P-3 Orion

The Lockheed P-3 Orion is a maritime patrol aircraft used by numerous militaries around the world, primarily for maritime patrol, reconnaissance, and anti-submarine warfare.


The P-3 Orion, originally designated P3V, is based on the same design philosophy as the Lockheed L-188 Electra. It is not the same plane structurally. It has had seven feet of fuselage removed fore of the wings, as well as myriad internal, external, and airframe production technique enhancements. It served as the replacement for the postwar era P-2 Neptune. The Orion is powered by four Allison T56 turboprops which give it a speed comparable to fast propeller powered fighters, or even slow turbofan jets such as the A-10. Many other countries have seen the value of this platform design and have developed similar patrol aircraft based on this model, with the Soviets adapting their own counterpart to the Orion, the Ilyushin Il-38. The P-3 also competes with the British Hawker Siddeley Nimrod adaptation of the de Havilland Comet and the French Breguet Atlantique.

The first production version, designated P3V-1, first flew 15 April 1961. Initial squadron deliveries to VP-8 and VP-44 began in August 1962. On 18 September 1962, the U.S. military transitioned to a unified designation system, making the aircraft the P-3A. Paint schemes have changed from an early 1960s blue and white scheme, to a mid 1960s white and grey, to 1990s low visibility gray. Over the years more than 40 combatant & noncombatant variants of the P-3 have been developed due to the rugged reliability displayed by the platform flying 12 hour plus missions over salt water while maintaining an excellent safety record. Versions have been developed for the National Oceanographic and Atmospheric Administration (NOAA) for research and hurricane hunting/hurricane wall busting, for U.S. Customs for drug interdiction and aerial surveillance mission with a rotodome adapted from the E-2 Hawkeye or an AN/APG-66 radar adapted from the F-16 Fighting Falcon, and for NASA for research and development.

There have also been unconfirmed claims of the CIA operating three P-3As, alternatingly described as having been painted all black or in the markings of the Taiwanese Air Force (RoCAF), for aerial surveillance and agent/leaflet delivery in the vicinity of the People's Republic of China. The veracity of these claims remains suspect.

The United States Navy's P-3s are slated for replacement between 2010–2013 by the Boeing P-8 Poseidon, which is based upon the Boeing 737-800 series airliner.


The P-3 has an internal bomb bay under the front fuselage which can house conventional Mark 50 torpedoes or Mark 46 torpedoes and/or special (nuclear) weapons. Additional underwing stations, or pylons, can carry other armament configurations including the AGM-84 Harpoon, AGM-84E SLAM, AGM-84H/K SLAM-ER, the AGM-65 Maverick, 5 in (12.7cm) Zuni rockets, and various other mines, missiles, and gravity bombs. The aircraft also had the capability to carry the AGM-12 Bullpup guided missile until that weapon was withdrawn from U.S./NATO/Allied service.

Crew complement

The number of crew on board a P-3 varies depending on the role being flown, the variant being operated, and the country who is operating. In US service, the normal complement for a P-3C is 11:

  • three pilots
  • two naval flight officers
  • two flight engineers
  • three sensor operators
  • one in-flight technician

Australian operations have a normal complement of 13, broken down as:

  • two pilots (captain and co-pilot)
  • two flight engineers
  • tactical co-ordinator
  • navigator/communication officer
  • sensor employment manager
  • six airborne electronic analysts.

Engine loiter shutdown

On many missions, an engine is shut down (usually the No. 1 engine - the port outer engine) once on station to conserve fuel and extend the time aloft and/or range when at low level. On occasion, both outboard engines can be shut down, aircraft weight, weather, and remaining fuel permitting. Long deep-water, coastal or border patrol missions can last over ten hours and may include extra crew. The record time aloft for a P-3 is a 21.5 hour flight undertaken by the Royal New Zealand Air Force's No. 5 Squadron in 1972.

Engine 1 is the primary candidate for loiter shutdown because it is the only one without a generator, and is not needed for electrical power. Eliminating the exhaust from engine 1 also improves visibility from the aft observer station on the port side of the aircraft.

