The purpose of the document is to provide the guidelines of the technological approach for developing a PHM system for EMAs with particular reference to their possible use as primary flight control actuators. It provides a basic description of the physics of the most common degradation processes,a reliability assessment and a discussion on the signals, with the associated data processing, required to build up an effective health monitoring system.
This standard defines requirements for the identification, assessment, mitigation, and prevention of risk in the manufacturing process through the application of Process Flow Diagrams (PFDs), Process Failure Mode and Effects Analysis (PFMEA) and Control Plans throughout the life cycle of a product. This standard aligns and collaborates with the requirements of AS9100, AS9102, AS9103, and AS9145. The requirements specified in this standard apply in conjunction with and are not alternative to contractual and applicable statutory and regulatory requirements. In case of conflict between the requirements of this standard and applicable statutory or regulatory requirements, the latter shall take precedence.
Three levels of fan structural analysis are included in this practice: Initial Structural Integrity In-vehicle Testing Durability (Laboratory) Test Methods The Initial Structural Integrity section describes analytical and test methods used to predict potential resonance and, therefore, possible fatigue accumulation. The In-vehicle (or machine) section enumerates the general procedure used to conduct a fan strain gage test. Various considerations that may affect the outcome of strain gage data have been described for the user of this procedure to adapt/discard depending on the particular application. The Durability Test Methods section describes the detailed test procedures for a laboratory environment that may be used depending on type of fan, equipment availability, and end objective. The second and third levels build upon information derived from the previous level.
This SAE Aerospace Information Report (AIR) presents metrics for assessing the performance of diagnostic and prognostic algorithms applied to Engine Health Management (EHM) functions. This document consolidates and expands upon the metric information previously contained in AIR4985 and AIR5909. The emphasis is entirely on metrics and as such is intended to provide an extension and complement to such documents as ARP4176, which provides insight into how to create a cost benefit analysis to determine the justification for implementing an EHM system.
This Aerospace Recommended Practice (ARP) offers best practice regarding the implementation of IVHM systems taking into account Human Factors, both the vehicle crew and the maintenance staff. The document will include considerations regarding both military and civil fixed wing aircraft. Safety implications will also be addressed.
This Aerospace Information Report (AIR) describes a Limited Engine Monitoring System that can be used by the flight crew or the maintenance staff, or both, to monitor the health of gas turbine engines in aircraft. This AIR considers monitoring of gas path performance and mechanical parameters, and systems such as low cycle fatigue counters and engine history recorders. It also considers typical measurement system accuracies and their impact. This AIR is intended as a technical guide. It is not intended to be used as a legal document or standard. AIR 1873 supplements ARP 1587, Aircraft Gas Turbine Engine Monitoring System Guide.
This Reliability Bulletin is provided as a guide for engineering and managment personnel concerned with Failure Mode and Effect Analyses (FMEA). In Addition, it provides information concerning technical and functional relationship of Failure Mode and Effect Analyses to associated disciplines, as for example, Maintainability, Safety, and System Effectiveness Analyses. This Bulletin covers requirements, concepts, interface, procedures and reports of FMEA. This Bulletin should contribute to greater utilization of FMEA results and to the understanding and appreciation of the purpose of FMEA on the part of engineering and management personnel.
Compilation of Freezing Brake Experience and Potential Designs and Operating Procedures to Prevent Its Occurrence
This Aerospace Information Report (AIR) describes conditions under which freezing (frozen) brakes can occur and describes operating procedures which have been used to prevent or lessen the severity or probability of brake freezing. This document also identifies design features that some manufacturers implement to minimize the occurrence of freezing brakes. This document is not an Aerospace Recommended Practice (ARP) and therefore does not make recommendations based on a consensus of the industry. However, part of this document’s purpose is to describe the design and operational practices that some are using to minimize the risk of frozen brakes. NOTE: The following information is based upon experience gained across a wide-range of aircraft types and operational profiles, and should NOT take precedence over Aircraft Flight Manual or Flight Operations Procedures.
This document is applicable to military aircraft where stakeholders are seeking guidance on the development and approval of Structural Health Monitoring (SHM) technologies and on the integration of these technologies into encompassing maintenance and operational support systems. The document will refer to those guidelines prepared under SAE ARP6461 that are relevant and applicable to military applications.
