2.5 Reading Sectional Charts
Key Takeaways
- Towered airports = blue; non-towered airports = magenta on sectional charts.
- Obstruction data: top number = MSL height, parenthetical number = AGL height.
- Maximum Elevation Figures (MEFs) show the highest feature in each grid square in hundreds of feet MSL.
- Airspace colors: Class B = solid blue, Class C = solid magenta, Class D = dashed blue, Class E surface = dashed magenta.
- For exam chart questions, methodically identify airspace first, then airports, obstructions, and terrain.
2.5 Reading Sectional Charts
Sectional charts (officially called VFR Sectional Aeronautical Charts) are the primary visual reference for navigating the National Airspace System. The Part 107 exam will include several questions that require you to interpret information from sectional chart excerpts provided in the test supplement.
Chart Scale and Grid
- Sectional charts use a scale of 1:500,000 (1 inch = 6.86 nautical miles)
- Latitude lines run east-west (horizontal) and are numbered in degrees north/south of the equator
- Longitude lines run north-south (vertical) and are numbered in degrees east/west of the Prime Meridian
- Each degree is divided into 60 minutes; coordinates are expressed as degrees and minutes (e.g., N33°45' W118°20')
Airport Symbols
Airports with Control Towers (Towered):
- Depicted in blue on sectional charts
- Symbol varies by runway configuration but is always blue
Airports without Control Towers (Non-towered):
- Depicted in magenta on sectional charts
- Same shapes as towered airports but in magenta color
Airport Data Block: The data block next to an airport symbol contains critical information:
KORD
CT - 120.75
ATIS 135.4
★ (beacon)
Key elements in airport data:
- Identifier — ICAO code (4 letters starting with K for contiguous US)
- CT — Control Tower frequency
- ATIS — Automatic Terminal Information Service frequency
- Elevation — Airport elevation in feet MSL
- Runway length — Longest runway in hundreds of feet
- Lighting — Star symbol (★) indicates rotating beacon
Airspace Boundaries
| Airspace | Chart Depiction |
|---|---|
| Class B | Solid blue lines with altitude labels |
| Class C | Solid magenta lines with altitude labels |
| Class D | Dashed blue lines with altitude in blue box |
| Class E (surface) | Dashed magenta line |
| Class E (700 ft AGL) | Magenta vignette/shading |
| Class E (1,200 ft AGL) | Blue vignette/shading |
Obstruction Symbols
Obstructions (towers, antennas, wind turbines, etc.) are critical for drone pilots:
| Symbol | Meaning |
|---|---|
| Solid dot with lightning bolt | Obstruction with lighting (lit at night) |
| Open dot with lightning bolt | Obstruction without lighting |
| Group obstruction symbol | Multiple obstructions in close proximity |
| UC (Under Construction) | Obstruction under construction |
Obstruction data includes:
- Top number: Total height above MSL (in feet)
- Bottom number in parentheses: Height above ground level (AGL)
Example: An obstruction marked 1340 (300) means the top of the obstruction is 1,340 feet MSL and 300 feet AGL.
Terrain and Elevation
- Contour lines show terrain elevation changes
- Maximum Elevation Figures (MEFs) appear in large bold numbers within each quadrangle (latitude/longitude grid)
- MEFs represent the highest known feature (terrain + obstacles + 100-200 ft buffer) in that grid square
- Read as hundreds of feet MSL: 34 = 3,400 feet MSL
- Useful for quick altitude reference
Latitude and Longitude on Sectional Charts
Finding coordinates on a sectional chart:
- Latitude increases going north (bottom to top)
- Longitude increases going west in the US (right to left for most of continental US)
- Each tick mark = 1 minute of latitude or longitude
- The grid squares between latitude and longitude lines are 30 minutes × 30 minutes
Visual Reference Points
Sectional charts show landmarks useful for visual navigation:
- Purple markings — Visual checkpoints in Class B/C airspace
- Railroad tracks — Shown as single lines with cross-hatches
- Major highways — Shown as parallel lines (interstates may be labeled)
- Power lines — Shown as lines with small circles
- Bodies of water — Blue shading
- Urban areas — Yellow shading
Exam Strategy: When given a sectional chart excerpt, methodically identify airspace boundaries first, then airports, then obstructions, then terrain. Take your time — chart questions require careful reading.
On a sectional chart, airports with control towers are depicted in what color?
An obstruction symbol on a sectional chart shows "1340 (300)." What does the "(300)" represent?
Maximum Elevation Figures (MEFs) on a sectional chart represent: