Restricted airspace
From Wikipedia, the free encyclopedia
Restricted airspace is an area (volume) of airspace in which the local controlling authorities have determined that air traffic must be restricted (if not continually prohibited) for safety or security concerns. It is one of many types of special use airspace designations and is depicted on aeronautical charts with the letter "R" followed by a serial number.
According to the USA Federal Aviation Administration (FAA): "Restricted areas denote the existence of unusual, often invisible, hazards to aircraft such as artillery firing, aerial gunnery, or guided missiles. Penetration of restricted areas without authorization from the using or controlling agency may be extremely hazardous to the aircraft and its occupants." One example of restricted airspace is the area in and around the facility known as Area 51.