E-3 Sentry

The E-3 Sentry is an airborne warning and control system (AWACS) aircraft that provides all-weather surveillance, command, control and communications needed by commanders of U.S., NATO and other allied air defense forces. As proven in Operation Allied Force[?], it is the premier air battle command and control aircraft in the world today.

The E-3 Sentry is a modified Boeing 707-320 commercial airframe with a rotating radar dome. The dome is 30 feet (9.1 meters) in diameter, six feet (1.8 meters) thick, and is held 14 feet (4.2 meters) above the fuselage by two struts. It contains a radar subsystem that permits surveillance from the Earth's surface up into the stratosphere, over land or water. The radar has a range of more than 250 miles (375.5 kilometers) for low-flying targets and farther for aerospace vehicles flying at medium to high altitudes. The radar combined with an identification friend or foe subsystem can look down to detect, identify and track enemy and friendly low-flying aircraft by eliminating ground clutter returns that confuse other radar systems.

The E-3 fleet completed its largest upgrade in 2001. Known as the Block 30/35 Modification Program, the upgrade includes four enhancements:

• Electronic Support Measure for passive detection, an electronic surveillance capability to detect and identify air and surface-based emitters.
• Joint Tactical Information Distribution System to provide secure, anti-jam communication for information distribution, position location and identification capabilities.
• An increase in the memory capability in the computer to accommodate JTIDS, EMS and future enhancements.
• Global Positioning System, a satellite-based positioning capability to provide precise global navigation.

Other major subsystems in the E-3 are navigation, communications and computers (data processing). Consoles display computer-processed data in graphic and tabular format on video screens. Console operators perform surveillance, identification, weapons control, battle management and communications functions.

The radar and computer subsystems on the E-3 Sentry can gather and present broad and detailed battlefield information. Data is collected as events occur. This includes position and tracking information on enemy aircraft and ships, and location and status of friendly aircraft and naval vessels. The information can be sent to major command and control centers in rear areas or aboard ships. In time of crisis, this data can be forwarded to the National Command Authorities[?] in the United States.

In support of air-to-ground operations, the Sentry can provide direct information needed for interdiction, reconnaissance, airlift and close-air support for friendly ground forces. It can also provide information for commanders of air operations to gain and maintain control of the air battle.

As an air defense system, E-3s can detect, identify and track airborne enemy forces far from the boundaries of the United States or NATO countries. It can direct fighter-interceptor aircraft to these enemy targets.

Experience has proven that the E-3 Sentry can respond quickly and effectively to a crisis and support worldwide military deployment operations. It is a jam-resistant system that has performed missions while experiencing heavy electronic countermeasures.

With its mobility as an airborne warning and control system, the Sentry has an greater chance of surviving in warfare than a fixed, ground-based radar system. Among other things, the flight path can quickly be changed according to mission and survival requirements. The E-3 can fly a mission profile for more than 8 hours without refueling. Its range and on-station time can be increased through inflight refueling and the use of an on-board crew rest area.

The aircraft are used as a surveillance asset in support of counter drug missions. U.S. Customs Service[?] officers may fly aboard the E-3 Sentry on precoordinated missions to detect smuggling activities.

Engineering, test and evaluation began on the first E-3 Sentry in October 1975. In March 1977 the 552nd Airborne Warning and Control Wing (now 552nd Air Control Wing, Tinker Air Force Base, Okla.), received the first E-3s.

Air Combat Command has 28 E-3s at Tinker, two at Elmendorf AFB, Alaska, and one at Kadena AB, Japan. Pacific Air Forces has four E-3 Sentries assigned to the 961st Airborne Air Control Squadron (AACS), Kadena AB and the 962nd AACS, Elmendorf AFB.

NATO has acquired 17 E-3A's and support equipment. The first E-3 was delivered to NATO in January 1982. The United Kingdom has seven E-3s, France has four and Saudi Arabia has five. Japan has four Boeing 767-based AWACS aircraft. The British RAF order followed expensive unsuccessful trials of a domestic product, the BAe Nimrod AEW3.

E-3 Sentry aircraft were among the first to deploy during Operation Desert Shield where they immediately established an around-the-clock radar screen to defend against Iraqi aggression. During Desert Storm, E-3s flew more than 400 missions and logged more than 5,000 hours of on-station time. They provided radar surveillance and control to more than 120,000 coalition sorties. In addition to providing senior leadership with time-critical information on the actions of enemy forces, E-3 controllers assisted in 38 of the 40 air-to-air kills recorded during the conflict.

The data collection capability of the E-3 radar and computer subsystems allowed an entire air war to be recorded for the first time in the history of aerial warfare.

In March 1996, the US Air Force activated the 513th Air Control Group, an AWACS Reserve Associate Program unit, which performs duties on active-duty aircraft.

During the spring of 1999, the first AWACS aircraft went through the Radar System Improvement Program. RSIP is a joint U.S./NATO development program that involves a major hardware and software-intensive modification to the existing radar system. Installation of RSIP will enhance the operational capability of the E-3 radar electronic counter-measures, and dramatically improve the system's reliability, maintainability and availability. U.S. installation is RSIP is scheduled for completion in fiscal 2004.

General Characteristics

• Primary Function: Airborne surveillance, command, control and communications
• Builder: Boeing Aerospace Co.
• Power plants: Four Pratt and Whitney TF33-PW-100A turbofan engines
• Thrust: 21,000 pounds (9,450 kilograms) each engine
• Length: 145 feet, 6 inches (44 meters)
• Wingspan: 130 feet, 10 inches (39.7 meters)
• Height: 41 feet, 4 inches (12.5 meters)
• Rotodome: 30 feet in diameter (9.1 meters), 6 feet thick (1.8 meters), mounted 11 feet (3.33 meters) above fuselage
• Speed: Optimum cruise 360 mph (Mach 0.48)
• Ceiling: Above 29,000 feet (8,788 meters)
• Maximum takeoff weight: 347,000 pounds (156,150 kilograms)
• Endurance: More than 8 hours (unrefuelled)
• Unit cost: Approximately $300 million
• Crew: Flight crew of four plus mission crew of 13-19 specialists (crew varies according to mission)
• Date deployed: March 1977
• USAF inventory: Active force 33; Reserve 0; Guard 0