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E-3 Sentry
United States Air Force E-3 Sentry
Type	Airborne Warning and Control System (AWACS)
Manufacturer	Boeing Integrated Defense Systems Northrop Grumman (radar)
Maiden flight	October 1975
Introduction	March 1977
Primary users	United States Air Force Royal Air Force French Air Force NATO
Produced	-1991
Number built	68
Developed from	Boeing 707-320

The Boeing E-3 Sentry is a military airborne warning and control system (AWACS) aircraft that provides all-weather surveillance, command, control and communications, to the United States, United Kingdom, France, NATO and other air defense forces. Production ended in 1992 after 68 had been built.^[1][2]

Contents 1 Background 1.1 Inventory 2 Radar System Improvement Program 3 Future direction 4 Operators 5 Specifications 5.1 USAF/NATO aircraft 5.2 Royal Air Force/Royal Saudi Air Force/French Air Force aircraft 6 References 7 External links 8 Related content

The E-3 Sentry is a modified Boeing 707-320B Advanced commercial airframe. Modifications included a rotating radar dome, single-point ground, and air refueling points. The dome is 30 feet (9.1 m) in diameter, six feet (1.8 m) thick at the center, and is held 14 feet (4.2 m) above the fuselage by two struts.^[1] It contains a hydraulically rotated antenna system that permits the AN/APY-1/2 radar system to provide surveillance from the Earth's surface up into the stratosphere, over land or water. Generators on each of the four engines provide the 1 megawatt of power required by the radar.^[1] The Pulse Doppler radar has a range of more than 250 miles (375 km) for low-flying targets at its operating altitude (essentially to the radar horizon), and the Pulse(BTH) beyond the horizon radar has a range of approximately 400 miles for aerospace vehicles flying at medium to high altitudes (essentially above the radar horizon). The radar combined with an SSR subsystem can look down to detect, identify and track enemy and friendly low-flying aircraft by eliminating ground clutter returns. ^[1][3][2]

The USAF E-3 fleet completed its largest upgrade in 2001. Known as the Block 30/35 Modification Program, the upgrade includes four enhancements: ^[4]

• Electronic Support Measures (ESM) for passive detection, an electronic surveillance capability to detect and identify air and surface-based emitters.
• Joint Tactical Information Distribution System (JTIDS) 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 (Link-16), ESM and future enhancements.
• Global Positioning System (GPS).

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.^[1]

The radar and computer subsystems on the E-3 Sentry can gather and present broad and detailed battlefield information. Data are 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 times of crisis, data can be forwarded to the National Command Authority in the United States.^[1]

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, whilst as an air defense asset, E-3s can detect, identify and track airborne enemy forces far from the boundaries of the United States or NATO countries and can direct fighter-interceptor aircraft to these enemy targets.^[1]

The E-3 as equipped in USAF and NATO service can fly without refueling for 8 hours or 4000 miles, whilst newer examples in British, French and Saudi service, equipped with CFM56-2 engines can fly for 10 hours or 5000 miles without refuelling. Its range and on-station time can be increased through inflight refueling and the use of an on-board crew rest area. The range and loiter time can be used to alter the flight plan as required for operation reasons. ^[1][2]

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, Oklahoma), received the first E-3s.^[1]

In total, 68 aircraft were built, with 2 hull losses (one USAF aircraft, one NATO aircraft) ^[5][6]

The United States Air Force have a total of 33 E-3 aircraft in active service. 28 of these are stationed at Tinker AFB and belong to the Air Combat Command. Four E-3 aircraft are assigned to the Pacific Air Forces and stationed at Kadena AB, Okinawa and Elmendorf AFB, Alaska. One aircraft (TS-3) is assigned to the Boeing Aircraft Company for testing and development purposes. ^[1]

NATO acquired 18 E-3As and support equipment for a NATO air defense force. Since all aircraft must be registered with a certain country, the decision was made to register the 18 NATO AWACS planes with Luxembourg, a NATO country that until that point had not had any air force. The first NATO E-3 was delivered in January 1982. Presently 17 NATO E-3A's are in the inventory, since one NATO E-3 was lost in a crash.^[6]

NATO members Britain and France are not part of the NATO E-3A Component, instead procuring E-3 aircraft through a joint project. Britain and France operate their E-3 aircraft independently of each other and of NATO. ^[7] Britain operates 7 aircraft and France operates 4 aircraft, all fitted with the newer CFM56-2 engines. ^[2] The British requirement came about following unsatisfactory tests with modified Hawker Siddeley Nimrod aircraft to replace the Avro Shackleton AEW platform in the early 1970s. ^[6]

The other operator of the type is Saudi Arabia which operates five aircraft, all fitted with CFM56-2 engines ^[2]. Japan has four Boeing 767 based aircraft equipped to similar standards. ^[1]

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 forces. During Desert Storm, E-3s flew more than 400 missions and logged more than 5,000 hours of on-station time. 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 history. 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.^[1]

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.^[1]

