Does the ADS-C contract really stay active after CPDLC logoff?
I’ve noticed something odd on several long-haul flights (A350 fleet).
After a CPDLC disconnection at FIR exit, the ADS-C contract sometimes remains active for several minutes — even when no new contract has been established by the next ATC center.
I’m wondering what the intended logic is here.
Should the aircraft terminate the contract automatically once CPDLC is closed, or is the ground system responsible for sending a cancel message?
Some manuals imply ADS-C is fully independent of CPDLC, while others say it “rides” on the same data link session.
Has anyone seen official guidance from ICAO Doc 10037, GOLD 2020 ed., or manufacturer FCOM references clarifying this?
Curious to hear how different operators handle it and what the “correct” behavior should be.