Jean wrote:
When we practice ILS approaches at EBLG, 05R has two DME reference
Have you loaded the approach and what are the waypoints you got? I would expect that there is no need to “dial a direct to IHH” on something like a G1000. It should be straightforward.
Stephan_Schwab wrote:
Have you loaded the approach and what are the waypoints you got? I would expect that there is no need to “dial a direct to IHH” on something like a G1000. It should be straightforward.
On G1000 it will load the approach and auto tune if there is not a current localiser Freq active. But that won’t automatically provide a “correct” DME equivalent.
I just landed in EBAW and the ILS to 29 you need two DMEs really for the hold and even the approach (it was foggy). You need ANT and IAD.
Stephan_Schwab wrote:
Have you loaded the approach and what are the waypoints you got? I would expect that there is no need to “dial a direct to IHH” on something like a G1000. It should be straightforward.
Yes we load / activate the approach but then we get the distance to the next point in the approach, not the DME distance published on the chart.
I agree with A_and_C that certain practices in approach design used here increase the risk when you substitute with GNSS while they’re forbidden in the US hence pilots there are never exposed to the increased risk. Dundee is exactly like this, you have navaids sharing an identifier that are not co-located. The NDB is like five kilometers away. Combined with GNSS, that’s an accident waiting to happen. Well, it has happened. This is not an issue with the technology of satelite navigation, it will guide you to the accident site with great precision, those approaches simply weren’t meant to be flown this way. And the authority commented this risk won’t be mitigated as it’s not a factor when you fly it as you’re taught.
I wouldn’t hold my breath when it comes to removal of such “features”. I think we’ll sooner get a GNSS approach to every instrument runway. If only they could avoid using NDBs for missed approaches.
I believe we had this already, but I’d like to come back to that part for a moment.
You load/activate the approach, say an ILS, and from the database a number of waypoints gets added to your flight plan in the FMS. My experience so far has been that those waypoints are the same points where on the chart you are supposed to check your altitude while following the glide path. Under these circumstances I don’t see value in knowning any distance to a DME facility. Isn’t it about being at x feet at point Y and that’s it?
Isn’t the whole GPS based navigation about being at a certain point in 3D space in a sequence of several points until touchdown? As long as I follow the correct sequence, loaded from the database and verified by comparing chart and flight plan in the FMS, what can go wrong?
How would, given the points were loaded from the database and verified by comparing with the chart, the issue of multiple navaids with the same name affect me? I can see the whole lateral flight path on the screen in front of me. If it looks different than the AIP or Jepp chart, I have a false database entry. How likely is that?
I think the reason for using NDB’s for the missed approach is in case of GPS system failure ( be it aircraft system or GPS coverage ).
It is a safety built in so you are not left without any guidance if the GPS quits.
I am not sure I ever saw an explanation for why EGKA has the NDB in the missed approach while EGMD doesn’t. The only difference I can think of is that EGMD has no terrain anywhere near.
Also a large %, possibly the majority, of IFR GA has no ADF.
JasonC wrote:
I just landed in EBAW and the ILS to 29 you need two DMEs really for the hold and even the approach (it was foggy). You need ANT and IAD.
Do you have two DME units? If not, do you re-identify the Station each time you switch between the two? Or do you use my recently discredited method of identifying both wellin advance and using the DME source switch and/or remote/freq switch?
A_and_C wrote:
I think the reason for using NDB’s for the missed approach is in case of GPS system failure ( be it aircraft system or GPS coverage ).It is a safety built in so you are not left without any guidance if the GPS quits.
No it is to save time and cost in procedure design. There is no safety case for retaining an NDB in the missed approach of a GPS approach.
A_and_C wrote:
I think the reason for using NDB’s for the missed approach is in case of GPS system failure ( be it aircraft system or GPS coverage ).It is a safety built in so you are not left without any guidance if the GPS quits.
That makes no sense to me. So what do you do if the NDB or ADF fails on an NDB approach? If one can’t use the GPS for the missed approach, they have no business doing the GPS approach in the first instance. In the US, there are about 15000 approaches based on GPS and none use an NDB for the missed approach..
