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GPS Overlay Computer Fixes

Hi there,

Any suggestions on how I should relate computer fixes on a GNS Overlay with a Jepp chart? The overlay has fixes i.e. F029 or D102K that are not labelled on the approach plate. Broad tips on the topic appreciated!

DMEarc

You are supposed to use the RNAV (GNSS) approach plate, which contains all of the necessary fixes. Here is an example:

LKBU (near Prague), Czech Republic

Ultranomad, that isn’t what he means. When you load an ILS/LOC/VOR or NDB approach on a GPS you get waypoint names that often are not on the Jepp chart.

This might help: Outdated but a start

EGTK Oxford

The naming convention is defined in ARINC 424

I’ve never managed to find the full ARINC 424 spec online. Would love to take a look…

EGEO

The short answer then appears to be that Jepp don’t publish the overlay charts

They publish the old navaid-based approach charts, which obviously have no GPS waypoints, though any half decent GPS database will contain the navaid names, verbatim.

They publish GPS approach charts, whose waypoints will match the GPS database waypoint names.

But, for Europe, they don’t publish “overlay” charts. I have never seen one in the Jeppview database.

Personally, I never fly “overlays” because on the KLN94 they are crap, with large chunks missing. DME arcs are always missing, etc. So I fly navaid-based procedures using the GPS OBS mode, or with the VOR receiver if intercepting a VOR radial on a SID and then flying DCT to a navaid i.e. it isn’t all that critical.

Administrator
Shoreham EGKA, United Kingdom

Personally, I never fly “overlays” because on the KLN94 they are crap

They are a little better on the GTN – good enough that they can be flown, but very careful monitoring is needed. The biggest issue is that it is difficult to distinguish between procedures for different aircraft categories. IAFs (transitions in Garmin-speak) that route via DME-arcs are entirely missing (well, I haven’t found one yet – I assume they would rely on an RF leg).

EGEO

The PPL/IR Europe RNAV Training Manual has an explanation of these waypoint names: http://www.pplir.org/using-the-rating/360-rnav-training-manual-v18

ESKC (Uppsala/Sundbro), Sweden

Quote " Jepps don’t publish overlay charts"

Two days back flying out of Berlin Schonefeld I departed on the BELID 6X SID, this is depicted for conventional navigation on chart 20-3 and for RNAV on chart 20-3E. The 20-3E chart states that it is an " overlay of chart 20-3 ".

I’m guessing that the perceived ideas of what JEPPS do and don’t do is due to what is published and approved by national authorities.

20-3E RNAV SID for EDDB:

Yes – it is called “OVERLAY”. So you are right, A&C.

But this is the first one I have ever seen. Every IFR GPS contains overlays for navaid approaches (even the Shoreham 02 and 20 NDB ones are in my KLN94, alongside the 02 and 20 RNAV ones) but I have never before today seen an “overlay” chart in Jeppview for any of these.

So I wonder why Jepp have decided to publish the “overlay” for this one?

99.9% of traffic to EDDB is going to be big jets and they will have the overlay in their FMS. And the overlay for just about every other navaid IAP of relevant to them, too, yet most of those will not be in Jeppview either.

There is nothing obviously special about the RNAV SID above. Even the crappy old KLN94 has the DB077, DB252, etc waypoints in its database, despite not being LoA approved for RNAV (how do I know this? )

Administrator
Shoreham EGKA, United Kingdom

Not all step down fixes are included in the Jeppesen GPS database. If they are on an ILS or LOC approach, if there is a MAP before the threshold for the localizer option, the waypoint won’t be in the database as well.

KUZA, United States
12 Posts
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