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Boeing E-3 Sentry

in 1987, USAF E-3s were upgraded under the "Block 30/35 Modification Program" to enhance the E-3's capabilities. On 30 October 2001, final airframe to be upgraded under this program was rolled out.[21] Several major enhancements were made, firstly the installation of electronic support measures (ESM) and an electronic surveillance capability, for both active and passive means of detection. The Joint Tactical Information Distribution System (JTIDS) provides rapid and secure communication for transmitting information, including target positions and identification data, to other friendly platforms. Global Positioning System (GPS) capability was also added. Onboard computers were also overhauled to accommodate JTIDS, Link-16, the new ESM systems and to provide for future enhancements.[21]

The Radar System Improvement Program (RSIP) was a joint US/NATO development program.[2] RSIP enhances the operational capability of the E-3 radars' electronic countermeasures, and dramatically improve the system's reliability, maintainability, and availability.[2] Essentially, this program replaced the older transistor-transistor logic (TTL) and emitter-coupled logic (MECL) electronic components, long-since out of production, with off-the-shelf digital computers that utilised a High-level programming language instead of assembly language. Significant improvement came from replacing the old 8-bit FFT with 24-bit FFTs, and the 12-bit A/D (Sign + 12-bits) with a 15-bit A/D (Sign + 15-bits).[9] These hardware and software modifications improve the E-3 radars' performance, providing enhanced detection with an emphasis towards low radar cross-section (RCS) targets.[2]

The RAF had also joined the USAF in adding RSIP to upgrade the E-3's radars. The retrofitting of the E-3 squadrons were 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 small French AWACS squadron. Installation was completed in 2006.[2][22]

Operational history

In March 1977 the 552nd Airborne Warning and Control Wing (now the 552d Air Control Wing) at Tinker AFB, Oklahoma received the first E-3 aircraft.[2] The 34th and last USAF Sentry was delivered in June 1984.[23] In March 1996, the USAF 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.[2]

Four-engined jet aircraft with disc-shaped radar on fuselage in-flight flanked by two jet fighters.
A RAF Boeing E-3D Sentry AEW1 accompanied by two Panavia Tornado F3s at Kemble Air Day. RAF AEW1s can be identified by the electronic support measures pods on the wingtips.[24]

The USAF have a total of thirty-one E-3s in active service. Twenty-seven 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) was assigned to Boeing for testing and development (retired/scrapped June 2012).[2]

In 1977 Iran placed an order for ten E-3's, however this order was cancelled following the 1979 revolution.

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 Sentries with Luxembourg, a NATO member that previously did not have any air force. The first NATO E-3 was delivered in January 1982.[24] The eighteen E-3s were operated by Number 1, 2 and 3 Squadrons of NATO's E-3 Component, based at NATO Air Base Geilenkirchen.[24] Presently 17 NATO E-3As are in the inventory, since one E-3 was lost in a crash.[23][25]

The United Kingdom and France are not part of the NATO E-3A Component, instead procuring E-3 aircraft through a joint project.[26] The UK and France operate their E-3 aircraft independently of each other and of NATO.[27] The UK operates six aircraft (with a seventh now retired)[28] and France operates four aircraft, all fitted with the newer CFM56-2 engines.[12] The British requirement came about following the cancellation of the British Aerospace Nimrod AEW3 project to replace the Avro Shackleton AEW2 during the 1980s. The UK E-3 order was placed in February 1987, with deliveries starting in 1990.[22][29] The other operator of the type, delivered between June 1986 and September 1987, is Saudi Arabia which operates five aircraft, all fitted with CFM56-2 engines,[12] This particular sale was hotly contested between the Reagan administration and opponents of the sale

E-3 Sentry aircraft were among the first to deploy during Operation Desert Shield, where they immediately established as an around-the-clock radar screen to defend against Iraqi forces. During Operation Desert Storm, E-3s flew 379 missions and logged 5,052 hours of on-station time.[30] 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 41 air-to-air kills recorded during the conflict.[2][30] NATO and RAF E-3s participated in the international military operation in Libya.[31]


