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A Methodology for Quantifying the Performance of an Engine Monitoring System
Published October 13, 2017 by SAE International in United States
Downloadable datasets availableAnnotation ability available
The purpose of this SAE Aerospace Information Report (AIR) is to present a quantitative approach for evaluating the performance and capabilities of an Engine Monitoring System (EMS). The value of such a methodology is in providing a systematic means to accomplish the following:
Determine the impact of an EMS on key engine supportability indices such as Fault Detection Rate, Fault Isolation Rate, Mean Time to Diagnose, In-flight Shutdowns (IFSD), Mission Aborts, and Unscheduled Engine Removals (UERs).
Facilitate trade studies during the design process in order to compare performance versus cost for various EMS design strategies, and
Define a “common language” for specifying EMS requirements and the design features of an EMS in order to reduce ambiguity and, therefore, enhance consistency between specification and implementation.
The techniques used for this methodology borrow from those used for testability analysis and are modified to apply to the unique aircraft supportability definitions in item 1 above. While the discussion and examples in this document focus on aircraft engines and their components, the methods and terms in this AIR are applicable to other systems. For example starting systems can be considered to be within the scope of the document.
It will be noted that many of the terms and measures used in the document reflect a military bias. It is anticipated that the methods described will either apply directly to commercial aviation measures or can be readily adapted.
AIR4985 has been reaffirmed to comply with the SAE Five-Year Review policy.
Data Sets - Support Documents
|TABLE 1||Sample Calculation of FDR%|
|TABLE 2||Component Descriptions|
|TABLE 3||Sample FDR% Analysis Logic|
|TABLE 4||Sample Calculation of FIR%|
|TABLE 5||Sample FIR% Analysis Logic|
|TABLE 6||Mean Time for Troubleshooting Methods|
|TABLE 7||Sample Calculation of MTTD|
|TABLE 8||Sample MTTD Analysis Logic|
|TABLE 9||Sample Calculation of EMS on IFSD Rate|
BackgroundEngine condition monitoring and rotorcraft HUMS(Health and Usage Monitoring Systems)can be used as a tool to track and restore engine performance, improve problem diagnosis, suggest solutions, promote better commercial and military aircraft operation, minimize in-flight failures, and reduce costs of engine maintenance. Because of these and other continuing objectives, the need for consolidated action by a group of experts to promote engine monitoring and rotorcraft conditio monitoring know-how and standards was identified. It was deemed appropriate by the SAE Propulsion Division to assign this task to a special committee designated as Committee E-32. The committee has existed for over 20 years and has 50 active members. Purpose / Charter Serves as a forum to gather, record, and publish expert information in the discipline of aircraft and helicopter engine condition monitoring and rotorcraft HUMS. The committee gathers and analyzes requirements for propulsion system monitoring for the various types of aircraft gas turbines and rotorcraft HUMS and develop standards and recommendations for the adoption of engine monitoring devices that affect the operation of gas turbine engines and rotorcraft. Objectives Identify potential engine and rotorcraft HUMS parameters suitable for sensing (pressure, temperature, etc.), and considerations involved in selecting parameters (potential problems, accuracy, cost, etc.). Analyze the various approaches to engine monitoring (e.g. airborne vibration monitoring systems and ground software interfaces, etc.) and establish criteria for the most cost-effective systems. Develop as appropriate, standards on engine and rotorcraft HUMS monitoring equipment and techniques, e.g. configuration of engine fittings for sensor connections, types of sensors, identification of signals which should be let to common diagnostic connectors, etc. Develop new requirements and uses for engine and rotorcraft HUS monitoring to promote cost-effective operation of aircraft. Sponsor technical conferences related to monitoring of air breathing engines and rotorcraft HUMS.
|AIR1872B||Guide to Life Usage Monitoring and Parts Management for Aircraft Gas Turbine Engines|