Peter wrote:
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).
Peter,
It applies to US airspace only I believe.
It applies to a small portion of US airspace below 10,000 MSL or 2500 AGL. Above these altitudes, it is required. The airspace below 10,000 only includes inside class C and B airspace and within the 30 NM Mode C veil of major airports.
Which does not include the majority of US Class D ATC controlled airports, at which you don’t need either a transponder or ADS-B Out, nor most Class E controlled airspace (ditto).
I believe the red dots on the map are Class B related ADS-B Out airspace starting in 2020, yellow is Class C.
Peter wrote:
What would happen if I upgraded my GTX330 to ADS-B (it was installed in 2005) and connected the KLN94 to it?
Peter,
The combination would provide ADS-B Out, but most of the parameters would not be emitted. Latitude/Longitude and pressure altitude would be broadcast, but all the integrity data and the geometric altitude would be missing. So the dynamic values of NIC, NACp, and NACv would be missing. I am not sure what the SIL and SDA values would be, but they would most likely be 0, but am not sure. A non certified receiver would be able to see you, but a certified system would not likely display a target with a NIC of 0.
The issue is not WAAS verses non WAAS, it is the data that is provided on the link between the KLN94 serial port and the GTX330ES. In theory, such a GPS could provide the data and would even meet the US standard 95% of the time, but the serial output from the older non WAAS GPS systems was never designed to provide this data. There are some non WAAS GPS sensors, but as a practical matter they are similar in price to WAAS units.
Silvaire wrote:
Which does not include the majority of US Class D ATC controlled airports, at which you don’t need either a transponder or ADS-B Out, nor most Class E controlled airspace (ditto).I believe the red dots on the map are Class B related ADS-B Out airspace starting in 2020, yellow is Class C.
So true. You can fly from the pan handle of Oaklahoma to Canada and as long as you stay below 10000 feet, no need for a transponder or ADS-B. Wyoming, North and South Dakota are wide open as is most of Montana, Nevada, Oregon, New Mexico, Utah, …
Many thanks, NCYankee.
I have asked one big avionics shop to find out the latest on the TAS605 ADS-B IN upgrade, or indeed whether it even exists. And whether it can be installed without a certified ADS-B OUT. For sure, it doesn’t sound like anybody in the UK has installed it!
but a certified system would not likely display a target with a NIC of 0.
This specific Q was raised earlier, inconclusively. I wonder if anyone has tested it. There are just 3 active TAS systems in reasonably common use so it should not be too hard. The problem is that two of them don’t support ADS-B… Aren’t newer SR22s fitted with the Garmin one, which has that option?
Peter wrote:
This specific Q was raised earlier, inconclusively. I wonder if anyone has tested it. There are just 3 active TAS systems in reasonably common use so it should not be too hard. The problem is that two of them don’t support ADS-B… Aren’t newer SR22s fitted with the Garmin one, which has that option?
Certified systems can’t show SIL 0 targets but Garmin Pilot etc can.
I have asked one big avionics shop to find out the latest on the TAS605 ADS-B IN upgrade, or indeed whether it even exists. And whether it can be installed without a certified ADS-B OUT. For sure, it doesn’t sound like anybody in the UK has installed it!
ADS-B IN has nothing to do with OUT.
NCYankee wrote:
You can fly from the pan handle of Oaklahoma to Canada and as long as you stay below 10000 feet, no need for a transponder or ADS-B. Wyoming, North and South Dakota are wide open as is most of Montana, Nevada, Oregon, New Mexico, Utah, …
You can do similarly down the spine of Scandinavia around the border between Sweden and Norway. Similar population density.
Peter wrote:
What seems clear is that nothing other than SIL=3 will ever show on any certified TAS system – see earlier posts around here
But if you have a certified TAS system, surely it will show the height and direction of Mode-S targets (with altitude). Since in Europe, ADS-B is by extended squitter only, by definition the aircraft emitting SIL=0 ADS-B will also have a Mode-S transponder which your certified TAS system will see – so it doesn’t matter so much that you don’t see ADS-B from that aircraft because you can see its Mode-S anyway. Any level of SIL, including zero, will be helpful because then the low cost non-certified things like PilotAware can also see the traffic, not just the expensive boxes that can use the Mode-S.
I am then confused.
The active TAS boxes like my TAS605 ping nearby transponders. They display Mode A targets (bearing but no no altitude shown), Mode C targets (bearing and relative altitude shown), and I thought that’s it.
But at least the Avidyne TAS6xx does pick up something from the Mode S return, as I reported here and here and here. It just doesn’t display it unless you have that specific kit mentioned.
I don’t think the TAS boxes extract anything out of the Mode S return, beyond the tail number. If you are radiating what in Europe is called Elementary Mode S then it is just the 24-bit ID (which can be translated into a tail number but probably only for N-regs) and 1 or 2 other things. Below 5.7T etc you aren’t supposed to be radiating more than that (Enhanced Mode S) but of course many are and then the Mode S stuff could include GPS lat/long and a copy of the baro derived pressure altitude (a copy of the Mode C basically) but I doubt these TAS boxes use any of that. If they did, anybody radiating Enhanced Mode S would be providing ADS-B OUT in all practical respects.
So I think Mode S is basically wasted for aircraft-to-aircraft conspicuity purposes, if you have an active (certified) TAS system and want to see other stuff. Mode C does that job adequately. Only ADS-B does it better because you then get proper accurate lat/long.
But I don’t understand the details of how this works and have never met anyone who does and who can write an explanation that makes sense.
For example, why did the TAS6xx box in the Cessna TTX N400UK display N-reg tail numbers, while my TAS6xx never displays any tail numbers. The TTX had an Avidyne MFD, connected via RS232 I believe, while I have a KMD550 MFD connected via ARINC429. Presumably the RS232 connection uses a different TIS protocol, special to Avidyne products… but it is empirically clear the TAS6xx box does pick up the target’s Mode S return – even if it throws away most of the data.
