I gather that the UK monitoring stations have been delegated to NATS which prob99 means they are unwilling to pay for them, since practically all route charge paying traffic uses ILS and they are getting almost zero money from those who might use LPV 
arj1 wrote:
+V – requires an extra ADC, attached to GTN/IFD. That is not used that often…
Yes, you can add +V approach but not many GA aircraft will use it.
+v is the annunciation on a WAAS GPS indicating advisory vertical guidance. It does not depend on any ADC data. It is advisory information only but otherwise works like a vertically guided procedure in that there will be a vertical CDI indication. It is only intended to be used to conduct a NPA descent from the FAF to the MDA(H) using the CDFA technique of a stabilized descent to the MDA(H). One can do this same descent by other methods such as Dive and Drive where you level off at the MDA(H), so all it is doing is providing a GP along the final approach course such that if you break out on final approach before reaching minimums, you can continue a stabilized descent using visual means below the MDA(H) to the runway. So even if it is not accurate as a precise glide path, there is no additional risk involved. The +V GP is not evaluated as a slope other than the standard TERPS/PANS-OPS based level OCS.
Maybe somebody forgot the UK hosts three of the monitoring stations – see page 2 which it should now turn off, and see if anybody in the north of Europe notices
Are you sure these stations aren’t just located in the UK but payd for by the EGNOS Operator (= the EU citizens)? In that case, UK would have little to say over switching stuff off.
Another interesting angle on this is that to receive “certified” ADS-B IN, or to emit “certified” (SIL=3) ADS-B OUT, you need a WAAS/EGNOS GPS source.
So if the signal was somehow denied to a given area (I doubt there is a provision for this, but technically you could emit a SBAS signal which has “valid coordinates” attached to it, and the receivers, to be certified, would need to check these and deny coverage if outside) that would blow a hole in a lot of policies.
Are you sure these stations aren’t just located in the UK but payd for by the EGNOS Operator (= the EU citizens)? In that case, UK would have little to say over switching stuff off.
If the EU continued to pay for them in full, that would be the case.
Does the UK remain a member of the European Space Agency?
Does the UK remain a member of the European Space Agency?
AFAIK, yes, because ESA has nothing to do with the EU.
Peter wrote:
Another interesting angle on this is that to receive “certified” ADS-B IN, or to emit “certified” (SIL=3) ADS-B OUT, you need a WAAS/EGNOS GPS source.
This is not a US requirement. A TSO C129 receiver may be used as long as it provides the required data elements. A TSO C145/146 receiver will provide the required data elements, regardless if it is in an SBAS environment or not. See AC 20-165B for US guidance on ADS-B Out and AC 20-172A for US guidance on ADS-B In. The difference between using a non SBAS GPS position source is what percent of the time the required integrity and accuracy parameters are met, like 95% vs almost 100% of the time. In the US, those using a non WAAS capable position source must check RAIM and availability of secondary radar for the flight using the FAA SAPT site.
The CAA is therefore content to let the avionics box select the highest integrity approach mode available, but any approach should only be flight-planned and flown to the LNAV minima.
The UK CAA says “should”, not “must”. This seems entirely consistent with long-established CAA policy which is to allow GA participants to manage their own risk where there is no corresponding risk to uninvolved third parties.
I wonder what, precisely, are the risks of continuing to fly UK RNAV approaches to LPV minima after termination of these working agreements?
How do these risks (if any) compare in severity to other risks affecting light GA in IMC?
if I fly an NDB-approach I have to respect the minima for that NDB-approach even if I know that the GPS overlay in my black box is far more accurate and would allow for far lower minima…
Why? Is this a legal requirement, or simply an attempt to err on the side of safety?
Jacko wrote:
Jacko
30-Dec-20 16:44
48 if I fly an NDB-approach I have to respect the minima for that NDB-approach even if I know that the GPS overlay in my black box is far more accurate and would allow for far lower minima…Why? Is this a legal requirement, or simply an attempt to err on the side of safety?
I think it’s a question of “gross negligence” – did you fly an IFR procedure? Yes. Did you fly it as per limitations provided (MDA)? No. Busted!
Jacko wrote:
The CAA is therefore content to let the avionics box select the highest integrity approach mode available, but any approach should only be flight-planned and flown to the LNAV minima.The UK CAA says “should”, not “must”. This seems entirely consistent with long-established CAA policy which is to allow GA participants to manage their own risk where there is no corresponding risk to uninvolved third parties.
I wonder what, precisely, are the risks of continuing to fly UK RNAV approaches to LPV minima after termination of these working agreements?
How do these risks (if any) compare in severity to other risks affecting light GA in IMC?
Yes,“should”, but the whole point of having an EWA is that you (as an aerodrome operator) know when your services could be affected by an unreliable SBAS services.
Just think for a second – someone hits a mast, because the channel you’ve used for LPV procedire have failed. And you just don’t know when it’s ok and when it is not.
Again, question of liability. Plus there would be no LPV procedure in the DB!
