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Turbine engine malfunctions account for a substantial portion of the maintenance actions required to keep both fixed and rotary wing aircraft operational. Undetected incipient component failures can result in secondary engine damage and expensive unscheduled maintenance actions. Recent developments of electrostatic methods now provide the potential for the detection of foreign object ingestion and early detection of distress in gas path components. This SAE Aerospace Information Report (AIR) seeks to outline the history of the electrostatic technique and provides examples of state-of-the-art systems for both inlet and exhaust gas debris monitoring systems along with examples of most recent testing.

This document applies to prognostics of aerospace propulsion systems. Its purpose is to define the meaning of prognostics in this context, explain their potential and limitations, and to provide guidelines for potential approaches for use in existing condition monitoring environments. This document also includes some examples. The current revision does not provide specific guidance on validation and verification, nor does it address implementation aspects such as computational capability or certification.

This document applies to prognostics of gas turbine engines and its related auxiliary and subsystems. Its purpose is to define the meaning of prognostics with regard to gas turbine engines and related subsystems, explain its potential and limitations, and to provide guidelines for potential approaches for use in existing condition monitoring environments. It also includes some examples.

This ARP provides an insight into how to approach a cost benefit analysis (CBA) to determine the return on investment (ROI) that would result from implementing a propulsion Prognostics and Health Management (PHM) system on an air vehicle. It describes the complexity of features that can be considered in the analysis, the different tools and approaches for conducting a CBA and differentiates between military and commercial applications. This document is intended to help those who might not necessarily have a deep technical understanding or familiarity with PHM systems but want to either quantify or understand the economic benefits (i.e., the value proposition) that a PHM system could provide.

This ARP provides an insight into how to approach a cost benefit analysis (CBA) to determine the return on investment (ROI) that would result from implementing a propulsion Prognostics and Health Management (PHM) system on an air vehicle. It describes the complexity of features that can be considered in the analysis, the different tools and approaches for conducting a CBA and differentiates between military and commercial applications. This document is intended to help those who might not necessarily have a deep technical understanding or familiarity with PHM systems but want to either quantify or understand the economic benefits (i.e., the value proposition) that a PHM system could provide.

To establish a specification for software input and output interfaces for condition monitoring and performance programs used to monitor equipment from multiple manufacturers. The purpose of standardizing these interfaces is to improve operational flexibility and efficiency of monitoring systems as an aid to cost effectiveness (e.g., easier implementation).

This SAE Aerospace Standard (AS) provides guidelines for the functional, performance, qualification and acceptance testing, and documentation requirements for the components of an airborne engine vibration monitoring (EVM) system which is intended for use as a turbojet engine rotor unbalance indicating system, per FAR 25.1305 (D)(3) on transport category airplanes. For the purpose of this document, this means a system which can provide real-time flight deck displays of engine vibration caused by rotor unbalance, throughout the flight envelope, which are suitable for: a Relating to engine vibration limits (where such limits are specified) b Use in ice shedding procedures c Helping the flight crew to determine which engine has the higher level of vibration, following an engine damage event. As a minimum, the functional capability for such a system shall include the ability to compute and display vibration levels specifically related to the rotational speed(s) of the engine rotor(s).

The purpose of this SAE Aerospace Information Report (AIR) is to provide management, designers, and operators with information to assist them to decide what type of power train monitoring they desire. This document is to provide assistance in optimizing system complexity, performance and cost effectiveness. This document covers all power train elements from the point at which the gas generator energy is transferred to mechanical energy for propulsion purposes. The document covers engine power train components, their interfaces, transmissions, gearboxes, hanger bearings, shafting and associated rotating accessories, propellers and rotor systems as shown in Figure 1. This document addresses application for rotorcraft, turboprop, and propfan drive trains for both commercial and military aircraft. Information is provided to assist in; a. Defining technology maturity and application risk b. Cost benefit analysis (Value analysis) c. Selection of system components d.

