Originally Posted by
DaveReidUK
No, listening.
The RAF in the UK used to be a common sight over major cities with their surveillance Islanders orbiting at FL100 (helpfully tracked on Heathrow's radar website for all to see):
The mission is now contractorised, I believe, not sure what equipment is currently used.
Listening watching and following. The military are not the the only ones over the big cities. I am surprised the yanks could be seen as a mod to the transponders prevents Live radar 24 etc seeing these aircraft any more.