Lesson 5.3

Lesson 5.3 – Airspace Classification

The National Airspace System is divided into different classes of airspace, each with its own dimensions, entry requirements, and operating rules. Understanding these classes is essential for safe and legal flight.

Reference:

FAA Pilot’s Handbook of Aeronautical Knowledge (PHAK), Chapter 15 – Airspace

Aeronautical Information Manual (AIM), Chapter 3

14 CFR Part 71 and 91.126 – 91.135

Class A Airspace

Extends from 18,000 feet MSL up to and including FL600.
IFR only — VFR flight is not permitted.
Requires an instrument rating and an IFR clearance.

Class B Airspace

Class B airspace surrounds the busiest airports in the United States. It is normally shaped like an upside-down wedding cake, with several layers that become wider as altitude increases.

Entry Requirements:

At least a Private Pilot certificate (Student Pilots may enter only with a specific instructor endorsement).
An explicit ATC clearance. You must hear the controller say “Cleared into Class Bravo airspace.”
Two-way radio communication.
Mode C transponder and ADS-B Out.

Operating Rules:

Comply with all ATC instructions.
Maximum speed is generally 250 knots below 10,000 feet MSL (often limited to 200 knots under the shelves or in VFR corridors).
VFR weather minimums: 3 statute miles visibility and clear of clouds.

Mode C Veil:

Many Class B areas have a 30-nautical-mile radius (the Mode C veil) in which a Mode C transponder and ADS-B Out are required even if you remain outside the actual Class B airspace.

Class C Airspace

Class C airspace usually surrounds medium-sized airports that have radar approach control.

Entry Requirement:

Two-way radio communication with ATC. You must hear your call sign.

Additional Equipment:

Mode C transponder and ADS-B Out are required.

Typical Structure:

Inner circle: approximately 5 NM radius from the surface to 4,000 feet AGL.
Outer shelf: approximately 10 NM radius from 1,200 feet AGL to 4,000 feet AGL (actual dimensions are charted and may vary).

Class D Airspace

Class D airspace surrounds airports that have an operating control tower.

Entry Requirement:

Two-way radio communication with the tower. You must hear your call sign.

Typical Dimensions:

Surface up to about 2,500 feet AGL with a radius of approximately 4 NM (check the chart for exact size).

When the control tower closes, Class D airspace normally reverts to Class E or Class G.

Class E Airspace

Class E is controlled airspace that is not designated as Class A, B, C, or D.

Entry Requirement for VFR:

None. No clearance or radio contact is required unless you request ATC services.

Class E may begin at the surface, 700 feet AGL, 1,200 feet AGL, or a higher altitude. A transponder and ADS-B Out are required above 10,000 feet MSL and in other areas as charted.

Class G Airspace

Class G is uncontrolled airspace.

Entry Requirement for VFR:

None.

Class G exists wherever no other class of airspace is designated. It typically extends from the surface up to the floor of the overlying Class E airspace.

Summary of VFR Entry Requirements

Airspace

What You Need to Enter (VFR)

Class A

Not authorized

Class B

Explicit clearance (“Cleared into Class Bravo”) + Private Pilot certificate (or endorsed Student) + Mode C & ADS-B

Class C

Two-way radio communication (hear your call sign) + Mode C & ADS-B

Class D

Two-way radio communication (hear your call sign)

Class E

No clearance or radio call required

Class G

No clearance or radio call required

Key Points to Remember

Class B requires an explicit clearance.
Class C and Class D require two-way communication (you must hear your call sign).
Class E and Class G require no clearance for VFR flight.
Always refer to the sectional chart for the exact lateral and vertical limits of any airspace.