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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

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Original Message:

Posted by: Julien Nico ( )
Organization:Aérazur - Zodiac Group
Date posted: Thu Apr 26 8:42:37 US/Eastern 2001
Subject: MTBF calculation for new components in utilization
Could someone provide me information on the way how to calculate MTBF of a new component in utilization. My component is installed on aircraft (this type of aircraft is only use since one year and fleet still increase). I know the cumulative fleet flight hour (which is 20,000 FH). Quantity per aircraft is 3 Fields data are two components have been removed and only one failure have been confirmed (the other was no fault found). I think the MTBF is: MTBF = 3*20,000 / 1 = 60,000 FH. MTBUR = 3*20,000 / 2 = 30,000 FH. Could you please confirm if I'm right or not (and give to me the correct way to calculate it)


Subject: MTBF Aircraft
Reply Posted by: Bruce Dudley ( )
Organization: Reliability Analysis Center
Date Posted: Thu Apr 26 11:31:30 US/Eastern 2001
The calculations for mean time between failure and mean time between unscheduled removal are reasonable for the data indicated. Given the operating time, failures and units under operation, the 80% confidence interval for confirmed failure is 26,000 hours to 568,000 hours MTBF(mean time between failure). The MTBUR(mean time between unscheduled removals)is 15,000 hours to 113,000 hours.

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