Sectional chart reference
Class C
Solid magenta lines.
What you are looking at
A solid, crisp MAGENTA line = Class C, a busy-but-smaller towered airport (a 5 NM core plus an outer shelf). Solid line = class boundary; magenta names it C.
Same 'solid line = class boundary' rule as B; the color just says which one. For a drone both B and C simply mean authorization; the NM/altitude detail is exam trivia.
The rule itself
No person may operate a small unmanned aircraft in Class B, Class C, or Class D airspace or within the lateral boundaries of the surface area of Class E airspace designated for an airport unless that person has prior authorization from Air Traffic Control (ATC).
Quoted in full from 14 CFR § 107.41. Authorization normally comes through LAANC.
Reading the numbers
Fractions like 41/SFC = top 4,100 MSL over a SURFACE core; 41/13 = top 4,100 / floor 1,300 MSL (the outer shelf). One layer's top/bottom, MSL (SFC = the ground).
Where people get this wrong
THE CLASS C EXCEPTION to 'color follows the tower': the airport inside Class C is TOWERED, so it's a BLUE dot, a blue towered dot sitting inside MAGENTA rings. 'Magenta = non-towered' is NOT a universal rule.
How it is tested
Class C is drawn with magenta rings. What color is the airport dot at its center, and why?
- Blue: the airport is towered
- Magenta: the airport is non-towered
- There is no dot
Show the answer
Blue: the airport is towered
Class C is the exception: a towered (blue) airport inside magenta class rings. Dot color = tower; line color = class convention.
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