USAF Academy Alert Area A-260 and Colorado Springs Class C · Denver Sectional, 3 Sep 2026 – 29 Oct 2026 · Denver.pdf (FAA current sectional, not redistributed), p. 1 · Not for navigation
Refer to the current Denver sectional excerpt over Colorado Springs. Directly over the city, the Class C shelf is charted as "102" over "SFC." What does "SFC" mean here?
Why: "SFC" is standard sectional chart notation for "surface." Where a Class C shelf is printed "102" over "SFC," the airspace has a ceiling of 10,200 feet MSL and extends all the way down to the ground — there is no gap of uncontrolled airspace below it at that location, unlike shelves farther from the primary airport (such as the "102/85" and "102/75" shelves also shown on this excerpt).
Invents a meaning for "SFC" that isn't an FAA sectional chart convention — it is simply the abbreviation for "surface," not a case-by-case ATC clearance process.
Confuses a permanent floor value with a temporary suspension — "SFC" describes where the airspace's floor sits (at ground level), not whether the airspace is currently active.
UA.II.A.K1 · Source: Denver.pdf, current edition sectional chart excerpt (gitignored full-resolution source; not redistributed — see sources/README.md) · Reviewed 2026-10-22