Maintainability is an attribute that is sought after by operators and maintainers all across the world, and has long been known as “one of the ‘‐ilities’” associated with deployment and use of equipment, such as quality, supportability, maintainability, reliability, and interoperability, among others. Senior leaders in the military and in commercial transportation sectors demand that original equipment manufacturers (OEMs) produce equipment and systems that possess these attributes so that their operations can be effective and economic.
Acquisition of equipment for the US military has traditionally focused on fielding equipment with high reliability and low maintainability cost. During World War II, military units prized the ubiquitous Jeep, the M‐14 rifle, and other equipment because they rarely failed, and when they did, they were easily repaired. The combination of low failure rates and easy maintenance results in high operational availability (the percentage of time the equipment is capable meeting its operational requirements), and leads to linkage of reliability and maintainability requirements. Meeting functional performance goals, while always a primary driver of system design, may not be sufficient to meet overall operational goals, if the system has low operational availability. Loss of availability can put military units at risk or commercial entities in danger of financial loss.
As systems and equipment have become more complex, these attributes have maintained their importance. In fact, reliability and maintainability (R&M) requirements are now so important in both military and commercial systems that it is common to have R&M requirements as part of the official system requirements documents and contract performance metrics; indeed, it is rare to see an acquisition without them. Both attributes have been described in requirements documents in many ways over the years, with an evolving need to quantify the attributes in some measurable way. The practice of R&M is now explicitly defined as part of the specialty engineering tasks grouped under systems engineering to further that objective.
System health management encompasses fault management as well as system design and development, and can improve a system's ability to meet overall R&M goals. This chapter discusses origins of R&M calculations for components and systems, but is not intended to provide a tutorial on reliability engineering. At the component level, reliability is a function of the component's design, manufacture, and use. At the system level, overall system reliability can depend on the interaction of individual components within the system and their interconnection and interaction. SHM has little effect on component‐level reliability and only impacts system‐level reliability by helping to avoid cascading failures, where the failure of one component results in unacceptable or out‐of‐specification loads on other components that would cause subsequent failure of another component. Maintainability on the other hand is a direct function of system use and maintenance practices. By reducing the time required to isolate and identify (diagnose) faults, SHM has a direct impact on the execution of maintenance actions and can directly improve maintainability.
Maintainability: Theory and Practice
System Health Management ; 309-317
2011-07-15
9 pages
Article/Chapter (Book)
Electronic Resource
English
AIAA | 1966
|NTIS | 1967
|Emerald Group Publishing | 1970
SAE Technical Papers | 1964
|Maintainability Program Standard
SAE Technical Papers | 2011