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Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum (src_forum@alionscience.com )
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 (JNico@zodiac.com )
Organization:Aérazur - Zodiac Group
Date posted: Thu Apr 26 8:42:37 US/Eastern 2001
Subject: MTBF calculation for new components in utilization
Message:
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)


Reply:

Subject: MTBF Aircraft
Reply Posted by: Bruce Dudley (bdudley@alionscience.com )
Organization: Reliability Analysis Center
Date Posted: Thu Apr 26 11:31:30 US/Eastern 2001
Message:
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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