A method and system for diagnosing a condition of an air-breathing aircraft engine are described. The method comprises obtaining a sample of lubricating fluid from the engine, filtering the sample to obtain a plurality of particles from the lubricating fluid, obtaining chemical composition data for the plurality of particles, determining a quantity of volcanic ash in the lubricating fluid by considering each one of the particles as composed partially of volcanic ash and partially of at least one other material and determining a first percentage of surface area of the particles covered by the volcanic ash and a second percentage of the surface area of the particles covered by the at least one other material, the volcanic ash having associated thereto a predetermined chemical composition, and diagnosing a condition of the engine based on the quantity of volcanic ash found in the lubricating fluid.

A method and system for diagnosing a condition of an air-breathing aircraft engine are described. The method comprises obtaining a sample of lubricating fluid from the engine, filtering the sample to obtain a plurality of particles from the lubricating fluid, obtaining chemical composition data for the plurality of particles, determining a quantity of volcanic ash in the lubricating fluid by considering each one of the particles as composed partially of volcanic ash and partially of at least one other material and determining a first percentage of surface area of the particles covered by the volcanic ash and a second percentage of the surface area of the particles covered by the at least one other material, the volcanic ash having associated thereto a predetermined chemical composition, and diagnosing a condition of the engine based on the quantity of volcanic ash found in the lubricating fluid.

To sensing an anomaly on the basis of a multi-dimensional time series sensor signal, in order to determine the next action for a countermeasure, survey, or the like, the present invention is configured such that a multi-dimensional feature vector for each time is extracted on the basis of a sensor signal, a reference feature vector for each time is extracted on the basis of a set of characteristic vectors for a predetermined learning period and the characteristic vector of each time, an anomaly measure is calculated on the basis of the difference between the feature vectors for the times and the reference feature vectors, an anomaly is detected by comparing the anomaly measure and a predetermined threshold value, and the anomaly-related sensor for the time the anomaly is detected is identified on the basis of a 2-dimensional distribution density of feature values.

To sensing an anomaly on the basis of a multi-dimensional time series sensor signal, in order to determine the next action for a countermeasure, survey, or the like, the present invention is configured such that a multi-dimensional feature vector for each time is extracted on the basis of a sensor signal, a reference feature vector for each time is extracted on the basis of a set of characteristic vectors for a predetermined learning period and the characteristic vector of each time, an anomaly measure is calculated on the basis of the difference between the feature vectors for the times and the reference feature vectors, an anomaly is detected by comparing the anomaly measure and a predetermined threshold value, and the anomaly-related sensor for the time the anomaly is detected is identified on the basis of a 2-dimensional distribution density of feature values.

A double frangible bearing support structure supports a low pressure rotor of an aircraft engine. The support structure has a first bearing assembly including a first bearing supported by a first bearing support adapted to buckle or frange when subject to a predetermined critical load resulting from an abnormal rotor imbalance. The support structure has a second bearing assembly comprising a second bearing having rolling elements disposed between inner and outer races. The outer race is connected to a second bearing support by means of frangible bolts adapted to fail when subject to a predetermined critical load resulting from radial displacements and loads of the low pressure rotor following decoupling/franging at the first bearing support.

A double frangible bearing support structure supports a low pressure rotor of an aircraft engine. The support structure has a first bearing assembly including a first bearing supported by a first bearing support adapted to buckle or frange when subject to a predetermined critical load resulting from an abnormal rotor imbalance. The support structure has a second bearing assembly comprising a second bearing having rolling elements disposed between inner and outer races. The outer race is connected to a second bearing support by means of frangible bolts adapted to fail when subject to a predetermined critical load resulting from radial displacements and loads of the low pressure rotor following decoupling/franging at the first bearing support.

A method includes obtaining a first test matrix for a first aircraft system and a second test matrix for a second aircraft system. The method also includes, during a first operational test of the first test matrix, obtaining sensor data that includes second sensor data that is not specified by the first test matrix. The method includes evaluating a second operational test of the second test matrix by processing the second sensor data using a second analytic model of the second aircraft system. The method also includes generating second predicted sensor data based on the evaluation of the second operational test. The method includes generating a second error measure by comparing a second subset of the sensor data to the second predicted sensor data. The method includes determining, based at least in part on a range of the second sensor data, a test coverage metric of the second test matrix.

Methods of determining a desired sensor probe location in a closed loop emissions control (CLEC) system of a gas turbine engine are provided. One method includes determining, at different locations, a plurality of temperature contour profiles for exhaust flowing through an exhaust duct, selecting an emissions component entrained in the exhaust to be measured, and determining a desired sensor probe installation location based on the emissions component to be measured and based on the plurality of temperature contour profiles.

Methods of determining a desired sensor probe location in a closed loop emissions control (CLEC) system of a gas turbine engine are provided. One method includes determining, at different locations, a plurality of temperature contour profiles for exhaust flowing through an exhaust duct, selecting an emissions component entrained in the exhaust to be measured, and determining a desired sensor probe installation location based on the emissions component to be measured and based on the plurality of temperature contour profiles.

A method of detecting flame state of a combustor of a turbine engine. The method includes determining at least one of a first derivative and a second derivative of a compressor discharge pressure of a compressor of the turbine engine; determining at least one of a first derivative and a second derivative of a gas turbine exhaust gas temperature of the exhaust gases output by the turbine engine; determining at least one of a first derivative and a second derivative of a gas turbine shaft/rotor speed of the turbine engine; determining at least one of a first derivative and a second derivative of combustor dynamic pressure monitoring; and determining a flame state of a combustor of the turbine engine based on the combustor dynamic pressure monitoring, the determined derivatives of the combustion dynamics, compressor discharge pressure, gas turbine shaft/rotor speed, and gas turbine exhaust gas temperature of the exhaust gases.