The value of controlled airspace in the United States is for the safety of all commercial and general aviation flights. Utter chaos reigns in skies without controlled airspace. With thousands of airplanes in the skies every day carrying hundred of thousand of people the necessity of a means of controlling them becomes relevant. The (FAA) Federal Aviation Administration is the regulative department of the United States Government that controls the skies in the U.S. The FAA divided the airspace into different categories, all of which have different regulations and limits on both horizontal and vertical airspace restrictions. They are broken down into basically three distinct airspaces: Class B, Class C, and Class D.

Class B airspace is controlled airspace that extends upward from the ground surface to a specified altitude of 10,000 msl (mean sea level). All aircraft that operate in this airspace are subject to regulations set forth by the FAA. Some of the requirements for the pilot to operate in Class B airspace are: the pilot must at the minimum hold a private pilot certificate, and a current medical certificate. The aircrafts operating in Class B airspace must have at least three pieces of equipment; the first is a two-way radio for communication. The second piece of equipment, a transponder, tracks the aircraft’s position. The third piece of equipment is a VOR (vertical omni range), which directs the pilot’s position. Also, in order to operate in Class B airspace a person must obtain a clearance for ATC (Air Traffic Control). The speed limit in Class B airspace is restricted to 200 knots.

Throughout the country, metropolitan airports designate Class C airspace with a set of rings, extending from the surface of the earth to an altitude of 4,000 feet above the airport elevation and a radius of 5nm (nautical miles) from the center of the airport. This area is known as a primary Class C airport. There is an outer ring that extends out 10 nm from the airport and above the surface from 1,200 feet to 4,000 feet. This area is used for transitioning to and from the airport. The operating rules in the Class C are similar to that of the Class B. The pilot is required to hold at least a private pilot license and a valid medical certificate and to be classified as “current.” Current requirement entails having completed at least three takeoffs and landings in the same type of aircraft. The pilot must also complete a biannual flight review with a certified fight instructor. The aircraft must be equipped with a two-way in order to communicate with ATC, which is required prior to entering the airspace. The aircraft needs to have a transponder with altitude encoding in order for ATC to track them in the air. The VOR is also required for navigation in and around this airspace. Flights at or below 2,500 feet within 4 nm of the airport must not exceed 200 knots. This speed restriction helps to alleviate the noise caused by large aircraft over densely populated areas. A pilot is required to have aboard the aircraft a sectional chart that depicts the airspace and transition areas.

The next airspace is the Class D. This area is generally the airspace above an airport, from ground level to 2,500 feet and outward for 4 nm. The Class D airspace is considered part of the airport itself. A pilot is required to hold the same license, have a valid medical certification as the Class C and they must adhere to the same current classification requirements. A pilot must already be in communication with ATC and be cleared before entering the Class D airspace. Once the pilot is cleared he is transferred to the airport tower, which handles all the traffic within that airspace. No matter whether the aircraft is on the ground or in the air, the local tower is responsible for guiding them safely within its boundaries. The speed is limited to 200 knots within this airspace as well.

The airspace categories are a valuable asset to the United States transportation system and has been designed to protect the public and ensure the safety of the thousands of aircraft that transverse the skies. These areas are configured to allow aircraft to fly from a relatively open area into the more congested airspace over the larger cities. Without this system and its transition areas, air travel would be a very dangerous form of transportation.

Bibliography

“Class B, C, D Airspace” AOPA’s Airport Directory. 2001-2001 ed.: 35-38

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