E-3 Sentry (AWACS): Aircraft profile
The E-3 Sentry is an airborne warning and control system, or AWACS, aircraft with an integrated command and control battle management, or C2BM, surveillance, target detection, and tracking platform.
The aircraft provides an accurate, real-time picture of the battlespace to the Joint Air Operations Center. AWACS provides situational awareness of friendly, neutral and hostile activity, command and control of an area of responsibility, battle management of theater forces, all-altitude and all-weather surveillance of the battle space, and early warning of enemy actions during joint, allied, and coalition operations.
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 11 feet (3.33 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). The radar combined with an identification friend or foe, or IFF, 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.
Major subsystems in the E-3 are avionic, navigation, communications, sensors (radar and passive detection) and identification tools (IFF/SIF). The mission suite includes consoles that display computer-processed data in graphic and tabular format on video screens. Mission crew members 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. 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 also be forwarded to the president and secretary of defense 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.
AWACS may be employed alone or horizontally integrated in combination with other C2BM and intelligence, surveillance, and reconnaissance elements of the Ground Theater Air Control System. It supports decentralized execution of the air tasking order/air combat order. The system provides the ability to find, fix, track and target airborne or maritime threats and to detect, locate and ID emitters. It has the ability to detect threats and control assets below and beyond the coverage of ground-based command and control or C2, and can exchange data with other C2 systems and shooters via datalinks.
With its mobility as an airborne warning and control system, the Sentry has a 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 approximately 8 hours without refueling. Its range and on-station time can be increased through in-flight refueling and the use of an on-board crew rest area.
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.
There are 33 aircraft in the U.S. inventory. Air Combat Command has 28 E-3s at Tinker. Pacific Air Forces has four E-3 Sentries at Kadena AB, Japan and Elmendorf AFB, Alaska. There is also one test aircraft at the Boeing Aircraft Company in Seattle.
NATO has 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 AWACS housed on the Boeing 767 airframe.
As proven in operations Desert Storm, Allied Force, Enduring Freedom and Iraqi Freedom, the E-3 Sentry is the premier C2BM aircraft in the world. AWACS aircraft and crews were instrumental to the successful completion of operations Northern and Southern Watch, and are still engaged in operations Noble Eagle and Enduring Freedom. They provide radar surveillance and control in addition to providing senior leadership with time-critical information on the actions of enemy forces.
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 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 involved a major hardware and software intensive modification to the existing radar system. Installation of RSIP enhanced the operational capability of the E-3 radar electronic counter-measures, and has improved the system's reliability, maintainability and availability.
Primary Function: Airborne battle management, command and control
Contractor: Boeing Aerospace Co.
Power Plant: Four Pratt and Whitney TF33-PW-100A turbofan engines
Thrust: 21,000 pounds each engine
Rotodome: 30 feet in diameter (9.1 meters), 6 feet thick (1.8 meters), mounted 11 feet (3.33 meters) above fuselage
Wingspan: 145 feet, 9 inches (44.4 meters)
Length: 152 feet, 11 inches (46.6 meters)
Height: 41 feet, 9 inches (13 meters)
Weight: 335,000 pounds (151,955 kilograms)
Maximum Takeoff Weight: 347,000 pounds (156,150 kilograms)
Fuel Capacity: 23,000 gallons (104,560 liters)
Speed: optimum cruise 360 mph (Mach 0.48)
Range: more than 5,000 nautical miles (9,250 kilometers)
Ceiling: Above 29,000 feet (8,788 meters)
Crew: Flight crew of four plus mission crew of 13-19 specialists (mission crew size varies according to mission)
Unit Cost: $270 million (fiscal 98 constant dollars)
Initial operating capability: April 1978
Inventory: Active force, 33 (1 test); Reserve, 0; Guard, 0
The Boeing E-3 Sentry is an American military airborne warning and control system (AWACS) aircraft that provides all-weather surveillance, command, control and communications, to the United States, United Kingdom, France, Saudi Arabia, and NATO air defense forces. Production ended in 1992 after 68 had been built.
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. The dome weighs approximately 1.5 tons and provides 1.5 tons of lift. It contains a hydraulically rotated antenna system that permits the AN/APY-1/2 passive electronically scanned array 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 one megawatt of power required by the radar. The Pulse Doppler radar has a range of more than 250 miles (400 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 (650 km) 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.
