Command mode failure sequence

In this cascading failure model, the first failure in the series (A in this example) effectively causes the other components to fail as they are each overstressed by the previous failure. In this example, the root cause of the final outcome is the failure of component A, and the coupling factor is the design vulnerability of the components to a stress level higher than the design limit. From another viewpoint, the first failure can also command the other components to operate prematurely. When component A fails in a certain mode, it provides its input to component B prematurely, which causes B to perform as intended (designed), except prematurely and unintended.This is often referred to as the command mode failure sequence. 

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