If it does display anything at all obviously :-)
Currently it works great with the TAS605.
It sounds like the behaviour might get “very interesting” with the -A TAS605 
What I don’t get is that since the blocking of display of “uncertified” targets is done at the display device, does this mean that if you have a TAS605 -A and it sees a conventional target it will always be displayed but if it sees a target which is either ADS-B only or ADS-B plus conventional (i.e. merged), that target will be blocked. Or would only ADS-B-only targets be blocked? How does the display device know that a target has been merged?
But there is another aspect here: surely if a target has been blocked from display and the decision to block it is done at the display device, the audio warnings must be blocked too, but the audio comes from the TAS or the GTX345. So how does that work?
which is to get a GTN750
I can’t do the “W” GPS update as yet, due to organisation. It is a big job and god knows who can do it around here. It needs to be done really well. I can do it by a freelance installer but would need a hangar and in the winter it would need to be a heated hangar (very rare). It could be done during the TKS downtime (Jan+Feb 2018) but I am not sure I want to micro-manage two big projects at the same time. And I won’t do it outside the (southern) UK because it is impractical to travel to it to check progress etc. That’s why I was hoping to keep going with the KLN94+KMD550 for another year perhaps; they do everything needed for IFR in Europe. The main driver would be LPV and the cost would be about 30k! There are a lot of connectivity issues to be resolved in the TB20; it would not be a trivial installation. The bottom line is that I have virtually no facilities here, and no test equipment should something not work.
But anyway the ADS-B IN upgrade is not feasible without spending the extra 30k on a new “W” stack.
I don’t dislike the Ipad but have no use for one in the cockpit. I am familiar with the IFD540 and the GTN750 so don’t need to be “sold” their features It’s definitely the way to go if one can organise it.
so few SIL=0 targets live in the UK
That is interesting in itself because it suggests there is no take-up of the “low cost ADS-B” proposals here. That would have been a big reason for adopting ADS-B IN. One doesn’t need traffic warnings for IFR flight (it’s mostly in CAS).
I have probably come back full circle on this i.e. not worth doing anything at all.
In order for an Avidyne TAS box to accept A429 altitude it needs to be higher than -4 PN. Current is -8 so anything -5 to -8 will accept A429 alt (and heading). Just went through this on a big install and we actually swapped out a TAS box with a newer one to make it work. Avidyne wants like >$3k to upgrade the SW on the box to the current -8 rev.
derek2 wrote:
In order for an Avidyne TAS box to accept A429 altitude it needs to be higher than -4 PN. Current is -8 so anything -5 to -8 will accept A429 alt (and heading). Just went through this on a big install and we actually swapped out a TAS box with a newer one to make it work. Avidyne wants like >$3k to upgrade the SW on the box to the current -8 rev.
Very useful info – thanks.
Peter wrote:
But there is another aspect here: surely if a target has been blocked from display and the decision to block it is done at the display device, the audio warnings must be blocked too, but the audio comes from the TAS or the GTX345. So how does that work?
Interesting point, so I’ve been re-reading the relevant TSO C195. It would appear that the ADS-B receiver has to determine the incoming SIL and it then determines that the display will not to display a SIL-0 target, Therefore this would suggest that the audio will also be inhibited by the receiver. In the case of the GTX345, I would therefore also assume (but can’t be certain) that it would also inhibit display of SIL-0 targets via the Bluetooth output to an iPad using Garmin pilot. I will ask some questions of Garmin and see what comes back
Extracts from the TSO. Bold sections are my additions for clarification.
1.21. When the ownship SIL is zero or the horizontal position integrity is greater than 0.6 NM,
ASSAP (Airborne Surveillance and Separation Assurance Processing – within the receiver ) shall (2169) signal that EVApp is Unavailable (fail) via the CDTI (cockpit display of traffic information) interface.
1.22. c. Traffic track shall (2174) have a SIL of 1 or greater and a NIC of 6 or greater to be
marked as a valid EVApp traffic.
I don’t think that the merged targets will be available on a traffic display device other than a Garmin system such as the GTN, GNS, G1000, G950. So what you would see on a non Garmin MFD would only be TAS/TCAS targets, but on a Garmin display or GTN, you would see merged targets with the SIL=0 targets only available as a TAS/TCAS target.
Isn’t ADSB Out on your wish list?
you would see merged targets with the SIL=0 targets only available as a TAS/TCAS target.
What would that mean?
Isn’t ADSB Out on your wish list?
It needs a “W” GPS which is a whole centre stack rework. I was just looking at installing ADS-B IN as a low-risk project.
Reading the TSO, I think the criteria for Enhanced Visual Acquisition (EVAcq) are more relevant than the ones for Enhanced Visual Approach (EVApp).
Then the criteria for ownship is NACp ≥ 5 (EPU < 0.5NM certainly achievable with a dumb GPS) and the criteria for the traffic is NACp ≥ 5 and SDA ≥ 1 no requirement on SIL or NIC.
you would see merged targets with the SIL=0 targets only available as a TAS/TCAS target.
And nothing if the traffic is ADS-B only with NACp and SDA set to 0 as per CAP1391 or CS-STAN CS-SC002b and no transponder. I’m sure there is good reasons but it still baffles me that traffic is not presented on the off-chance that its position is dodgy.
I got this from a source in the USA, and it is found here and was written by the same Avidyne guy who used to post here There is some very funny reading on that Avidyne forum, with some well known characters tearing their hair out…
So, as expected, the TAS605 needs a WAAS GPS source. Can a GTX345 be used for that and if so, what (if anything) useful would the GTX345 then do, over my existing GTX330? In terms of installation work, I would need to install the extra WAAS antenna, and then when the IFD/GTN box(es) go in later, another 1 or 2 of them. But then the GTX345 would not need its antenna, would it? But then I could just put the GTX330 back in
Incidentally, does anyone know if SIL=3 GPS data have to be ARINC429 or can it be RS232? Is the data stream published anywhere?
Peter wrote:
Incidentally, does anyone know if SIL=3 GPS data have to be ARINC429 or can it be RS232?
It can come on RS232 using the Garmin ADSB+ protocol or on an ARINC429 bus using ARINC743a. The GNS and GTN units output the RS232 format.
NCYankee wrote:
I don’t think that the merged targets will be available on a traffic display device other than a Garmin system such as the GTN, GNS, G1000, G950. So what you would see on a non Garmin MFD would only be TAS/TCAS targets, but on a Garmin display or GTN, you would see merged targets with the SIL=0 targets only available as a TAS/TCAS target.
I received the answer back from Garmin about what can be displayed from the GTX345 and as suggested above, the GTX will disregard any SIL-0 targets.
“The simple answer is that any ADS-B received as SIL-0 will be ignored by our GTX series devices. As for a TAS/TCAS/TCAD and ADSB IN equipped aircraft (GTX 345 with GTS 800 etc) and an intruder with an SDA of 0 and a SIL of 0, the TAS target would still be forwarded as a TAS/TCAS/TCAD target.”
