Air Defense Identification Zone (North America)

The Air Defense Identification Zone (ADIZ) is an area surrounding much of North America – namely airspace surrounding the United States and Canada – in which the ready identification, location, and control of civil aircraft over land or water is required in the interest of national security. This ADIZ is jointly administered by the civilian air traffic control authorities and the militaries of both nations, under the auspices of the North American Aerospace Defense Command (NORAD). The Federal Aviation Administration (FAA) handles the requests of international aircraft and Transport Canada handles Canadian requests. Any aircraft flying in these zones without authorization may be identified as a threat and treated as an enemy aircraft, potentially leading to interception by fighter aircraft.

An aircraft entering an ADIZ is required to radio its planned course, destination, and any additional details about its trip through the ADIZ to a higher authority, typically an air traffic controller. The aircraft must also be equipped with a radar transponder.

With the outbreak of World War II, the United States asserted control of coastal airspace in 1940, and this took on a sense of urgency after the Japanese attack at Pearl Harbor. However, by 1943 the Axis powers no longer posed a severe threat to the safety of North America. With the outbreak of the Korean War, the Air Force placed its forces on alert and uncovered major weaknesses in the coordination of domestic defense units. An air defense command and control structure was developed in 1950, creating five Air Defense Identification Zones around North America. If radio interrogation failed to identify an aircraft in the ADIZ, the Air Force launched interceptor aircraft to identify the intruder visually. The air defense system reached its peak in 1962, however with the deployment of the SS-6 ICBM in the USSR, strategic threats shifted overwhelmingly to ICBM attacks, and bomber intrusions were considered to be less of a threat.

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