Airspace Classes Overview

Introduction

• Airspace is divided into classes by the FAA using letters (e.g., Class A, Class B).
• Airspace can be controlled (managed by ATC) or uncontrolled.

Controlled Airspace

Class A (Alpha)

• Covers the entire US.
• Altitude: 18,000ft MSL to 60,000ft MSL.
• IFR only; requires:
  • Mode C transponder
  • ADS-B Out
  • DME above FL240
• Speed limit: Mach 1

Class B (Bravo)

• Around 37 busiest airports in major cities.
• Depicted by solid blue lines on charts.
• Altitude blocks with floor and ceiling in hundreds of feet MSL.
• 3D shape: upside-down wedding cake.
• Inner sector: surface to ~10,000ft MSL.
• 30 nm Mode C veil (magenta circle on chart).
• Requires ATC clearance.
• VFR weather minimums: 3 statute miles visibility.
• Speed limit: 250 knots inside and 200 knots in corridors and below.

Class C (Charlie)

• Medium-sized airports, less busy than Class B.
• Depicted by magenta lines on charts.
• Inner core: surface to ~4,000ft AGL, radius 5 nm.
• Outer shell: 1,200ft AGL to 4,000ft AGL, radius 10 nm.
• VFR weather: 3 statute miles visibility.
• Speed limit: 200 knots within 4 nm of airport.
• Requires radio communication but not ATC clearance.

Class D (Delta)

• Less busy airports.
• Depicted by dashed blue lines on charts.
• Range: surface to airspace above or 2,500ft AGL.
• VFR weather same as Class C.
• Speed limit: 200 knots.
• Requires two-way radio communication.

Class E (Echo)

• Controlled airspace not A, B, C, or D.
• Floor: usually 1,200ft AGL.
• Depicted by shaded magenta (transition areas) and blue vignettes.
• Transition areas: 700ft AGL, down to surface in some airports.
• Rare cases: starts at 14,500ft MSL.
• Extends up to 18,000ft MSL and above 60,000ft MSL.
• VFR weather below 10,000ft MSL same as Class C and D; above increases minimums.

Uncontrolled Airspace

Class G (Golf)

• Where controlled airspace does not exist.
• Not depicted on charts.
• Entry: no requirements.
• VFR weather:
  • Below 10,000ft MSL: 1 mile visibility (day), 3 miles (night).
  • Below 1,200ft AGL: clear of clouds (day), stricter at night.
  • Above 10,000ft MSL: aligns with high altitude Class E requirements.
  • Exception: Traffic pattern at night near runway.

Conclusion

• Further types of airspace will be covered in Part Two.