551st Electronic Systems Wing

The 551st Electronic Systems Wing (551 ELSW) is a wing of the United States Air Force whose focus is on 'behind the scenes' electronic work. Located at Hanscom Air Force Base, Massachusetts, they work on AWACS, Joint STARS, MP-RTIP, Mission Planning, and weather systems.

Now responsible for the development and sustainment of command and control systems, the 551st ELSW takes its designation from a wing that laid the foundation for modern-day airborne surveillance.

Cold War period
The 551st Airborne Early Warning and Control Wing, established and activated in 1954, was charged with tracking air and sea activity along the United States eastern seaboard.

The wing received its first airborne asset on March 2, 1955, when an RC-121D landed at Otis Air Force Base. The plane was the first of many assigned to the 551st to patrol the skies over much of the Atlantic Ocean. The RC-121D was eventually upgraded to the EC-121H Warning Star in 1963. The newer model supplanted the slower voice and manual Teletype data relay system previously employed by the RC-121D and instead provided instantaneous automated relay of air defense surveillance and early-warning information by data-link directly to ground-based communication facilities.

The 551 AEWC Wing provided critical surveillance data to Air Defense Command and Control computers and the North American Air Defense Combat Operations Center in Colorado Springs, Colo., for air defense evaluation and action. The data also enabled more versatile airborne control of interceptor missile and aircraft weapons systems.

During the Cold War period, the 551st provided surveillance support for major world events, including tracking over Cuba during the Cuban Missile Crisis and tracking Russian aircraft and naval vessels off Iceland and the East Coast of the United States.

The wing also provided surveillance over Johnston and Christmas islands during nuclear testing by the Atomic Energy Commission and performed a variety of surveillance services in Southeast Asia during the Vietnam War.

In its first 10 years, the wing flew continuous missions over the Atlantic Ocean 24 hours a day, seven days a week, compiling more than 350,000 flying hours. Among other honors awarded to the wing was the Air Force Outstanding Unit Award for its significant performance.

Between 1965 and 1967, three aircraft of the wing crashed into the Atlantic killing fifty members of the wing. The tail numbers of the aircraft were 55-0136, 55-5262, and 53-0549.

The wing was inactivated December 31, 1969.

Component squadrons

 * 960th Airborne Early Warning and Control Squadron: 8 March 1955-31 July 1969
 * 961st Airborne Early Warning and Control Squadron: 18 December 1954-31 December 1969
 * 962d Airborne Early Warning and Control Squadron: 8 July 1955-31 December 1969
 * 966th Airborne Early Warning and Control Squadron: 1 February 1962-1 May 1963; 1 July-15 November 1969
 * 4753d Air Defense (Training) Squadron: 22 April 1968-31 December 1969.

Re-designation
The wing was re-designated April 18, 2006, when the Battle Management Systems Wing changed to the 551st Electronic Systems Wing. The 551st ELSW is now responsible for rapid development and fielding of airborne battle management command, control and communications systems in support of combatant commanders, special operations forces and worldwide allies.

The 551st Electronic Systems Group, formerly the Airborne Warning and Control Systems Group, is responsible for all aspects of modernization and sustainment of the United States and international E-3 Sentry aircraft and airborne early warning and control fleets.

Aircraft operated

 * Lockheed C-121 Constellation, 1955–1969
 * RC-121, 1955–1962
 * EC-121, 1963–1969

Stations

 * Otis AFB, Massachusetts, 18 December 1954-31 December 1969
 * Hanscom AFB Massachusetts, 17 December 2004–present

Lineage

 * Established as 551st Airborne Early Warning and Control Wing on 11 October 1954
 * Activated on 18 December 1954
 * Inactivated on 31 December 1969


 * Redesignated 551st Airborne Warning and Control Wing on 31 July 1985
 * Consolidated (6 April 2006), with the Battle Management Systems Wing, which was established on 23 November 2004.
 * Activated on 17 December 2004
 * Redesignated 551st Electronic Systems Wing on 17 April 2006.

Assignments

 * 8th Air Division (Airborne Early Warning and Control), 18 December 1954
 * Eastern Air Defense Force, 1 July 1957
 * 26th Air Division (SAGE), 1 July 1959
 * First Air Force, 1 April 1966
 * 21st Air Division; 4–31 December 1969
 * Electronic Systems Center, 17 December 2004–present

Similar units

 * 751st Electronic Systems Group, formerly the Joint Surveillance Target Attack Radar System Systems Group, is responsible for all aspects of the development, acquisition and sustainment of the Joint STARS system.
 * 851st Electronic Systems Group, formerly the E-10/MP-RTIP Systems Group, is responsible for developing, acquiring, testing, sustaining and improving the $1.5 billion Multi-Platform Radar Technology Insertion Program.
 * 951st Electronic Systems Group, formerly the Mission Planning Systems Group, develops and supports a suite of mission planning systems that meet the needs of more than 40 Air Force aircraft and weapons systems.
 * 551 ELSW weather systems division acquires and fields terrestrial weather and strategic systems capability, then delivers decision-quality environmental information to Air Force and Army commanders to support global military operations in peace and war.