Note 1 to entry: A failure mode can be determined by the function lost or other state transition that occurred.

Note 2 to entry: Examples of hardware failure modes might be for a valve, "does not open", or for an engine, "does not start". An example of software failure mode might be that the “timeout logic times out earlier than required”.

Note 3 to entry: A human failure mode is determined by the function lost as a result of human action, whether committed or omitted.