Helping Global Hawk Fly With the Rest of Us

When the United States Air Force (USAF) planned to start operations of the Global Hawk Unmanned Aircraft System (UAS) at Beale Air Force Base (AFB) they turned to the MITRE Corporation for an analysis of nearby air traffic that fly in the vicinity of Beale where a portion of the planned Global Hawk mission would occur. Using several data sources, MITRE analyzed flight paths of both transponding and non-transponding aircraft to characterize the air traffic patterns in the vicinity of Beale AFB. In addition to examining aircraft with beacon transponders, which represented flights under air traffic control and some uncontrolled flights, it was critical to examine operations of nontransponding flyers such as hang gliders, hot air balloons, and some general aviation aircraft. These airspace users may either not be equipped with transponders or may not be using them; they rely on their eyes to "see-and-avoid" other traffic. Global Hawk's cruise altitude is well above most other aircraft so the key flight phases to investigate were early in climb and late in descent, when the likelihood of encounters with low altitude, non-controlled and non-transponding aircraft is greatest. Specifically, interest was in those operating in the altitude range from the ceiling of Class C airspace above Beale AFB (4100 feet) up to positive control airspace (Class A airspace with a floor of 18,000 feet). The results offer insight into the air traffic around Beale AFB by quantifying hourly and day-of-the-week patterns, showing an altitude distribution of the traffic, providing a breakdown of users by air carrier and general aviation operations and by class of aircraft flown, and by tabulating nearby origin/destination airports used. The Air Force used this information in requesting FAA permission to operate Global Hawk out of Beale AFB.