The equal apportionment by components allocation method distributes the total failure rate allocation across all components in the entire system. This is the only allocation method that is not performed recursively down the system tree. You enter the failure rate or MTBF goal for the top-most assembly, which represents the system. You do not enter weight factors for lower-level items. Instead, the weight factor for all parts is computed using the following equation:

100 / Number of Parts in the Entire System

System Failure Rate Goal: 100 FITs

Subsystem A

Part 1

Part 2

Subsystem B

Part 3

For the top-most assembly (system), you enter a failure rate goal of 100 in its Allocation pane. For more information, see ARINC and Equal Apportionment Methods. No other allocation data is required.

When allocation calculations run, the weight factor is computed for the parts in this system using the following equation:

100 / 3 = 33.3

Because the weight factor is the same for each part, the failure rate for subsystem A, which has two parts, is 66.6, and the failure rate for subsystem B, which has one part, is 33.3.

Subsystem = Weight Factor * Number of Parts

Subsystem A = 33.3 * 2

Subsystem B = 33.3 * 1

The system tree for this scenario would look like this:

System failure rate goal: 100 FITS

Subsystem A (66.6%)

Part 1 (33.3%)

Part 2 (33.3%)

Subsystem B (33.3%)

Part 3(33.3%)