Long mission today for an RAF Boeing RC-135W (reg. ZZ664).
The Rivet Joint took off from RAF Waddington at around 07:00 CET to carry out a SIGINT mission.
The aircraft flew the entire eastern flank of NATO, from Estonia to Romania, where it is now (17:00 CET).
There are no other aircraft in the area to provide an escort for the RC-135, so we can assume that it will not be flying over the Black Sea (where, in recent times, it has only ever flown when escorted).