RE:
An example of an acft flying through oceanic airspace with no ADS/CPDLC:
"BAW43, crossed position 'AAA' 1200 F370, estimate position 'CCC' 1255, 'DDD' next"
In this instance, ATC will not be able to verify the flight status of the acft for almost an hour, but our requirement is to ascertain ops normal every 30 min. If there is an intermediate waypoint that will reduce this gap that is not a compulsory reporting point ( i.e FIR boundary etc.), atc may reply:
"BAW43, Copy estimates, report 'BBB' FL370".