Oszacowanie liczby pęknięć zmęczeniowych struktury nośnej samolotu oraz kosztów jej naprawy w pierwszym okresie eksploatacji.

In the paper it is presented a probabilistic method of estimation of fatigue cracks number in an airplane supporting structure in the first utilization period. First period of utilization means time from the airplane manufacture till first general repair (overhaul). The starting point of the methods is application of a stochastic fatigue crack development models - the model proposed by Paris and Erdogan. The airplane structure is devided into zones. In each zone the Paris equation with relevant coefficients is on duty. Increment of fatigue crack lenght in each zone is described by different Paris equation resolutions. It was assumed that initial lenght of fatigue crack in each zone is random variable described by general distribution function. Considerations regard on statistical unreliability connected with detection. This method makes possible between others determination of crack probability of determined lenght, expected value and variance of general number of cracks in an airplane structure and expected value and variance of costs connected with control and repair of cracks. Considerations are illustrated by numerical example.