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How to read airspace classes on a sectional chart
On a sectional, Class B is solid blue, Class C solid magenta and Class D dashed blue, and a Part 107 flight in any of them needs prior ATC authorization. Class E has several looks: dashed magenta marks a surface area that needs authorization, while a faded magenta or blue edge only marks where Class E starts above ground.
What do the airspace lines look like?
| Airspace | Chart look | Typical shape | Part 107 authorization |
|---|---|---|---|
| Class B | Solid blue lines | Layered upside-down wedding cake near major airports, often to 10,000 ft MSL | Yes |
| Class C | Solid magenta lines | Inner and outer rings; core usually to 4,000 ft above airport elevation | Yes |
| Class D | Dashed blue lines | Around towered airports, usually up to 2,500 ft above airport elevation | Yes |
| Class E surface area | Dashed magenta lines | Around an airport without a tower that has weather reporting | Yes |
| Class E starting at 700 ft AGL | Faded magenta band | Class G below the band | No |
| Class E with a 1,200 ft AGL floor or higher, next to Class G that extends higher | Faded blue band | Class G below | No |
| Class A | Not charted on sectionals | 18,000 ft MSL up to and including FL600 | Not relevant below 400 ft AGL |
| Class G | No special depiction | Uncontrolled airspace | No |
Sources (checked 2026-11-12): FAA Aeronautical Chart Users' Guide; FAA Aeronautical Information Manual; 14 CFR 107.41 (eCFR).
How do I read the numbers inside a shelf?
Stacked numbers in blue or magenta give the ceiling over the floor in hundreds of feet MSL: 40/12 means the airspace runs from 1,200 to 4,000 ft MSL, and SFC as the floor means the surface. A Class C airport at 1,100 ft MSL with the usual design reaches about 5,100 ft MSL, printed as 51.
How do I read a Class D ceiling?
A number in brackets inside the dashed blue circle is the ceiling in hundreds of feet MSL, so [28] is 2,800 ft MSL. A minus sign, as in [-30], means the Class D runs from the surface up to, but not including, that altitude, because other airspace begins above.
Where can I practice on a real chart?
Open the free chart lessons with tap-to-read cues on FAA figures 20, 26 and 69 and chart questions under each one.
Does Class E need authorization?
Only a Class E surface area designated for an airport. A shaded edge such as the faded magenta ring means Class E begins at 700 ft AGL and the airspace below is Class G, so a flight at 400 ft AGL needs no ATC authorization. Remember Remote ID, registration and 107.51 still apply.
Free practice questions on this topic
6 original questions from the Sectional Cue bank. Try each one, then open the answer.
Class A dimensions
1. Which altitude band is designated Class A airspace over the contiguous United States?
- From 14,500 ft MSL up to, but not including, 18,000 ft MSL
- From 18,000 ft MSL up to and including FL600
- From 10,000 ft MSL up to and including FL450
Show answer and explanation
B. From 18,000 ft MSL up to and including FL600
Class A runs from 18,000 ft MSL up to and including FL600. The 14,500 to 18,000 ft MSL band is Class E, which sits below Class A. The 10,000 ft and FL450 values are not Class A boundaries.
Source: AIM 3-2-2
Class C ceiling calculation
2. A Class C primary airport sits at 1,100 ft MSL and its airspace follows the usual design. About what ceiling would the chart show?
- 40, meaning 4,000 ft MSL
- 25, meaning 2,500 ft MSL
- 51, meaning 5,100 ft MSL
Show answer and explanation
C. 51, meaning 5,100 ft MSL
Class C normally extends to 4,000 ft above the airport elevation, so 1,100 plus 4,000 gives 5,100 ft MSL, printed as 51. A label of 40 would ignore the airport elevation. A ceiling of 2,500 ft above the airport is the usual Class D design, not Class C.
