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7 Rare Symbols Found On VFR Sectional Charts

You don't see these every day...

1) Airports Below Sea Level

How low can you go? In the US, minus 210' MSL. And it happens in Death Valley, at the Furnace Creek airport (L06). But that doesn't necessarily mean you'll always have a low density altitude. Furnace Creek's average summertime high is 116F.

So when you see the word "Minus" in front of an airport's field elevation, you'll know that you're going below sea level while you're still in the air.


2) Objectionable Airports

Have you even seen the word "Objectionable" on a sectional? It's usually found at private airports that potentially conflict with their surrounding airspace.

In this case, Nichols Field, (0CL3), is located under the San Diego Class B shelf. The problem? They drop skydivers through the Class B from 13,000 feet. That's something you wouldn't necessarily expect on your arrival to San Diego.


3) FAR Part 93 Areas

The Eglin/Valparaiso area is covered in a FAR Part 93 area. What does that mean? You need clearance prior to entering the north/south corridor (the dark blue areas). The reason you need a clearance is due to the large amount of military training happening both at Duke airfield (KEGI), as well as the Eglin/Valparaiso joint use field (KVPS).


4) Special Military Activity Area (SMAR)

You'll find these in a few places in the US. This one, which covers Florida from the Gulf Coast to the Atlantic Ocean, is used for cruise missile testing, as well as supporting aircraft.

These areas may be rarely used, but it's always a good idea to talk to Flight Service to make sure the area isn't active. After all, nobody wants to get their airplane in the way of a cruise missile.


5) NDB With DME

You don't find these too often, but if you come across an NDB with a blue square around it, you have an NDB with DME.

How do you use it? First, dial the NBD frequency in your ADF. Then, dial the VOR frequency in your nav radio. You won't get a VOR signal on your CDI, but you will have DME.


6) Remote Communications Outlet (RCO)

RCOs are simply remote antennas used by Flight Service. Typically, Flight Service antennas are paired with a navaid. But in this case, there's no navaid in the area. You typically find RCOs in remote areas. Here, the RCO is located in the Rocky Mountains.

This example is actually a dual RCO, with the Ashton RCO available on 123.625, and the Yellowstone RCO on 119.4


7) Ocular Glare

Large solar farms can cause blinding glare if you're flying near them. To give you a heads up, the FAA has started charting them on sectionals.

The example below is the Crescent Dunes Solar Energy Project northwest of Tonopah, NV.


Want to learn even more about the sectional chart you use every day, as well as how to read NOTAMs (including TFRs) like a pro? Check out our VFR Charts online course, amp up your skills, and impress everyone in the hangar with your knowledge.

Colin Cutler

Colin Cutler

Colin is a Boldmethod co-founder and lifelong pilot. He's been a flight instructor at the University of North Dakota, an airline pilot on the CRJ-200, and has directed the development of numerous commercial and military training systems. You can reach him at

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