May 1, 2000 12:00 PM -- Anthony M. Smith: "Over the past 20 years, I have spoken with hundreds of maintenance managers, supervisors, and technicians from Fortune 500 companies, government facilities, international organizations and others about their maintenance strategies, costs and problems. Recurring themes always include one of the following:
- My preventive maintenance (PM) program just grew over the years. I have no credible reason for it except that we have done it for 15 to 20 years, so it must be OK. I know it isn't, but don't know what to do for improvement.
- Our maintenance program is almost 100% reactive, but I have neither the time nor the smarts to do anything about it. (Incidentally, reactive maintenance is the most expensive option to use.)
- Downtime and loss of output is eating my lunch, and I don't know what to do. (As you might guess, the first or second theme causes the third.)
Another recurring theme is the focus on keeping all plant equipment 100% serviceable-always ready if needed. I call this philosophy Preserving Equipment, and it is often the principal strategy behind most non-reliability-centered PM programs."
"At first blush, preserve equipment seems logical. But upon closer scrutiny, it fosters unnecessary problems, such as promoting a tendency to treat all equipment as equally important and creating conservative or premature maintenance actions. Many times, current
PM tasks are intrusive actions and can lead to errors and rework as often as 50% of the time. What is RCM? The preserve-equipment strategy was practiced religiously by commercial aviation until the appearance of the first jumbo jet-the B747-100. In the early 1960s, the FAA stipulated a 747 PM program that was to have three times as much preventive maintenance than required for the 707 because it would carry three times as many passengers.
Recognizing the economic difficulties of such a rule, United Airlines led a team to re-evaluate the concept of PM and to determine the correct strategy to achieve both safety and economics of operation with commercial aircraft. The result, successfully employed on the 747 and all subsequent jet aircraft, was what we today know as reliability-centered maintenance (RCM).
The key for United Airlines was to abandon the preserve-equipment philosophy for a preserve-function philosophy. The premise is that a system and plant have certain roles or functions to perform, and the job for maintenance is to keep those functions available on demand-preserve function."