Operational history

Developed during the Cold War, the P-3's primary mission was to track and eliminate ballistic missile and fast attack submarines in the event of war. Reconnaissance missions in international waters led to occasions where Soviet fighters would "bump" a U.S. Navy P-3 or other P-3 operators such as the Royal Norwegian Air Force. On one occasion in the 1980s the MiG and pilot did not survive the "bump" while trying to ward off a P-3 photographing a Soviet fleet exercise. The P-3 lost more than of its wing in the collision. The P-3 completed its mission and returned to base. Cuban Missile Crisis In October 1962, P-3As flew several blockade patrols in the vicinity of Cuba. Having just recently joined the operational Fleet earlier that year, this was the first employment of the P-3 in a real world "near conflict" situation.Vietnam : Operation Market Time Beginning in 1964, forward deployed P-3s began flying a variety of missions under Operation Market Time from bases in the Philippines and Vietnam. The primary focus of these coastal patrols was to stem the supply of materials to the Viet Cong by sea, although several of these missions also became overland "feet dry" sorties. During one such mission, a small caliber artillery shell passed through a P-3 without rendering it mission incapable. During another overland mission, it is rumored, but not confirmed, that a P-3 shot down a North Vietnamese MiG with Zuni missiles. The only confirmed combat loss of a P-3 also occurred during Operation Market Time. In April 1968, a U.S. Navy P-3B of Patrol Squadron TWENTY-SIX (VP-26) was downed by anti-aircraft artillery (AAA) fire in the Gulf of Thailand with the loss of the entire crew. Two months earlier, in February 1968, another of VP-26's P-3Bs was operating in the same vicinity when it crashed with the loss of the entire crew. Originally attributed to be an aircraft mishap at low altitude, later conjecture is that this aircraft may have also fallen victim to AAA fire from the same source as the subsequent aircraft loss in April. Iraq: Desert Shield / Desert Storm On August 2, 1990 Iraq invaded Kuwait and was poised to strike Saudi Arabia. Within forty-eight hours of the initial invasion of Kuwait, U.S. Navy P-3Cs were the first American forces to arrive in the area. One of these responding P-3Cs was a modified aircraft with a prototype system known as “Outlaw Hunter.” Undergoing trials in the Pacific after being developed by the Navy’s Space & Naval Warfare Systems Command, "Outlaw Hunter" was testing a specialized over-the-horizon targeting (OTH-T) system package when it responded. Within hours of the start of the coalition air campaign, “Outlaw Hunter” detected a large number of Iraqi patrol boats and naval vessels attempting to make a run from Basra & Umm Qasar to Iranian waters. “Outlaw Hunter” vectored in strike elements which attacked the flotilla near Bubiyan Island destroying 11 vessels and damaging scores more. During Desert Shield, a P-3 using infrared imaging detected a ship with Iraqi markings beneath freshly painted bogus Egyptian markings trying to avoid detection. Several days before the January 7, 1991 commencement of Operation Desert Storm, a P-3C equipped with an APS-137 Inverse Synthetic Aperture Radar (ISAR) conducted coastal surveillance along Iraq and Kuwait to provide pre-strike reconnaissance on enemy military installations. Fifty-five of the one hundred and eight Iraqi vessels destroyed during the conflict were targeted by P-3C aircraft. Hainan Island incident In April 2001 an aerial collision between a United States Navy EP-3E Aries II, a signals reconnaissance version of the P-3C, and a People's Liberation Army Navy J-8IIM fighter resulted in an international incident between the United States and China. The J-8IIM crashed and its pilot was killed. The EP-3 came close to becoming uncontrollable, at one point sustaining a near inverted roll, but was able to make an emergency landing on Hainan. The crew and plane were subsequently detained by Chinese authorities, accused of "killing the Chinese pilot". After several days, the crew was repatriated separately to the United States while the aircraft remained in China, reported taken apart for research on American technology. Although the crew attempted to destroy as much classified material, hardware and software on the aircraft prior to the emergency landing, there is little doubt that the EP-3 was exploited by Chinese intelligence services. An American team was later permitted to enter Hainan in order to dismantle the aircraft, which was subsequently airlifted back to United States for reassembly and repair. Pakistan In late 2006, the US announced the intention to sell three P-3C Orions equipped with the E-2C Hawkeye 2000 AEW system to the Pakistan Navy, along with 10 regular P-3Cs. The AEW aircraft will provide Pakistan with search surveillance and control capability for maritime operations.