The purpose of this SAE Aerospace Information Report (AIR) is to provide management, designers, and operators with information to assist them to decide what type of power train monitoring they desire. This document is to provide assistance in optimizing system complexity, performance and cost effectiveness. This document covers all power train elements from the point at which the gas generator energy is transferred to mechanical energy for propulsion purposes. The document covers engine power train components, their interfaces, transmissions, gearboxes, hanger bearings, shafting and associated rotating accessories, propellers and rotor systems as shown in Figure 1. This document addresses application for rotorcraft, turboprop, and propfan drive trains for both commercial and military aircraft.

The purpose of this SAE Aerospace Information Report (AIR) is to provide management, designers, and operators with information to assist them to decide what type of power train monitoring they desire. This document is to provide assistance in optimizing system complexity, performance and cost effectiveness. This document covers all power train elements from the point at which aircraft propulsion energy in a turbine or reciprocating engine is converted via a gear train to mechanical energy for propulsion purposes. The document covers aircraft engine driven transmission and gearbox components, their interfaces, drivetrain shafting, drive shaft hanger bearings, and associated rotating accessories, propellers, and rotor systems as shown in Figure 1. For guidance on monitoring additional engine components not addressed, herein (e.g., main shaft bearings and compressor/turbine rotors), refer to ARP1839.

The ice bath recommended herein is similar to that described in SAE AIR 46. Some material not presented in AIR 46, including preferred dimensions, has been added.

The thermocouple design recommended herein is presented as one for which the correction to the observed emf, because of thermal conduction along the stem and wires, is within the limits presented in the accompanying figure. On referring to the figure, it is seen that no restriction is placed upon the diameter of the thermocouple or stem, and the longitudinal dimensions are expressed in terms of wire and stem diameters. The type of stem, such as packed ceramic stick, refractory insulating tubing, etc., also is left open to choice. Thus the sizes of wires and supporting stems may be varied over wide ranges to match particular requirements where conduction errors are to be limited or controlled.

The ice bath recommended herein is similar to that described in SAE AIR 46.* Some material not presented in AIR 46, including preferred dimensions, has been added.

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: 1 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). 2 Facilitate trade studies during the design process in order to compare performance versus cost for various EMS design strategies, and 3 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 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).

This SAE Aerospace Information Report (AIR) presents metrics for assessing the performance of prognostic algorithms applied for Engine Health Management (EHM) functions. The emphasis is entirely on prognostics and as such is intended to provide an extension and complement to such documents as AIR5871, which offers information and guidance on general prognostic approaches relevant to gas turbines, and AIR4985 which offers general metrics for evaluating diagnostic systems and their impact on engine health management activities.

The NET EMF of a thermoelectric circuit can be thought of as originating entirely in the regions of temperature gradient. Any extraneous materials, such as switch or connector terminals, in a temperature gradient may cause an error in the temperature measurement. In addition to circuitry errors, jet engine thermocouple indications require correction for the effects of conduction, radiation, response rate, and gas velocity. The magnitudes of the corrections depend on the thermocouple design and the environmental conditions. Performance curves for several typical jet engine thermocouples are presented, with the methods of making the various corrections.

This Aerospace Information Report (AIR) is a general overview of typical airborne vibration monitoring (AVM) systems with an emphasis on system hardware design considerations. It describes AVM systems currently in use. The purpose of this AIR is to provide information and guidance for the selection, installation, and use of AVM systems and their elements. This AIR is not intended as a legal document but only as a technical guide.

This Aerospace Information Report (AIR) is a general overview of typical airborne engine vibration monitoring (EVM) systems applicable to fixed or rotary wing aircraft applications, with an emphasis on system design considerations. It describes EVM systems currently in use and future trends in EVM development. The broader scope of Health and Usage Monitoring Systems, (HUMS ) is covered in SAE documents AS5391, AS5392, AS5393, AS5394, AS5395, AIR4174.