A method of determining one or more fuel characteristics of an aviation fuel for powering a gas turbine engine of an aircraft includes: measuring one or more trace substance parameters of the fuel, the one or more trace substance parameters each associated with a respective trace substance in the fuel; and determining one or more fuel characteristics of the fuel based on the one or more trace substance parameters. Further, a fuel characteristic determination system, a method of operating an aircraft, and an aircraft.

An operation/maintenance management method of an integrated system including a plurality of components or devices includes selecting an index and a period for evaluating the integrated system, acquiring prediction information for input information for use in computation of the index, creating a future prediction scenario by combining the input information, computing an evaluation index related to the scenario, and comparing and displaying evaluation index computation results related to a plurality of scenarios.

An operation/maintenance management method of an integrated system including a plurality of components or devices includes selecting an index and a period for evaluating the integrated system, acquiring prediction information for input information for use in computation of the index, creating a future prediction scenario by combining the input information, computing an evaluation index related to the scenario, and comparing and displaying evaluation index computation results related to a plurality of scenarios.

A checking method for checking a power plant of an aircraft, the power plant comprising at least one engine and an air inlet for feeding said at least one engine with air, the power plant including a cloggable filter filtering the air upstream from the engine. An aircraft power check is performed by: determining, in flight or on the ground, the current power actually being developed by the engine without making any allowance for any power losses resulting from the engine being installed in the aircraft or from a level of clogging of the filter, the aircraft power check being considered as being successful when the current power is greater than or equal to a guaranteed minimum power.

A checking method for checking a power plant of an aircraft, the power plant comprising at least one engine and an air inlet for feeding said at least one engine with air, the power plant including a cloggable filter filtering the air upstream from the engine. An aircraft power check is performed by: determining, in flight or on the ground, the current power actually being developed by the engine without making any allowance for any power losses resulting from the engine being installed in the aircraft or from a level of clogging of the filter, the aircraft power check being considered as being successful when the current power is greater than or equal to a guaranteed minimum power.

Systems and method for synchrophasing aircraft engines are disclosed. One method comprises receiving data indicative of a sensed vibration level associated with a first aircraft engine and a second aircraft engine operating at a substantially same operating speed and commanding one or more momentary changes in operating speed of the second aircraft engine until the sensed vibration level substantially reaches a target vibration level. The momentary changes in operating speed of the second aircraft engine is commanded irrespective of phase information associated with imbalances of the first and second aircraft engines.

Systems and method for synchrophasing aircraft engines are disclosed. One method comprises receiving data indicative of a sensed vibration level associated with a first aircraft engine and a second aircraft engine operating at a substantially same operating speed and commanding one or more momentary changes in operating speed of the second aircraft engine until the sensed vibration level substantially reaches a target vibration level. The momentary changes in operating speed of the second aircraft engine is commanded irrespective of phase information associated with imbalances of the first and second aircraft engines.

A system for controlling a turbine is disclosed. The system includes a turbine control fuel governor that has a plurality of VCPIDs operating in parallel with one another. Each VCPID is associated with a respective turbine parameter and one or more external parameters. Each VCPID incorporates feedback from the parallel operating VCPIDs to feed an integral term of a current VCPID in the following manner: a previous derivative gain and a previous proportional gain are summed and subtracted from a selected output for the turbine to yield a result, and the result is input to an integral gain portion of the current VCPID.

A system for controlling a turbine is disclosed. The system includes a turbine control fuel governor that has a plurality of VCPIDs operating in parallel with one another. Each VCPID is associated with a respective turbine parameter and one or more external parameters. Each VCPID incorporates feedback from the parallel operating VCPIDs to feed an integral term of a current VCPID in the following manner: a previous derivative gain and a previous proportional gain are summed and subtracted from a selected output for the turbine to yield a result, and the result is input to an integral gain portion of the current VCPID.

A bumpless transfer fault tolerant control method for aero-engine under actuator fault is disclosed. For an aero-engine actuator fault, by adopting an undesired oscillation problem produced by an active fault tolerant control method based on a virtual actuator, in order to solve the shortage of the existing control method, a bumpless transfer active fault tolerant control design method for the aero-engine actuator fault is provided, which can guarantee that a control system of the reconfigured aero-engine not only has the same state and output as an original fault-free system without changing the structure and parameters of a controller, to achieve a desired control objective, and that a reconfigured system has a smooth transient state, that is, output parameters such as rotational speed, temperature and pressure do not produce the undesired transient characteristics such as overshoot or oscillation.