Two prototype AWACS aircraft with JT3D engines, one fitted with a Westinghouse Electric radar and the other with a Hughes Aircraft Company radar. Both converted to E-3A standard with TF33 engines.
Production aircraft with TF33 engines and AN/APY-1 radar, 24 built for USAF later converted to E-3B standard, total of 34 ordered but the last 9 completed as E-3C.[32] One additional aircraft retained by Boeing for testing,[32] 18 built for NATO with TF33 engines and five for Saudi Arabia with CFM56 engines.[32]
These are not AWACS aircraft but CFM56 powered tankers based on the E-3 design. Eight were sold to Saudi Arabia.[32]
E-3As with improvements, 24 conversions.[32]
Production aircraft with AN/APY-2 radar, additional electronic consoles and system improvements, ten built.[33]
One E-3A aircraft used by Boeing for trials later redesignated E-3C.[32]
Production aircraft for the Royal Air Force to E-3C standard with CFM56 engines and British modifications designated Sentry AEW.1, seven built.[32]
Production aircraft for the French Air Force to E-3C standard with CFM56 engines and French modifications, four built.[32]
USAF Block 40/45 modification.[33]


Four-engined jet aircraft in-flight with landing gear partially extended. A large disc-shaped radar perches on two convergent struts on the aft fuselage.
NATO E-3s have the registration LX on the tail.[24] The chin bulges house an ESM suite.[24]

The French Air Force purchased four E-3F aircraft similar to the British E-3D aircraft.
All planes are assigned to the Escadron de Détection et de Commandement Aéroporté (ECDA, Air detection and command squadron) and are based at Avord Air Base.[34]
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.[24] Responsible for monitoring airspace for NATO operations around the world.
  • Squadron 1
  • Squadron 2
  • Squadron 3
  • Training wing
 Saudi Arabia
The Royal Saudi Air Force purchased five E-3A aircraft and eight KE-3A tanker aircraft in 1983.[35]
  • No. 18 Squadron
 United Kingdom
The Royal Air Force purchased seven E-3Ds by October 1987. Six are operational and one is used for training. The aircraft are designated Sentry AEW.1.[24]
 United States of America
The United States Air Force currently has 32 E-3s.
Tactical Air Command 1976–92
Air Combat Command 1992–present
960th Airborne Air Control Squadron 2001–present (NAS Keflavik, Iceland 1979–92)
963d Airborne Air Control Squadron 1976–present
964th Airborne Air Control Squadron 1977–present
965th Airborne Air Control Squadron 1978–79, 1984–present
966th Airborne Air Control Squadron 1976–present
960th Expeditionary Airborne Air Control Squadron 2002–present
Air Force Reserve Command
970th Airborne Air Control Squadron 1996–present
Pacific Air Forces
962d Airborne Air Control Squadron 1986–present
961st Airborne Air Control Squadron 1979–present

Incidents and accidents

Yukla 27, serial number 77-0354 crash site
Jet aircraft resting on ramp with a nose-down attitude. The nose was blackened during a fire. On top of it is a circular radar.
Fire-damaged USAF E-3 on Nellis AFB ramp.

The E-3 has been involved in three hull-loss accidents.

  • On 22 September 1995, a U.S. Air Force E-3 Sentry (callsign Yukla 27, serial number 77-0354), crashed shortly after take off from Elmendorf AFB, Alaska. The plane lost power to both port side engines after these engines ingested several Canada Geese during takeoff. The aircraft went down about two miles (3 km) northeast of the runway, killing all 24 crew members on board.[36][37]
  • On 14 July 1996, a NATO E-3A, LX-N90457, c/n 22852, ex-79-0457, overran the runway and dipped into the sea on takeoff from Preveza AB, Preveza, Greece. The fuselage broke into two, destroying the aircraft, but there were no casualties among the 16 crew members on board.[38] It allegedly suffered a birdstrike during take off, but no evidence of a birdstrike was found.[25][39]
  • On 28 August 2009, a USAF E-3C, 83-0008, was severely damaged[40] while landing at Nellis Air Force Base, after experiencing a nose-wheel failure. The failure resulted in a fire that caused a reported US$100 million in damage.[41] The accident was determined to be pilot error:[42] at an altitude of about 100 feet, both the co-pilot, and the pilot, lost track of their height above ground. The aircraft struck the ground with such force that the nose wheel strut broke. The aircraft slid along the runway for 4,500 feet.[43]

Specifications (USAF/NATO)

External images
Boeing E-3 Sentry
Hi-res cutaway of the Boeing E-3 Sentry

Data from[16]

General characteristics


See also

Related development
Aircraft of comparable role, configuration and era
Related lists


