Looking intently over the instrument panel directly in front of us, my seven year old son and I went back and forth. “Is that it?” He called, pointing over one way. “No, I don’t think so,” I replied. “There! Those lights – is that it!?” He called back. “Those look like runway lights to me. Let’s start down and line up.” My son, Reid, and I were on the home flight simulator. As he has practiced and gained more ability, what used to be slamming the throttle to full power and yanking back on the stick to take off and do crazy maneuvers has morphed into a much more skilled demonstration of what he’s learned. The mission today was to take off from one airport and land at another. Pulling out our map and plotter, we chose the short hop between Gwinnett (KLZU) and Peachtree Dekalb (KPDK). Drawing a line between the two airports, we reviewed how to measure both the miles between them and the course direction. I asked him if he remembered the compass directions. Pointing to each cardinal direction clockwise from the top, he replied “Never – Eat – Soggy – Waffles.” Today’s flight headed waffles (west) so we took off and pointed that way with the compass. In addition to knowing which way to fly, we use “pilotage” to compare what we see outside to what is on our map. Today, let’s look around the map we used for our flight to learn some of the basics of the aviation map, called a sectional chart.
Airports that have a control tower are shown as a blue symbol, like Gwinnett, where we took off. The magenta ones don’t have a control tower. Instead, they are pilot controlled, meaning pilots announce their position to other pilots on the radio instead of having a controller watch it all. Next to each airport symbol is an information block of text about the airport. Let’s read through the block for Gwinnett:
The airport identifier is LZU. We can contact the tower on 124.1. The star means that the tower operates part time, so the little blue “C” means that the tower frequency turns into the Common Traffic Advisory Frequency when the tower is closed. We get our weather, or Automatic Terminal Information Service (ATIS), on 132.275. On the last line, the airport elevation is 1062 feet. The *L means that the runways are lighted (the L), but with limitations (the asterisk). This asterisk usually means that the pilot can control the runway lights by keying the microphone button on the CTAF frequency. The 60 means that the longest runway is 6000 feet long (it is always shown in hundreds). Finally, 123.05 is the Unicom Frequency.
At the top of the airport symbol, the open star means that a rotating light beacon is turned on from sunset to sunrise. The ticks on the left, right and bottom indicate fuel is available.
The triangles with a dot in them (much like the A’s in the Clayviation logo) are obstruction symbols. These are usually towers and stacks. The smaller triangles are for obstructions over 200ft high. If they are over 1000ft high, they have the taller symbol. If they have little lightning bolts coming from the top, this doesn’t mean they shoot lightning (or do they?) – this just means that they have high intensity lights. Finally, look at the two numbers by the obstruction. The one in parenthesis is how tall the obstruction is. The number without parenthesis is the height of the top of the obstruction in relation to mean sea level. Basically, it’s what your altimeter would read.
3. Airspace Rings
Knowing what kind of airspace you are in is important for two main reasons: Who you need to be talking to and what sort of visibility and cloud clearance you need to have to fly. While airspace is a whole blog to itself, let’s just cover some basics. The airspace categories are A, B, C, D, E, and G. They generally move from more restrictive (A) to the least restrictive (G). For the purposes of today’s flight, let’s break down how to find each one:
–Class A is only above 18,000 feet so you won’t find it charted on the map.
–Class B is around the busiest airports like Atlanta and are shown with light blue bands. Looking near Gwinnett, you can see the blue band of Atlanta’s Class B pass just to the west of the airport.
–Class C has a solid magenta band.
–Class D (like around Gwinnett) has a dashed blue band.
–Class G airspace is usually from the ground 1200ft (mountainous areas out west have some special cases).
-You can think of Class E airspace as “filling in everywhere else.” You’ll notice lots of thick magenta rings with a hard edge that fades to a solid edge. There is one around around Gwinnett. This is a little bowl of airspace that dips that class E at 1200ft down to 700ft above the ground in that area. An area with a dashed magenta band means that the Class E is brought all the way down to the surface.
As a navigation aid, Very High Frequency Omni Directional Radio Ranges are usually easier to navigate than they are to say. Just stick with calling it a “VOR.” From the station (a small building with a white cone on the top), radio signals are sent out in every direction, almost like spokes on a bike tire. A pilot can basically hop on any of the radials using an instrument in the airplane and follow the radial to or away from the station. You’ll find the VOR at the center of the large compass ring on the map. Each VOR has an information box that shows its frequency and identifier. Look for the box to say either VOR, VORTAC, or VOR DME (all variations on the VOR, but works the same to us). Once the frequency is tuned in the airplane, you can turn it up to listen to the Morse code. This is how you make sure you are receiving the right signal.
Because of the popularity of navigating between VOR stations, the light blue lines are airways between two stations that show you the course direction already measured for you.
The different terrain elevations and features are shown as varying shades of color ranging from greens (lower elevations) through tans up to browns (higher elevations). Contour lines show lines of equal elevation. You’ll notice the very large blue numbers (A five-nine in the picture above). This is the Maximum Elevation Figure. In each quadrangle (black box of latitude and longitude) of the map, this number is the highest elevation or obstruction in that sector. It is in hundreds of feet, so in this case, 5,900 feet is the highest thing in that region.
7. Roads & Railroads
Because they are such good visual aids from the air, major roads and railroads are shown along with the towns they connect.
8. Water Features
Lakes, rivers and oceans are shown in blue. Out here where I live in “Georgia’s Lake Country,” they make for easy visual checkpoints.
9. City Lights
All of the yellow shown around more dense areas are basically what the city lights will look like from above at night. While primarily useful for night flight, it also gives an indication of denser buildings and population, which is useful for day flight as well.
10. Power Lines
You might be wondering how you could see or navigate tiny wires. Actually, it isn’t as much the wires as much as the path cut through the trees that is easy to spot from the air. Sure, you can see the various poles and structures that hold the wires, but the path cut through the woods makes them easy to spot.
Map Your Course
These items are certainly not everything that you will find on a map, but whether you are a student pilot or even a passenger on a flight, knowing some of these basics will help a complicated mess of data turn into meaningful information. While you can pick up a Sectional Chart at most airports, you can also order them online here. You can get them either one by one or with a chart subscription. With a subscription, one is mailed to you each time a new one is published (usually every 6 months). When I was in my initial training, my primary source of navigating was comparing my map to what I saw outside. Now my iPad shows the same map, but the GPS drops my position right on the screen. It kinda feels like cheating. But even with the convenience of technology I always fly with a paper backup. You just can’t beat the battery life and reliability of a paper chart.
Subscribe to our mailing list for great content each week! Follow us at facebook.com/FlyClayviation and Twitter/Instagram @clayviation