What does a blue airport symbol mean on a sectional chart?

A blue airport symbol depicts an airport with an operating control tower during published hours. Read the surrounding airspace boundary separately because the airport color does not by itself identify the airspace class.

What does a magenta airport symbol mean?

A magenta airport symbol depicts an airport without an operating control tower. It can still have active traffic and may sit inside controlled airspace, so non-towered does not mean empty or automatically Class G.

What is the flag symbol on a sectional chart?

A flag marks a visual checkpoint used for VFR position reporting or navigation. It is not a state boundary, wind indicator, or special-use airspace symbol.

How do you read obstruction numbers such as 1549 (612)?

The first number is the elevation at the top of the obstruction in feet MSL. The number in parentheses is the obstruction height in feet AGL. In this example the top is 1,549 feet MSL and the structure is 612 feet AGL.

What does the large blue number with a small superscript mean?

It is a Maximum Elevation Figure for the quadrangle, expressed in thousands and hundreds of feet MSL. It is a conservative charted terrain and obstruction value, not a drone altitude authorization.

33 CORE SYMBOLS

Part 107 chart key

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Read by family

A sectional is five systems drawn on top of each other.

Airports and radio

Tower status, services, beacons, airport data, CTAF, and traffic clues.

Airspace boundaries

Class B, C, D, and E lines, vignettes, floors, ceilings, and equipment veils.

Navigation and position

Latitude, longitude, isogonic lines, VFR waypoints, and chart orientation.

Terrain and obstructions

Towers, lighting, groups, wind turbines, spot elevations, and MEF.

Activities and special use

MOAs, restricted areas, parachute jumps, gliders, wildlife, and alert areas.

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FAA-style symbol desk

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Airports & radio

Towered airport

Blue airport or runway symbol.

What it means: The airport has an operating control tower during published hours. The runway layout may be drawn inside the symbol.
Drone read: Expect concentrated manned traffic. Check the airspace class, authorization path, airport frequencies, and traffic pattern before operating nearby.
Exam trap: Blue describes the airport symbol, not every airspace boundary around it. Read the surrounding lines separately.
Memory line: Blue airport = tower.

Source: FAA Chart Users' Guide, VFR airport symbols

Frequently asked questions

What does a blue airport symbol mean on a sectional chart?: A blue airport symbol depicts an airport with an operating control tower during published hours. Read the surrounding airspace boundary separately because the airport color does not by itself identify the airspace class.
What does a magenta airport symbol mean?: A magenta airport symbol depicts an airport without an operating control tower. It can still have active traffic and may sit inside controlled airspace, so non-towered does not mean empty or automatically Class G.
What is the flag symbol on a sectional chart?: A flag marks a visual checkpoint used for VFR position reporting or navigation. It is not a state boundary, wind indicator, or special-use airspace symbol.
How do you read obstruction numbers such as 1549 (612)?: The first number is the elevation at the top of the obstruction in feet MSL. The number in parentheses is the obstruction height in feet AGL. In this example the top is 1,549 feet MSL and the structure is 612 feet AGL.
What does the large blue number with a small superscript mean?: It is a Maximum Elevation Figure for the quadrangle, expressed in thousands and hundreds of feet MSL. It is a conservative charted terrain and obstruction value, not a drone altitude authorization.

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