3. Search for failure modes

A failure mode is the way in which a medium can stop working or operate in a degraded mode.

For each component identified, we need to find one or more functions associated with it, such as

• total loss of function ;

• degraded state of function ;

• non-realization of the function at a given time ;

• unintentional operation of the function.

The mode is a way, for each component, to achieve one of these malfunctions.