Class C Airspace and Operating Requirements
Class C airspace protects airports with an operating control tower and radar approach control ? one notch down in complexity from Class B, with a simpler two-tier structure instead of a multi-ring wedding cake. This lesson covers Class C's shape, its authorization requirements, and how it compares to the Class B airspace covered in the previous lesson.
What defines a Class C airport
Class C airspace is established around airports with an operating control tower that also have radar approach control service and a certain volume of IFR operations or passenger traffic ? meaning ATC has the radar tools to actively sequence and separate traffic approaching and departing, one level below the very busiest Class B hubs. This is a meaningful distinction from Class D (covered in the next lesson), which has a control tower but not necessarily radar approach control.
The two-tier shape
Unlike Class B's multi-ring wedding cake, Class C is typically built from just two tiers: an inner core with roughly a 5-nautical-mile radius extending from the surface up to about 4,000 feet AGL above the airport's elevation, and an outer shelf extending out to roughly 10 nautical miles, with a floor around 1,200 feet AGL up to that same approximate 4,000-foot ceiling. Exact dimensions vary somewhat by airport, but this two-tier pattern is the standard Class C structure.
The same floor-altitude nuance applies as in Class B
Just as with Class B, whether a specific Part 107 flight actually needs authorization depends on whether its operating altitude reaches the floor of the tier covering that location ? not simply lateral proximity to the airport. A flight at 150 feet AGL under the outer shelf (typical floor around 1,200 feet AGL) is below that floor and not actually inside Class C airspace at that point. A flight anywhere within the inner core, whose floor typically reaches the surface, is inside Class C regardless of how low it flies.
Authorization requirement under 14 CFR 107.41
Any Part 107 flight that will actually operate within the Class C volume ? inner core or outer shelf, at or above that tier's floor ? requires prior ATC authorization before the flight, obtained through LAANC or FAA DroneZone (Lessons K and L), exactly the same authorization mechanism used for Class B and Class D.
Real-world scenario: a regional airport inspection job
A pilot is contracted to inspect solar panels on a warehouse roof 7 nautical miles from a mid-size regional airport with Class C airspace. Checking the sectional chart, the pilot finds this location falls under the outer shelf, with a floor of 1,200 feet AGL. Since the inspection flight will stay at 100 feet AGL, well below that floor, the flight does not enter Class C airspace and no 107.41 authorization is required for this specific job ? though the pilot still checks for any other applicable restrictions, such as a nearby TFR (Lesson J), before launching.
Class C's two-tier structure: inner core to the surface, outer shelf with a raised floor around 1,200 feet AGL.
View Larger| Feature | Class B | Class C |
|---|---|---|
| Typical shape | Multi-ring inverted wedding cake | Two-tier (inner core + outer shelf) |
| Traffic complexity | Highest ? busiest hub airports | High, one level below Class B |
| Radar approach control | Yes | Yes |
| Sectional chart color | Solid dark blue | Solid magenta |
| 107.41 authorization | Required within actual boundaries | Required within actual boundaries |
How is Class C different from Class B?
Class C uses a simpler two-tier structure (inner core plus one outer shelf) around airports one level below the traffic complexity of Class B, which uses a multi-ring wedding-cake shape. Both require 107.41 authorization within their actual boundaries.
Does the outer shelf of Class C extend to the surface?
Typically not ? the outer shelf's floor is usually around 1,200 feet AGL, while only the inner core's floor typically reaches the surface.
What color represents Class C airspace on a sectional chart?
Solid magenta lines, distinct from Class B's solid dark blue.
Test Your Knowledge
Answer the questions below to check your understanding. Every answer can be found in the lesson above.