You don’t need a SBAS position source to broadcast DO260A ADS-B. You can achieve it with non-SBAS navigator and a TT31.
It works well, as the aircraft I usually fly is wired this way.
A SBAS position source is only required for high integrety DO260*B* ADS-B. But such installation is not covered by CS-STAN and requires a full STC (just like the FAA does). Even though it can be achieved with a TT31 as well.
For now, eurocontrol plans to mandate DO260B ADS-B only for aircraft > 5,7 T or > 250 KTAS from 2020.
I believe that both TAS / TCAS systems will show the target but, due to the potential for incorrect position data, TCAS systems will not provide RAs
That’s possible, looking at the whole spectrum of TAS/TCAS systems, from the GA boxes all the way to bizjets an airliners. I too have read somewhere that at the upper end of that spectrum it does work that way i.e. all ADS-B traffic can be displayed but you don’t get the resolution advisory (RA is applicable only to some bizjets, and airliners).
However, in piston GA, we have mainly
AFAIK, with some discussion here which I have just spent ages reading and trying to make sense of, probably none of the Avidyne boxes support ADS-B or ever will, either due to the TAS box upgrade requirement or the ADS-B OUT requirements. Garmin support it. Honeywell never will.
So, what SIL level do the Garmin GTS boxes require?
Incidentally I would upgrade my TAS605 to ADS-B IN if it was possible but based on this it is not possible unless I upgrade my GPS to a W box (and actually the MFD also to something else i.e. basically the whole centre stack) – because the ADS-B OUT cannot be done with what I have. Strange that Avidyne have tied the two together. Maybe it is their STC that ties them together, because ADS-B OUT (done with a GPS → GTX330 in my case) is entirely separate to ADS-B IN (done by upgrading the TAS605 box). Also I have not yet spoken to anyone who has seen the Avidyne TAS6xx ADS-B upgrade working for real.
Guillaume wrote:
You don’t need a SBAS position source to broadcast DO260A ADS-B. You can achieve it with non-SBAS navigator and a TT31.
It works well, as the aircraft I usually fly is wired this way.
But is that legal? Unless your aircraft is a) experimental and b) restricted to flying in uncontrolled airspace in (e.g.) UK, I was informed that simply wiring up my GNS430 to my GTX330-ES would be illegal. As the signal would be broadcasting the ID of the plane, the authorities would know pretty quickly that I’d wired the two together…..
Unless your aircraft is a) experimental and b) restricted to flying in uncontrolled airspace in (e.g.) UK, I was informed that simply wiring up my GNS430 to my GTX330-ES would be illegal. As the signal would be broadcasting the ID of the plane, the authorities would know pretty quickly that I’d wired the two together…..
They probably don’t care, not because they could not tell (I believe the FAA runs some sort of noncompliant emitter detection programme in the USA, so it is “technically possible”) but because ATC doesn’t have a database of which aircraft have an ICAO CofA 
Hence it is completely possible to e.g. file and fly IFR in the Eurocontrol system in, ahem, any homebuilt 
This sort of thing came up before here…
IOW, anything that a homebuilt can radiate, a certified plane can also radiate, and detection will be impossible.
OTOH you will have a problem next time you visit an avionics shop which realises what you have and refuses to work on the plane, or when you need the German IFR Certificate…
My question about connecting two existing devices in a certified aeroplane was to do with being visible to the reportedly 1000 UK users of Pilot Aware and similar devices under VFR. Nievely I hope that my transponder (always on!) is already visible to high end piston and other TCAS equipped traffic.
These thoughts are partly triggered by a 12Hr cross country in the Carolinas last week in an aircraft having TIS displayed on a 530. It was strikingly clear that flight following always called the exact same traffic that was already visible in the aircraft. In UK, not only would the chaotic ‘Basic Service’ likely not call the traffic, but nothing in the aircraft would see it either, apart from the 30% or so that might be spottedly visually.
Of course I could festoon the cockpit with cables and antennas etc. and use a non certified ‘portable’ device like Pilot Aware which would make me visible to other users of compatible proprietary systems and vice versa. Doubtless I will. But this really does IMHO start to mitigate against the ‘look out the window’ principle of flying, requiring constant and potentially distracting attention to an interface like iPad which at the moment with Sky Demon or Foreflight only gets referred to every few minutes.
