One can think of a routine or common procedure to be applied (here it is in case of technical sequence of operations) on any system.
When some exception occurs - the common/ normal routine is NOT followed by another one is followed. I want to use an appropriate word for this.
Few words i have thought of myself that doesn't quite fit.
alternate proceduresounds like a replacement so doesn't indicate that it should be used only for exception.
exceptional procedureis not appropriate because exceptional is quite often connotative to "great"
irregularis not appropriate because this secondary method is also standardized for the given situation.
I want one appropriate word (as an adjective to the process) that indicates that it is not a "normal" procedure but to be used under some exception.