Aviation Airspace Classifications

In the United States there are 6 classifications of airspace.  They are Alpha, Bravo, Charlie, Delta, Echo and Golf.  As a pilot you must know the different classification of each and at what altitudes they reach.  There are various rules for each type of airspace along with weather minimums for VFR pilots and speed limits within these airspaces.  In this discussion we will talk about the classes of airspace and the speed limits within each airspace.  To learn about weather requirements for a VFR Pilot within these spaces please refer to VFR Pilot Weather Minimums.

General Terms:

AGL:  Above Ground Level

MSL:  Mean Sea Level

FL:  Flight Level

Class A  Class Alpha Airspace can be found above FL180 (18,000 feet MSL) and goes to FL600 (60,000 feet MSL).  This airspace is reserved for business class jets and fast movers.  VFR aircraft are not permitted to fly in Class Alpha airspace.  When flying every pilot knows that you must keep your altimeter setting set to a station within 100 nautical miles of a station to make sure you are flying at the proper altitude.  To ensure that every pilot is flying at the same level above FL180, each pilot at the point of climbing thru 18,000 feet MSL resets their altimeter setting to 29.92.  All pilots entering Class A airspace must have filed an IFR flight plan and received an ATC Clearance.  There is no restrictions on speed in Class A airspace.

Class B Class Bravo Airspace is that airspace found around some of the busiest airports in the United States in which commercial traffic can be found in abundance.  As a VFR Student Pilot you need special training from a flight instructor and an endorsement in your logbook to be able to fly within Class B airspace.  Class Bravo airspace is specifically designed for each airport, but generally contains a surface area and at least two other layers resembling an upside down wedding cake.  Class B airspace generally goes from the surface to 10,000 feet MSL.  All aircraft entering class Bravo airspace will receive separation services from other aircraft.  The speed limit within Class Bravo airspace is 250 KIAS (Knots Indicated Airspeed), there however is a rule to this and we will touch on that in a moment.

ATC clearance to enter the Bravo:

Chicago Approach Rainbow001 over the Joliet VOR inbound to land.

Rainbow001 Chicago Approach Standby

with this clearance the controller knows that you are out there but has not cleared you to enter the Bravo airspace.

Chicago Approach Rainbow001 over the Joliet VOR inbound to land

Rainbow001 Chicago Approach cleared into the Bravo maintain VFR at or above 3000 altimeter 30.01 Squawk 5201 and Ident

With this clearance the controller has given you specific instruction to enter the Bravo.  In order to enter the Bravo Airspace you MUST here the Key words CLEARED TO ENTER THE BRAVO.

Speed limit rules within the Bravo are 250 KIAS as stated above, but there is a rule to this exception.  By this time you should have read the section on VFR charts and understand what the tiers of airspace are and how to tell what altitudes they affect.  If you exit and inner tier and are flying below one of the outer tiers the max speed limit is 200 KIAS.  You can be hit with an FAA Violation if you are cruising at 250 KIAS and are turned outbound and come out of the Bravo below the veil of another.  It is up to the pilot to maintain the speed so you must know where you are all all times even if you are vectored by ATC and end up under the tier of another Bravo Ring you are in violation if you are currently moving faster than 200 KIAS.

CLASS C Class Charlie Airspace is the airspace from the surface to 4,000 feet above the airport elevation. Class C airspace will only be found at airports that have an operational control tower, are serviced by a radar approach control, and that have a certain number of IFR operations. Although Class C airspace is individually tailored to meet the needs of the airport, the airspace usually consists of a surface area with a 5 nautical mile (NM) radius, an outer circle with a 10 NM radius that extends from 1,200 feet to 4,000 feet above the airport elevation and an outer area. Pilots must establish and maintain two-way radio communications with the ATC facility providing air traffic control services prior to entering airspace. Pilots of visual flight rules (VFR) aircraft are separated from pilots of instrument flight rules (IFR) aircraft only. The speed within a the lateral boundaries of a Class C airport is 250 KIAS.  Aircraft may maintain at or below 250 KIAS until within 4 NM of the airport where the speed max speed allowed drops to 200 KIAS.