The first E-3 Sentry rolled out of the Boeing factory on February 1, 1972
The USAF E-3 fleet completed its largest upgrade in 2001. Known as the Block 30/35 Modification Program, the upgrade includes four enhancements:
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).
Since the Boeing 707 is no longer in production, the E-3 mission package has been fitted into the Boeing E-767 for the Japan Air Self Defence Force. The E-10 MC2A was intended to replace the United States operated E-3 (along with the RC-135 and the E-8 Joint STARS), but the E-10 program has been canceled. The USAF has now taken a new direction with the E-3 platform. It is investing and currently testing its block 40/45 modification. Currently, the USAF has one Block 40/45 E-3 that is under going flight testing, research and development. Another program that is currently in R&D is the Airframe Modernization Program (AMP). AMP would provide the E-3 with a glass cockpit and possibly re-engine the USAF fleet of E-3's with an engine that is more reliable and at least 20% more fuel efficient. New engines would give the USAF E-3's a longer range, longer time on station, shorter critical runway length (meaning the E-3 could now operate with a full fuel load on a runway with only 10,000 feet at higher temperatures and pressure altitude) and at a higher altitude that would provide better range for its line of sight sensors.
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 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.
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.
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.
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 the 552d Air Control Wing at Tinker Air Force Base, Oklahoma received the first E-3 aircraft.
Radar System Improvement Program
The Radar System Improvement Program (RSIP) was a joint U.S./NATO development program. RSIP enhances the operational capability of the E-3 radar electronic counter-measures, and dramatically improve the system's reliability, maintainability and availability. 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).
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.
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.
The U.K. also has joined the U.S. in adding RSIP to upgrade their radar. Retrofit of the fleet was completed in December 2000. Along with the RSIP upgrade was installation of the Global Positioning System/Inertial Navigation Systems which dramatically improve positioning accuracy. In 2002, Boeing was awarded a contract to add RSIP to the French AWACS fleet. Installation was completed in 2006.
In total, 68 aircraft were built, with 2 hull losses (one USAF aircraft, one NATO aircraft).
The United States Air Force have a total of 33 E-3s in active service. 28 are stationed at Tinker AFB and belong to the Air Combat Command (ACC). Four are assigned to the Pacific Air Forces (PACAF) 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.
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-3As are in the inventory, since one NATO E-3 was lost in a crash.
NATO members United Kingdom and France are not part of the NATO E-3A Component, instead procuring E-3 aircraft through a joint project. The UK and France operate their E-3 aircraft independently of each other and of NATO. The UK operates seven aircraft and France operates four aircraft, all fitted with the newer CFM56-2 engines. 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.
The other operator of the type is Saudi Arabia which operates five aircraft, all fitted with CFM56-2 engines. Japan has four Boeing E-767 aircraft equipped to similar standards.
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 Operation 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.
In March 1996, the US Air Force activated the 513th Air Control Group (513 ACG), an ACC-gained Air Force Reserve Command (AFRC) AWACS unit under the Reserve Associate Program. Collocated with the 552 ACW at Tinker AFB, the 513 ACG which performs similar duties on active duty E-3 aircraft shared with the 552 ACW.
Two prototype AWACS aircraft with JT3D engines, one fitted with a Westinghouse radar and the other with a Hughes radar. Both converted to E-3A standard with TF33 engines.
Production aircraft with TF33 engines and AN/APY-1 radar, 25 built for USAF later converted to E-3B standard. 18 built for NATO with TF33 engines and five for Saudi Arabia with CFM56 engines.
These are not AWACS aircraft but CFM56 powered tankers for Saudi Arabia, 8 built.
E-3As converted with AN/APY-2 radar and other improvements, 24 conversions.
Production aircraft with system improvements, nine built. NATO E-3A aircraft although not re-designated have been modified to the same equipment standard.
One E-3A aircraft used by Boeing for trials later redesignated E-3C.
Production aircraft for the Royal Air Force to E-3C standard with CFM56 engines and British modifications designated Sentry AEW.1, seven built.
Production aircraft for the French Air Force to E-3C standard with CFM56 engines and French modifications, four built.
USAF Block 40/45 modification with Airframe Modernization Program (AMP).
British designation for the E-3D.
used for E-3 Sentry crew proficiency training. No mission equipment.
More photos: E-3 Sentry (AWACS) photo gallery
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