Or I could spend $2.50 on a serial cable and be instantly visible (meaning with an exact position) to all these systems. Oh well…
Nievely I hope that my transponder (always on!) is already visible to high end piston and other TCAS equipped traffic.
That is a very good point – if one flies with Mode C ON then one should be visible to the better equipped traffic (with their active TAS systems).
The rest of the matrix is mind boggling…
Steve6443 wrote:
But is that legal? Unless your aircraft is a) experimental and b) restricted to flying in uncontrolled airspace in (e.g.) UK
Please check EASA CS-STAN Change CS-SC002b
However, the voluntary transmission of additional ADS-B data (e.g. GPS position and velocity) can be accepted when the position and velocity quality indicators report the lowest quality, the equipment manufacturer has stated compatibility with the directly connected GNSS source, and the transponder is not authorised in accordance with ETSO-C166b or equivalent.
a) EASA CS-STAN applies to Annex I aircraft (EASA aircraft)
b) there is no ADS-B mandates which requires ETSO-C166b carriage in CAS europe wide for < 5.7 T or < 250 KTAS aircraft (contrary to the US which is going to require SIL 3 DO 260B ADS-B in controlled airspace from 2020).
However, there might be some local area in europe which requires DO 260B ADS-B carriage. I’m not aware of any.
You should check airspace regulation and see what surveillance device is required.
I indeed think that wiring your GTX 330 ES to a non-SBAS source would be illegal as your GTX 330ES is likely to be authorised in accordance with ETSO-C166b. But TT31 with firmware 2 is not.
Now regarding ADS-B in.
Low end GA : Very very few aircraft are equipped with a fixed “ADS-B in only” device in europe as no services (TIS-B / FIS-B) are provided. I’ve yet to see one.
High end GA / airliners : They are equipped with TCAS and almost none of them use ADS-B in.
There is no ADS-B in mandate so the adoption rate is going to be very slow.
I recently did a jumpseat flight in a brand new 737 : it still uses regular TCAS without ADS-B in input.
TCAS TA/RA are provided with mode A/C/S transponders and don’t require any sort of ADS-B.
But by broadcasting DO 260A ADS-B you will be visible on FR24 or portable devices such as Pilot Aware.
Many thanks for that great and very clear post, Guillaume. Interesting comments…
But by broadcasting DO 260A ADS-B you will be visible on FR24 or portable devices such as Pilot Aware.
I would expect FR24 and the other portable ADS-B IN capable boxes to be grateful for any ADS-B signal…
Steve6443 wrote:
But is that legal? Unless your aircraft is a) experimental and b) restricted to flying in uncontrolled airspace in (e.g.) UK, I was informed that simply wiring up my GNS430 to my GTX330-ES would be illegal. As the signal would be broadcasting the ID of the plane, the authorities would know pretty quickly that I’d wired the two together…..
Even for SDA=2 under CS-ACNS, an SBAS position source is not required under EASA regulation (in contrast to the FAA regulation):
AMC1 ACNS.D.ADSB.070 Horizontal Position and Velocity Data Sources
(a) GNSS Standards
(1) Basic GNSS System Approval
To be approved, the horizontal position and velocity data source should hold an EASA equipment authorisation in accordance with either ETSO-C129a, or ETSO- C196, or ETSO-C145/ETSO-C146, including the additional qualification requirements as specified in paragraph (2) below.
However, in order to make the modification, you either need to do it under an STC (Garmin has one, not Trig yet) or use the very restricted offer in CS-STAN, and most modern transponders can’t.
What would happen if I upgraded my GTX330 to ADS-B (it was installed in 2005) and connected the KLN94 to it? That connection is already there, since 2005, for auto GND/AIR switching but it never worked so the switching is done with a differential air switch. I heard Garmin did a fix for the GTX330 firmware to make it work with a KLN94, a year or two ago.
Would it radiate ADS-B OUT, even illegally?
Even for SDA=2 under CS-ACNS, an SBAS position source is not required under EASA regulation (in contrast to the FAA regulation)
Is the FAA reg applicable to the aircraft or to the airspace?
Lots of people ask me whether an N-reg is required to have ADS-B after 2020, which is the FAA position (for all controlled airspace AIUI).
