Hi.
I am currently completing the final steps of my school work which is evaluation of performance reliability of Zlín aircraft on our school. The aim of my work is to prove that our fleet is safe. I have already wrote about every single failure which appeared in the last 6 years and discussed about our aircraft maintenance. The last part is calculation of reliability. I have already calculated mean time between failures (easy one) but that is not enough in my opinion. I would like to add other numbers to make the prove better. Do you know any other formulas to calculate things connected to reliability of aircraft? The data i have are types of failures, number of failures, total time flown during each year for every aircraft and calculated mean time between failures. I have found some formulas on the internet (picture added) but the description and way how to calculate it is too much for me (as i am not a mathematician student). Therefore i am looking for a simpler formulas or a program which would help me. I am really grateful for every answer.
Hi Michal,
To calculate the failure rate for each component you can divide the number of failures by the number of executed missions. The time interval that you get will be based on the test duration. For example, if you have data for one year, the calculated failure rate will be Lambda (failure/year).
If you assume that a failure obeys the exponential failure distribution you can calculate the failure rate like this: Lambda = 1/MTTF.
For Reliability calculation you just need the following formula:
R(t) = exp(-Lambda*t)
Note that all there are lots of assumptions related to the above-mentioned explanations.
If you have any other question related to the safety and reliability please do not hesitate to ask.
Koorosh Aslansefat
Thank you very much Koorosh.
Your comment is really helpful. I will use your formula and will do my best to complete my work in the next few days. I will let you know if something comes in my mind.
Have a nice day.
Well i got problem here. I will try to give an example.
I have year 2009 where 24 failures occurred during 260 hours of service. I calculated lambda as 24:260 = 0,092. Now i am trying to calculate reliability. I was not sure what exp means so i used google to find calculator (https://www.medcalc.org/manual/exp_function.php )
I put in 0,092 * 260 and that is 4,08. If I understand reliability correctly it should mean percentage of safe operation during a certain time when multiplied by 100. If i multiple 4,08 by 100 i get 408% of safe operation.
Where am i doing a mistake please?
I have checked the website that you have mentioned.
exp(-0.092*260) = 4.0895544305505E-011
E-011 means you should divide the 4.089 by 100000000000.
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