Timothy wrote:
There are a couple of respects in which the FMC helps.
ATC can quickly contact you…
How do they do that if you don’t have mode S which gives your callsign? I realise that they can call “aircraft in the vicinity of XXX” but does that work in practise — particularly on a busy frequency?
But that is all they can do. Another reason why Mode S is a good thing. 
Silvaire wrote:
I spend my ‘entire life’ flying around the edges of complex Class B airspace, each segment of which is controlled by a different person on a different frequency, with many such segments. I rarely talk to anybody but the Class D towers or CTAF for the airports at which I’m operating, obviously on a different frequency. The concept of tuning in additional frequencies and possibly different squawk codes after leaving tower, to allow each Class B controller to potentially contact me if I were to potentially enter Class B etc by mistake strikes me as silly, a totally impractical and distracting ‘solution’ if the airspace of interest is anything more complex than a simple single frequency Class D around an airport.
Yes but US airspace around major airports is a piece of cake compared to the UK. It is regular, well charted and simple to avoid with moving map software or even DME. The UK is a complete mess.
Another reason why Mode S is a good thing
That, however, enables the argument that the CAA will go after pilots in the order of lowest hanging fruit first i.e.
None of this is rocket science and it was all done to death in the “Mode S wars” whose legacy we still live with. This is much assisted by EASA which has banned a fresh installation of a Mode C box (except when replacing an identical failed Mode C box) so has effectively traded safety (Mode C is used by TAS/TCAS systems) for conspicuity/enforcement (Mode S radiates the aircraft reg and makes it much easier to catch the pilot). I am sure anyone who flies with TAS/TCAS would much rather everybody used Mode C, than the present situation where Mode S is used by a small % of aircraft, and a lot of the others are flying invisible. And I am sure many would install a Mode C box (especially e.g. gliders, when you can pick them up cheaply on US Ebay) if they could do so legally.
ADS-B, should it ever become legally relevant in Europe, will face the same issues all over again. People will do the same tricks there as they do now, assisted by the fact that it will “never” be mandatory in most of Class G VFR. You aren’t required to fix/replace a broken transponder, or a broken altitude encoder, which gets around this unenforced law quite neatly
Mode S radiates Mode C and is perfectly visible to TAS/TCAS.
Mode S ES also squitters ADS-B, thus enhancing safety further.
The LAA for instance have a reasonably straightforward process for adding ADS-B to Mode-S – unfortunately only uncertified (even with certified boxes) right now. But all the low cost traffic awareness systems will show it.
PilotAware now shows gliders (FLARM via the OGN), ADS-B, other PilotAware stations, and soon multilaterated Mode-S from OGN ground stations.
Timothy wrote:
But that is all they can do.
Yes, but does it actually work? We are all trained to pick out our own callsign among the chatter on a busy frequency, but what about recognising that a geographical reference is about you?
Swedish controllers occasionally mix up what language you are using and call you in Swedish when you last call was in English or vice versa. I’ve seen reasonably experienced pilots miss calls because of that. (Swedish R/T uses a Swedish-language phonetic alphabet so how the callsigns are read out will depend on the language used.)
Airborne_Again wrote:
Yes, but does it actually work?
I guess it’s better than nothing, and if you are on the FMC and know you have only Mode A or C (or even no transponder) then you might be more attuned to listening for that call.
With Dublinpilot and Silvaire here.
Only two solutions exist : reduce the volume of CAS or ease access to it.
To me, what make things easy is having the same ATCO manage both sides of a CAS border, giving control service inside and FIS outside. That’s how every working system … works (France, Germany, US, even Spain). In France, I usually plan flights across airspace, being confident I will get across.
It seems the British are the only to turn CAS borders into the Chinese Wall, protecting the cash from the Huns ?
