4
PRODUCT SUPPORT

As noted in Chapter 1, product support costs greatly exceed those for design and manufacture. Not unexpectedly, lowering support costs (a peacetime issue) is a key driver for changing the way prime equipment and support resources must be designed for the future. Battle readiness (effectiveness and availability) is the critical issue, however. Any change in support operations must first address the wartime environment and balance that with peacetime considerations.

CURRENT ENVIRONMENT

The user's responsibility for product support begins in the conceptual phases with the formulation of a maintenance strategy and is formalized as part of the contractual requirements. These requirements range from specifications for design attributes that support the maintenance concept to specifications for the design and acquisition of support resources for implementation of the concept. Once fielded, the user operates and maintains the product with the support resources. These resources include support equipment, spare parts, repair material, trained personnel, maintenance instructions and aids, and repair facilities.

Maintenance techniques and resources may differ for the various categories of equipment (e.g., electronics, hydraulics, propulsion, structures). Yet they share a common objective: specification of product support in advance of product design. Although product support effectiveness depends directly on design attributes, inadequate attention is given these issues in contemporary equipment acquisition. Support considerations are equally critical for prime equipment and support equipment.

Maintenance Attributes

At present, maintenance resources are planned, designed, and acquired to fit the as-built weapons systems. Design attributes that make for difficult maintenance situations are compensated for by more sophisticated maintenance resources, including highly skilled maintenance technicians using complex instructions. Another way of compensating for difficulty is to remove and replace entire assemblies containing failed or damaged items, rather than attempt to repair them.



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Enabling Technologies for Unified Life-cycle Engineering of Structural Components 4 PRODUCT SUPPORT As noted in Chapter 1, product support costs greatly exceed those for design and manufacture. Not unexpectedly, lowering support costs (a peacetime issue) is a key driver for changing the way prime equipment and support resources must be designed for the future. Battle readiness (effectiveness and availability) is the critical issue, however. Any change in support operations must first address the wartime environment and balance that with peacetime considerations. CURRENT ENVIRONMENT The user's responsibility for product support begins in the conceptual phases with the formulation of a maintenance strategy and is formalized as part of the contractual requirements. These requirements range from specifications for design attributes that support the maintenance concept to specifications for the design and acquisition of support resources for implementation of the concept. Once fielded, the user operates and maintains the product with the support resources. These resources include support equipment, spare parts, repair material, trained personnel, maintenance instructions and aids, and repair facilities. Maintenance techniques and resources may differ for the various categories of equipment (e.g., electronics, hydraulics, propulsion, structures). Yet they share a common objective: specification of product support in advance of product design. Although product support effectiveness depends directly on design attributes, inadequate attention is given these issues in contemporary equipment acquisition. Support considerations are equally critical for prime equipment and support equipment. Maintenance Attributes At present, maintenance resources are planned, designed, and acquired to fit the as-built weapons systems. Design attributes that make for difficult maintenance situations are compensated for by more sophisticated maintenance resources, including highly skilled maintenance technicians using complex instructions. Another way of compensating for difficulty is to remove and replace entire assemblies containing failed or damaged items, rather than attempt to repair them.

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Enabling Technologies for Unified Life-cycle Engineering of Structural Components Maintenance attributes may be divided into three major classes: Reliability—this determines how often the action is required. Repairability—this denotes the ease and speed with which an item can be mended. Fault isolation—this determines the ease with which a malfunction can be determined, located, and accessed. As long as present mechanical design and manufacturing processes use tried and proven assembly techniques, repairs to mechanical devices and structures during peacetime will only require conventional mending techniques (e.g., welding, riveting, use of relatively simple adhesives). These are within the present capabilities of the Military Services. Increasing the reliability of a product—i.e., reducing the frequency of maintenance actions—is the single most important way to improve the support environment. To operate reliably, a component needs to be free of critical defects (from design, material selection, or manufacturing), and it needs to be designed so that it is insensitive (as much as possible) to variation in use and abuse. If it does not fail, resources do not have to be expended to fix it, to provide skills and tools to effect the fix, or to take the item out of service during the fix. Improving fault isolation, fault location, access, and handling for the repair requires deliberate, special efforts that are not always included in present designs. Difficult repairs, sophisticated maintenance resources, and unnecessary consumption of large assemblies drive support costs to unplanned levels. In addition, high failure rates require large stockpiles of spare parts and repair material at repair sites, whether these are combat units or intermediate-level shops or depots. Peacetime operations allow repairs to take longer than estimated and, if necessary, malfunctioning or damaged items may be returned to the manufacturer for repair. The information needed to estimate these support costs during the design process is not available. As discussed earlier, mechanical and structural design is advancing rapidly. New materials such as advanced composites and new material processes such as microwave and ultrasonic bonding will require either more complex repair procedures or else more consideration in the design process for simplifying maintenance technicians' tasks. However, with few exceptions, present system and equipment specifications do not address support issues during the design process. They invoke design attributes for product support in two distinct ways: The first is to actually describe the desired serviceability features in terms that a design engineer can understand. The features are developed from experience with predecessor equipment and from lessons learned by the user and maintainer as well as the extent of the skill and ability of the person preparing the requirements. Examples may be found in the specifying of fasteners, access panels, gauges, warning devices, and specific safety features. The second is to impose quantitative measures on certain supportability attributes such as reliability, maintainability, and testability that need translation to design features by a specialist engineer. The translation is required because the metrics are either statistical in nature or sufficiently abstract that a design engineer has difficulty addressing them in the conceptual stages. The specified magnitude of the metrics in turn is usually developed from some similar predecessor equipment.

