Maps

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by Stu Simpson

In aviation’s low-level VFR arena pilots can choose between several different maps with which to navigate. We use maps (actually, the correct term here is chart) published by the government, by aviation groups, and even by auto clubs. Granted, not every flight you’ll make is a cross-country flight. But no matter what you fly, sooner or later, you’re going to stray from the familiar turf of your own airport’s backyard, and you’re going to need a map.

So which map is best? Which has the most detail, the best scale and will be easiest to read in a busy, possibly windy cockpit? Simple questions with a not so simple answer; it depends.

It depends, among other things, on where you want to go, how fast you’re going to get there, and what toys you have to play with (VOR, ADF, GPS, and such).

The three most common charts used in the Calgary area are the 1/500,000 VFR Navigation Chart (VNC), the 1/250,000 VFR Terminal Area Chart (VTA), and the Alberta Aviation Council’s map that has scales of both 1/500,000 and 1/1,000,000. The first two are put out by the federal government. Let’s look at the AAC‘s first.

The AAC puts out a new map every five years, the most recent one being the 1993 version. One side of the page covers the entire province in the one to a million scale. The other side, in a one to half-million scale, only covers the area south of a line through Bonneyville, and east of a line through Exshaw. Oddly enough, the Council has been one of the strongest supporters of the Banff and Jasper airports, yet those strips don’t appear on their most useful chart.

It’s clear from the outset that this map was designed purely for conventional pilots flying with electronic nav aids, which is fair, because those are the people who fill the AAC’s roster. VORs figure prominently in these maps and the compass roses that accompany each of them are large and easy to read. The symbology for the VORs is the same as on the government’s charts, but not so for the NDBs. They’re indicated as small black triangles and their identifier boxes block out all the features beneath them. The government’s identifier boxes are printed to leave the underlying features visible.

The one shining feature of the AAC’s map (and one reason why so many are sold) is that it lists dozens of farm strips that aren’t shown on the government’s maps. Each of the Council’s maps comes with a guide book giving pertinent information on each airport that the map displays, including those out-of-the-way farm strips. One can simply read the lat/long coordinates from the guide book and then transpose the location to another map.

Another feature unique to AAC maps is their display of section, township, and range lines, which can be useful in some remote areas.

But unless you’re flying an airplane with a VOR receiver or an ADF (which tunes and points to the NDBs) the AAC’s maps are almost useless as serious navigation tools. The only features that are readily visible are large bodies of water, large population centres, major highways, and electronic nav aids. Important things like towns, roads, railways, and topographical features are either excluded or printed in such light color as to be almost unreadable.

Let’s make a huge leap in scale and look at the VTAs. VFR Terminal Area Charts are printed in 1/250,000 scale and depict a relatively small area surrounding major airports and their accompanying population centres. A key notion here is congestion. Just as these areas tend to be cluttered on the ground, they’re almost as much so on paper, especially in one to half-million scale.

Ergo, the VTA, with a better scale that defeats the clutter. These maps are especially good if you’re unfamiliar with the area depicted on them. They clearly show airspace restrictions, reporting points, significant landmarks, and all the information needed to use the airports shown. The level of detail is, quite simply, wonderful.

Calgary has a VTA chart (Edmonton’s is on the reverse side) and you might just think this is the answer to your navigational nightmares. Maybe, maybe not.

You see, the large scale that makes the VTA’s so easy to read also makes them a bit cumbersome, particularly over longer distances, and especially in an open cockpit. The VTA must be folded rather largely to be of any significant use.

The problem is twofold (pun very much intended). First, folding the map to have your course showing leaves you with a |–(TRY TO BE MORE PRECISE.)–| fairly hefty chunk of paper in your cockpit. If it’s an open cockpit, that means more paper flapping in the wind, and in the worst case scenario, a hefty chunk of paper leaving your cockpit.

Secondly, the folds might hide significant nav points along either side of your course. If you’re well prepared though, you’ll have your map arranged so that the folds complement the route. But if you’re covering a significant distance, you might find yourself doing some in-flight folding.

The speed of your airplane might be a factor in deciding whether you use this map. Faster planes will eat up the distance depicted on the VTAs in very short order, and if you’re navigating from point to point, you might find yourself getting behind the flight. Obviously, with ultralights this is rarely a problem.

Which brings us to our remaining map, the 1/500,000 VNC. VNCs are the standard VFR chart and show just about anything you could ask for. All the topographic details are there, as are roads, powerlines, obstructions, and of course, airports. The detail makes for very accurate navigation, even at lower altitudes where far-off nav points might not be visible. The scale is perfect and it allows a pilot to pick his points in advance and plan ahead.

The scale also lends itself well to long distance flights at any speed. When the map is folded it’s small enough not to be a bother, yet allows plenty of distance on either side of your course line. The VNCs cover tremendous territory. The Calgary chart, for example, covers all of southern Alberta, most of southern B.C., and a fair chunk of several American states. That’s pretty good navigational value.

The main drawback, and the only one as far as I can see, is the VNC’s clutter in congested areas. Naturally, a pilot who’s familiar with a congested area will have an easier time flying there. For one who’s not familiar with the area, a VTA might be just the ticket, provided one exists for that area.

So which map is best? In my mind, the one to half-million VNC gets the nod. It combines the best of all possible features for VFR point-to-point navigation. It’s easy to read, and therefore easy to use. To be fair though, if I were planning a flight to the lower mainland of B.C., my first purchase for the trip would be the Vancouver VTA.

My next purchase would be a GPS so I wouldn’t have to deal with all those maps in the first place.

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