Civilian uses

Several P-3s have been N-registered and are operated by civilian agencies. The United States Customs Service has a number of P-3A and P-3Bs used for maritime patrol. NOAA operates two WP-3D variants specially modified for hurricane research. One P-3B, N426NA, is used by NASA as an Earth science research platform, primarily for the NASA Science Mission Directorate's Airborne Science Program. It is based at Goddard Space Flight Center's Wallops Flight Facility, Virginia.

Aero Union, Inc. operates eight ex-USN P-3As configured as air tankers, which are leased to the U.S. Forest Service, the California Department of Forestry and Fire Protection and other agencies for firefighting use. A unique capability of the P-3 is that on so-called "downhill runs," i.e. when the plane is commencing a low pass to drop fire retardant, it is possible to put the propellers into "Beta" range, which is reverse-thrust mode, in order to slow the plane for the drop of water-based retardant. Several of these aircraft were involved in the U.S. Forest Service airtanker scandal but have not been involved in any catastrophic aircraft mishaps.


  • P-3A: The original production version; 157 built.
  • P-3A (CS): Four with ex-USN P-3As reequipped with AN/APG-66 radars for use by the United States Customs Service.
  • EP-3A: Seven modified for electronic reconnaissance testing.
  • NP-3A: Three modified for the U.S. Naval Research Laboratory.
  • RP-3A: Two modified for scientific uses for the former Oceanographic Development Squadron EIGHT (VXN-8) at NAS Patuxent River.
  • TP-3A: 12 modified for training duties in Fleet Replacement Squadrons with all ASW gear removed.
  • UP-3A: 38 reconfigured as utility transports with all the ASW gear removed.
  • VP-3A: Three WP-3As and two P-3As converted into VIP/staff transports.
  • WP-3A: Four converted for weather reconnaissance.
  • P-3B: Second main production version/series.
  • EP-3B: Two P-3As converted into ELINT aircraft during the Vietnam War.
  • NP-3B: One P-3B converted into a testbed, for the U.S. Naval Research Laboratory.
  • P-3BR: Modification to P-3A model for Brazilian Air Force. Eight aircraft with EADS avionics.
  • P-3C: Third main production version/series.
    • P-3C Update I: New and improved avionics, 31 built.
    • P-3C Update II: With infra-red detection system (IRDS), sonobuoy reference system (SRS), and able to carry the AGM-84 Harpoon anti-ship missile; 44 built.
    • P-3C Update II.5: 24 aircraft with more reliable LTN-72 inertial navigation system and enhanced communications equipment.
    • P-3C Update III: 50 aircraft with new acoustic processor, sonobuoy receiver, plasma displays, and improved auxiliary power unit (APU).
    • P-3C Update IV: P-3C with Boeing Update 4 avionics suite. Update 4 was going to be common avionics interior for P-3Cs and its planned replacement aircraft, the Lockheed P-7A, which never made it to production. One one P-3C was converted to UD4 interior and that aircraft was later stripped and turned into an Special Mission aircraft.
    • P-3C AIP(US)/UIP(RNoAF) with interior modification to add ASQ-222 mission computer, ASQ-78A/B acoustics system, APS-137 ISAR radar
    • P-3C BMUP (US) 25 aircraft/CUP (RNlAF) with interior modification to convert UD2 and UD2.5 to carry ASQ-227 mission computer and ASQ-78B acoustics suite
  • EP-3: ELINT aircraft for the Japanese Maritime Self-Defence Force.
  • NP-3C: One P-3C converted into a testbed for the U.S. Naval Research Laboratory.
  • RP-3C: One P-3C modified to replace the RP-3A.
