Class C is the layered airspace around radar-served towered airports. The core reaches the surface, the shelf starts higher, and the chart shows both in magenta.
Only with prior ATC authorization under 14 CFR 107.41, at any altitude. Class C usually has a 5 NM radius core from the surface up to 4,000 feet above the airport elevation and a 10 NM radius shelf that starts no lower than 1,200 feet. Its altitudes are printed in magenta on the chart.
The AIM describes Class C as the airspace around airports that have an operational control tower, are served by a radar approach control and have a certain number of IFR operations or passenger enplanements. Each area is individually tailored. Beyond the charted limits there is a procedural outer area, normally 20 NM from the primary airport, where Class C services are provided but participation is voluntary; the AIM says this outer area is not charted.
On a sectional, the MSL ceiling and floor of each sector are printed in solid magenta figures with the last two zeros dropped. A ceiling of T means the Class C goes up to, but not including, the floor of the overlying Class B. Class C is identified by name, and separate magenta boxed notes give the approach control frequencies used by arriving VFR aircraft (generally within 20 NM). A note appears when the Class C operates less than continuously.
The manned-aircraft rules in 14 CFR 91.130 (two-way radio contact, transponder and ADS-B Out equipment) are Part 91 rules for pilots of manned aircraft. For a drone the gate is the authorization described on our 14 CFR 107.41 page, which has no altitude threshold.
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).
AIM 3-2-4, Class C Airspace
Although the configuration of each Class C airspace area is individually tailored, the airspace usually consists of a 5 NM radius core surface area that extends from the surface up to 4,000 feet above the airport elevation, and a 10 NM radius shelf area that extends no lower than 1,200 feet up to 4,000 feet above the airport elevation.
Chart Users' Guide, Controlled Airspace
Class C Airspace is shown on Sectionals and TACs. The MSL ceiling and floor altitudes of each sector are shown in solid magenta figures with the last two zeros eliminated.
Chart Users' Guide, Controlled Airspace
A ceiling value of “T” indicates the ceiling is to, but not including, the floor of the overlying Class B airspace.
The 20 NM outer area is a procedural radar-service area and is not charted; the charted Class C is the core and the shelf.
Chart altitudes drop the last two zeros and are MSL: a printed 41 means 4,100 feet MSL.
A ceiling of T does not mean a numeric altitude: it means up to, but not including, the floor of the overlying Class B.
14 CFR 107.41 names Class C without any altitude exception, so the 400-foot AGL limit in 107.51 does not remove the need for authorization.
Quick quiz: 3 questions
Similar to the FAA test, not the actual test questions. Each answer shows its FAA source.
Question 1 of 3
Refer to the chart excerpt. What do the magenta numbers 41 over 13 just north of ATLANTIC CITY INTL (ACY) mean?
Tap the figure to open it full size.
A Class C airspace with a floor of 1,300 feet AGL and a ceiling of 4,100 feet AGL.
B Class C airspace with a floor of 1,300 feet MSL and a ceiling of 4,100 feet MSL.
C Class C airspace that extends from the surface up to 4,100 feet MSL; the 13 is the field elevation.
Show the answer
Answer: B. Class C airspace with a floor of 1,300 feet MSL and a ceiling of 4,100 feet MSL.
Class C altitudes are printed in solid magenta with the last two zeros dropped, ceiling on top and floor below, both in MSL. So 41 over 13 is a floor of 1,300 feet MSL and a ceiling of 4,100 feet MSL. Inside the inner ring, labeled 41 over SFC, the Class C reaches the surface.
Refer to the chart excerpt. A remote pilot wants to fly a small UA at 100 feet AGL near Sandston, which is inside the inner ring around RICHMOND INTL (RIC) where the chart shows 42 over SFC. Is ATC authorization required?
Tap the figure to open it full size.
A No, because small UA flights below 400 feet AGL do not need authorization in controlled airspace.
B Yes, because this is Class C airspace from the surface up to 4,200 feet MSL.
C No, because the Class C floor here is 1,400 feet MSL.
Show the answer
Answer: B. Yes, because this is Class C airspace from the surface up to 4,200 feet MSL.
The magenta 42 over SFC means Class C from the surface up to 4,200 feet MSL. The 400-foot AGL limit in 14 CFR 107.51 is a separate rule. 14 CFR 107.41 requires prior ATC authorization to operate a small UA in Class C airspace at any altitude, which a remote pilot normally requests through LAANC or FAA DroneZone.
What is the base of the outer volume of Class C airspace?
A 4000 feet AGL.
B 1200 feet AGL.
C 1200 feet MSL.
Show the answer
Answer: B. 1200 feet AGL.
(Class C airspace is composed of two cylinders. The inner cylinder starts at the surface and goes to 4000 feet AGL. The outer cylinder starts at 1200 feet AGL to 4000 feet AGL. Refer to “Class C: Definitions” for more information.)
The shelf is the 10 NM radius part of Class C that extends no lower than 1,200 feet up to 4,000 feet above the airport elevation, around the 5 NM core that reaches the surface.
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