The sectional chart is the most important piece of paper in your flight bag. Once you can read it fluently, cross-country navigation opens up. Here's every symbol, color, and marking explained.
A VFR sectional aeronautical chart is published by the FAA at a scale of 1:500,000 (roughly 1 inch = 6.86 nautical miles). Each chart covers approximately 340 × 340 miles and is updated every 56 days. The chart contains more information per square inch than almost any other document in aviation — airports, airspace, terrain, obstructions, navigation aids, special use areas, and more.
Learning to read a sectional is not difficult, but it takes time in the air with the chart in hand. This guide covers every major symbol category. After reading it, pull up a sectional chart for your local area (free at SkyVector.com or the FAA's VFR chart portal) and identify each type.
Sectional charts are oriented with true north up. The coordinate grid shows latitude and longitude. The key to interpreting everything on the chart is the chart legend, printed on the reverse side or folded into the margins. Every symbol on the chart is explained there — if you see something unfamiliar, check the legend before guessing.
The chart uses color systematically: blue for controlled airspace and certain airports, magenta for other airspace types and non-towered airports with approaches, brown for terrain (contour lines), green for lower terrain/vegetation, and white for higher terrain. Water is blue.
Every airport on the sectional has a symbol with associated data. Understanding airport symbols tells you whether you need a radio, whether there's a control tower, and what services are available.
Next to every airport symbol is a data block. Reading from top to bottom, it typically shows:
Traffic pattern altitude: The standard traffic pattern altitude is 1,000 ft AGL, but exceptions are noted in the Chart Supplement (formerly Airport/Facility Directory). Always check the Chart Supplement for your destination airport before flying — pattern altitudes, noise abatement procedures, and local notes are there.
Solid blue circles of varying diameters represent the concentric rings of Class B airspace. Each ring has a label showing the altitude floors and ceilings, e.g. "30/SFC" means from the surface to 3,000 ft MSL in that ring. The innermost ring typically extends from the surface upward.
Solid magenta circles in two rings (5 nm and 10 nm radius) represent Class C. The inner ring typically goes from the surface, the outer ring from about 1,200 ft AGL. Altitude labels appear on the chart.
Dashed blue circles surround towered airports. Class D typically extends to 2,500 ft AGL. The ceiling altitude is shown in a box near the airport, e.g. "[25]" means 2,500 ft MSL is the ceiling.
Class E is shown in three ways on sectional charts:
Restricted areas appear as blue hatched outlines labeled "R-####". MOAs appear as magenta hatched outlines labeled by name. Warning areas appear as blue hatched outlines with "W-####". Alert areas are light blue with "A-####". Each has an associated altitude range and time of use — check the legend and NOTAMs for current status.
Brown contour lines show terrain elevation. Each line represents a specific elevation — the interval is printed on the chart (typically 500 ft in most areas, 1,000 ft in mountainous areas). The closer the lines are together, the steeper the terrain. Green color indicates lower elevations; brown/tan indicates higher elevations.
Each quadrant on the chart (bounded by latitude and longitude lines) contains a large blue number — the Maximum Elevation Figure. This represents the highest terrain or man-made obstacle in that quadrant, rounded up to the next 100 feet and then adding 100 feet. Flying at or above this altitude gives 100 ft of clearance over any obstacle in that quadrant. This is a critical navigation planning tool.
Wind turbine farms are depicted with a specific propeller symbol and have proliferated significantly in the Midwest and plains states. They represent genuine hazards and require careful terrain awareness.
VORs appear as compass rose symbols (a hexagon surrounded by a compass rose) in blue or magenta. The name, frequency, and Morse code identifier appear next to the symbol. The compass rose shows magnetic variation-corrected bearings from the VOR. Radials are measured from the VOR outward (magnetic), so a VOR compass rose allows you to immediately visualize which radial you're on from your position on the chart.
Non-directional beacons appear as a magenta circle with a dot in the center, with name and frequency. Less common than VORs but still on many charts.
Feather symbols extending from runways indicate ILS (instrument landing system) or localizer approaches. The feather points in the direction of the approach. Relevant for situational awareness about where IFR aircraft will be descending — stay clear of these paths near airports in IMC.
The practical skill is matching what you see on the chart to what you see out the window — pilotage. As you fly, identify large lakes, rivers, highways, railroads, cities, and prominent terrain features and verify they match the chart. Build a habit of checking your position against the chart every 10–15 minutes on a cross-country, not just relying on GPS.
When planning, measure distances with a plotter. Course lines are drawn with a plotter aligned to the nearest meridian (line of longitude) to get true course, then converted to magnetic heading using the variation shown on isogonic lines (dashed magenta lines labeled with their variation, e.g., "5°W").
Free digital sectionals: Practice chart reading at SkyVector.com — free, always current, and allows zoom. Identify airport data blocks, airspace boundaries, MEFs, and obstacles in your area before your next flight.
Sectional charts are updated every 56 days. Using an out-of-date chart is illegal for navigation (FAR 91.103 requires that a pilot be familiar with all available information — an outdated chart may not reflect new obstacles, airspace changes, or NOTAMs). Free digital charts through ForeFlight, Garmin Pilot, or SkyVector are always current. If using paper charts, check the edition date on the chart cover.