Why do we do maintenance? To keep our Work Center Supervisor and Division Chief happy? So we can make liberty call and go home? Good answers but not quite what we’re looking for. Simply put, maintenance is done to ensure equipment performs when it is needed.
So we know why it is done, but how should we be doing it? The equipment life-cycle can be met or extended by using corrective maintenance or preventive maintenance. Corrective maintenance is just like it sounds. If a system breaks, it gets fixed. Preventive maintenance is all about keeping equipment from breaking down or at least holding off a failure as long as possible. On the surface it would seem like Preventive is always the way to go. Not so fast! As we’ll see, some things are best when left to run to failure. So, what kind of maintenance should we do, and how often should we do it?
“The Navy’s approach is to perform maintenance only when there is evidence of actual or predictable equipment failure, while ensuring operational readiness, safety, and equipment reliability,” says Capt. Jerry Prendergast, the Naval Sea Systems Command (NAVSEA) assistant deputy commander for maintenance, modernization, environment, and safety.
“This strategy, known as Condition Based Maintenance, has proven to be cost effective, and has been used successfully for decades, not only in the Navy, but in commercial industry as well,” he said.
To determine the most effective maintenance approach, Preventive or Corrective, for a given equipment item, there are rules that need to be followed.
Reliability Centered Maintenance (RCM) is the strategy that provides these rules and guidelines. RCM analysis tells us what maintenance should be performed and when, based on a number of factors including Sailor operational experience, operational data, equipment performance, and engineering expertise. Following the 12 phase process contained in MIL STD 3034A, RCM ensures we do preventive maintenance to properly manage safety, environmental and regulatory risks. When such risk factors don’t exist, RCM makes sure that doing preventive maintenance is cost effective by evaluating the benefits of preventing failure versus the cost and mission impacts if failure were allowed to happen.
The purely corrective maintenance strategy, also known as fix-when-fail, is appropriate for many systems and equipment. For a handful of critical systems, it is imperative to prevent failures; but for most equipment, a balance between preventive and corrective maintenance procedures is optimum.