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Enabling Technologies for Unified Life-cycle Engineering of Structural Components Both approaches have shortcomings. Lessons-learned feedback is rarely circulated to those who write specifications; consequently, few if any of the reliability, maintainability, and supportability metrics are translated into the specific design attributes. The use of metrics (together with their magnitudes) based on or scaled to predecessor equipment may be expedient for preparing a specification but does not provide a thorough statement of requirements for the planned application and expected life of the equipment. This methodology does not drive the design process to take maximum advantage of state-of-the-art materials and processes to attain major improvements in supportability. There is a very large accumulation of data on the current support environment (repair actions, parts use, labor costs, etc.), but these data have not been transformed into knowledge for use during design. Knowledge of what is (and is not) currently attainable would allow realistic yet sufficiently stringent supportability metrics to be specified. Stringent requirements would demand attention by the design engineer, who would develop appropriate design features; yet this procedure does not occur. There are proprietary studies from nondefense industries that clearly demonstrate that designers can design according to supportability requirements if they are provided. Field data systems are intended to provide information to support labor and cost-accounting functions. Transfer of knowledge to designers is not a primary objective. The U.S. Air Force ''Blue Team'' program attempts to bring support information to the designers by bringing contractor representatives and active-duty support personnel together. The program's shortcomings are that (a) it is too limited because it reaches a very small fraction of the design population and (b) it is too brief to provide in-depth involvement of the participants with tools and maintenance activities. The Air Force is addressing the integration of data needs for support planning under its Computer-aided Acquisition and Logistics System (CALS) management program. The current practice places the burden of improved product support on the acquisition of more sophisticated support resources to make up for the inadequacies of the prime equipment. Unfortunately, although product support is extremely costly and often wasteful, it may not really jeopardize peacetime operations, where cost and safety are the primary considerations. Battle Readiness Postulated battle scenarios include the challenge to fight battles in austere environments at unpredictable geographic locations; these would be nearly impossible to sustain if the support resources had to continue to compensate for prime equipment shortfalls. To cope effectively with such scenarios, maintenance must be performed with minimally skilled maintenance personnel who possess no specialized knowledge concerning the maintenance task, ranging from changing a tire to repairing battle damage. In addition, the inability to locate spares at all strategic locations demands that materials at hand must, to the best of the front-line (e.g., organizational level) team's capability, suffice for emergency maintenance. These same conditions prevent the use of voluminous maintenance manuals. They also demand that correct fault isolation be possible and that damage assessment or imminent failure assessment be made accurately with the skill and equipment at hand. All three maintenance attributes (reliability, repairability, and fault isolation) will need to be improved to meet future demands. The solution to these problems is complicated with structural components because new materials are placed into use constantly, requiring not only new manufacturing techniques but also new maintenance techniques and tools. Although the behavior of conventional materials under

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Enabling Technologies for Unified Life-cycle Engineering of Structural Components normal operating stresses is well understood, accurate prediction of failure mechanisms from abnormal sources (for example, maintenance damage, energy weapons) is highly immature, as are remedial actions. The greatest uncertainty is the operating conditions (e.g., turbine disks in the F-100 engine—Appendix C, Stephen Finger presentation), not the understanding and knowledge of how materials fail. The introduction of new materials provides still more unknowns concerning product life and product support. In addition, trade-offs in structural components that favor manufacturing techniques may have a large effect on the maintenance techniques. For example, progressive assembly buildup may simplify construction but requires progressive dismantling to gain access for repair. FUTURE ENVIRONMENT The future design environment will require that comprehensive facts regarding operating condition, behavior, failures, and maintenance actions gathered from field experience be interpreted as "design guides" to be used in a design process. The design process (itself changing in the future, as discussed in Chapter 2) will incorporate the design guides. Also, it will translate accurate and specific design information into automated maintenance aids ranging from built-in test devices (e.g., strain gauges, crack detectors, operability decision circuits) to portable computers containing comprehensive maintenance instructions (to replace clumsy, often incomplete maintenance manuals). The flow of information from support to design will be faster than at present and will be more reliable, complete, and usable. This will be accomplished by automated data capture, transformation, and transmission. SIGNIFICANCE OF THE CHANGE Design features to improve the maintenance environment will not only simplify the maintenance tasks but also decrease the number of different skills required to perform maintenance. Properly designed access panels and removal and replacement techniques will reduce both the maintenance time and the dexterity required. Thus, fewer highly skilled maintenance technicians will be required.