of the process, Stanley Nowlan and Howard Heap, originally intended. Therefore, this books details True RCM.
RCM is a remarkable process and can be defined as follows. The terms zero based, failure management strategies, and operational environment bear further explanation.
 | Reliability Centered Maintenance is a zero-based, structured process used to identify the failure management strategies required to ensure an asset meets its mission requirements in its operational environment in the most safe and cost effective manner. |
Zero-based
Each RCM analysis is carried out assuming that no proactive maintenance is being performed. In other words, Failure Modes and Failure Effects are written assuming that nothing is being done to predict or prevent the Failure Mode. In this way, consequences of each Failure Mode can be assessed and solutions can be formulated with no bias towards what is currently being done.
Failure Management Strategies
Notice that the definition states that RCM is used to identify failure management strategies, not maintenance tasks. As explained earlier, managing assets requires more than just scheduled maintenance. Therefore, RCM provides powerful tools for developing other solutions, as detailed in Figure 1.2.
Operational Environment
How an asset is maintained depends on far more that just what an asset is. When solutions for assets are formulated, the following issues regarding the operational environment must be considered.
•Physical environment in which the asset will be used (e.g., cold weather, desert climate, controlled environment)
•Operational tempo (e.g., 24 hour operation, system runs 6 hours each day)
•Circumstances under which the system will be operated (e.g., stand-alone, one of four systems runs at one time but is rotated every month)
•Redundancy (e.g., the system or any of its components operate in the presence of a backup)
These issues can greatly influence not only what maintenance tasks are identified and how often they are performed, but also other solutions such as equipment design and training programs. Therefore, the operational environment must be clearly defined.
1.8 Defining Performance in the Context of RCM
In the context of RCM, there are two features regarding equipment performance that responsible custodians must carefully examine: design capability and required performance.
Asset owners perform RCM to determine what actions must be taken to ensure that equipment meets mission requirements. A mission could be towing a piece of equipment to the construction site, launching an aircraft from an aircraft carrier, or ensuring that there is adequate plant air for the downstream manufacturing process. But when it comes to defining performance, equipment custodians must be specific about what their assets can do (design capability) and what they need them to do (required performance). The following discussion illustrates this point.
Take, for example, a water tube steam boiler. As illustrated in Figure 1.13, the design capability is a Maximum Allowable Working Pressure (MAWP) of 500 psi. However, the required performance is 650 psi. Is this scenario acceptable? Absolutely not, because what the organization requires (650 psi) exceeds the design capability of the boiler (500 psi).
Figure 1.14 illustrates another example. Here, the design capability is an MAWP of 650 psi and the required performance is 500 psi. Is this scenario acceptable? Yes, because what the organization requires (500 psi) fits within the design capability of the asset.
Figure 1.13 Organizational requirements exceed design capability
Figure 1.14 Organizational requirements fit within the design capability of the asset
This may seem to be an incredibly simple concept—so basic and fundamental that it doesn’t even warrant being mentioned. It appears that way. However, this concept is a very serious issue. If an organization gets it wrong, it can turn deadly. In fact, it has turned deadly.
Three Air Tanker Crashes
The National Transportation Safety Board (NTSB) investigated three air tanker crashes. The following information was reported in the NTSB Safety Recommendation dated April 23, 2004.
On August 13, 1994, a Lockheed C-130A Hercules experienced an in-flight separation of the right wing near Pearblossom, California, while responding to a forest fire near the Tahachapi Mountains. All three crewmembers were killed and the airplane was completely destroyed. (An aircraft similar to the C-130A can be seen in Figure 1.15.)
Figure 1.15 C-130 Aircraft, similar to the C-130A Tanker that crashed on August 13, 1994 and June 17, 2002 (Photo from Photo NSA online; http://www.nsa.gov/about/photo_gallery/index.shtml.)
Figure 1.16 C130A June 17, 2002, crash site from the NTSB report (Photo from NTSB, September 24, 2002, NTSB Advisory, Update on Investigations of Firefighting Airplane Crashes in Walker, California and Estes Park, Colorado; http://www.ntsb.gov/pressrel/2002/020924.htm )
On June 17, 2002, another Lockheed C-130A Hercules experienced an in-flight breakup that was initiated by separation of the right wing, followed by separation of the left wing, while executing a fire retardant drop over a forest fire near Walker, California. Both wings detached from the fuselage at their respective center wing box-to-fuselage attachment locations. All three flight crewmembers were killed, and the airplane was completely destroyed. Figure 1.16 depicts the June 2002 crash site.
On July 18, 2002, a Consolidated Vultee P4Y Privateer experienced an in-flight separation of the left wing while maneuvering to deliver fire retardant over a forest fire near Estes Park, Colorado. Both crewmembers were killed and the airplane was destroyed. (A similar aircraft is shown in Figure 1.17.)
