Directing The AIR WAR

At all hours of day and night, E-3 Sentry AWACS (Airborne Warning and Control System) jet transports crammed with sophisticated radar gear operated by highly trained specialists are flying over Saudi Arabia. They serve both as airborne flight controllers for all of the allied sorties and as spotters of enemy aircraft, missile and ships.

Radar Modes The 30-foot rotating dome contains two antennas mounted back-to-back: the primary radar antenna and the Identification Friend or Foe (IFF) antenna. The searchlight-like beams from these allow controllers to see down to ground level to detect ships and low-flying planes into the stratosphere to detect incoming missiles and for more than 200 miles beyond the horizon. The radars can be operated in several different modes: IFF-- Identification Friend or Foe radios contact special radio transmitter/receivers on all aircraft in the vicinity to ascertain their identities and other characteristics, including elevation and direction of flight. PDNES-- Pulse Doppler radar, like that used in airports, shows the position and sped of aircraft but not their elevation. PDES-- Pulse Doppler elevation scans show the aircraft’s height as well as its location and speed. BTH-- Beyond-the-horizon radar shows the position of aircraft but not their speed and elevation. Used for extended range surveillance. Maritime-- Very high frequency radar can distinguish reflections off ships from those off the ocean’s surface. Passive-- With radar acting only in a receiving mode, technicians can detect enemy radar and electronic countermeasures without broadcasting a signal that would give their own position away. Identification Friend or Foe

The AWACS planes have a sophisticated IFF system that contacts special radio transmitter/receivers on planes and missiles. These units continuously broadcast the aircraft’s direction, altitude and identification code.

An enemy plane or missile will not be able to broadcast the correct identification code and will be instantly recognized as a foe. Controllers see such intruders on their color-coded consoles as a red inverted “V” and also hear a warning tone in their headsets. One reason the Israeli Air Force has not been able to retaliate for Iraq’s Scud missile attacks is that pilots have not been given the codes that would identify them as friendly and thereby prevent them from being shot down Looking Beyond the Horizon

Conventional radar uses very high frequency radiation that penetrates the Earth’s ionosphere and continues out into space. Beyond-the-horizon radar uses much lower frequencies that bounce off the ionosphere and are thereby reflected back toward the Earth’s surface far from the radar site. Radar waves that strike an aircraft are bounced back to the ionosphere, where they are reflected back to the AWACS plane. Because only a very small fraction of the radar waves makes this entire journey, very sensitive receivers are required. Boeing E-3 Sentry

Airframe: Based upon Boeing’s Model 707/717 Maximum speed: 530 m.p.h. Normal operating speed: About 350 m.p.h. Endurance: 22 hours with one refueling, 11 hours without Maximum range: 6,496 nautical miles Ceiling: 39,000 feet Station altitude: 30,000 feet Radar search radius: 220 nautical miles Tracking capability: 100 targets Armament: None Air Crew: The cockpit houses a crew of four, including the pilot, copilot, navigator and flight engineer. AWACS Specialists The mission crew commander is in charge of radar surveillance and supervises the two kinds of specialists that man the many radar consoles and auxiliary display units. The total number of specialists usually ranges between 12 and 15, according to the demands of the situation.

Air Surveillance Technicians keep track of all the friendly and enemy aircraft in the vicinity, as well as ships, ground troops and missiles. They also handle all communication with ground stations.

Weapons controllers guide the aircraft that are attacking enemy planes and missiles, coordinating their efforts and alerting them to threats. They can also warn of incoming Scud missiles, coordinate close air support for ground troops and point out enemy ships to Navy patrols.