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RELIABILITY GROWTH TESTING 1.0 RGT Definition: MIL-STD-785 distinguishes reliability growth testing (RGT) from reliability qualification testing (RQT) as follows: Reliability Growth Test (RGT): A series of tests conducted to disclose deficiencies and to verify that corrective actions will prevent recurrence in the operational inventory. (Also known as "TAAF" testing). Reliability Qualification Test (RQT): A test conducted under specified conditions, by, or on behalf of, the government, using items representative of the approved production configuration, to determine compliance with specified reliability requirements as a basis for production approval. (Also known as a "Reliability Demonstration," or "Design Approval" test.) 2.0 RGT Application Effectiveness: An effective way to explain the concept of RGT is by addressing the most frequently asked questions relative to its use as summarized from "Reliability Growth Testing Effectiveness" (RADC-TR-84-20). For more information consult this reference and MIL-HDBK-189, "Reliability Growth Management." Who pays for the RGT? Does the government end up paying more? The usual case is that the government pays for the RGT as an additional reliability program cost and in stretching out the schedule. The savings in support costs (recurring logistics costs) exceed the additional initial acquisition cost, resulting in a net savings in Life Cycle Cost (LCC). The amount of these savings is dependent on the quantity to be fielded, the maintenance concept, the sensitivity of LCC to reliability and the level of development required. It is the old "pay me now or pay me later situation" which in many cases makes a program manager's situation difficult because his or her performance is mainly based on the "now" performance of cost and schedule. Does RGT allow contractors to "get away with" a sloppy initial design because they can fix it later at the government's expense? It has been shown that unforeseen problems account for 75% of the failures due to the complexity of today's equipment. Too low an initial reliability (resulting from an inadequate contractor design process) will necessitate an unrealistic growth rate in order to attain an acceptable level of reliability in the allocated amount of test time. The growth test should be considered as an organized search and correction system for reliability problems that allows problems to be fixed when it is least expensive. It is oriented towards the efficient determination of corrective action. Solutions are emphasized rather than excuses. It can give a nontechnical person an appreciation of reliability and a way to measure its status. Should all development programs have some sort of growth program? The answer to this question is yes in that all programs should analyze and correct failures when they occur in prequalification testing. A distinction should be in the level of formality of the growth program. The less challenge there is to the state-of the-art, the less formal (or rigorous) a reliability growth program should be. An extreme example would be the case of procuring off-the-shelf equipment to be part of a military system. In this situation, which really isn't a development, design flexibility to correct reliability problems is mainly constrained to newly developed ROME LABORATORY RELIABILITY ENGINEER'S TOOLKIT A-53

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