Ultranomad wrote:
I am not sure about the official side of things, but having carefully studied some existing RNAV (GNSS) approaches, I’d say thay can be designed to fit the existing data if necessary.
I think so too. With every new Jeppesen revision, a few more airports around here get additional RNP approach plates, more or less unnoticed. Most of them not LPV yet but LNAV only for the time, and I strongly doubt that all these new procedures (which are, as Ultranomad points out, just GPS-based versions of existing non-precision approaches) are actually test-flown and calibrated.
Peter wrote:
These ops run on the cheap, single pilot (a medical every 6 months)…
I was “copilot” on a trislander once (by pure luck). Pilot definitely had less (/no) time to chat compared to “Big metal” jumpseats. Fun flight though.
Bathman wrote:
Are you sure that the case? (Again hanger chat – zero evidence) but in the I’ve been told that the “full works” has to be done as satellite based approaches are different from terrestrial ones.
I am not sure about the official side of things, but having carefully studied some existing RNAV (GNSS) approaches, I’d say thay can be designed to fit the existing data if necessary. The result may not be optimal, but it will still be more useful than a corresponding NDB approach. Also, I suspect the need for calibration flights will greatly decrease with switching to a GNSS approach (but that’s for @Dave_Phillips to give an authoritative answer)
I also have heard that some new GNSS approaches are being planned, including for some GA fields which currently do not have a published approach. Timing seems to be around 2018.
Ultranomad wrote:
If an instrument approach is already in place, it means the terrain has been surveyed and obstacle protection assured, so developing a GNSS approach becomes a no-brainer in most cases. I’d say the new approach will typically cost less to develop than one year’s upkeep of an NDB.
Are you sure that the case? (Again hanger chat – zero evidence) but in the I’ve been told that the “full works” has to be done as satellite based approaches are different from terrestrial ones.
is proposing that all instrument runways which today have a non-precision instrument approach should get an APV (typically a GPS approach) before end January 2020.
If they fund it, it will happen 
I doubt they will, especially in post-brexit UK
There is not much cost involved. As I read it, only runways are affected which already have instrument approaches
It is still c. 30k per IAP even if there is an existing IAP. We had a thread here years ago about a Slovakian company doing it for a bit less. I have no idea why another survey is needed… maybe the protected area is a different shape? An NDB approach needs way more area, especially if authorised without DME. With a 30 degree bearing error (typical at coastal locations) you could be miles off the centreline at say 5nm…
out of all the instrument approaches that NDB approaches were the cheapest to maintain. Hence their longevity.
I think a service contract on an NDB is c. 5k-10k a year, and there may be an annual flight test. David Philips will know more.
One problem is that you need an IAP for most AOC ops involving paying passengers, yet in the UK many of these have been flown in shagged old heaps which for many years didn’t have GPS or even an autopilot. Like the Channel Islands ops. But they had an ADF, so an NDB was the best way to legalise the whole dodgy proposition. These ops run on the cheap, single pilot (a medical every 6 months)…
Also state financed navaid maintenance distorts the cost picture and keeps the old navaids serviced for ever (Croatia e.g. – LDLO, LDSB…).
The question is also the bureaucracy – our club is looking to install night lighting and, as a second step, apply for an IFR approach but the BR have told us not to delay but to apply now for an RNAV so that it will be approved by 2020 ;-)
Bathman wrote:
What about cost for all of this?
There is not much cost involved. As I read it, only runways are affected which already have instrument approaches. So all the difficult and expensive stuff (obstacle survey, airspaces, approach lights, PAPI, …) are already there. It is only about defining an additional PBN approach (e.g. GPS based LPV approach) on paper and updating the databases accordingly.
If an instrument approach is already in place, it means the terrain has been surveyed and obstacle protection assured, so developing a GNSS approach becomes a no-brainer in most cases. I’d say the new approach will typically cost less to develop than one year’s upkeep of an NDB.
What about cost for all of this? In the UK airfields are private enterprises and so the installation of a new approach will cost the airfield money and that might be money that they will not recuperate. Even if it offers a lower minima.
I was of the impression (purely hanger talk – zero evidence) that out of all the instrument approaches that NDB approaches were the cheapest to maintain. Hence their longevity.
