I wonder what this guy was doing: https://globe.adsbexchange.com/?ica...576&zoom=9.3&showTrace=2022-02-15&trackLabels Top speed reached was 875 knots and it doesn't look like it was an artifact from MLAT. If you zoom in, you can see him accelerating and slowing down again, so I'd guess he really was hammering it. Edit: at 12:09:25Z, he reached a top speed of 1023 kt...
You know what the color signifies, there is a legend at the bottom. Transponders can be switched into a mode that doesn't transmit altitude, not too rare for a pilot to just select the wrong mode. Then this is also chosen if the altitude the transponder is transmitting is wrong, so some defect. Not sure why the military sometimes operates in this mode, can't tell you.
I'm aware of the legend at the bottom. But black isn't on there. I'm assuming black means it's not transmitting the altitude properly. I don't think I've seen a plane not show the altitude before.
For what it's worth, F-15s are not that uncommon in that area. I didn't have time to observe that much this week, but when I spot more, I'll post a few more (I saw four of them doing an air defense exercise last week, near RAF Mildenhall).
That area over the sea north of East Anglia,where all the squiggly lines are, is an Air-To-Air refuelling area - if you turn on "UK A2A Refuelling" from the "layers"/map icon, you will see the area as an overlay. There is often a refueller using ADSB flying round and round in ovals there. It is then "visited" by various fighter jets on MLAT, so not as reliably tracked. I have noticed the fighters disappear from the map, I suspect while they are being refuelled (can take 20+ mins), and briefly appear again afterwards, only to zoom off and then vanish from the map again. So do they turn off their transponders while "connected"?. The refuellers more often than not come from RAF Brize Norton in Oxfordshire. There are often fighter jets around the north west coast of Wales as they are based at RAF Valley on Anglesea and are out most days. Not always easy to track though due to a) MLAT and b) lack of feeders in the area. The mountains of Wales also often have larger planes that don't appear on the map as they are practicing low flying so would need more feeders than unfortunately there are. These too also often come from RAF Brize Norton - sometimes you can see them fly across to Wales at low level and then "disappear". Though if you actually live there you certainly know about them!
Very nice view of refueling ops today: https://globe.adsbexchange.com/?ica....310&lon=2.261&zoom=12.1&showTrace=2022-05-09 3 F15s working with a KC-135. 2 Refueling, one as a sentry high up.
Another F15 having fun: https://globe.adsbexchange.com/?ica...76&zoom=11.5&showTrace=2022-05-23&trackLabels Speeds up to 1184 knots, seriously fast. (Not sure if it might have been a glitch in MLAT, but it showed this speed in two consecutive points, 30s and ~4 nm apart. 30s for 4 nm, without having actually calculated just doesn't sound plausible. *thinks* Nope. 1200 kts is 1 nm every 3s. 4 nm should have been 12s, not 30.) How does MLAT calculate the speed?
