All eyes fixed on the future, the United States Navy looks to extend condition-based maintenance (CBM) technologies into the supply chain.

The Vision

In the year 2015, on some future naval platformÐperhaps USS BLUE SKYÐa machine will begin to falter in one of its pre-defined failure modes. This automatically will trigger a series of events to correct the failure and update the mission-readiness status of the platform in real-time. The "trigger" for some failure modes will, in fact, precede the actual functional failure, thus allowing for mitigating action to prevent an unplanned failure. This includes the pre-ordering of parts to complete necessary (and timely) maintenance without the inccurring of unnecessary logistics delays.

The type of early warning outlined for the futuristic USS BLUE SKY also will allow a commander to assess the potential risk of the impending failure against the mission profile. That's because a pre-validated, engineered work-order candidate, residing in a current or future database, will contain the required configuration data to identify the parts and tools necessary to accomplish the repair. In turn, the ship that work-order candidate is on will no longer be required to carry a large load of contingency spare parts, since the trigger mechanism will provide ample lead time for those parts to be put into the supply chain.

Building blocks for the adjacent sidebar's "BLUE SKY" vision of the future are in-place now—yet, much still remains to be done. Why should we do it?

The answer lies in existing Chief of Naval Operations (CNO) policy and validated requirements for future naval platforms. Navy and and Department of Defense (DoD) initiatives, such as SHIPMAIN, CBM Plus, Engineering for Reduced Maintenance, Sense and Respond Logistics, Focused Logistics, and various Future Naval Capabilities provide vehicles and, in some cases, resources to achieve this future vision.

The Navy's Integrated Condition Assessment System (ICAS),

as the program of record for shipboard machinery condition monitoring, provides the technology insertion opportunity to advance CBM and Sense and Respond capability. There is no silver bullet in any of the aforementioned efforts. Acquisition managers and technical warrant holders need to skillfully steer the work of these diverse, but related efforts, and harvest the offerings that support the requirements. There have been and will be successes to build upon, and there will be disappointments along the way. With no ready-made solutions available, there needs to be continued investment, engineering and trials, demonstrations and incremental fielding of advances via spiral development. The advances that are fielded will come largely from operating within the current framework of programs, organizations and policies.

Background
The case for condition-based maintenance (CBM) has been made. CNO effectively ended any debate in 1998 by issuing OPNAVINST 4790.16 (Condition Based Maintenance Policy). This instruction extended the more limited 1992 CBM directive (OPNAVINST 4700.7J) by mandating CBM application to all naval platforms.

The intelligent application of sensing, processing and decision support technologies has a significant role in supporting Navy CBM policy. In the intervening years, there has been significant R&D investment in enabling technology, resulting in incremental improvement of fielded technologies and the associated maintenance and logistics applications, including, but not limited to, the previously referenced ICAS, the shipboard Preventive Maintenance System (PMS) Scheduler (SKED) and the Organizational Maintenance Management System—Next Generation (OMMS-NG). What has been missing is a tight integration between systems and linkage to supporting logistics and supply chain applications.

Navy enterprise resource planning (ERP) implementation is on the horizon. However, as of this writing, (October 2005), there is no afloat ERP template.

Application integration, to include available commercial off-the-shelf (COTS) products through development of software adapters, provides the vehicle to improve effectiveness and efficiency of today's legacy applications onboard fielded platforms. Integration also will provide a stepping stone to the future of seamless information exchange among maintenance, logistics and operational readiness applications, both afloat and ashore.

Development and acquisition of CBM-enabling technologies must follow the same reliability-centered maintenance (RCM) engineering principles of applicability and effectiveness as those used for development of maintenance requirements and tasks. A key concept is illustrated in Fig. 1, which plots resistance to failure versus operating age. In summary, a CBM enabling technology needs to be able to sufficiently detect the onset of a dominant failure mode (Potential Failure) in advance to prevent Functional Failure. In cases where this may not be possibleÐeither due to the nature of the failure and/or limitations of the technologyÐthere may still be value in automating the detection of a failure for automated generation of a pre-defined work-order candidate.

Assuming, first, that RCM principles are employed for the identification of dominant failure modes to which enabling CBM technology can be applied, and second, that the technology being inserted is both applicable and effective, other issues need to be considered. Most significantly among these are information technology (IT) interface requirements and bandwidth limitations.

The NAVSUP MHM – S&RL initiative
As sponsored by the Naval Supply Systems Command (NAVSUP), the Machinery Health Monitoring, Sense and Respond Logistics (MHM – S&RL) system was de-signed to enable and demonstrate auto-nomous initiation of a technically validated, pre-formatted work-order candidate, populated with associated parts and related material. The work order trigger is based on the automated recognition and validation of a predefined failure mode on a machine of interest, resulting in actionable information being passed up-line to legacy maintenance and logistics systems.

MHM-S&RL is focused on demonstrating this capability on the GSS 200 STAR Low Pressure Air Compressor (LPAC), a Navy design manufactured by both Dresser-Rand and Rix Industries. Failure modes are detected and processed using RLW Inc.'s S2NAP technology interfaced with legacy shipboard applications (ICAS, PMS SKED, and NTCSS suite). MIMOSA-based software adapter interfaces were developed under this project between S2NAP and ICAS, as well as between ICAS and PMS SKED.

The team
MHM – S&RL interfaces with multiple applications and networks. No single entity has all of the required expertise to develop the technology and interfaces. Under sponsorship of NAVSUP's Command Science Advisor, the engineering group RLW assembled a multi-disciplinary team as shown in Table 1.

Additionally, by way of acknowledgement, the Navy organizations listed in Table 2 also are...(Read whole article)