web analytics

United States Airspace Classes Explained

As an aviation student, you must have an in-depth knowledge of controlled airspace and airspace classes, and how they affect flight.

The concept of airspace is one of the most important aspects of aviation. It is essential to organizing aircraft traffic, and yet those who fly through it on airliners seldom have any idea about these airspace classes. While we cannot “see” airspace, it exists on navigation charts, under the operation of the Federal Aviation Administration (FAA.) The differences between the types of airspace, however, is one of the first realities of flying taught to student pilots, especially if their flight school is located at a somewhat busy airport with a control tower.

Learning about these divisions and the ways in which they affect air travel are an important part of becoming a safe and professional aviator. It is especially vital for new pilots to understand that the classification of airspace is not always the same. Sometimes it changes due to security protocols around air shows, airport maintenance, weather emergencies, volcanic activity, and the movement of government officials.

Good pilots always check for FAA-issued Notices to Airmen (NOTAMS) to determine if alterations to airspace classifications have taken place along their proposed route. Pilots should check for changes 25 nautical miles on both sides of their course so that they can adjust their navigation, if necessary. Airspace restrictions apply to pilots as well as drone operators.


Types of Airspace

To understand how the FAA divides airspace, it is best to first have a grasp of three broad classifications of it. These include

  1. Uncontrolled airspace
  2. Special use airspace
  3. Controlled airspace

In uncontrolled airspace, air traffic controllers do not provide their services. Usually, these areas do not see a lot of air traffic. For the most part, when pilots aviate in uncontrolled airspace, they are flying under visual flight rules (VFR). The rules guiding VFR are different under various conditions, meaning that conditions are generally clear and calm. Many general aviation flights take place in uncontrolled airspace.


Restricted and Special Use Airspace Classes

In restricted or special use airspace classes, pilots must pay special attention to how the FAA has issued its specifications. Special use airspace has different permissions, and it is not a good idea for pilots to break these rules. Here is a quick rundown of the various kinds of special use airspace:

Prohibited airspace:

Airplanes other than those very few which are specially ordered to, such as emergency aircraft or military patrols, are not allowed in prohibited airspace. Prohibited airspace is enacted over Camp David, as well as many areas in Washington DC. The FAA denotes prohibited airspace on navigational charts with a large blue P.

Restricted airspace:

These areas are considered “highly controlled,” and usually do not permit VFR flight. Area 51 and places where military or weapons training is undertaken is usually fenced off as a restricted area. Occasionally, pilots might gain permission from the controlling agency to pass through the airspace while flying IFR, but this is usually rare. Restricted airspace is marked with an R on sectional charts, and marked off with a blue line.

Warning Areas:

Warning areas are considered potentially hazardous places to fly, usually because air traffic controllers are not providing services in this area. They are mostly located along the coast of the United States to a distance of 12 nautical miles. They are also called “Whiskey areas,” because they are marked with a W on aeronautical charts, and in the phonetic alphabet used in aviation, W is “whiskey.”

Military Operations Area (MOA):

The only pilots permitted in an MOA are the military pilots conducting an operation. This zone is marked in red on aeronautical charts and is in place to keep military flights separate from airliners, charters, or general aviation flights.

Alert Areas:

Student pilots might first become familiar with Alert Areas before any others. They are marked off, but a blue border and the letter A. Alert areas are where traffic is high. It might include a lot of flight training. Pilots are allowed to cross through Alert Areas, but they should take great caution and watch carefully for other aircraft.

TFR (Temporary Flight Restriction):

A TFR is a temporary limitation around an area which is of special security concerns. They might become enacted over national sports events, movements by the President , or encompass the launchpad before a rocket liftoff.

National Security Areas:

Magenta lines that are dashed and thick mark off these areas, where places like sensitive military areas or nuclear power plants are located. Pilots may fly over them, but are asked to stay above a certain altitude.


Controlled Airspace Classes

When pilots and air traffic controllers refer to controlled airspace classes, they are speaking of the areas in the sky in which air traffic controllers give their services. Some of these may not be supplied 24 hours a day, but they may be at busy airports. In these areas, pilots may fly under instrument flight rules (IFR) as well as VFR.

Here are the different classifications of controlled airspace:

Class A:

Airplanes must have IFR clearances. 18,000 feet MSL (mean sea level) to flight level (FL) 600, over water that is 12 nautical miles of a coastline. Sometimes, gliders are allowed to fly here.

Class B:

Busy airports; ultralight aircraft usually do not fly here. From the ground to 10,000 feet MSL.

Class C:

Large airports with radar approach capabilities. Surface to 4,000 AGL (above ground level).

Class D:

Above an airport in medium to small cities. Surface to 2,500 feet AGL.

Class E:

Airspace not already designated as A, B, C, or D and is still in controlled airspace. It is also sometimes called “weather controlled.” Sometimes, Class E goes down to the surface or as low as 700 feet AGL.

When a pilot is in one of the above controlled airspace classes, he or she speaks with air traffic controllers many times. He or she talks to one to gather the latest information about the weather and receive clearance to taxi. The ATC professionals are coordinating with one another as well as those in nearby locations. They guide the pilot throughout the controlled airspace through landing.


Leave a Comment