SRC Forum - Message Replies
Forum: Reliability & Maintainability Questions and Answers
Topic: Reliability & Maintainability Questions and Answers
Topic Posted by: Reliability & Maintainability Forum
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998
Posted by: Wayne
Date posted: Sun Sep 29 1:31:56 US/Eastern 2002
Subject: Maintainability Demonstration
In MIL-471A Method 9, it is stated that in order to demonstrate a minimum of 30 tasks, the selected sample must be at least 4 times. What if my entire sample is only 40? In this unique case, can i still use the stratification procedure based on failure frequency to select 30 tasks out of the entire 40? Will the sample chosen be a good representation?
Reply Posted by: BWD
Date Posted: Tue Oct 1 9:15:49 US/Eastern 2002
In the case of a small number of possible maintenance tasks, the best way to determine the unit mean and maximum time to repair is to perform all the tasks at least once. Then you can apply the expected failure rates to find the number of times each repair would be experienced in the field. Average and maximum calculations can be made using these data.