A lubrication system is disclosed. The lubrication system may be used in conjunction with a gas turbine engine for generating power or lift. The lubrication system utilized a flow scheduling valve which reduces lubricant flow to at least one component based on an engine load. The lubrication system may further include a main pump which may be regulated by an engine speed. Thus, a lubrication system which provides a lubricant to engine components based on the load and speed of the engine is possible. The system may improve efficiency of the engine by reducing the power previously spent in churning excess lubricant by at least one engine component as well as reducing the energy used by a lubricant cooler in cooling the excess lubricant. The lubricant cooler size may also be minimized to reduce weight and air drag due to the reduced lubricant flow.

Methods and apparatus are disclosed to determine material parameters of a turbine rotor. An example apparatus includes a rotor geometry determiner to determine a geometry of the rotor, a node radius calculator to calculate radial node locations of radial nodes including a first radial node, a thermocouple interface to record first temperature values over an interval, a first thermal stress calculator to calculate first thermal stress values at one or more of the radial nodes over the interval, a node temperature calculator to calculate second temperature values at respective internal nodes of the first radial node, a reference value lookup to lookup first material parameter information, a second thermal stress calculator to determine second thermal stress values, a thermal stress comparator to calculate a difference between the thermal stress values, and, in response to the difference not satisfying a threshold, a material parameter adjuster to determine material parameters.

A minimum creep life location (MCLL) on a blade for a turbine blade design is received. A temperature at the MCLL on the blade is monitored. When the temperature at the MCLL exceeds a predetermined threshold, a cooling air supply is adjusted to lower the temperature below the threshold during engine operation.

Distress models can be generated to model current or future deterioration of components. By correlating distress models with maintenance costs and material consumption, cumulative cost models and cumulative material models can be developed to optimize engine removal timing in order to maximize asset and portfolio value.

The invention relates to a device for monitoring the lifetime of at least one hydraulic apparatus of an aircraft that is subject to ventilations in hydraulic pressure during flight, comprising an interface for receiving measurement data which are representative of hydraulic pressure (P). The invention is characterised in that the device comprises a processing device, comprising a means for detecting a pressure (P) load (SOLL.sub.END) of a damaging nature, which load is defined by the fact that the pressure (P) comprises a pressure increase (ΔP.sub.AUG) that is greater than a predetermined damage threshold (S.sub.ΔP), followed by a pressure decrease (ΔP.sub.DIM) that is greater than the threshold (S.sub.ΔP), a means for calculating a pressure variation magnitude that is equal to the maximum increase (ΔP.sub.AUG) and the maximum decrease (ΔP.sub.DIM), a means for projecting the magnitude onto a decreasing curve or straight line of a damage model in order to determine the permissible number of loads corresponding to the magnitude, a means for calculating a potential damage ratio that is equal to a number of reference loads divided by the permissible number, a means for increasing a count of accumulated ratios by said ratio.

The present disclosure provides methods and systems for operating a multi-engine rotorcraft. The method comprises driving a rotor of the rotorcraft with a first engine while a second engine is de-clutched from a transmission clutch system that couples the rotor and the second engine, instructing the second engine to accelerate to a re-clutching speed, and controlling an output shaft speed of the second engine during acceleration of the second engine to the re-clutching speed by applying a damping function to a speed control loop of the second engine.

A method can comprise: performing a finite element static analysis of an inspected blade of an inspected bladed rotor, the inspected blade having a repair blend profile modeled thereon, the repair blend profile exceeding a threshold repair size; performing a finite element modal analysis of the inspected blade having the repair blend profile; performing a fatigue assessment based on results from the finite element static analysis and the finite element modal analysis, the fatigue assessment including limits based on material properties of the inspected blade, the material properties based on test results at a threshold significance level; and repairing the inspected bladed rotor with the repair blend profile in response to the fatigue assessment meeting a deterministic criteria.

A method of repairing an integrally bladed rotor (IBR) may comprise: performing a vibratory analysis of a rotor module including a first inspected IBR with a potential repair shape for the IBR; determining an undesirable vibratory characteristic of a second inspected IBR in the rotor module; iterating the potential repair shape for the first IBR to eliminate the undesirable vibratory characteristic of the second inspected IBR; and repairing the first IBR with a selected repair shape based on determining the potential repair shape eliminates the undesirable vibratory characteristic.

The invention relates to a device for monitoring the lifetime of at least one hydraulic apparatus of an aircraft that is subject to ventilations in hydraulic pressure during flight, comprising an interface for receiving measurement data which are representative of hydraulic pressure (P). The invention is characterised in that the device comprises a processing device, comprising a means for detecting a pressure (P) load (SOLL.sub.END) of a damaging nature, which load is defined by the fact that the pressure (P) comprises a pressure increase (ΔP.sub.AUG) that is greater than a predetermined damage threshold (S.sub.ΔP), followed by a pressure decrease (ΔP.sub.DIM) that is greater than the threshold (S.sub.ΔP), a means for calculating a pressure variation magnitude that is equal to the maximum increase (ΔP.sub.AUG) and the maximum decrease (ΔP.sub.DIM), a means for projecting the magnitude onto a decreasing curve or straight line of a damage model in order to determine the permissible number of loads corresponding to the magnitude, a means for calculating a potential damage ratio that is equal to a number of reference loads divided by the permissible number, a means for increasing a count of accumulated ratios by said ratio.

A full authority digital engine controller (FADEC) based system is also disclosed. The system includes a processor, and a tangible, non-transitory memory configured to communicate with the processor, the tangible, non-transitory memory having instructions stored thereon that, in response to execution by the processor, cause the FADEC to perform operations. The operations may include measuring a first temperature at a first sensor disposed at a first known location of an engine, measuring a second temperature at a second sensor disposed at a second known location of the engine, and estimating at least one of a stress or a strain of a part or component in the engine based on the first temperature and the second temperature. The system may control fuel flow and/or other engine effectors during a thrust transient to limit the estimated stress or the estimated strain of the component from exceeding a predetermined threshold.