OVERVIEW: The EP-3E ARIES II is a four-engine, long-range signals intelligence (SIGINT) aircraft based on the P-3C Orion platform and operated by the United States Navy. It was developed as a modernized successor to the ARIES I variant, supporting strategic and tactical intelligence operations through electronic surveillance and signal interception.

DETAILS: The EP-3E ARIES II entered service in 1993 as an extensive upgrade to earlier EP-3E models, integrating improved ELINT and COMINT systems, enhanced signal processing capabilities, and expanded operator workstations. Built on the P-3C airframe and powered by four Allison T56-A-14 turboprop engines, the aircraft is optimized for long-endurance missions over maritime and littoral regions. It features multiple external antenna arrays, dorsal and ventral fairings, and onboard consoles for electronic surveillance across a wide range of frequencies. The system is used to intercept radar and communication signals, conduct electronic order of battle development, and provide real-time intelligence to Navy and joint forces.

The designation “EP” refers to “Electronic Patrol,” and “3E” denotes the variant within the P-3 family. The Aries II upgrade introduced new digital signal processors, modernized operator stations, enhanced data links, and improved mission system reliability compared to the earlier Aries model. Additional external fairings and antenna arrays distinguish, capable of supporting both strategic-level surveillance and tactical fleet operations across global theaters.

TYPE: Strategic Signals Intelligence (SIGINT) Aircraft

FUNCTION: Used to intercept, analyze, and report electronic emissions across the electromagnetic spectrum in support of fleet situational awareness, threat tracking, and strategic intelligence. It supports joint and naval forces with real-time electronic surveillance during peacetime and conflict.

NOTE:
IOC: 1969 (P-3 base model), 1993 (EP-3E ARIES II)
Manufacturer: Lockheed (USA)
Operators: United States
Conflict used in: Global War on Terrorism, surveillance operations in Middle East, Indo-Pacific, and international airspace

SOURCE:
U.S. Navy Naval Air Systems Command (NAVAIR): https://www.navair.navy.mil ; Lockheed Martin: https://www.lockheedmartin.com ; Jane’s All the World’s Aircraft: https://www.janes.com ; Federation of American Scientists (FAS): https://www.fas.org/man/dod-101/sys/ac/ep-3.htm ; Naval Aviation News Archives ; U.S. Department of Defense Historical Systems Reports