout in the engine, the minimum fuel flow limit is increased from the initial value to a first value to obtain an adjusted fuel schedule, and fuel is caused to be injected into the combustor according to the adjusted fuel schedule.

There is described a method and system for in-flight start of an engine. The method comprises rotating a propeller; generating electrical power at an electric generator embedded inside a propeller hub from rotation of the propeller; transmitting the electrical power from the electric generator to an engine starter mounted on a core of the engine via an electric power link; and driving the engine with the engine starter to a sufficient speed while providing fuel to a combustor to light the engine to achieve self-sustaining operation of the engine.

Systems and methods for conditionally performing engine operational tests for a turbine engine are provided. A system comprising at least one processor can be configured to obtain sensor data associated with at least one sensor for a turbine engine. The sensor data identifies a current fuel flow associated with the turbine engine. The system can determine a predicted fuel flow of the turbine engine based at least in part on the current fuel flow and a fuel flow reduction associated with an engine operational test. The system can compare the predicted fuel flow to at least one threshold. The system can selectively initiate the engine operational test based on comparing the predicted fuel flow to the at least one threshold.

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.

Systems and methods for detecting inclement weather in the vicinity of an aircraft engine are described herein. At least a first engine parameter and a second engine parameter are obtained, each engine parameter varies with changing weather conditions. An arithmetic value is determined as a function of at least the first engine parameter and the second engine parameter. The arithmetic value varies with changing weather conditions. A rate of change of the arithmetic value is determined. Inclement weather is detected when the rate of change exceeds a threshold.

The method allows to detect flameout in a combustor of a turbine system; it includes the steps of: A) measuring angular acceleration of a shaft of the or each turbine of the turbine system, B) calculating a flameout indicator as a function of the angular acceleration, and C) carrying out a comparison between the flameout indicator and at least one threshold.

A controller for a gas turbine, wherein the gas turbine includes the compressor arranged to operate at a rotational speed n, the combustor and the fuel supply including the first fuel supply and the second fuel supply, wherein the compressor is arranged to provide air to the combustor at a steady state air mass flow rate m.sub.ss and wherein the fuel supply is arranged to supply fuel at a fuel mass flow rate m.sub.total to the combustor. The controller is arranged to, responsive to a load change L to the load L, control the compressor to provide air to the combustor at a new air mass flow rate m.sub.TR, wherein the new air mass flow rate m.sub.TR is within a range between a first threshold m.sub.LBO and a second threshold m.sub.SUR.

Methods and systems are provided for presenting an energy state associated with an aircraft with respect to an operating envelope region for a procedure to restart an engine of the aircraft. One method involves providing a graphical user interface display having a first reference axis corresponding to a first energy state parameter and a second reference axis corresponding to a second energy state parameter different from the first energy state parameter, providing a graphical representation of an operating envelope region associated with a procedure for starting an engine of the aircraft with respect to the first and second reference axes, obtaining current values for the first and second energy state parameters for the aircraft, and providing a graphical representation of the aircraft positioned with respect to the first and second reference axes based on the current values for the first and second energy state parameters.