Airspace, Communications & Other Such Things

by Harold Green
Published in Midwest Flyer – June/July 2019 issue

It seems that airspace communications with air traffic control (ATC) remain a mystery to some folks. Let’s take a look at what is involved. We’ll take it by airspace type. However, please note that this discussion is just an overview and cannot address all the regulatory details in the limited space herein. This discussion is intended to merely review, or perhaps for some, introduce the subject.

There are some common-sense rules that apply to all radio communications. First, listen to what is going on or being said before you transmit. This will give you a good sense of what is happening. You will find out how many and what type of aircraft are communicating with the facility to whom you are going to speak and generally how busy the facility is. It will also give you a sense of when you can communicate without disrupting things.

When you report in, do so concisely without embellishing anything, and tell the controllers what type of airplane you are flying and your position. Your aircraft type should include more than Cessna or Piper, etc. Most manufacturers offer airplanes with a wide range of performance, and not only the controllers, but also other pilots would like to know about how fast your plane is so they can plan accordingly. A Cessna 210 is a great deal faster than a Cessna 152, and a Piper Malibu is much faster than a Tomahawk. Remember, since you are flying an airplane, your location includes your altitude.

It doesn’t matter what airspace you are dealing with…you should always attempt to listen and then report when you are several minutes away from the boundary of the airspace. (NOTE: Minutes, not miles, because you may be doing 3 miles per minute at 180 knots, or maybe 1 1/2 miles per minute at 90 knots, so distance is not as important as time.)

It is necessary to give yourself and the controllers time to react. Besides, when entering a control zone, you may be told to standby, and unless your call sign is used, you may NOT enter their airspace, so you might find yourself circling. Therefore, it is best to allow sufficient time for everyone to react. As an added aid, take a look at your sectional to see if there are little banner symbols on it. These symbols define points for which the location is defined on radar or is otherwise specified and known to controllers.

The definition of airspace classification is assumed to be familiar to all. If not, a review of the Aeronautical Information Manual (AIM) is in order.

For our purposes, we will divide the airspace into two types: general airspace and control zones. General airspace is Class G, E and A. This is airspace which has no or few specific geographic boundaries. Control Zones are Class B, C and D. These areas have specific geographic boundaries depicted on sectional charts. This discussion will NOT address special use airspace.

General Airspace Classes

First, we will take on “general airspace” classes. There is no need to discuss Class A airspace (AIM 3-2-2) here because operation above 18,000 feet is mandated to be Instrument Flight Rules (IFR) and, in any event, all communications are with Air Route Traffic Control Centers (ARTCC) and subject to the same rules as Class E airspace.

Class G airspace is the least complex. The FAA defines Class G as NOT being controlled airspace (AIM 3-3-1). There are no formal requirements for communication in Class G airspace. However, there is a common sense requirement to communicate with traffic at pilot-controlled airports.

Class E airspace (AIM 3-2-6) is where we spend the majority of our time flying. There is no regulatory requirement to talk with anyone while flying in Class E unless you are IFR. However, Class E controllers operating out of Air Route Traffic Control Centers are the fine folks who provide flight following services to VFR pilots on a workload permitting basis, so most of us will talk to them at least occasionally while flying cross country. The only thing that is required is to identify yourself, define your location, and if you are not squawking VFR 1200 on your transponder because departure control gave you a different squawk, tell them what you are squawking. It is also useful to tell controllers your destination. Typical: “Chicago Center, Piper Warrior November 54321, 15 north of Timbuktu at four thousand five hundred (4,500). VFR to Hindustan. Squawking 4577. Requesting flight following.” (I know, the book says you should first establish contact and if they are busy, that is a good idea. But if they are not busy, this gets the job done quicker with less fuss.) The squawk 4577 assumes you have just left departure control and they told you to squawk 4577.

Control Zones

Now it’s on to specific “control zones.”

The least complex control zone airspace is Class D (AIM 3-2-5).  Class D is intended to give a control tower a region of control to sequence traffic within the Class D airspace. Generally, Class D airspace extends in a 10-mile radius from the controlling facility, usually from the surface up to 2,500 feet above ground level (AGL). However, it may be modified to accommodate instrument approaches.

You will obviously need a two-way radio to enter Class D airspace, and you cannot assume that Class D facilities have radar available. Further, Class D airspace is where you will never need a transponder. Therefore, when reporting your location, it is important to be complete.

