Peter wrote:
Anyway, pop down to Southampton EGHI and listen on 120.225, to all the airliners flying the NDB (yeah right) approach. They ask for the NDB IAP officially but the approach is coupled all the way down to the MDA.
What is wrong with that? 
Prior to doing the EASA IR skill test (converting from FAA) , I decided to get some training and was surprised that the instructor told me to load the NDB procedure, follow the CDI, and monitor the ADF. In France this is apparently perfectly acceptable, and even expected by the examiner who wants to see you use your equipment to the fullest. I later had a similar experience during my ME IR skill test.
Aviator,
Absolutely. You could look on the description “NDB XX” as a means of loading a magenta line into the GPS.
Let us remember that the bulk of overlays in USA are approved as RNAV approaches.
What is wrong with that?
I didn’t say there was anything wrong with it.
Just making the point that the bigger boys already have solutions to nonprecision approaches which give them a GS. Their MDA will probably be the published MDA – I don’t think there is a “CAT2/CAT3” equivalent.
This is not an overlay like most IFR GPSs have. That is LNAV only.
The airline business is into multi sensor navigation in a big way with the primary back up to GPS being DME/DME
AandC this applies to airways? In the approach environment the line of sight for DME/DME might not be available, especially with planned de commissioning of VOR/DME and VORTAC stations. Whether it provides LPV type accuracy for vertical navigation would be another question.
…a minor thread drift.
If a RAIM failure occurs after the FAWP, the receiver is allowed to continue operating without an annunciation for up to 5 minutes to allow completion of the approach (see receiver operating manual). If
the RAIM flag/status annunciation appears after the FAWP, the missed approach should be
executed immediately.
This is from the FAR AIM which I always find intriguing. Non WAAS GPS will not issue a RAIM failure notice and switch out of APP mode once you have passed the FAF, or FAWP in FAA speak, and you can continue with the approach in blissful ignorance that the GPS is providing lateral guidance from known last position and not from pseudo DME/DME.
While the UK has an NDB as part of most GNSS approaches I am not aware examiners delve too deeply into the innards of GPS approaches other than a RAIM prediction when setting up the approach, which technically is not required for WAAS enabled approaches.
So the big boys fly their coupled non-precision approaches with home made glideslope parameters? I find that rather hard to believe.
Shorrick_Mk2 wrote:
So the big boys fly their coupled non-precision approaches with home made glideslope parameters? I find that rather hard to believe.
Some FMS systems have such guidance programmed into them as part of the database. Certainly Proline 21 will fly a “visual” approach with lateral and vertical guidance to any runway end at a 3 degree glideslope. No use in proper IMC at a strange airport as there is no terrain clearance considered, but mighty useful at times.
I think it constructs a VNAV line from the FAF to the MAP – a bit like +V on a GPS LNAV approach.
Or is it really always 3 degrees?
My understanding is that an approach has to be loaded, even on an FMS. You load a GNSS approach from the menu, a requirement to ensure sequencing and auto slew, you would load LOC/ILS using approach pre view, either manually or from a menu, but use pre view to ensure the LOC is set correctly on the HSI. NDB and VOR would be as per your C172 procedure, just ensuring you have tuned, identified and displayed on the HSI. Am not aware of authorised DIY approaches available on FMS type equipment where you load waypoints manually, other than for visual orientation.
On an ILS the magenta CDI auto slews to the LOC display on intercept, and if the LOC fails you go around. ie it doesn’t switch back to a magenta line display.
Peter wrote:
I think it constructs a VNAV line from the FAF to the MAP – a bit like +V on a GPS LNAV approach.
Or is it really always 3 degrees?
You can alter it. It’s like a vnav descent profile
RobertL18C wrote:
Am not aware of authorised DIY approaches available on FMS type equipment where you load waypoints manually, other than for visual orientation
Neither am I . On Proline 21 you select the approach you want in the FMS and it has all the waypoints coded. This is the same for a visual approach. I suppose once you’ve loaded any approach you could go in and add or remove waypoints but that would be a daft thing to do.
