Fleet Analysis Example

This example appears in the Reliability growth reference.

The following table presents data for a fleet of 27 systems. A cycle is a complete history from overhaul to overhaul. The failure history for the last completed cycle for each system is recorded. This is a random sample of data from the fleet. These systems are in the order in which they were selected. Suppose the intervals to group the current data are 10,000; 20,000; 30,000; 40,000 and the final interval is defined by the termination time. Conduct the fleet analysis.

Solution

The sample fleet data set can be grouped into 10,000; 20,000; 30,000; 40,000 and 52,110 time intervals. The following table gives the grouped data.

Based on the above time intervals, the maximum likelihood estimates of $$\widehat{\lambda }\,\!$$ and $$\widehat{\beta }\,\!$$ for this data set are then given by:


 * $$\begin{matrix}

\widehat{\lambda }=0.00147 \\ \widehat{\beta }=0.93328 \\ \end{matrix}\,\!$$

The next figure shows the System Operation plot.