  1. ^ Quote:"...and the first flight of an E-3 with full mission avionics was from Seattle on 25 May 1976."[1]
  1. ^ Eden et al 2004, p. 94.
  2. ^ a b c d e f g h i j k l m n o p q r "Factsheet : E-3 SENTRY (AWACS) : E-3 SENTRY (AWACS)". US Air Force. May 2006. Retrieved 26 May 2007. 
  3. ^ Wilson 1998, p. 72.
  4. ^ a b Eden et al 2004, p. 92.
  5. ^ a b "AWACS to Bridge the Technological Gap". Air University. Retrieved 14 February 2009. 
  6. ^ a b c Davies 2005, p. 2.
  7. ^ Simonsen, Erik (March 2007). "Still keeping watch" (PDF). Boeing. Retrieved 21 August 2011. 
  8. ^ Davies 2005, pp. 5–6.
  9. ^ a b "AWACS Surveillance Radar" (PDF). Northrop Grumman. Retrieved 10 February 2009. 
  10. ^ Taylor et al 1976, p. 246.
  11. ^  
  12. ^ a b c d e "Airborne Warning and Control System (AWACS)". Boeing. Retrieved 26 May 2007. 
  13. ^ "Completes Mission System Flight Testing for US AWACS Block 40/45 Upgrade" (Press release). Boeing. 10 September 2008. Retrieved 13 July 2011. 
  14. ^ "EADS, Northrop Grumman, Partt and Whitney To Offer NATO AWACS Upgrade". Defense Daily International. 13 July 2001. Retrieved 8 September 2010. 
  15. ^ Batey, Angus, Early warning, Aviation Week and Space Technology, 21 April 2014, p.54
  16. ^ a b "E-3 Sentry (AWACS): Specifications". Retrieved 18 August 2011. 
  17. ^ "Boeing E-3 Airborne Warning and Control System (AWACS)" (PDF). Boeing. Retrieved 22 August 2011. 
  18. ^ "E-3 Sentry (AWACS)". Retrieved 9 November 2009. 
  19. ^ Wilson 1998, p. 73.
  20. ^ "E-3 Sentry (AWACS)".  
  21. ^ a b "E-3 Sentry (AWACS)". Retrieved 26 May 2007. 
  22. ^ a b "AWACS For United Kingdom and France". Boeing. Retrieved 26 May 2007. 
  23. ^ a b "U.S. and NATO AWACS". Boeing. Retrieved 21 August 2011. 
  24. ^ a b c d e f g Wilson 1998, p 75.
  25. ^ a b "Military Safety".  
  26. ^ "AWACS For United Kingdom and France". Boeing. Retrieved 26 September 2010. 
  27. ^ "E-3 Specifications (707 Platform) and Worldwide Fleet". Boeing. Retrieved 26 September 2010. 
  28. ^ Hoyle, Craig. "RAF ISTAR watch: a Shadowy arrival, and saving Sentinel". Flightglobal. Retrieved 27 September 2013. 
  29. ^ Lake 2009, p. 44.
  30. ^ a b Veronico and Dunn 2004, p. 83.
  31. ^ "NATO starts patrolling Libyan air space".  
  32. ^ a b c d e f g h Pither 1998, pp. 40–42
  33. ^ a b "E-3 Sentry (AWACS) Variants". Retrieved 21 August 2011. 
  34. ^ Wilson 1998, p 76.
  35. ^ Wilson 1998, pp. 75–76.
  36. ^ "CVR transcript Boeing E-3 USAF Yukla 27–22 SEP 1995". Aviation Safety Network. 16 October 2004. Retrieved 21 August 2011. 
  37. ^ "Yukla 27". Airborne Early Warning Association. Retrieved 22 August 2011. 
  38. ^ Hurturk 1998, p. 358.
  39. ^
  40. ^ "The Fate of Balls 8". Airborne Early Warning Association. Retrieved 22 August 2011. 
  41. ^ "E-3 damaged while landing at Nellis". US Air Force, 31 August 2009. (copy on Wikisource)
  42. ^ "Pilot error led to AWACS crash at Nellis". Retrieved 16 May 2010. 
  43. ^
  • Davies, Ed. "AWACS Origins: Brassboard – Quest for the E-3 Radar".  
  • Eden, Paul, ed. (2004). The Encyclopedia of Modern Military Aircraft. London: Amber Books.  
  • Hurturk, Kivanc N (1998). History of the Boeing 707. Buchair UK.  
  • Lake, Jon. "Aircraft of the RAF – Part 10 Sentry AEW.1".  
  • Pither, Tony (1998). The Boeing 707 720 and C-135. Air-Britain (Historians).  
  • Veronico, Nick; Dunn, Jim (2004). 21st Century U.S. Air Power. Grand Rapids, Michigan: Zenith Imprint.  
  • Wilson, Stewart (1998). Boeing 707, Douglas DC-8, and Vickers VC-10. Fyshwick, Australia: Aerospace Publications.  

External links

  • Royal Air Force E-3 Sentry information
  • NATO AWACS-Spotter Geilenkirchen website
  • Airborne Early Warning Association website
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