 |
 |
 |
 |
| |
|||||
|
|
|
Obsolescence is, and will continue to be, a challenge to military systems. Many of our electronic systems, such as Joint STARS, JTIDS, Milstar, and AWACS were designed over ten years ago. They will continue to be used for many years and will require replacement parts that will no longer be available. Commercial parts, especially integrated circuits (ICs), are rapidly improving, with faster clock speeds and lower power consumption. Typically, they are replaced by newer versions after only a year or two on the market. The significant increase in commercial component business and the declining defense market has led many suppliers to reduce or eliminate military fabrication lines. These changes decrease our ability to produce military systems to a single baseline, and degrade our ability to repair failed equipment. These obsolescence problems are typically referred to as Diminishing Manufacturing Sources and Material Shortages (DMSMS, or simply DMS). Usually, we resolve these problems by using form, fit, and function replacementsóat significant cost increasesórather than using replacements incorporating newer technologies. The reason is that the cost to remedy a specific DMS problem is small compared to a major technology insertion. However, the error in this reasoning is that it does not assess future DMS problems and cost impacts. Finding a Better Solution Faced with these obsolescence problems, the Economic and Decision Analysis Center (EDAC) and D053 are developing the Collaborative Obsolescence Management and Evaluation Tool (COMET) for the Joint STARS program. This tool can show the degree of obsolescence in different parts of a system and can estimate the cost for replacement parts. COMET is Web-based, and provides a hierarchical summary of the current DMS status of the Joint STARS fleet. Current Capabilities
The current version of COMET is based on the status of active devices (ICs, transistors, diodes, and so on); all costs are for part replacement. In particular, COMET provides separate DMS evaluations and cost estimates at the fleet, aircraft, subsystem, line replaceable unit (LRU), and circuit card assembly (CCA) levels (see illustration). These evaluations reflect the likelihood and degree of impending DMS problems, enabling program leaders to accurately budget the funds necessary for resolving the problem. Besides the assessment for the current fiscal year, COMET projects of DMS status and cost for four additional years. The obsolescence status is shown at each level. In the online COMET database, a color bar illustrates the proportion and number of parts that fall within specified availability levels. For example, red indicates that fewer than 20 percent of the parts in this category are commercially available, and green indicates that more than 80 percent of the parts are available. Also, COMET provides information about individual parts, including the DMS assessment for five years and where and in what quantity the part is used. COMET highlights DMS problem areas at the subsystem or LRU overview matrix by showing the status for each subsystem or LRU by aircraft. Users can then determine which components are responsible for the problems by navigating down through the lower levels. In addition, users can evaluate the impact of proposed design changes by substituting the modified database for the original one. In the future, it will not be necessary to change databases to look at the impact of program modifications. DMS Assessment and Projection Methods Several organizations, including EDAC, have developed IC obsolescence assessment methods. COMET currently uses the best known of these methods, which is provided by Transition Analysis of Component Technology, Inc. (TACTech). However, COMET can accommodate any method of obsolescence rating with minor modifications to the COMET database. (Another method that is available to the Government is from the Electronic Component Obsolescence Management or ECOM tool from Uwohali, Inc.) Cost Estimation The costs presented in the current version of COMET are for the replacement of active components only, since typical DMS remedies involve part emulation or substitute parts. COMET can compare this solution with the costs separately determined for technology insertion (replacement at higher levels such as the circuit card or the LRU). Future Plans A future version of COMET will provide a trade-off capability for choosing among a much broader set of DMS solutions. The tool will consider the replacement of higher-level components (CCAs, LRUs, or even subsystems) and evaluate other types of piece parts. Program managers may eventually want to provide access to the prime contractor, sub-contractors, component manufacturers, and advanced technology houses. Conclusion Although COMET is still in development, the current version has a number of capabilities that can help any program plan and budget for the resolution of obsolescence problems. It incorporates an easy-to-use graphical interface to the system parts database and analytical methods for manipulating data. These features can help the program manager assess the overall health of the electronics in the system and find the problem areas. Also, the manager can get a rough estimate of the cost to resolve the problems over the next five years, making budgeting easier. Currently, the cost algorithms are being fine tuned and the model calibrated to agree with the new Joint STARS indentured parts list. The information for the Joint STARS program was gathered from a variety of resources. Similarly, users can adapt COMET to analyze DMS problems on any other program. COMET can use any indentured parts list (preferably in electronic format) to generate its database; EDAC personnel can then calibrate COMETís parameters to the new program. As we gather experience and improve COMET, we believe that it will become an extremely useful tool for users, logistics commands, and contractors. We encourage program managers to explore this tool and send us feedback. For more information, please contact Virginia Day using the employee directory. |
Solutions That Make a Difference.® |
|
|
