Lockheed P-3A Orion

The P-3A Orion was the first production version of Lockheed's long-range maritime patrol and anti-submarine warfare aircraft, developed from the L-188 Electra airliner. A four-engine turboprop, it replaced the P2V Neptune in U.S. Navy patrol squadrons, carrying sensors, sonobuoys, depth charges, mines and torpedoes to hunt submarines and conduct ocean surveillance over very long endurance missions. The Orion first flew in 1959, and as the P3V-1, redesignated P-3A in 1962, it began reaching squadrons VP-8 and VP-44 that year.

The P-3A was powered by four Allison T56-A-10W engines with water-methanol injection and could loiter for many hours on patrol. Later P-3B and the definitive P-3C variants brought more powerful engines and advanced avionics. Built in large numbers and widely exported, the Orion served the U.S. Navy and many allied nations for over half a century as the backbone of land-based maritime patrol aviation.