PJ2
As I understand it ADS-B would have been no use at all for ATC/location purposes in a non-radar, e.g. (Oceanic) enviroment - the one in which AF was in.
Also, again as I understand it, ADS-C in it's normal mode would only squirt out a report crossing a waypoint....unless ADS Emergency was selected, in which case it sends a report every few minutes (?5).