The aircraft sent out a squawk code, which is used to provide effective communication between air traffic control and aircraft. 7700 is the most well know of these codes and it is used to indicate an emergency. The nature of the emergency is still unclear.
According to flightradar24.com, the Boeing KC-135R Stratotanker took off from the RAF Mildenhall air station in Holywell Row, UK, at 10:11 am today (Wednesday).
The initial destination is not known.
The aircraft appears to have flown up until Romania, nearly reaching Bucharest before it circled for a certain amount of time above Brasov.
Then, the aircraft turned around and flew all the way back to the UK to return to where it took off from.
More to follow…