- Airborne early warning and control
An airborne early warning and control (AEW&C) (or more commonly and historically an AWAC) system is an airborne radar system designed to detect aircraft at long ranges and control and command the battle space in an air engagement by directing fighter and attack plane strikes. AEW&C/AWAC units are also used to carry out surveillance, including over ground targets and frequently perform C2BM (command and control, battle management) functions similar to an Airport Traffic Controller given military command over other forces. Used at a high altitude, the radars on the aircraft allow the operators to distinguish between friendly and hostile aircraft hundreds of miles away.
AWAC/AEW&C aircraft are used for both defensive and offensive air operations, and are to the NATO and USA forces trained or integrated Air Forces what the Command Information Center is to a Navy Warship, plus a highly mobile and powerful radar platform. The system is used offensively to direct fighters to their target locations, and defensively in order to counter attacks by enemy forces, both air and ground. So useful is the advantage of command and control from a high altitude, the United States Navy operates AWAC aircraft off its Supercarriers to augment and protect its Carrier Command Information Centers (CICs)
AEW&C is also known by the older terms "airborne early warning" (AEW) and "airborne warning and control system" (AWACS, // ay-waks).
- 1 General characteristics
- 2 History of development
- 3 National use
- 4 Helicopter AEW systems
- 5 AWACS systems
- 6 List of AEW&C aircraft types
- 7 See also
- 8 References
- 9 External links
Modern AEW&C systems can detect aircraft from up to 250 miles (400 km) away, well out of range of most surface-to-air missiles. One AWACS plane flying at 30,000 feet (9,100 m) can cover an area of 120,460 square miles (312,000 km2). Three such aircraft in overlapping orbits can cover the whole of Central Europe. In air-to-air combat, AEW&C systems can communicate with friendly aircraft, extend their sensor range and give them added stealth, since they no longer need their own active radar to detect threats. However, by the nature of radar, AWACS aircraft can be detected by opposing forces beyond its own detection range. This is because the outgoing pulse reduces in strength the further it travels. Therefore, a signal intended to reflect back must be strong enough to cover at least twice the distance between the sender and the target—more in practice due to absorption losses.
History of development
As part of their early use of radar, the British developed a radar set that could be carried on an aircraft for "Air Controlled Interception". The intention was to cover the North West approaches where German long range Fw 200 Condor aircraft were a threat to shipping. A Vickers Wellington bomber (serial R1629) was fitted with a rotating antenna array. It was trialled for use against aerial targets and then for possible use against German E boats. Another installation was a radar equipped Wellington used to direct Bristol Beaufighters onto Heinkel He 111s, which were air-launching V-1 flying bombs.
In February 1944 the U.S. Navy ordered the development of a radar system that could be carried aloft in an aircraft as Project Cadillac. A prototype system was built and flown in August on a modified TBM Avenger torpedo bomber. Tests proved successful, with the system being able to detect low flying formations at a range in excess of 100 miles (160 km). The U.S. Navy then ordered production of the TBM-3W, the first AEW aircraft to enter service. TBM-3Ws fitted with the AN/APS-20 radar entered service in March 1945, with some 36–40 eventually being constructed.
In 1958, the Soviet Tupolev Design Bureau was also ordered to design an AWACS aircraft. After trying to fit the projected radar instrumentation in a Tu-95 and a Tupolev Tu-116, the decision was made to use the Tu-114 fuselage instead. This solved the problems with cooling and operator space that existed with the narrower Tu-95 and Tu-116 fuselage. To meet the flight range requirements, the plane was fitted with an air-to-air refueling receiver. The resulting plane, the Tu-126, was used by the Soviet Air Forces until it was replaced by the Beriev A-50 in 1984.
Many countries have developed their own AEW&C systems, although the Boeing E-3 Sentry and Northrop Grumman E-2 Hawkeye are the most common systems worldwide. The E-3 Sentry was built by the Boeing Defense and Space Group (now Integrated Defense Systems) and is based on the Boeing 707-320 aircraft. 65 E-3 were built and it is operated by NATO and four nations. The specially designed Grumman E-2 Hawkeye entered service in 1965 and has been operated by eight different nations. Over 168 have been produced so far and new versions continue to be developed making it the most widely used AEW system. For the Japan Air Self-Defense Force, the E-3 technology has been fitted into the Boeing E-767.
