ABSTRACT
This paper is an outgrowth of an investigation to determine what is the main source of failure in the Polish operational aviation. The proper understanding of failure data is valuable in prediction of the future needs in a specified planning horizon or for specified operational hours. The major effort of the study was the reliability analysis for two types of aircraft, which are used in the Polish operational aviation. As the main results the value of the number of hours between failures is presented and this distribution is tested with some mathematical models. The description of the data by Weibull distribution, which is one of the most frequently used functions in reliability analysis, has been tested. Then, the same test has been performed for another mathematical distributions. It has been observed that for an aircraft of first type the best description can be given by different distribution as for the second type and that the standard Weibull distribution is not always the best reliability model. The potentially causes of this behavior are discussed in the article. Additionally, the change of the number of the failures as a function of time is presented. It is observed that this behavior varied for the different types of aircraft.
