The only issue for Europe is whether you think there’s enough ADS-B OUT equipped traffic to see in your area, given that there are no ground stations to rebroadcast non-equipped Mode C traffic. My judgement is that if you have any other reason to replace the transponder, I would do it. The number of equipped aircraft in Europe is only going to rise.
My view might be colored by flying in an area where 99% or more of traffic is at minimum ADS-B OUT equipped and once you can see virtually all other traffic on e.g. Foreflight you don’t want to do otherwise. It’s been totally revolutionary for me: it’s interesting to change course slightly to avoid traffic and see them do the same thing, all without any visual contact, radio contact or ATC role, and that’s likely to happen at least once on every flight I make.
I use a GTX335 (not 345) meaning only ‘OUT’ capability, plus a Stratus receiver. This works well too and provides the IN data in the cockpit via Wi-Fi versus Bluetooth, which I prefer.
In my (French) experience, ADS-B In is a waste of time. Practically no small planes have Out. You’ll get to see airliners and anything PC12 sized and above.
That said, it did save my life or close when I saw on ADS-B something that was completely concealed visually, climbing on a converging course. So maybe not a COMPLETE waste of time.
The US is, as 172driver and Silvaire say, a completely different story.
Is there a real TCAS option for our small plane? I mean a device that can spot a C mode?
My steed sports ADSB IN/OUT, and Powerflarm.
From what I can observe, there are more and more ADSB aircraft equipped. I would say that about 80-90% of the latest homebuilts taking to the air around here are ADSB equipped. A such, ADSB will give you traffic advisories, and a better, but certainly not complete, overview of the traffic around you. Always remember that there still some stealth flying crafts around…
History has alas recorded yet another missed opportunity by the european NAAs and EASA, insisting on Mode S iso ADSB…
One fun thing about ADSB is the data displayed on my screen… callsign, try of A/C, GS, course, track vector, and speed difference. It is also put to good use to find your flying friends once airborne in the Alps, or to try to intercept (good luck on that one…) @eurogaguest1980 somewhere over France enroute to some EuroGA fly-in 
It is also put to good use to find your flying friends
I get some of that too, but typically I’m on the receiving end of an RV fly-by
greg_mp wrote:
Is there a real TCAS option for our small plane? I mean a device that can spot a C mode?
At ~10K – yes, TAS from Garmin or Avydine (@Peter could shed some light on that – he’s got one)
Or, if installing new, you could install transponder Lynx NGT-9000+ (9000+ is important detail! 9000 without the plus sign is just like GTX-345), that one has got:
Mode-S ES, ADS-B IN, ADS-B OUT, TAS, etc.
Still gonna cost you ~10K, but just 10K, not Mode-S(3K?)+10K.
Ok, but when you fly VFR in places where there are a lot a plane, it can be a good help.For IFR you don’t usually need that.
This is also worth a read.
We have had many threads around this topic. The main issue is that you can have
The former cannot in general display “uncertified OUT” systems.
The latter can generally display both "uncertified OUT and “certified OUT” systems.
So you have this matrix, where lots of people think they can see more than they actually can, and who think they are visible to more than they actually are…
As to your Q
Is there any point in upgrading a transponder in order to be able to see VFR traffic?
I mean, how much GA traffic am I likley to see in terms of percentage?
you are implicitly talking of “certified ADS-B” which will be visible to everyone with any ADS-B IN, but you will not see any traffic using the “portable” systems.
For more excrutiating detail, search on e.g. “SIL=0” (with the quotes).
Yes I have an “active TAS” system but it cost £13k in 2013. This covers the broadest common denominator in GA, because more people have a Mode C/S transponder than anything else. However, the current mad UK CAA bust-them-all policy ensures that around 50% fly with their TXPs turned off… And I don’t think flying around with some other system improves this. But you probably don’t want to spend that much money!
I don’t have ADS-B OUT since it would cost a few k and I am always visible on Mode S, and one day (when Avidyne can do an exchange box) I will update my TAS605 to a TAS605A which does ADS-B IN which should improve target display accuracy.
As a guess, I would put certified ADS-B OUT traffic at no more than 5% of total GA, so you will see very little. But many more will see you because a lot of Skyecho etc boxes have been sold.
However, the above percentages vary with altitude. At higher levels, say 3000ft+, most people are radiating Mode C/S and probably more than 5% are radiating ADS-B OUT. The “invisible” crowd is mostly found below 2000ft.
I am installing a GNX375 and ADL190 /RS232 Combiner for flight plan transfer. I agree that for collision avoidance the only workable system is a certified TAS system in Europe. But there are other advantages more unit integration related. The GNX375 has also FIS-B option which should play with the ADL device for weather input . I choose the GNX to get rid off the old altitude encoder, old GTX330 non ES, to have FIS-B weather in Europe over ADL FIS-B on the GNX. This will allow to have weather on a mobile device and meanwhile check the METAR TAFs on the GNX or vice versa. The ADS-B is nice to have for an N reg in Europe you never know were the next owner will be located. and anyway it’s time to replace the KLN90 with something that can fly transitions and LPV. So for me the ADSB situation is not black and white……the GNX will see only certified ADSB-out the other ADS traffic will be catched by the ADL device… I am hoping for improved service from ATC …but maybe that’s wishful thinking :-)
However, the current mad UK CAA bust-them-all policy ensures that around 50% fly with their TXPs turned off…
I find that attitude insulting to other pilots and a threat to my security. It could be considered a good reason to avoid the UK.
Here is an interesting blog article…. he makes +ve reference to the UK/NZ/AU experiment as worth expanding. Opinions?