After World War 2, the United Kingdom deployed a substantial AEW capability with American Douglas AD-4W Skyraiders, designated Skyraider AEW.1, which in turn were replaced by the Fairey Gannet AEW.3, using the same AN/APS-20 radar. When the Gannet was withdrawn, the Royal Air Force (RAF) redeployed the radars from the Gannets onto Avro Shackleton MR.2 airframes, redesignated Shackleton AEW.2. To replace the Shackleton AEW.2, an AEW variant of the Hawker Siddeley Nimrod, known as the Nimrod AEW3, was ordered in 1974. However, after a protracted and problematic development, this was cancelled in 1986, and seven E-3Ds, designated Sentry AEW.1 in RAF service, were purchased instead.
The Russian Air Force is currently using around 15–20 Beriev A-50 and A-50U "Shmel" in the AEW role. The "Mainstay" is based on the Ilyushin Il-76 airframe, with a large non-rotating disk radome on the rear fuselage. These replaced the 12 Tupolev Tu-126 that filled the role previously.
The Royal Australian Air Force and the Turkish Air Force are deploying Boeing 737 AEW&C aircraft. Unlike the E-2 and E-3, the Boeing 737 AEW&C does not use a rotating disk radome (rotodome) but instead has a large dorsal fin. It will probably be marketed towards many existing E-2 customers, who would otherwise have no choice but to purchase a system intended for an aircraft carrier, due to lack of options.
In early 2006, the Pakistan Air Force ordered six Saab 2000 fitted with Erieye AEW systems from Sweden in a deal valued roughly $1bn. In December 2006, the Pakistan Navy requested three excess P-3 Orion aircraft equipped with Hawkeye 2000 AEW systems, the overall cost of the program is $855mn. China and Pakistan also signed a memorandum of understanding (MoU) for the joint development of AEW&C systems. A total of $278m AWACS deal has been struck with China.
Some AEW systems feature additional command and control functionality, airborne warning and control system aircraft. These are often referred to as airborne early warning and control (AEW&C) systems.
Helicopter AEW systems
There are only four helicopter-based AEW platforms in existence. One is the Royal Navy Sea King ASaC7 naval helicopter. It is operated from the Royal Navy's Invincible-class aircraft carriers. The creation of Sea King ASaC7, and earlier AEW.2 and AEW.5 is the consequence of the harsh lessons learnt by the Royal Navy in the 1982 Falklands War when the lack of AEW coverage for the task force was a major tactical shortcoming. Also, the Spanish Navy fields the SH-3 Sea King in the very same role, operated from the carriers Principe de Asturias and Juan Carlos I
Another helicopter is the Russian-built Kamov Ka-31, deployed by Indian Navy on Krivak-III frigates and reportedly used by the Russian Navy on its sole Kuznetsov aircraft carrier. It is fitted with E-801M Oko (Eye) airborne electronic warfare radar that can track up to 20 targets simultaneously with aerial detection range 90 mi (150 km) and surface warships up to 160 mi (250 km).
The most modern helicopter-based AEW is the AgustaWestland EH101 AEW of the Italian Navy.
Boeing/Westinghouse AWACS system
This is a specific system with a rotating radar dome "rotodome" radome designed and built by Boeing (Defense & Space Group) using Westinghouse (now Northrop Grumman) radar. It is mounted on either the E-3 Sentry aircraft (Boeing 707) or more recently a modified Boeing 767. Only the Japanese Air Self-Defense Force has the 767 version, calling it the E-767.
Elta/Israeli Aircraft Industries (IAI) PHALCON radar
Israel has developed the IAI/Elta Phalcon system, which uses an AESA (Active Electronically Scanned Array) in lieu of a rotodome antenna. The system was the first such advanced radar placed into service. The original Phalcon was mounted on a Boeing 707 platform  and developed for the Israeli Defense Force and for export. A Boeing 707 Phalcon system was delivered to Chile in 1993 where it is known as the “Condor”.
The Phalcon AEW&C aircraft is based on four sensors: phased-array radar, phased-array IFF, ESM/ELINT and CSM/COMINT. When one of the sensors reports a detection, the system automatically initiates an active search of the complementary sensors.
The second generation improvement of the Phalcon system was accomplished in the development of the Israeli ground based IAI EL/M-2080 "Green Pine" radar target tracking system used by the Israeli Defense Force. This system has been exported to several countries.