This Aerospace & Automotive Recommended Practice offers best practices and a methodology by which IVHM functionality relating to components and subsystems should be integrated into vehicle or platform level applications. The intent of the document is to provide practitioners with a structured methodology for specifying, characterizing and exposing the inherent IVHM functionality of a component or subsystem using a common functional reference model, i.e., through the exchange of design-time data and the application of standard vehicle data communications interfaces. This document includes best practices and guidance related to the specification of the information that must be exchanged between the functional layers in the IVHM system or between lower-level components/subsystems and the higher-level control system to enable health monitoring and tracking of system degradation severity.
In order to realize the benefits of Integrated Vehicle Health Management (IVHM) within the aerospace and defense industry there is a need to address five critical elements of data interoperability within and across the aircraft maintenance ecosystem, namely • Approach • Trust • Context • Value • Security In Integrated Vehicle Health Management (IVHM) data interoperability is the ability of different authorized components, systems, IT, software, applications and organizations to securely communicate, exchange data, interpret data, use the information and derive consistent insight from the data that has been exchanged to derive value.
This AIR will address the need for a strategy to achieve aircraft operating certificate holder maintenance efficiencies within the existing regulatory environment as well as the need for regulation, policy, and guidance changes in the long-term to accommodate more complex IVHM solutions. This document will analyse which IVHM solutions can be incorporated within existing maintenance procedures and which also comply with regulations, policy, and guidance. One of the AIR’s objectives is to define best practices for aircraft operating certificate holders to engage with regulators to get approval for simpler IVHM applications leading to maintenance efficiencies. Additionally, this document will analyse the barriers that existing regulations, policy, and guidance present to the implementation of more advanced IVHM solutions. The result is a set of recommendations to certify and implement end-to-end IVHM solutions for the purpose of gaining maintenance efficiencies.
Aircraft Turbine Engine Fuel System Component Endurance Test Procedure (Room Temperature Contaminated Fuel)
This SAE Aerospace Recommended Practice describes a method for conducting room temperature, contaminated fuel, endurance testing when the applicable specification requires nonrecirculation of the contaminants. The objective of the test is to determine the resistance of engine fuel system components to wear or damage caused by contaminated fuel operation. It is not intended as a test for verification of the component's filter performance and service life. ARP1827 is recommended for filter performance evaluation.
This SAE Aerospace Information Report (AIR) is applicable to rotorcraft structural health monitoring (SHM) applications, both commercial and military, where end users are seeking guidance on the definition, development, integration, qualification, and certification of SHM technologies to achieve enhanced safety and reduced maintenance burden based on the lessons learned from existing Health and Usage Monitoring Systems (HUMS). While guidance on SHM business case analysis would be useful to the community, such guidance is beyond the scope of this AIR. For the purpose of this document, SHM is defined as “the process of acquiring and analyzing data from on-board sensors to evaluate the health of a structure.” The suite of on-board sensors could include any presently installed aircraft sensors as well as new sensors to be defined in the future. Interrogation of the sensors could be done onboard during flight or using ground support equipment.
Various gas systems are classified in a broad sense, component operation is described in moderate detail, pertinent design parameters are discussed, and possible modes for system operation are listed.
The ARP shall cover the objectives and activities of Verification & Vallidation Processes required to assure high quality and/or criticality level of an IVHM Systems and Software.
This Bulletin provides a brief description of tin whisker formation and describes various methods recommended by government and industry to reduce the risk of tin whisker-induced failures in electronic hardware. It is not a mandate nor does it contain any requirements. A tin whisker is a single crystal that emerges from tin-finished surfaces. Tin whiskers can pose a serious reliability risk to electronic assemblies that have pure tin finish. The general risks fall into several categories: [1, 2, 3, 8, 16] Short Circuits: The whisker can create a short circuit, either by 1) growing from an area at one potential to an area at another or 2) breaking free and later bridging these areas. In some cases, these shorts may be permanent and cause catastrophic system failures. A transient short may result if the available current exceeds the fusing current of the whisker, and the whisker can fuse open.
This SAE Aerospace Information Report (AIR) examines the need for and the application of a power train usage metric that can be used to more accurately determine the TBO for helicopter transmissions. It provides a formula for the translation of the recorded torque history into mechanical usage. It provides examples of this process and recommends a way forward. This document of the SAE HM-1 IVHM Committee is not intended as a legal document and does not provide detailed implementation steps, but does address general implementation concerns and potential benefits.
