Blog #12: 1/31/23: Historical aviation: Boeing E-3 Sentry, the Eyes in the Sky
Boeing E-3 Sentry over an undisclosed location. AWACS: Airborne Warning and Control System. October, 2004.
Source: (By Senior Airman Roslyn Ward - usaf.mil, Public Domain, https://commons.wikimedia.org/w/index.php?curid=127132264)
Welcome to the next Brooke in the Air blog! Today, another venture in historical military aviation: Examining one of my favorites, the Boeing E-3 Sentry AWACS!
I’ve repeatedly said I would try and stay away from modern aircraft or aircraft otherwise in service, but honestly I cannot stay away from some of these. The E-3 is one such plane and to say that battlefields would be overrun by the enemy or entire battles would be lost would not be an understatement. The ultimate in battlefield command, control, communication, and coordination, the E-3 is the ideal support weapon, more valuable than any gun, bomb, or missile.
Lockheed E(R)C-121 Warning Star, in 1955, predecessor to the Boeing E-3 Sentry.
Source: (By USAF - U.S. Air Force photo [1], Public Domain, https://commons.wikimedia.org/w/index.php?curid=6594475)
The E-3 was derived from the Boeing 707-320B jet airliner, only 68 E-3 Sentries were produced until the production line ended in 1992. The E-3 was designed to replace the turboprop-powered EC-121 Warning Star, produced by Lockheed - a military version of the the famed passenger airliner Lockheed Constellation - and in service throughout the 1950s and was retired by the mid-1960s. See above photo for reference.
Welcome ceremony for the first E-3 Sentry at Tinker Air Force Base, Oklahoma, 1977.
Source: (1977. http://www.tinker.af.mil/shared/media/photodb/photos/100329-F-1156C-001.jpg. United States Air Force Historical Archives)
In 1977, after more than a decade of testing, research, and an initial request for proposals by the then-new US Air Force, the first E-3 was delivered for active duty. The request for proposals received submissions by Boeing, Douglas, and Lockheed who hoped to follow up their Warning Star with a successor aircraft. The companies were all issued contract in the early 60s with Lockheed, ironically, being eliminated by July of 1966. Boeing was selected as the winner after debuting the prototype E-3 in 1968.
Close-up of E-3 Rotodome
Spinning at 6 revolutions per minute, the rotodome is powered by 5,000 PSI hydraulics within the aircraft.
Source: (By ILA-boy - Own work, GPL, https://commons.wikimedia.org/w/index.php?curid=4207665)
Control Room aboard an E-3 Sentry during Operation Provide Comfort, April 1991 - Op Provide Comfort provided protection of Kurdish refugees
Source: (Public Domain, https://commons.wikimedia.org/w/index.php?curid=2315399)
In 1977, the E-3’s enormous rotodome underwent structural reinforcement to enhance its mission profiles and durability, as part of its final production upgrades as the de facto E-3A. The rotodome (literally, rotating radar dome) was a Hughes/Westinghouse Electric Phased Doppler Technology. Other features included a bail-out tunnel/chute, a 3,500-5,000 PSI hydraulic system to drive the rotodome itself, Single-point ground and air refueling both, and shift-mandated crew rest area. Additional electrical generators mounted within the E-3’s quartet of General Electric (GE)TF-34 turbofan engines provide 1 megawatt of power for the aircraft’s powerful doppler radar and various electronic systems. Sadly, Iran placed an order for 10 E-3 Sentries in 1977 but this order was cancelled by the Iranian Revolution.
Left without mid-air refueling, the E-3 Sentry (flow by both NATO and the USAF) has a range of nearly 8,000 kilometers, or 4,600 miles, or 8 hours of flying time. However, with mid-air refueling, the range is practically unlimited; limited only by the human endurance of her crew and maintenance limitations.
E-767 of the Japanese Air Self-Defense Force, Mt. Fuji in the background
Source: (By 航空自衛隊ホームページ, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=61587864)
Northrup Grumman Joint STARS - Joint Surveillance Target Attack Radar System (J-STARS) of the USAF, re-developed along with the E-3 Sentry, from the Boeing 707 airliner
Source: (By US Air Force - usaf.mil, Public Domain, https://commons.wikimedia.org/w/index.php?curid=70220960)
Boeing E-7 (E-737 per the RoKAF) of the Republic of Korea (RoKAF/South Korea) Airborne Warning & Control System, probable successor to the E-3 Sentry, Defence Photograph Magazine
Source: (By 대한민국 국군 Republic of Korea Armed Forces - 공중조기경보통제기, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=36991666)
As far as its future status, NATO has decided to invest in an extension program to keep Boeing’s E-3 fleet flying until 2035. The United Kingdom (UK) decided to divert funds from maintenance, upgrades, and extensions of their E-3Ds, in order to favor a replacement program. Japan has decided to favor the E-767, a specially made 767 for the Japan Air Self-Defense Force since by the time they expressed interest in the AWACS program, the Boeing had discontinued the production line of the E-3. The E-767 was a 767 base model airliner, modeled heavily on the E-3 Sentry. For the US Air Force, the role of the E-3 is increasingly relegated to the RC-135 and the E-8 Joint STARS (pictured above), until the Department of Defense’s acquisition of around 8 of Boeing’s new E-7 Wedgetails (pictured left), a scaled up version of the beloved Boeing 737 airliner, retiring 15 of its 31 E-3 Sentries. This subsequent replacement by the E-7 is slated, per the Pentagon, to begin in 2027. Virtually all NATO allies and even tacit allies of the US fly variants of the E-3, from the UK to Chile.
Suffice it to say, despite many different aircraft trying, no plane does more to assert command and control over the battlespace than the E-3 Sentry. The Sentry facilitates global battlefield communication, intelligence, and ground control to and of allied forces, enabling victory where it would not have been possible.
