Originally Posted by
Gonzo
It's basically a system that forces airlines to be far more accurate in terms of telling ATC when they will be ready for start. From that, the system will build an ideal departure sequence; and from that output a Target Start Approval Time (having taken into account all sorts of things such as slot times, departure route and wake separations etc) to ATC.
So it sounds like it doesn't have a lot of relevance to arriving flights, apart from which it would need to know inbound passenger loads to be of much use for planning immigration resource requirements.