Set Mct max Calculation Method

RAM Commander implements the advanced approach to the Mctmax calculation in the maintainability module.

1.	Open the Product tree view.

2.	From the Project menu, choose Configuration. The Project Configuration dialog box opens.

3.	Select the Mctmax calculation method from the combo list:

Choose OK

The MIL-HDBK-472 applies the lognormal distribution to the repair times in the standard deviation calculation not taking in the account the item’s failure rates.

As many users have noticed however, the results were sometimes paradoxical. That's why RAM Commander allows the user to perform Mct max calculation based on various repair times distribution assumptions. Users may now choose one of the following methods of the Mct max calculation:

1	MIL-HDBK-472 (Lognormal Distribution):

2	Weighted Lognormal Distribution

This is similar to the MIL-HDBK-472 based on lognormal distribution, but takes in the account the failure rates in the standard deviation calculation:

3	Normal Distribution

The standard deviation calculation is based on the hypothesis of the repair times’ normal distribution:

4	Empirical Distribution

Does not use any distribution assumption and is based on the predicted repair times. The implementation algorithm consists of several steps:

A histogram of Mcti and corresponding pi is built, where

cumulative (Mcti in ascending order) distribution histogram is used to define the confidence level (CL) for each value of Mct:

Mctmax is calculated by the linear interpolation of Mctk. i.e. if the required value of CL (usually 90% or 95% ) falls between CLk and CLk+1, then