for the A320, FCTM OP 040 ECAM HANDLING:
"in general, all guarded switches must be xchecked by pf & pm (except on grd) to prevent the flight crew from performing irreversible actions"
however, they don't say anything about the colours.
i will tend to agree with emach: Red- Action on this switch is irreversible. Black- Action on this switch is reversible.
Last edited by Feather44; 4th April 2017 at 18:35.