Mode 'S' mandatory for gliders.

[chrisN]

Cobalt, I was pointing also to what seems to me at least a third issue – that if all the things (not only gliders) below, say, a TMA, have transponders, then descending CAT gets TCAS triggers all the time – because TCAS does not know that the CAT will level out before reaching the below-TMA level – so lots of false alerts. So ATC tell the below-TMA people to switch off.

Presumable the same could happen as a result of ATC’s collision alert system.

So would ATC tell people to switch off – as they reportedly are doing in Holland – or not?
-----------------
And another post on u.r.a.s. said:

“With Mode S, an ATC unit can instruct any S-transponder not to respond to signals from that unit.

“It will still respond to TCAS. However TCAS does not, at present, cope with multiple threats, so guess how much use your mode S will be if you fly in gaggles. FLARM would be a better bet!
[snip]

Chris N.