Source: AIM 3-2-4; FAA Aeronautical Chart Users' Guide (July 2026)
Class D purpose
3. What feature does an airport need for Class D airspace to surround it?
- A runway longer than 5,000 ft
- An operating control tower
- Scheduled airline service with radar approach control
Show answer and explanation
B. An operating control tower
Class D is designed around airports that have an operating control tower. Runway length does not decide the class. Scheduled airline service with radar approach control is more typical of Class C or Class B.
Source: AIM 3-2-5
Class E 700 ft floor
4. In Figure 26, area 2 lies inside the shaded magenta ring around Cooperstown. What airspace is there from the surface up to 700 ft AGL? (uses Figure 26, open the free chart lesson)
- Class E from the surface, because the airport has an AWOS
- Class D up to 700 ft AGL around Cooperstown
- Class G, with Class E beginning at 700 ft AGL
Show answer and explanation
C. Class G, with Class E beginning at 700 ft AGL
A faded magenta ring means Class E begins at 700 ft AGL inside it, so the airspace below is Class G and a 400 ft AGL flight needs no ATC authorization. A Class E surface area would be drawn with a dashed magenta line, and an AWOS does not create one. Class D needs a control tower and a dashed blue line, neither of which is shown.
Source: FAA-CT-8080-2H, Figure 26; Chart Users' Guide; 14 CFR 107.41
Class E surface area
5. In Figure 26, a dashed magenta line surrounds Jamestown Regional (JMS), just south of area 4. What does it mean for a Part 107 flight inside it? (uses Figure 26, open the free chart lesson)
- It is Class D airspace, so the pilot should call the tower on 118.425
- It is Class G up to 700 ft AGL, so no authorization is needed
- It is Class E airspace extending to the surface, so ATC authorization is required
Show answer and explanation
C. It is Class E airspace extending to the surface, so ATC authorization is required
A dashed magenta line marks a Class E surface area, and Part 107 requires ATC authorization in Class E airspace designated for an airport. Jamestown is printed in magenta with no tower, and 118.425 is its ASOS, so the Class D answer is wrong. The 700 ft floor is shown by the wider shaded ring, not the dashed line.
Source: FAA-CT-8080-2H, Figure 26; Chart Users' Guide; 14 CFR 107.41
Class C surface area
6. In Figure 69, a real estate photographer wants to fly at 120 ft AGL at area 3, close to Corpus Christi International. What is required? (uses Figure 69, open the free chart lesson)
- Prior ATC authorization, because area 3 is in Class C from the surface to 4,000 ft MSL
- Nothing, because a flight below 400 ft AGL is always under Class C
- A radio call to the tower on 119.4 just before takeoff
Show answer and explanation
A. Prior ATC authorization, because area 3 is in Class C from the surface to 4,000 ft MSL
Area 3 lies inside the inner ring marked 40 over SFC, so Class C starts at the surface and runs to 4,000 ft MSL. Part 107 requires prior ATC authorization to fly there. The surface area has no gap below 400 ft, and a radio call to the tower is not how a remote pilot gets authorization.
Source: FAA-CT-8080-2H, Figure 69; 14 CFR 107.41
Related guides
- MSL vs AGL: altitude math on a sectional chart
- Special use airspace and military routes for drone pilots
- Airspace authorization and LAANC for Part 107 pilots
- Free sectional chart practice
- All Part 107 guides
Study the charts on your phone
Sectional Cue has 1150+ original questions with explanations, 27 FAA figures you can tap to read, and timed 60-question rehearsals. About 152 questions and three chart lessons are free.
Sources
- FAA Aeronautical Chart Users' Guide, checked 2026-11-12
- FAA Aeronautical Information Manual, checked 2026-11-12
- 14 CFR 107.41 (eCFR), checked 2026-11-12
How this page was made: written by Certloom Learning from the sources above, with the rules checked against the current regulation text. Practice items are original questions from the app's reviewed bank. Spot an error? certloomlearning@gmail.com.