Reliability Centered Maintenance - Historical Background

Historical Background

The term "reliability-centered maintenance" was first used in public papers authored by Tom Matteson, Stanley Nowlan, Howard Heap, and other senior executives and engineers at United Airlines (UAL) to describe a process used to determine the optimum maintenance requirements for aircraft. Having left United Airlines to pursue a consulting career a few months before the publication of the final Nowlan-Heap report, Matteson received no authorial credit for the work. However, his contributions were substantial and perhaps indispensable to the document as a whole. The US Department of Defense (DOD) sponsored the authoring of both a textbook (by UAL) and an evaluation report (by Rand Corporation) on Reliability-Centered Maintenance, both published in 1978. They brought RCM concepts to the attention of a wider audience. The text book described efforts by commercial airlines and the US Navy in the 1960s and 70s to improve the reliability of their new jet the Boeing 747.

The first generation of jet aircraft had a crash rate that would be considered highly alarming today, and both the Federal Aviation Administration (FAA) and the airlines' senior management felt strong pressure to improve matters. In the early 1960s, with FAA approval the airlines began to conduct a series of intensive engineering studies on in-service aircraft. The studies proved that the fundamental assumption of design engineers and maintenance planners—that every airplane and every major component in the airplane (such as its engines) had a specific "lifetime" of reliable service, after which it had to be replaced (or overhauled) in order to prevent failures—was wrong in nearly every specific example in a complex modern jet airliner.

This was one of many astounding discoveries that have revolutionized the managerial discipline of physical asset management and have been at the base of many developments since this seminal work was published. Among some of the paradigm shifts inspired by RCM were:

• an understanding that the vast majority of failures are not necessarily linked to the age of the asset (this is often modeled by the "memoryless" exponential probability distribution)
• changing from efforts to predict life expectancies to trying to manage the process of failure
• an understanding of the difference between the requirements of assets from a user perspective, and the design reliability of the asset
• an understanding of the importance of managing assets on condition (often referred to as condition monitoring, condition based maintenance and predictive maintenance)
• an understanding of four basic routine maintenance tasks
• linking levels of tolerable risk to maintenance strategy development

Today RCM is defined in the standard SAE JA1011, Evaluation Criteria for Reliability-Centered Maintenance (RCM) Processes. This sets out the minimum criteria for what is, and for what is not, able to be defined as RCM.

The standard is a watershed event in the ongoing evolution of the discipline of physical asset management. Prior to the development of the standard many processes were labeled as RCM even though they were not true to the intentions and the principles in the original report that defined the term publicly.

Today companies can use this standard to ensure that the processes, services and software they purchase and implement conforms with what is defined as RCM, ensuring the best possibility of achieving the many benefits attributable to rigorous application of RCM.