Interpreting Map Filters in Charts

Charts General
1

In “map filters” one can turn on and off “Controlled Airspaces” and “VFR Airspaces.”

One can also turn off and on “IFR Airports” and “VFR Airports.”

Unfortunately, I have no idea what these terms mean. That’s not because I am an utter air-navigation novice. To the contrary, I have spent a fair amount of time studying the following:

Class G airspace.
Glass E airspace.
Class D airspace.
Class C airspace.
Class B airspace and, yes, of course:
Class A airspace (which most of my simulated, weak single-engine planes cannot even reach).

Based merely upon my current understanding (after a fair amount of study), I would consider all but one of those “controlled” airspace in the U.S.

Likewise, I currently would decide what was a “VFR airport” based on the situational weather at the time I was deciding.

But I suspect MY opinions (to which I make no claim to perfection or even expertise) do not coincide with Navigraph’s “filter” designations.

Can you help me understand what YOU (Navigraph) mean by VFR airports as opposed to IFR airports?

And what YOU (Navigraph) mean by “controlled” airspace?

How do these terms relate (in Navigraph’s view) to G, E, D, C, B and E airspace?

Perhaps most important of all – do YOUR chart “filters” change what those terms mean based on latest known weather / cloud base / visibility at the time the chart is called up?

In other words, when you say “IFR airports” do YOU mean that which cannot currently be landed or departed without an instrument rating when the CURRENT WEATHER (so that the filter shows different airports at different days / times?)

That would be pretty cool, if so – but it might be too cool to expect, frankly.

In any event, does the possibility of an SVRF clearance get taken into account in such determinations?

I like the product. And I’d like to understand still more. So I hope I receive a helpful response!

I’m not giving or attempting to receive any advice for real-world flying, by the way. I’m merely seeking to understand Navigraph’s own terminology for simulation purposes, using, in particular, Microsoft’s wonderful flight simulator 2020.

2

Hi,

Basically, these designations stem from the ARINC 424 specification through which our navdata is delivered from Jeppesen and interpreted. There is an entire record type named controlled airspaces and it is precisely these airspaces that are toggled with the said switch in our apps.

IFR airports are those thare are specificed to have IFR capability in the same ARINC 424 specification. VFR airports are those that are not coded to have this capability. It has nothing to do with weather an these designations remain static and in accordance with the Jeppesen navdata. For weather, check the METAR tab in the Charts app which will provide the current conditions and whether they are suitable for VFR or other rules.

Kind regards,

Stephen

3

Thanks for taking the time to answer.

I googled ARINC 424, but to be honest it added little that was helpful to my practical understanding.

I’m still not at all sure what makes an airport “IFR capable” – after all, almost all airports seem to be served by radio (Unicom or Multicom), and I’m not sure what more would be needed to decide that an AIRPORT (as opposed to a plane or a pilot) would need to be “IFR capable.” Does this refer to “towered” airports? That would make some sense, I guess, although it’s not my current understanding that an un-towered airport never appears in an IFR flight plan.

Furthermore, I’m still wondering what the filter means by “uncontrolled airspace” if it is unrelated to the traditional alphabet airspace designations I mentioned. And if it is, then I would expect “uncontrolled” airspace to mostly underlie OTHER airspace that sits on top of it (vertically). And the Charts, given their two-dimensional nature, don’t seem ideal to display such mostly vertical distinctions, or turn them off and on.

I don’t doubt what you say, but is there any way I can gain a more practical (i.e., useful for flight planning) understanding and meaning behind Jeppesen’s method for formatting things, if that’s what the filters turn upon?

It would be nice, by way of contrast, if the Chart filters could turn off or on B-airspace, or D-airspace, and so forth – since it is these kind of airspace designations that seem most practical for flight planning.

Is there any current plan or thought to adding more variety to the “filtering” functionality down the road? Especially for VFR flight, I think that might really help.

In the meantime, I’ll play with the filters and see what appears and doesn’t appear when I click them, and see if I can somehow generalize in a way that makes flight planning easier.

Again, thanks for your response.

4

Update: since my original posting, I have been tinkering with the Chart Filters, turning them off and on one-by-one. I cannot draw any firm and certain conclusions, because the area covered by Navigraph Charts is so very large and I obviously cannot look at that entire area in detail (without devoting the rest of my life to the task). So what I notice might have exceptions that I haven’t yet found, for all I know.

But I have indeed noticed, preliminarily, some interesting regularities that I suspect might be (but still might not be) true. (To the extent they turn out to be incorrect, or simply to be boring “old news” for more experienced users, I apologize for wasting your reading time.)

For example, when I turned OFF the “VFR airports” it seemed to me that green-colored airports vanished, leaving only blue-colored airports.

Likewise, when I turned OFF the “IFR airports” it seemed to me that blue-colored airports vanished, leaving only green-colored airports.

I am not certain of the significance of those colors – but I haven’t yet found any “green” airports with charts, or any “blue” airports without them. If that regularity holds, then the filters for “VFR” and “IFR” airports would have a new usefulness for me.

Another possible regularity that I notice preliminarily: when I turn on “VFR airspaces” and turn off all other airspaces, all I have found to remain visible so far in the USA are “class E” airspaces (although perhaps class G remain unshown, for practical reasons?). However, these “class E” spaces do not seem always to be confined to the vicinity of a particular “type” of airport.

Interestingly, in England (the only part of Europe I looked at), the “VFR airspaces” that remained when I turned off all the other airspaces (at least those I looked at, and I didn’t check them all) did not seem to be labeled class E. They had other labels, however – and it made me suspect that flying in Europe might in some ways be rather different from flying in the USA, at least as to some terminology (which doesn’t seem unlikely).

If anybody has any observations or insights (or corrections) that bear upon any of this, I would find them interesting to read.

And, let me say again that I’m not giving or attempting to receive any advice for real-world flying, and obviously don’t purport to be an expert or even unusually knowlegable. I’m merely seeking to understand Navigraph’s own terminology and color-coding for simulation purposes, using, in particular, Microsoft’s delightful flight simulator 2020.

5

Here is a great PDF Resources from Navigraph explaining what the symbols mean and the difference between “Blue” and “Green” Aerodromes (Or what you in the US call Airports; I’m from Canada)

6

PatzerDeluxe said: “In other words, when you say “IFR airports” do YOU mean that which cannot currently be landed or departed without an instrument rating when the CURRENT WEATHER (so that the filter shows different airports at different days / times?)”

Simply put, my understanding is that an IFR airport is one that has some kind of published instrument approach, and conversely, a VFR airport is one that does not have a published instrument approach. The designation has nothing to do with what the actually weather happens to be at some particular time.
Al