Israel has recently put in service a third generation variant of the Phalcon system on a highly modified Gulfstream G550  aircraft. Equipped with a more efficient and compact version of this airborne radar made by the ELTA division of Israel Aircraft Industries (IAI), the Gulfstream 550 CAEW is a long endurance, high altitude, rapid pop-up and descent system with unobstructed 360° coverage.
Israel Aircraft Industries (IAI) was marketing its Phalcon airborne early warning (AEW) system to China in competition with the British defense firm GEC-Marconi. In 1996 Tel Aviv and Beijing signed an agreement on purchasing the Phalcon radar system, which China insisted should be fitted onto Russian Ilyushin Il-76 aircraft. The Phalcon's triangular radar array would be mounted on the rear quarter fuselage of the Il-76 to provide full 360° scan coverage. Beijing was expected to acquire several PHALCON AEW systems, and reportedly could buy at least three more [and possibly up to eight] of these systems. But in July 2000 the United States pressured Israel to back out of a $1 billion agreement to sell China four Phalcon phased-array radar systems.
The India Air Force agreed in 2004 to purchase three systems for $1.1 billion. Russia and Israel on 10 October 2004 signed a tripartite agreement to facilitate the equipping of the Indian Air Force (IAF) with the Phalcon airborne warning and control systems. The IAF plans to mount the Phalcon radar and surveillance systems from IAI on Il-76 aircraft supplied by Russia. India received its first AWACS on 25 May 2009.
List of AEW&C aircraft types
- Airborne Surveillance Platform
- Avro Shackleton AEW.2
- Beriev A-50 Shmel
- Boeing 737 AEW&C
- Boeing E-3 Sentry
- Boeing E-767
- Boeing PB-1W Flying Fortress
- British Aerospace Nimrod AEW3
- Douglas AD-3W/4W/5W Skyraider
- DRDO AEW&CS
- EADS CASA C-295 AEW
- Embraer R-99A Erieye
- Fairey Gannet AEW.3
- Grumman AF-2W Guardian
- Grumman E-1 Tracer
- Grumman E-2 Hawkeye
- Grumman TBM-3W Avenger
- HESA IrAn-140
- IAI 707 Phalcon / Gulfstream G550
- IAI Eitam
- KJ-1 AEWC
- Lockheed EC-121 Warning Star
- Lockheed EC-130V Hercules
- Lockheed P-3 AEW&C
- Saab 340 AEW&C (S 100 B/D Argus)
- Saab 2000 AEW&C
- Shaanxi Y-8 AWACS/Y-8J AEW
- Tupolev Tu-126
- ^ "AWACS: NATO’s eyes in the sky – How does it work in practice?". http://www.nato.int/issues/awacs/practice.html.
- ^ Air-Britain, Aviation World, 2004
- ^ Hodges, R "Air controlled interception" Radar Development to 1945 R W Burns (ed)
- ^ Flypast April 1987: "The First AWACS"
- ^ "BAe Nimrod AEW 3." Spyflight. Retrieved: 21 October 2010.
- ^ "Arms deal underway, first Israeli Phalcon lands in India – Israel News, Ynetnews". Ynetnews.com. June 20, 1995. http://www.ynetnews.com/articles/0,7340,L-3721499,00.html. Retrieved June 1, 2009.
- ^ 07-Apr-2008 11:12 EDT (April 7, 2008). "Sweden Finalizes Saab 2000 AEW&C Contract With Pakistan". Defenseindustrydaily.com. http://www.defenseindustrydaily.com/sweden-finalizes-saab-2000-aewc-contract-with-pakistan-02377/. Retrieved June 1, 2009.
- ^ "C4ISRJournal.com". C4ISRJournal.com. December 11, 2006. http://www.c4isrjournal.com/story.php?F=2416333. Retrieved June 1, 2009.
- ^ "$278m AWACS deal struck with China: PAF » www.idrw.org / Indian Defense Research Wing". Idrw.org. http://www.idrw.org/2008/12/18/278m_awacs_deal_struck_with_china_paf.html. Retrieved June 1, 2009. [dead link]
- ^ B707 Phalcon, “Israeli Weapons.com”
- ^ “Israel Now Flying New Phalcon AWACS”, “By Aero News 2/20/06 on OCNUS.NET”, “Oct 4, 2006”
- NATO AWACS-Spotter Geilenkirchen website
- FAS.org E-3 Sentry information
- Boeing AWACS website
- Airborne Early Warning Association website
- TU-126 MOSS AWACS – history of development- in Russian
- Aiborne radar "Gneis-2" – in Russian
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