Note that you MUST report in before entering Class D airspace. Once communication is established, it is no longer necessary to use the entire identification of your aircraft. It is generally sufficient to respond using the last three or four characters. For example, in responding to the tower, it is quite acceptable to say something like “Skylane 345.” If there is another plane with a similar call sign, it is important to be precise. For example, there could be another plane with the call sign ending in 345. In this case, use your entire call sign (i.e. 32345).

The definition for establishment of communication for Class D airspace is the same as Class C. If the controller uses your call sign, you may enter even if you are told to standby. If the controller does NOT use your call sign, you may NOT enter. You should be listening to the controlling frequency at least 5 minutes out to ascertain what is happening with respect to traffic.

Around some Class D zones, you may see a series of black rings. These rings define a Terminal Radar Service Area (TRSA). These define a control zone that provides the same services as Class C areas defined in the next paragraph. The crucial difference is that TRSA services are voluntary. TRSAs are a holdover from the days before the U.S. and European airspaces were “harmonized.” You won’t find them in Europe and you won’t find Class F airspace in the U.S. So there! Initial contact goes something like this: “Timbuktu Tower, Piper Archer 4327 is 15 northwest at four thousand five hundred (4,500) with Charlie. Landing Timbuktu.” Typical Response: “Roger 4327. Wind 15 knots from 320, gusting 35. Plan on Runway 32. We have one on downwind for 32. Report left base for 32.”

Then we come to Class C airspace (AIM 3-2-4), which generally extends from the surface to 4,000 feet AGL, with a 5-mile circle centered on the airport, and then another ring going out 10 miles from the center, from 1,200 to 4,000 feet AGL. Note here that we get into equipment requirements. Of course, you need a two-way radio as in Class D, but now you need a transponder as well. The initial contact is the same as in Class D. Also, as in Class D, if the controller responds with your call sign, you are allowed to enter Class C, but if not, you must remain outside Class C. Example, “Piper 2345, standby,” allows you to enter Class C, but if the response is “Aircraft calling Timbuktu, standby,” you may not.   Communications from the controller in Class C will be more detailed than with Class D because Class C controllers all have radar. In this case, it is necessary to repeat instructions from the controller, particularly altitude and headings. Their manual demands they hear you repeat these numbers. Eventually you will be told what runway to use (i.e. Rwy 32), and usually what part of the pattern to enter (i.e. left base), and then told to contact the tower on a specified frequency, such as 118.5. You then respond with “2345 going to tower on 118.5.” You make the next contact by saying, “Timbuktu tower, Piper 2345 on left base for 32.” Tower will respond with further instructions and you are home free!

Last to be considered is Class B airspace (AIM3-2-3). The “B” in Class B airspace stands for the busiest. All of the previous comments apply, BUT in Class B, you MAY NOT enter until you hear the words “Cleared to enter Class Bravo.” The top of Class B generally goes up to 10,000 feet above the surface. Usually, there are multiple rings of various lower levels surrounding the airport. In addition, there are a few things different you should be aware of.

First, if you are a student pilot, you need a specific endorsement from an instructor in order to operate in each Class B area you will be operating in. Second, there is a 30-mile ring surrounding the Class B airport that is known as the Mode C veil. Inside this ring, you MUST have an altitude encoding transponder. Third, when operating in Class B airspace, cloud clearance requirements are “clear of clouds,” since you are always in radar contact and in communication with the controllers. Most Class B areas have defined VFR corridors, which can be used to operate near the Class B area. These are depicted on the appropriate Terminal Area Chart (TAC). VFR services will be provided on a workload-permitting basis. Otherwise, communications are the same as for Class C airspace.

In short, communications are the same with all; it’s the services provided that differ. It is best to consider these areas as providing service, rather than restrictions placed on the pilot. After all, as taxpayers and purchasers of aviation fuel, we pay the controllers’ salaries, and they, in the final analysis, work for us and generally do a good job on our behalf.   

EDITOR’S NOTE: Harold Green is an Instrument and Multi-Engine Instrument Instructor (CFII, MEII) at Morey Airplane Company in Middleton, Wisconsin (C29). A flight instructor since 1976, Green was named “Flight Instructor of the Year” by the Federal Aviation Administration in 2011 and is a recipient of the “Wright Brothers Master Pilot Award.” Questions, comments and suggestions for future topics are welcomed via email at, or by telephone at 608-836-1711 (

DISCLAIMER: The information contained in this column is the expressed opinion of the author only, and readers are advised to seek the advice of their personal flight instructor and others, and refer to the Federal Aviation Regulations, FAA Aeronautical Information Manual and instructional materials before attempting any procedures discussed herein.

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