5.3.1 If subjected to an orderly shut-down, the
IBS should, upon turn-on, come to an initial default state.
5.3.2 After a power interruption full functionality
of the IBS should be available after recovery 000 of all subsystems.
The IBS should not increase the recovery time of individual subsystem
functions after power restoration.
5.3.3 If subjected to a power interruption the
IBS should, upon restoration of power, maintain the configuration
in use and continue automated operation, as far as practicable Safety
related automatic functions should only be restored upon confirmation
by the operator.