Jacko wrote:
I wonder what, precisely, are the risks of continuing to fly UK RNAV approaches to LPV minima after termination of these working agreements?
If the EGNOS/GPS system temporarily doesn’t provide the level of service required for LPV, it won’t necessarily be NOTAMed for that airport; that’s one of the (the only?) things the working agreement does in practice: establish a communication channel and procedures for that kind of NOTAM to be published.
Does it have an actual safety impact? Seen narrowly, no. I believe that the PFD or navigator will annunciate the loss of integrity anyway. Seen broadly, you’ll have the surprise when trying to do the approach instead of having planned a different approach, or another destination, before takeoff. So some safety impact.
Is there any LPV procedure in the UK for which the navigator won’t provide a +V “glideslope” vertical guidance?
And – apart from the way the published minima is required to be interpreted, legally – is there any difference in safety between flying
given that the airport will have been surveyed for obstacle clearance to LPV requirements ?
Since I can’t see the UK playing hardball with the other side and pulling the power supply to the three EGNOS monitoring stations, the chances of actual EGNOS integrity loss are just the same as they always were.
The only real risk I see is with Jepp removing the LPV procedures from their databases.
I am confident that even if I had LPV, from Day 1, I would not have yet seen a single instance of needing to fly it in the UK. Every airport which I have flown to in “OVC002” wx has had, and continues to have, an ILS.
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!
Setting aside the question as to how anyone could prove beyond reasonable doubt and in the absence of such an idiotic admission of “guilt” at what height aircrew saw (or thought they saw) approach lights, what exactly is the alleged offence? SERA 3101 (An aircraft shall not be operated in a negligent or reckless manner so as to endanger life or property of others)?
There was a time when it was an offence under the ANO recklessly or negligently to endanger one’s own aircraft, but no longer. Even then, the CAA’s success rate in reckless endangerment prosecutions was rather dismal. Having wasted a ton of money trying and failing to prove reckless endangerment in the Ullswater hydroplaning case, I doubt if there’s a huge appetite to flush more of the CAA’s budget down the same kazi.
Jacko wrote:
SERA 3101 (An aircraft shall not be operated in a negligent or reckless manner so as to endanger life or property of others)?Even then, the CAA’s success rate in reckless endangerment prosecutions was rather dismal.
Jacko,
I’m more concerned about the insurance and the lack of 3D approaches (don’t have enough knowledge to assess the BaroVNAV applicability).
Although, as I pointed out before, with UK CAA so far the lack of any RNAV approaches at small airfields is overwhelming.
I hope with what is now NPA 2020-02 we’ll get more leeway (looks like circling approaches are going to be allowed at non-instrument runways with no published IAPs).
And I think the LPV approaches will disappear from the databases in a couple of months time, although I read somewhere that there is an ongoing conversation between NATS/CAA and EASA re: EGNOS agreement. And I agree with Peter on ILS/LPV argument – at those places where LPV is available now, ILS is present as well. I think smaller regional airports are going to affected more – it was their backup option for a 3D approach, which is going.
Time will tell.
LPV is available to a number of remote airports in Scotland (Barra for example) that have no alternate instrument approach, so the loss of LPV will have a definite impact on bad weather capability.
arj1 wrote:
Plus there would be no LPV procedure in the DB!
There are no LPV procedures in the DB today either — there are RNP procedures. The only difference between LPV, LNAV/VNAV and LNAV are the minima and they are not in the DB. So unless there is an RNP procedure with LPV minima but without LNAV minima (unlikely) they will all be in the DB. Another question, of course, is if the UK CAA will request that Jeppesen disables the glideslope.
The main user case of having RNP in UK small airfields is to avoid having to call for VFR overhead joins 
ignoring this aspect, we can already fly IFR on GPS to any non-controlled GA airfields although common sense would restrict to only those we are familiar with, the secondary benefit of published RNPs is to fly on GPS to other airfields rather than just “coming back at home IFR in bad weather” 
From LNAV to LPV the extra operational benefit (reduction about -100ft agl ceiling & -500m visbility/rvr) is rather very minimal for the typical GA flyers, I personally would be on ILS runways on those days (not because 200MDH but rather for that +2km runway lenght) and for those with limited currency venturing in visibility less than 2km is considered “reckless” anyway
Practically, this is only relevant for controlled airfield but in these just ask ATC for “RNP24” and make your mind about it depneding on your equipement and your flight planning !
Looking at the phyiscs of Category “0A” aircrafts (like the ones Jacko flies with sub 40KCAS stall speeds), the LPV→LNAV minimas could be seen as rather very restrictive on “long 500m runway” but how many “0A aircrafts” are LPV equipped?
Airborne_Again wrote:
arj1 wrote: Plus there would be no LPV procedure in the DB!There are no LPV procedures in the DB today either — there are RNP procedures. The only difference between LPV, LNAV/VNAV and LNAV are the minima and they are not in the DB. So unless there is an RNP procedure with LPV minima but without LNAV minima (unlikely) they will all be in the DB. Another question, of course, is if the UK CAA will request that Jeppesen disables the glideslope.
Yes, all right. They are just RNP. :)
But you’ve actually pointed out yourself about the LPV glideslope. All those things in the SBAS data block and the EGNOS channel.
Airborne_Again wrote:
There are no LPV procedures in the DB today either — there are RNP procedures. The only difference between LPV, LNAV/VNAV and LNAV are the minima and they are not in the DB. So unless there is an RNP procedure with LPV minima but without LNAV minima (unlikely) they will all be in the DB. Another question, of course, is if the UK CAA will request that Jeppesen disables the glideslope.
That is not my understanding, regarding what is in the database. In order for LP or LPV minimums to be available in the database, a FAS (Final Approach Segment) block is required. This defines the precise location of the lateral path for the SBAS based procedure. It includes the runway number and sets the minimum lateral and vertical alarm limits. It even contains a CRC check field created by the authority that codes the procedure. That needs to be confirmed by the navigator and the the data in the FAS block is used to construct the lateral and vertical paths. As far as the minimums that should be able to be flown, it all depends on the annunciation of the service level by the SBAS navigator. If LPV is annunicated, in the US, we may fly to the LPV DA or LNAV/VNAV DA or the LNAV minimums. If LNaV/VNAV is annunciated, we may fly to the LNAV/VNAV or LNAV minimums. If LNAV or LNAV+V is annunciated, we may fly to the LNAV MDA. All downgrades are to LNAV without +V. We also have the LP or LP+V as a possible annunciations. They allow descent to the LP or LNAV minimums. If the procedure is coded with LPV, LNAV/VNAV and LNAV minima, only LPV or LNAV will be annunciated. To get LNAV/VNAV, the procedure would have to be coded with LNAV/VNAV as the highest service available on the procedure. The FAS data block is only required for LPV or LP procedures and without it, only LNAV/VNAV or LNAV minimums can be coded.
I have included a screenshot of the FAS data block for my airport that has an LPV 200. You can see what data is used to define the LPV path.
Precisely; the concern here is that Jepp will remove the FAS data block from the database.
However, AIUI, this is not used for the +V functionality. But… Jepp could remove the +V also, although as posted earlier by NCyankee the +V does not require SBAS (with the latest boxes) so this is less likely.
