R&M 2000. The Tactical Air Command approach

World Abstracts on Microelectronics and Reliability costs while improving fielded mission accomplishment. Contractors will continue their efforts to improve production quality and to eliminate systemic causes of field failures. The R&M 2000 initiative Air Force R&M policy letters. JOHN L. PIOTROWSKI. IEEE Trans. Reliab. R-36, 278 (1987). This paper details the first four of a continuing series of policy letters which will generate the impetus for needed R&M improvements in Air Force systems. The first policy letter deals with R&M 2000 Environmental Stress Screening. This article discusses reasons for emphasizing this technique and provides some of the specific guidelines. Policy letter two establishes the requirement for all new systems to have "twice the reliability" and "one-half the maintainability" of the system being replaced. The third R&M policy letter focuses on the requirement for design engineers to design-in system characteristics which allow for ease of maintenance in the often harsh operational environment. The final policy letter details the minimum acceptable reliability of electronic systems. The policy letter sets a mean time between failures of 2000 hours for a line replaceable unit in an airborne fighter environment, the harshest environmental condition. The article closes with a discussion of quality and its importance. R&M 2000. The Tactical Air Command approach. JIMMIE V. ADAMS. IEEE Trans. Reliab. R-36, 297 (1987). This paper describes the Tactical Air Command (TAC) methodology for stating R&M requirements for new systems and improving the combat capabilities ofexisting systems. It focuses on why TAC chose to state R&M in broad, output terms and illustrates three ways the R&M 2000 program has increased the emphasis on supporting fielded systems. Specifically, attention is given to two new technologies which should profoundly affect the maintainability of tactical systems. Half-maintainability - - a formidable goal. BERNARD L. RETTERER and NED H. CRISC1MAGNA.IEEE Trans. Reliab. R36, 324 (1987). A recent letter issued by HQ USAF/CV established a Double-R/Half-M policy for developing reliability and maintainability (R&M) requirements for the next generation of systems. This paper reviews the second portion of that policy, Half-M, and assesses the feasibility and implications of achieving the goal, as well as the programmatic elements considered most likely to assist in achievement of the goal, The paper discusses measures of maintainability, trends and concepts influencing maintainability, and the maintainability of current systems. The results of a survey of maintainability practitioners are presented as part of the assessment of the Half-M goal. Optimal logic for multi-channel protective systems duing online maintenance. TAKEHISAKOHDA, HIROMITSU KUMAMOTO, KOICHt INOUE and ERNEST J. HENLEY. IEEE Trans. Reliab. R-36, ")5 (1987). Protective systems have two kinds of failures: failed dangerous (FD) and failed-safe (FS). The former can lead to serious damage to the plant, while the latter can result in financial loss because of unnecessary protective actions. Frequently, protective system channels must be maintained and repaired during plant operation, i.e., while they are in service. When this happens, one must choose whether the output of a channel being maintained should be set to the on or off position. On means the protective system protects against the F D failure, and is vulnerable to FS failures. We develop a systematic method to determine the output default values, and solve the more general problem of determining the optimal logic connections for the remaining channels. Analytic formulae are presented for transition failure rates are constant with time, and the channels are in voting configurations. R&M 2000. The Strategic Air Command perspective. JAMESP. MCCARTttV. 1EEE Trans. Reliab. R-36, 295 (1987). This

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paper discusses the force multiplier effects of R&M from an operating command perspective whose assets range from intercontinental ballistic missiles to complex command, control, and communication systems. When expressing a need for new systems, operational commands will state their requirements in operational terms which then must be translated into contractual terms. A new office has been formed to insure that clear requirements are formed. While forming requirements, specific attention must be given to the requirements for ease of maintenance. The manpower and materials implications of this up front planning are illustrated with the Minuteman III ICBM missile guidance set. R&M 2000 and the Air Force acquisition process. BERNARD P. RANDOLPH. IEEE Trans. Reliab. R-36, 287 (1987). This paper discusses the impact of R&M 2000 on the acquisition process. The paper emphasizes the interest level during the acquisition process, and the opportunities created by the proper implementation of advanced technology to improve the reliability and maintainability of systems. The use of electronics in weapon systems may be the way in which weapon systems gain increased capability to counter the threats of the 1990s. There are many opportunities to effect needed increases in reliability and maintainability by applying newer technologies. R&M 2000 environmental stress screening. JOHN W. L1TTLEFIELD. IEEE Trans. Reliab. R-36, 335 (1987). This paper is concerned with the impact on the US defense industry of the US Air Force R&M 2000 plan and other efforts for a dramatic improvement in the reliability and lifecycle cost of military systems. The paper generally discusses the aims and techniques of environmental stress screening (ESS) with quantitative examples from experience gained at the Litton Guidance and Control Systems Division. R&M 2000. The engineering connection. FRANK S. GOODEEL. IEEE Trans. Reliab. R-36, 303 (1987). This paper introduces 5 principles and 21 associated building blocks representative of successful approaches used within industry to produce reliable and maintainable systems. Several building blocks are singled out for discussion because of recent initiatives undertaken by the Air Force. These topics include modularity, technician transparency, simplification, computer-aided tools, and environmental stress screening. The 21 building blocks provide a strong foundation upon which to build weapon systems with increased combat capability. The requirement to maintain the designed-in reliability and maintainability (R&M) attributes through careful attention to quality control issues also receives emphasis. Those factors which most strongly influence variability in the desired system performance must be identified. Finally, the paper emphasizes the crucial role of education in truly integrating the design aspects of R&M into engineering disciplines. A new Monte Carlo method for evaluating system-failure probability. HIROMITSU KUMAMOTO,TSUNEHIKOTANAKAand KOICH1 INOUE. IEEE Trans. Reliab. R-36, 63 (1987). This paper proposes, under a rare-event assumption, a new "Coverage Monte Carlo" method for evaluating the topevent probability of a coherent fault tree. All the min cuts are assumed to be known. A Karp-Luby Monte Carlo (KLM) estimator with minimum variance is derived in a different manner. The K L M evaluates an inclusion-exclusion formula excluding the first sum of products. A new coverage Monte Carlo (NCM) estimator evaluates the formula excluding the first and the second sums of products. The NCM yields an estimator with a smaller variance than the K L M which becomes a linear time procedure in the number of min cuts. Upper bounds on the numbers of trials necessary to attain a given coefficient of variation are derived for K L M