The Radar System Improvement Program (RSIP) was a joint U.S./NATO development program.^[1] RSIP enhances the operational capability of the E-3 radar electronic counter-measures, and dramatically improve the system's reliability, maintainability and availability.^[1] This hardware and software modification to the E-3 improves radar set performance providing enhanced detection of targets, with an emphasis toward those with a low radar cross section (RCS).^[1] Major advantages include: Increased range against reduced RCS targets to include cruise missiles; Improved electronic counter-counter measures (ECCM) against current threats; Improved radar system reliability and maintainability (R&M); and Improved radar control and maintenance panel (RCMP) with embedded test equipment.^[1] RSIP utilizes a Pulse Doppler Pulse Compression (PDPC) waveform, increases data sampling rates, increases range and velocity resolution, increases signal integration time, adds new signal processing algorithms to enhance detection sensitivity and unambiguous range determination, and improves radar set monitoring and control. RSIP is a huge leap forward in a variety of factors. It increases the ability to detect and track smaller targets at greater distances, akin to giving the radar a set of binoculars. It also improves the reliability and maintainability for the radar hardware, which decreases the number of spares and amount of down time needed for repairs. Improved control and processing algorithms tailored to current threat data enhances system electronic counter-countermeasure (ECCM) capabilities. The improved electronic counter-counter measures mean it will be much more difficult for enemy forces to deceive or "jam" the AWACS with false electronic signals. U.S. installation of RSIP was completed in fiscal year 2004, and France completed their aircraft in 2005. ^[1][8]

Since the Boeing 707 is no longer in production, the E-3 mission package has been fitted into a Boeing 767 for the Japan Air Self Defence Force.

The E-10 MC2A, based upon the Boeing 767-400ER airframe, was intended to replace the United States operated E-3 (along with the RC-135 and the E-8 Joint STARS), but budget cutbacks have clouded its future.

North Atlantic Treaty Organisation (NATO)

Based in Geilenkirchen, Germany, 18 E-3 AWACS were purchased - one lost in Greece. All of these aircraft are officially registered as aircraft of Luxembourg, a NATO member with no other Air Force. Responsible for monitoring airspace for NATO operations around the world.

• Squadron 1
• Squadron 2
• Squadron 3
• Training Wing

 France

The French Air Force purchased 4 E-3F aircraft similar to the British E-3D aircraft.

• EDCA 01.036
• EDCA 02.036

 Saudi Arabia

The Royal Saudi Air Force purchased five E-3A aircraft and eight KE-3A tanker aircraft in 1983.

• No. 18 Squadron RSAF

 United Kingdom

Royal Air Force purchased 6 (later increased to 7) E-3D aircraft in December 1986. The aircraft are designated Sentry AEW1.

• No. 8 Squadron
• No. 23 Squadron

 United States

The United States Air Force purchased 34 E-3As (24 later modified to E-3B and 10 to E-3C). One E-3B crashed, killing all 24 crew members onboard, after ingesting several Canada geese into its two left engines at Elmendorf AFB, Alaska on September 22, 1995. Another is on loan to Boeing Integrated Defense Systems for continuous testing, research, and development.

• 552d Air Control Wing has 28 E-3s stationed at Tinker AFB, Oklahoma---Picture of the 76-1604, a US Air Force E-3B Sentry
• 960th AACS
• 963rd AACS
• 964th AACS
• 965th AACS
• 966th AACS
• 3rd Wing has 2 at Elmendorf AFB, Alaska
• 962nd AACS
• 18th Wing has 2 at Kadena AB, Japan
• 961st AACS

General characteristics

• Crew: Flight crew:4
  Mission crew:13-19
• Length: 152 ft 11 in (46.61 m)
• Wingspan: 145 ft 9 in (44.42 m)
• Height: 41 ft 4 in (12.6 m)
• Wing area: 3,050 ft² (283.4 m²)
• Empty weight: 162,000 lb (73,480 kg)
• Loaded weight: 325,000 lb (147,400 kg)
• Max takeoff weight: 347,000 lb (156,000 kg)
• Powerplant: 4× Pratt and Whitney TF33-PW-100A turbofan, 21,000 lbf (93 kN) each

Performance

• Maximum speed: 530 mph (855 km/h)
• Range: 4,000 NM (8 Hours), unrefueled (7,400 km)
• Service ceiling: 29,000 ft (9,000 m)

General characteristics

• Crew: Flight crew:4
  Mission crew:14
• Capacity: 35
• Length: 152 ft 11 in (46.61 m)
• Wingspan: 145 ft 9 in (44.42 m)
• Height: 41 ft 4 in (12.6 m)
• Wing area: 3,050 ft² (283.4 m²)
• Empty weight: 185,000 lb (83,990 kg)
• Loaded weight: 335,000 lb (152,090 kg)
• Max takeoff weight: 334,000 lb (151,636 kg)
• Powerplant: 4× CFM International CFM56 turbofan, 24,000 lbf (107 kN) each

Performance

• Never exceed speed: 0.83 mach
• Maximum speed: 0.78 mach (855 km/h)
• Cruise speed: 0.72 mach (eco)
• Range: 4,000 NM unrefueled, much more refueled (7,400 km)
• Service ceiling: 43,000 ft (13,106 m)
• Rate of climb: 2000 ft/mn ()

• Royal Air Force E-3 Sentry information
• NATO AWACS-Spotter Geilenkirchen website
• World's AirSpace's E-3 page

Related development

• KC-135 Stratotanker

Comparable aircraft

• Beriev A-50 Mainstay

Designation sequence

• E-1 - E-2 - E-3 - E-4 - E-5 - E-6

Related lists

• List of active United States military aircraft
• List of active United Kingdom military aircraft

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