Dependency modeling of an avionics power-supply for testability analysis

Dependency modeling (DM) can be used to provide an accurate measure of the testability attributes of items ranging in complexity from individual circuit-cards to complete weapon systems. This paper presents a method for performing testability analysis on an avionics power supply (PS) using DM. The level of indenture used in the DM process is assessed, and limitations of the model are described. The testability analysis tool used to compute the testability figure of merit (TFOM) is the weapon system testability analyzer (WSTA). The results of the modeling effort provide a measure of the fault detection capabilities of the power supply. In addition to PS assessment, the DM process as defined herein provides the benefits of: (1) a structured approach to diagnostic predictions; (2) the ability to adapt the model to the level of detail desired; (3) integration of reliability, maintainability and supportability considerations in the analysis; and (4) a framework for both go-nogo and diagnostic test development.