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Invisible Radar Area

Across the United States there are Airport Surveillance Radar sites that do not have boundaries shown on the sectional chart, but you nevertheless should use them ... where are they?

Across the United States there are Airport Surveillance Radar sites that do not have boundaries shown on the sectional chart, but you nevertheless should use them ... where are they?

When you fly into or out of a Class D, C, or B airspace areas you are required to communicate with ATC. Once outside these areas, VFR pilots are not required to communicate with anyone. The pilot looks at the chart and finds those chart symbols: Blue dash lines for Class D; Magenta circles for Class C; Blue circles for Class B; and Gray circles for a TRSA. If we are not inside or near these symbols then there is no controller to talk to right? Wrong!

There are Airport Surveillance Radar sights on the chart that are not shown with dashed lines or circles of any color. But they do exist and cover large areas of critical airspace. These areas are around military bases assigned to military air traffic controllers. What do military controllers have to do with you? You are not going to be landing (read: trespassing) at any military bases, but you might be surprised to know that at these military radar sights, 80% of the traffic handled by the military controllers is civilian.

Figure 1

Take a look at the Seymour Johnson Air Force Base in North Carolina (above). Seymour Johnson air traffic controllers are all Air Force controllers, but they interact with civilian traffic in the exact same ways as FAA controllers. These radar sights use VHF radio frequencies that are common to civilian air traffic control. The military radar sights are just another piece of the puzzle that makes up the overlapping radar coverage nationwide.

Another example is Fort Campbell in Kentucky (below). Ft. Campbell Army controllers handle civilian traffic including those inbound to the near-by Outlaw Airport in Clarksville, Tennessee.

Figure 2

Neither Seymour Johnson AFB, nor Ft. Campbell AAF have concentric circles around their airspace like a TRSA or Class C airspace would have. In fact, the exact boundaries are not shown on the chart at all ... but you can determine that they exist. Look back carefully at the airport information for both Seymour and Campbell. Just before the base name you will see a small solid blue circle with the letter "R" inside...

That "R" means that airport surveillance radar is available at this base. Only the Control Tower frequency is listed in the airport information, so to get the Approach Control frequency for that base you look on the inside tab of the sectional chart. The tab has a listing of all "Class B, Class C, TRSA, and selected radar approach control frequencies" that are located on that chart.

You should use the military radar surveillance areas like you would a Terminal Radar Service Area (TRSA). A mode C, altitude reporting, transponder is not required. You cannot land at the military base, but you can get all the radar services available for the airspace in the surrounding area. This service includes traffic advisories -- which can be a very important thing to have around a military base.

BOTTOM LINE: Use all the services available to you to stay informed and safe as you fly. Radar controllers (civilian or military) can point out traffic, smoothly sequence you into a busy airport, and locate you if you get lost. When planning a flight, you should know where radar services exist and how to contact the controller -- and you should have the information handy so that you can put it to good use.

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About This Author:
Paul A. Craig is a Gold Seal Multiengine and Instrument Flight Instructor. He currently holds a total of 11 Flight Certificates including his ATP. Craig is a previous winner of the North Carolina and Tennessee Flight Instructor of the Year award, the NCVT Outstanding Teacher award and has served as the regional representative of the National Air and Space Museum. Craig is an FAA Aviation Safety Counselor and the author of eight books, including Pilot In Command, The Killing Zone: How and Why Pilots Die, and Controlling Pilot Error: Situational Awareness (all from McGraw Hill).
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