Originally Posted by
SpringHeeledJack
I'm not quite sure I get your drift G-AZRG.
I was referring to that even on un-filtered adsb sites there seems to have been a sporadic, or even total blackout of locations/flight info, whereas usually in the last years AF1 shows up on most of the trackers as well as the reserve fleet, plus transports and command posts etc. This time it seemed not to be the case.
The two VC-25s rarely send ADS-B - on the couple of dozen occasions they have overflown this part of the UK in the last four years or so, I've only noted its use on a couple of occasions (both by 82-8000 while flying as AF1). The most recent of those was November last year - plotted on Heathrow's WebTrak
here, and a non-ADS-B overflight in March of this year
here.
Of course they send Mode S, which in theory would allow them to be plotted by MLat, but it may well be that the trackers using this technique voluntarily suppress tracking of AF1.