Airbus ATC AUTO mode
good day
FCOM says:
AUTO: In flight : Selected transponder operates.
AUTO: On ground : Selected transponder only operates in mode S (Selective aircraft
interrogation mode).
could anyone explain what is the difference between "operates" and "only operates in mode S"? what modes are operating else rather than mode S in AUTO (in flight) or ON?
did not find anything either in OM/TM/FM or in the web.
thanks in advance