Potential Failure Mode and Effects Analysis in Design (Design FMEA), Potential Failure Mode and Effects Analysis in Manufacturing and Assembly Processes (Process FMEA)
This FMEA Standard describes Potential Failure Mode and Effects Analysis in Design (DFMEA) and Potential Failure Mode and Effects Analysis in Manufacturing and Assembly Processes (PFMEA). It assists users in the identification and mitigation of risk by providing appropriate terms, requirements, ranking charts, and worksheets. As a Standard, this document contains requirements "must" and recommendations "should" to guide the user through the FMEA process. The FMEA process and documentation must comply with this Standard as well as any corporate policy concerning this Standard. Documented rationale and agreement with the customer is necessary for deviations in order to justify new work or changed methods during customer or third-party audit reviews.
This ARP provides insights on how to perform a cost benefit analysis (CBA) to determine the return on investment that would result from implementing an integrated Health Management (HM) system on an air vehicle. The word “integrated” refers to the combination or “roll up” of sub-systems health management tools to create a platform centric system. The document 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 HM systems but want to either quantify or understand the economic benefits (i.e., the value proposition) that a HM system could provide.
This SAE Aerospace Recommended Practice (ARP) provides best practices and guidance for creating an architecture for integrated vehicle health management systems. Where possible, this document will also provide references to tools to conduct architectural trades. Finally, this document will provide use cases to expose considerations and stakeholders to be included in these trades and utilization of an IVHM system (which may lead to new functional or non-functional requirements).
This document is applicable to civil aerospace airframe structural applications where stakeholders are seeking guidance on the definition, development and certification of Structural Health Monitoring (SHM) technologies for aircraft health management applications. For the purpose of this document, SHM is defined as “the process of acquiring and analyzing data from on-board sensors to evaluate the health of a structure.” The suite of on-board sensors could include any presently installed aircraft sensors as well as new sensors to be defined in the future.
SAE JA6097 (“Using a System Reliability Model to Optimize Maintenance”) shows how to determine which maintenance to perform on a system when that system requires corrective maintenance to achieve the lowest long-term operating cost. While this document may focus on applications to Jet Engines and Aircraft, this methodology could be applied to nearly any type of system. However, it would be most effective for systems that are tightly integrated, where a failure in any part of the system causes the entire system to go off-line, and the process of accessing a failed component can require additional maintenance on other unrelated components.
This AIR provides descriptions of aircraft actuation system failure-detection methods. The methods are those used for ground and in-flight detection of failures in electrohydraulic actuation systems for primary flight control. The AIR concentrates on full Fly-By-Wire (FBW) flight control actuation though it includes one augmented-control system. The background to the subject is discussed in terms of the impact that factors such as the system architecture have on the detection methods chosen for the flight control system. The types of failure covered by each monitoring technique are listed and discussed in general. The way in which these techniques have evolved is illustrated with a historical review of the methods adopted for a series of aircraft, arranged approximately in design chronological order.
This document describes reliability testing that is performed to support aerospace applications.
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 SAE Aerospace Recommended Practice (ARP) provides guidelines for the design of Integrated Vehicle Health Management (IVHM) systems. This guidance is technology-independent; the principles are therefore generally applicable to the majority of potential IVHM design scenarios, including “clean sheet” system design, where IVHM is considered as a primary design consideration and the retrofit of existing systems with IVHM capability, where the design process leverages and supports existing system elements. In either case, the document will provide guidance on the design considerations for an IVHM system throughout the analysis, concept development, and synthesis stages of the IVHM Design process and provide discussion for the users’ consideration on the trades, metrics, and lifecycle impacts of IVHM design decisions.
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.
A rough outline of the document is as follows: 1. Introduction to IVHM and rationale for the document 2. Identification of different (internal and external) stakeholders. Customers, maintenance personnel, sales and marketing and finance. Systems designers, RM&S experts, etc. Need to link requirements to design rationale, including a cost-benefit-analysis. 3. Requirements breakdown structures, from high level system requirements to lower level sub-system requirements, and finally down to component specifications. 4. Links to other systems engineering processes such as V&V, architecture design, program milestones, etc. 5. Examples of good and bad requirement practices. Maybe individual case studies or an example of an entire system. 6. Conclusions.
Three levels of fan structural analysis are included in this practice: Initial Structural Integrity In-vehicle Testing Durability Test Methods The Initial Structural Integrity section describes analytical and test methods used to predict potential resonance and, therefore, possible fatigue accumulation. The In-vehicle (or machine) section enumerates the general procedure used to conduct a fan strain gage test. Various considerations that may affect the outcome of strain gage data have been described for the user of this procedure to adapt/discard depending on the particular application. The Durability Test Methods section describes the detailed test procedures that may be used depending on type of fan, equipment availability, and end objective. Each of the previous levels builds upon information derived from the previous level. Engineering judgment is required as to the applicability of each level to a different vehicle environment or a new fan design.