ATC Clearance:

Springfield Approach Rainbow001 3 miles south of the Boliver Airport inbound to land.

Last Aircraft calling Approach Standby

You have not been cleared to enter the airspace with this Response.

Springfield Approach Rainbow001 3 miles south of the Boliver Airport inbound to land.

Rainbow001 Springfield approach Standby

You may now go ahead and proceed inbound towards the airport and have been cleared to enter the Charlie.  The key words for you entry clearance into the Class C is your Tail Number.  Anytime operating in a Class C the Approach controller responds with your tail number you have received clearance.  It is better if you are given directions for your entrance as you would defiantly know that you have been cleared, but all that is required by the FAA is that your be responded to with the use of your Tail number.

Class D  Class Delta Airspace which is generally that airspace from the surface to 2,500 feet above the airport elevation. Class D airspace only surrounds airports that have an operational control tower. Class D airspace is also tailored to meet the needs of the airport. Pilots are required to establish and maintain two-way radio communications with the ATC facility providing air traffic control services prior to entering the airspace. No separation services will be provided to pilots of VFR (Visual Flight Rules) aircraft. Pilots operating under VFR must still use "see-and-avoid" for aircraft separation. Airports without operating control towers are uncontrolled airfields. Here pilots are responsible for their own separation and takeoff and landings. Uncontrolled airports use a "UNICOM" frequency that pilots will transmit their intentions to other aircraft using the airport.

When using the Unicom Frequency your order of announcement is:  What Airport your loacted at, Who You are, Where you are, What your doing
and What Airport you are located at.

Examples:  Joplin Traffic Rainbow001 at GA Parking taxiing to RWY13 Joplin

Joplin Traffic Rainbow001 Departing RWY13 Joplin

Joplin Traffic Rainbow001 departing the area to the north climbing thru 2000 for 6500 Joplin

Speed limits within the lateral boundaries of the the Class Delta airspace are 250 KIAS unless you are within 4 NM of the airport then the speed drops to 200 KIAS.

Class E  Class Echo Airspace which is generally that airspace that is not Class A, B, C, or D. Class E airspace extends upward from either the surface or a designated altitude to the overlying or adjacent controlled airspace. If an aircraft is flying on a Federal airway below 18,000 feet, it is in Class E airspace. Class E airspace is also the airspace used by aircraft transiting to and from the terminal or en route environment normally beginning at 14,500 feet to 18,000 feet. Class E airspace ensures IFR aircraft remain in controlled airspace when approaching aircraft without Class D airspace or when flying on "Victor airways" -- federal airways that are below 18,000 feet. NOTE: VFR aircraft can fly up to 17,500 feet IF they can maintain VFR weather clearance criteria (and the aircraft is equipped to fly at 17,500 feet).  There are some airports that are Classified as Echo airspaces.  These airports must have a weather reporting capabilities, NOT and ATIS OR ASOS.  Just someone inside that can give you an airport advisory.  They are generally contacted on the UNICOM for that airport.  If you try to contact them, they may or may not answer.  These airport are NOT an Air Traffic Controller and can not give you vectors or directions.  They are generally an airport employee.  Most class Echo airspace airports are privately owned or may be owned by the city or county in which they are located.

Class G Class G Airspace is uncontrolled airspace. IFR aircraft will not operate in Class G airspace*. VFR aircraft can operate in Class G airspace.  Class Golf airspace is generally from the surface to either 700 ft AGL or 1200 ft AGL.  Class Golf airspace can be found in some mountainous regions to reach as high at 14,500 MSL.  There are specific weather minimums for VFR aircraft when flying in Class G airspace and those will be covered in the Weather Minimums Chapter.