LeSving wrote:
There is no requirements for Mode S or ADS-B in any airspace in the regulations.
As 1207/2011 requires that aircraft under IFR always have mode S, there is no point in additionally require it in certain kinds of airspace, is there? The effect is that you must have mode S regardless of the airspace.
Silvaire wrote:
Mexican Class E
I haven’t found any usage of class E in Mexico. They use D and G, but D does not require ADS-B Out. There is a mode C veil of sorts around Mexico City. Other than that is seems that throughout Mexico, the only airspace that is ADS-B Out is A which is above 19,500, so it seems to me the mandate does not affect UAT because none of the airspace outside of Mexico City seems to require it. They may add more airspace in the future or designate some E airspace areas, but not currently. Do you know of any areas that use E or that will end up requiring ADS-B Out?
wigglyamp wrote:
Maybe not in the US but they certainly do in Europe. I was involved in upgrading a KingAir B350 quite a few years ago and very quickly we had a report of incorrect pre-selected altitude coming back from ATC.
Preselect altitude is not part of the ADS-B Out broadcast, it is from the transponder enhanced surveillance capability. So any transponder H or L will provide this data. H has no ADS-B Out capability.
it seems to me the mandate does not affect UAT because none of the airspace outside of Mexico City seems to require it. They may add more airspace in the future or designate some E airspace areas, but not currently. Do you know of any areas that use E or that will end up requiring ADS-B Out?
I think maybe you’re right. It seems that like some other countries they generally (capital city excepted) go straight from G to D, with nothing in between, but like the US and unlike some other countries they don’t require much equipment for D.
The effect is that you must have mode S regardless of the airspace.
The effect is you have to look in the AIP for requirements. Mode S will do you no good certain places. ADS-B is required, like outside the coast, low level, IFR and VFR. Inland, below FL195, only Mode C is required. I can’t imagine you are denied flying the occasional trip without ADS-B, but that’s another matter and it’s up to ATC.
Lots of people have wondered about this. They have asked Avinor (ATC) and the CAA about requirement for Mode S, as well as other requirements for IFR avionics. The answer is always the same. There are no requirement for Mode S in any airspace below FL195 now matter flight regime, and no requirements are planned. In fact the CAA had issued a AIC about this, saying essentially they don’t care what we are using, as long as we have what is needed for the airspace as per AIP.
Now, you may say that EASA requires Mode S for IFR. This is correct. ATC couldn’t care less though, as this is very irrelevant for them.
Most people have since long changed to Mode S anyway. This is no real problem.
LeSving wrote:
Now, you may say that EASA requires Mode S for IFR. This is correct. ATC couldn’t care less though, as this is very irrelevant for them.
We seem to be in agreement on this, but I don’t understand why it should have take all this time as I wrote – several posts ago – first
Airborne_Again wrote:
Whether ATC in Norway will notice or care if you only have mode C, I have no idea.
Then
But of course if Norwegian authorities don’t enforce the EU regulation in question, then it is moot.
but I don’t understand why it should have take all this time
Perhaps the title of the thread: Was Mode S really necessary?
Clearly the answer is hardly 
That, and I think you and I have a different understanding of necessary.
LeSving wrote:
but I don’t understand why it should have take all this timePerhaps the title of the thread: Was Mode S really necessary?
Clearly the answer is hardly
That, and I think you and I have a different understanding of necessary.
@LeSving, necessary for whom? Not for you and me, for sure.
For Eurocontrol & airliners? Quite likely.
arj1 wrote:
necessary for whom? Not for you and me, for sure.
That’s not obvious to me. The whole rational for mode S was issues with mode A/C which reduced the usability of secondary radar for ATC. In principle, mode S increases the capacity of the ATC system by increasing accuracy and reliability of secondary radar. That should benefit GA as well when we are operating as controlled flights in areas where a large number of aircraft is operating. (And it doesn’t matter that typical GA levels are essentially empty of enroute traffic as a radar antenna will see traffic at all levels.)
In hindsight, it would of course have been better to go straight to ADS-B which offers benefits to GA such as very cheap and accurate traffic information using ADS-B in. But no one could know that GPS would exist (or be sure that it would be available, reliable and accurate enough) when mode S was developed.
The whole rational for mode S was issues with mode A/C which reduced the usability of secondary radar for ATC.
I think rationale in this instance means excuse, because there is no evidence this was a real world limitation, one that actually affected ATC operations. What can be seen clearly though is that Mode S provided full-time mandatory tracking by tail number, and Mode C doesn’t, and UAT doesn’t.
