The EA-37B Compass Call (formerly EC-37B) is an

electronic warfare aircraft An electronic-warfare aircraft is a military aircraft equipped for electronic warfare (EW), that is, degrading the effectiveness of enemy radar and radio systems by using radar jamming and deception methods. In 1943, British Avro Lancaster aircr ...

based on the

Gulfstream G550 The Gulfstream G550 is an American business jet aircraft produced by the General Dynamics' Gulfstream Aerospace unit in Savannah, Georgia, US. The certification designation is GV-SP. A version with reduced fuel capacity was marketed as the G50 ...

entering service with the

United States Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...

with the first example delivered on 23 August 2024 to

Davis–Monthan Air Force Base Davis–Monthan Air Force Base (DM AFB) is a United States Air Force base southeast of downtown Tucson, Arizona. It was established in 1925 as Davis–Monthan Landing Field. The host unit for Davis–Monthan AFB is the 355th Wing (355 WG) ass ...

for crew training. The plane is replacing the EC-130H Compass Call. The role of the Compass Call is to disrupt enemy command and control communications,

radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...

s, and navigation systems, significantly hindering adversary coordination as part of the Counter-Command, Control, Computers, Communications, Cyber, Intelligence, Surveillance, and Reconnaissance Targeting (Counter-C5ISRT) mission. The jet will be able to conduct jamming of radars, electronic systems and communications. It will thus be able participate in

Suppression of Enemy Air Defenses Suppression of Enemy Air Defenses (SEAD ), also known in the United States as " Wild Weasel" and (initially) "Iron Hand" operations, are military actions to suppress enemy surface-based air defenses, including surface-to-air missiles (SAMs), an ...

(SEAD) missions by disrupting an enemy's ability to coordinate sensors and use weapon batteries that target friendly aircraft.

Design

EA-37B are Gulfstream G550 business jet airframes modified with electronic warfare equipment by

L3Harris L3Harris Technologies, Inc. is an American technology company, defense contractor, and information technology services provider that produces products for command and control systems, wireless equipment, tactical radios, avionics and electroni ...

and

BAE Systems BAE Systems plc is a British Multinational corporation, multinational Aerospace industry, aerospace, military technology, military and information security company, based in London. It is the largest manufacturer in Britain as of 2017. It is ...

. The most distinctive feature are the large

antenna array An antenna array (or array antenna) is a set of multiple connected antenna (radio), antennas which work together as a single antenna, to transmit or receive radio waves. The individual antennas (called ''elements'') are usually connected to a s ...

s conformally mounted on either side of the fuselage; these are based on the radar arrays found on the G550 CAEW (Conformal Airborne Early Warning). The aircraft has gone through multiple "Baseline" iterations throughout its development, with Baseline 4 being the latest. It incorporates BAE Systems' Small Adaptive Bank of Electronic Resources (SABER) technology. Among the equipment also found on the aircraft are: Network Centric Collaborative Targeting (NCCT) systems, System Control and Monitoring subsystems, Radio Frequency Receiver (RFR) subsystems, Software-defined Radio (SDR) subsystems, Counter Radar Assembly, Array Panels, AN/ARC-210 RT-2036 radios, KG-250 In-line Network Encryptors, KY-100 Narrow/wideband Terminals, KIV-77 Mode 4/5 Identification Friend or Foe (IFF),

AN/PYQ-10 The AN/PYQ-10 Simple Key Loader (SKL) is a ruggedized, portable, hand-held fill device, for securely receiving, storing, and transferring data between compatible cryptographic and communications equipment. The SKL was designed and built by Ralph ...

C Simple Key Loaders

History

On 7 September 2017, the

US Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...

awarded L3 Technologies (now

) a contract to replace the EC-130H Compass Call with an aircraft based on the

. The new aircraft was expected to "re-host" up to 70% of the mission equipment currently used on the EC-130H. On 23 October 2018,

Secretary of the Air Force The secretary of the Air Force, sometimes referred to as the secretary of the Department of the Air Force, (SecAF, or SAF/OS) is the head of the Department of the Air Force and the service secretary for the United States Air Force and United Sta ...

Heather Wilson Heather Ann Wilson (born December 30, 1960) is the 11th President of the University of Texas at El Paso. She previously served as the 24th Secretary of the United States Air Force from 2017 through 2019, as the 12th president of the South Dak ...

, approved

Air Combat Command The Air Combat Command (ACC) is one of nine List of Major Commands of the United States Air Force, Major Commands (MAJCOMs) in the United States Air Force, reporting to Headquarters, United States Air Force (HAF) at the Pentagon. It is the prim ...

's request to replace the EC-130H Compass Call aircraft from the

55th Electronic Combat Group The 55th Electronic Combat Group, located at Davis-Monthan Air Force Base, provides combat-ready aircraft, crews, maintenance, and operational support to combatant commanders. The group is a Geographically Separated Unit which falls under the c ...

(ECG) located at Davis-Monthan AFB, Arizona, with EA-37B aircraft (then known as EC-37B). The basing decision memorandum was signed on 15 November 2018. The first airframe was delivered to the air force in September 2023 for evaluation and testing. On 23 August 2024, the first ready aircraft (serial number 19-5591) was delivered to Davis-Monthan AFB to begin pilot training. The aircraft's first mission training sortie was flown on 2 May 2025 by the

43rd Electronic Combat Squadron The 43d Electronic Combat Squadron is a United States Air Force unit. Its current assignment is with the 55th Electronic Combat Group, being stationed as a tenant unit at Davis-Monthan Air Force Base, Arizona as a geographically separated uni ...

out of

Offutt Air Force Base Offutt Air Force Base is a U.S. Air Force base south of Omaha, adjacent to Bellevue in Sarpy County, Nebraska. It is the headquarters of the U.S. Strategic Command (USSTRATCOM), the 557th Weather Wing, and the 55th Wing (55 WG) of the ...

, Nebraska.

Designation

Originally designated EC-37B, as an electronic warfare version of the

C-37B The Gulfstream G550 is an American business jet aircraft produced by the General Dynamics' Gulfstream Aerospace unit in Savannah, Georgia, US. The certification designation is GV-SP. A version with reduced fuel capacity was marketed as the G50 ...

transport jet under the tri-service aircraft designation system. The designation was officially changed to EA-37B on 14 November 2023 to better reflect the aircraft's role and capabilities although the name change had been hinted at before. The new designation does however conflict with that of the unrelated A-37 Dragonfly, itself a non-systematic designation.

Operators

: 10 aircraft ordered, 5 delivered as of May 2025. Operated by the

, a part of

. * The

Italian Air Force The Italian Air Force (; AM, ) is the air force of the Italy, Italian Republic. The Italian Air Force was founded as an independent service arm on 28 March 1923 by Victor Emmanuel III of Italy, King Victor Emmanuel III as the ("Royal Air Force ...

plans to acquire two EA-37B Electronic Attack mission system packages to convert two Gulfstream G550 into EA-37B. The $680 million sale was approved by the

US State Department The United States Department of State (DOS), or simply the State Department, is an executive department of the U.S. federal government responsible for the country's foreign policy and relations. Equivalent to the ministry of foreign affairs o ...

on October 7, 2024. Note these are not to be confused with the G550 CAEW also operated by the Italian Air Force.

Specifications

References

External links

{{US EW aircraft EA-37B EA-37B Twinjets 2020s United States electronic warfare aircraft Electronic countermeasures Low-wing aircraft Aircraft with retractable tricycle landing gear