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AIR5317 establishes the foundation for developing a successful APU health management capability for any commercial or military operator, flying fixed wing aircraft or rotorcraft. This AIR provides guidance for demonstrating business value through improved dispatch reliability, fewer service interruptions, and lower maintenance costs and for satisfying Extended Operations (ETOPS) availability and compliance requirements.

This SAE Aerospace Information Report (AIR) provides an overview of temperature measurement techniques for various locations of aircraft gas turbine engines while focusing on current usage and methods, systems, selection criteria, and types of hardware.

This Aerospace Information Report (AIR) presents considerations specific to machine learning (ML) applied to propulsion system health management (aka EHM), illustrated via examples. These examples are used to highlight concerns and approaches that are unique to EHM, including the typical design space for propulsion systems, terminology, data collection and processing methods, requirements, and characteristics of machine learning models that have been developed and are being implemented.

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 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.

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.

This SAE Aerospace Information Report (AIR) reviews the precautions that must be taken and the corrections which must be evaluated and applied if the experimental error in measuring the temperature of a hot gas stream with a thermocouple is to be kept to a practicable minimum. Discussions will focus on Type K thermocouples, as defined in National Institute of Standards and Technology (NIST) Monograph 175 as Type K, nickel-chromium (Kp) alloy versus nickel-aluminium (Kn) alloy (or nickel-silicon alloy) thermocouples. However, the majority of the content is relevant to any thermocouple type used in gas turbine applications.

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.

ARP5120 provides recommended best practices, procedures, and technology to guide the physical and functional design, development, integration, verification, and validation of highly reliable Engine Health Management (EHM) systems for aircraft engines and Auxiliary Power Units (APUs). This SAE Aerospace Recommended Practice (ARP) also serves as a concise reference of considerations, approaches, activities, and requirements for producing the end-to-end engine health management system comprised of both on and off-board subsystems for the sensing, acquisition, analysis, detection, and data handling functions for EHM. These functions may also be used to effect continued operation or return to service decisions when demonstrated as compliant with the applicable airworthiness requirements defined by the responsible Aviation Authority. Where practical, this document delineates between military and commercial practices.

The process detailed within this document is generic and can be applied to commercial and military applications. It applies to the entire end-to-end health management system throughout its lifecycle, covering on-board and on-ground elements. The practical application of this standardized process is detailed in the form of a checklist.

The on-board element described here are the source of the data acquisition used for off-board analysis. The on-board aspects relating to safety of flight, pilot notification, etc., are addressed by the other SAE Committees standards and documents.

This document does not prescribe hardware or software assurance levels, nor does it answer the question “how much mitigation and evidence are enough”. The criticality level and mitigation method will be determined between the ‘Applicant’ and the regulator.

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 Aerospace Information Report (AIR) presents metrics for assessing the performance of diagnostic and prognostic algorithms and systems delivering propulsion health management functions.

This SAE Aerospace Recommended Practice (ARP) examines the whole construct of an Engine Health Management (EHM) system. This keystone document gives a top-level view and addresses EHM description, benefits, and capabilities, and provides examples. This ARP purposely addresses a wide range of EHM architectures to demonstrate possible EHM design options. This ARP is not intended as a legal document and does not provide detailed implementation steps, but does address general implementation concerns and potential benefits. Other SAE documents (Aerospace Standards, Aerospace Recommended Practices, and Aerospace Information Reports) address specific component specifications, procedures and "lessons learned".

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.

The SAE E-32 Committee is requested to develop standards for Commercial Aircraft Engine Monitoring to support the Continued Airworthiness of aircraft in general, with particular emphasis on the ETOPS (Extended Operations) to support the regulations. 14CFR A33.3 (c) ETOPS Requirements. For an applicant seeking eligibility for an engine to be installed on an airplane approved for ETOPS, the Instructions for Continued Airworthiness must include procedures for engine condition monitoring. The engine condition monitoring procedures must be able to determine prior to flight, whether an engine is capable of providing, within approved engine operating limits, maximum continuous power or thrust, bleed air, and power extraction required for a relevant engine inoperative diversion. For an engine to be installed on a two-engine airplane approved for ETOPS, the engine condition monitoring procedures must be validated before ETOPS eligibility is granted.

The purpose of this SAE Aerospace Information Report (AIR) is to provide information that would be useful to potential users/operators and decision makers for evaluating and quantifying the benefits of an Engine Monitoring Systems (EMS) versus its cost of implementation. This document presents excerpts from reports developed to analyze "actual aircraft cost/benefits results". These are presented as follows: a. First, to outline the benefits and cost elements pertaining to EMS that may be used in performing a cost versus benefits analysis. b. Second, to present considerations for use in conducting the analysis. c. Third, to provide examples of analyses and results as they relate to the user/operator and decision-maker community. The document encompasses helicopters and fixed wing aircraft and distinguishes between civilian and military considerations.

The process detailed within this document is generic and can be applied to commercial and military applications. It applies to the entire end-to-end health management system throughout its lifecycle, covering on-board and on-ground elements. The practical application of this standardized process is detailed in the form of a checklist. The on-board element described here are the source of the data acquisition used for off-board analysis. The on-board aspects relating to safety of flight, pilot notification, etc., are addressed by the other SAE Committees standards and documents. This document does not prescribe hardware or software assurance levels, nor does it answer the question “how much mitigation and evidence are enough”. The criticality level and mitigation method will be determined between the ‘Applicant’ and the regulator.

This SAE Aerospace Recommended Practice (ARP) provides guidance for the design of flanges on temperature sensors intended for use in gas turbine engines. Three figures detail the configuration of standard size flange mounts with bolt holes, slotted flanges, and miniaturized flanges for small probes.