Airborne early warning at sea: from the E-1 Tracer to the E-2D

Carrier airborne early warning (AEW) grew from wartime radar experiments into a line of dedicated carrier aircraft: the E-1B Tracer, which entered squadron service in 1960, the E-2 Hawkeye family, and the E-2D Advanced Hawkeye, which reached initial operational capability in October 2014. The line also shows how designations, squadron names, and dates shift between official Navy sources, which matters to anyone who matches a document or program record to an aircraft.

Wartime experiments

The National Naval Aviation Museum's E-1B Tracer page starts with World War II. In early 1943, scientists at the Radiation Laboratory at the Massachusetts Institute of Technology began work on what became the APS-20 AEW radar. The test aircraft was a TBM Avenger torpedo plane designated XTBM-3W, and the effort carried the codename Project Cadillac. Testing ran from 1944 to 1945.

After the war, TBM-3W Avengers and later modified attack aircraft, including the AD-3W Skyraider, filled the AEW role. The museum's E-2C Hawkeye page adds the AF Guardian to the list of attack and antisubmarine airframes adapted to the mission.

The E-1B Tracer

In 1955, engineers at Grumman Aircraft Engineering Corporation set out to build a dedicated AEW aircraft from the S2F Tracker antisubmarine airplane. They chose the TF-1 Trader, the carrier on-board delivery version, for its large cabin. To fit a teardrop-shaped radome, they replaced the single tail with twin fins and rudders. The aerodynamic prototype first flew on December 17, 1956.

The Tracer began entering squadron service in 1960, and its first deployment was with Carrier Airborne Early Warning Squadron (VAW) 11 aboard USS Constellation (CVA 64) that year. Tracer-equipped VAW squadrons logged 56 deployments in support of operations over Southeast Asia. The aircraft was designated WF-2 at first and became the E-1B in 1962. The museum lists a crew of two pilots and two radar operators and says operational service ended in 1977.

The E-2 Hawkeye

The museum describes the E-1B as an interim measure. The Navy wanted a platform built from the start for the mission, with a higher service ceiling and room for the Air Tactical Data System. Grumman's answer, Design 123, had a wingspan of over 80 feet, a pressurized fuselage section, four vertical tail surfaces, and a 24-foot diameter rotodome.

Ordered as the W2F-1, the airplane was redesignated the E-2A in 1962. The first E-2As joined VAW-11 two years later, and their first combat deployment, to the waters off Vietnam, came in 1965. The museum lists several firsts, including the first carrier-based turboprop airplane and the first nose-tow catapult launch from a carrier, USS Enterprise (CVAN 65), in 1962. Naval Air Systems Command (NAVAIR) also states that the first E-2 was delivered to VAW-11 in 1964.

Later versions followed:

• E-2B: An upgraded computer system installed in 49 E-2As led to their redesignation as E-2Bs between 1969 and 1971.
• E-2C: The E-2C, with upgraded engines and radar systems, first flew in September 1972. The Navy's E-2 fact file says it became operational in 1973 and passed one million flight hours in August 2004. The museum lists its crew as two pilots and three Naval Flight Officers.
• Hawkeye 2000: The fact file describes this newest E-2C variant as adding a new mission computer, improved radar displays, and Cooperative Engagement Capability.

The E-2D

The museum states that E-2D deliveries to the fleet began in July 2010. NAVAIR's release on initial operational capability reports that the E-2D reached that milestone on October 10, 2014, with VAW-125 as the first operational squadron. The same release says NAVAIR's E-2/C-2 Airborne Tactical Data System Program Office (PMA-231) had designated 2014 the "Year of the Hawkeye" to mark 50 years of E-2 service since the first delivery to VAW-11.

Five E-2Ds of VAW-125 began the type's first deployment on March 11, 2015, with Carrier Air Wing 1 aboard USS Theodore Roosevelt (CVN 71). The fact file gives the E-2 crew as five, the same total as the E-2C crew the museum lists.

Where the sources disagree

The Navy fact file states that the E-1 saw service from 1954 to 1964. The museum's E-1B page puts the first flight of the aerodynamic prototype in December 1956, entry into squadron service in 1960, and the end of operational service in 1977. The fact file's 1954 start precedes the 1955 design start the museum reports, and its 1964 end matches the year the first E-2s reached VAW-11.

The 2010 fleet delivery date and the 2014 operational capability date are different milestones, and both come from Navy pages. Naming has also changed. The 2014 and 2015 NAVAIR releases call VAW units Carrier Airborne Early Warning squadrons, while the VAW-120 page calls the unit an Airborne Command and Control Squadron. The VAW designation stayed the same.

The fact file was last updated on 17 September 2021, and the museum pages carry no publication date.

Why it still matters

Records and manuals refer to aircraft by designation, squadron, and date, and in this line each of those changed: the WF-2 became the E-1B in 1962, the W2F-1 became the E-2A the same year, 49 E-2As became E-2Bs between 1969 and 1971, and Navy pages name the VAW units differently. Matching a document to an aircraft means reading the designation, the date, and the source together.

Sources

1. 1E-1B Tracer · National Naval Aviation Museum, Naval History and Heritage Command
2. 2E-2C Hawkeye · National Naval Aviation Museum, Naval History and Heritage Command
3. 3E-2 Hawkeye Airborne Command and Control Aircraft · U.S. Navy
4. 4U.S. Navy's E-2D Advanced Hawkeye aircraft achieves Initial Operational Capability · Naval Air Systems Command (NAVAIR)
5. 5Advanced Hawkeye makes maiden deployment on Theodore Roosevelt · Naval Air Systems Command (NAVAIR)
6. 6Airborne Command & Control Squadron (VAW) 120 · Commander, Naval Air Force Atlantic