  • OP-3C: 10 P-3C converted to reconnaissance aircraft for the Japanese Maritime Self-Defence Force.
  • UP-3C: Equipment test aircraft for the Japanese Maritime Self-Defence Force.
  • UP-3D: ELINT training aircraft for the Japanese Maritime Self-Defence Force.
  • RP-3D: One P-3C modified for atmospheric research, to collect atmospheric data.
  • WP-3D: Two P-3Cs modified for NOAA weather research, including hurricane hunting.
  • EP-3E Aries: 10 P-3As and 2 EP-3Bs converted into ELINT aircraft.
  • EP-3E Aries II: 12 P-3Cs converted into ELINT aircraft.
  • NP-3E: Various aircraft used for tests.
  • P-3F: Six P-3C Orions delivered to the former Imperial Iranian Air Force in the late 1970s; three aircraft still operational with the Islamic Republic of Iran Air Force.
  • P-3G: Original designation of the Lockheed P-7A.
  • P-3H: Proposed P-3C upgrade.
  • EP-3J: Two modified from P-3As for FEWSG use as a simulated adversary EW platform in exercises; later transferred to the former Tactical Electronic Warfare Squadron THIRTY-THREE (VAQ-33), then transferred to the former Fleet Air Reconnaissance Squadron ELEVEN (VQ-11).
  • P-3K: five aircraft originally of P-3B standard but subsequently updated, delivered to New Zealand in 1965-67, replacing Short Sunderlands. The original P-3Bs were operated by No. 5 Squadron RNZAF from Whenuapai, Auckland. These received part of the P-3C Update II package and some local innovations, then being designated P-3K (for Kiwi), together with a P-3B purchased second hand from the Royal Australian Air Force and brought up to P-3K standard. Aircraft were re-winged and underwent a further round of avionics and sensor updates in 2005 (P-3KII).
  • P-3N: Two P-3B modified for coast guard missions for the RNoAF.
  • P-3P: Six ex-RAAF originally of P-3B standard but subsequently updated for the Portuguese Air Force. Being replaced by newer P-3C Update II.5s formerly operated by the Royal Netherlands Navy.
  • P-3T: Two P-3A modified for Royal Thai Navy.
    • VP-3T: One P-3A modified for Royal Thai Navy VIP use and some surveillance operations.
  • P-3W: Designation used internally by the Royal Australian Air Force (RAAF) to distinguish the first 10 P-3C aircraft procured in the P-3C Update 2 configuration (1978-79) from the second 10 aircraft which were procured in the Update 2.5 configuration (1982-83). The older aircraft were designated as P-3Cs and the newer aircraft P-3Ws. All were equipped with the British AQS-901 Acoustics Processor. Eventually with various system upgrades to the mission systems the two types mergerd into one and they are now all known as AP-3Cs.
  • AP-3C: All Royal Australian Air Force P-3C/W aircraft which have been fully upgraded with totally new mission systems by L-3 Communications to include an Elta SAR/ISAR RADAR and a GD-Canada Acoustic Processor system.
    • TAP-3: 3 modified B-models for training duties with the Royal Australian Air Force, with all the ASW gear removed and passenger seating installed. Removed from service with the full introduction into service of the AP-3C Simulator. Designator reflected them as being 'Training Australian P-3'
  • P-3CK: Designation of the eight former P-3B aircraft that the Republic of Korea Navy procured from the USN and which are in the process of being rebuilt with P-3C configuration wings and fitted with updated Mission System Equipment by Korea Aerospace Industries and L-3 Communications.
  • P-3AEW&C (originally nicknamed "Sentinel"): Eight P-3B aircraft were converted into Airborne Early Warning and Control aircraft. The P-3AEW&Cs are used by U.S. Customs and Border Protection for drug interdiction and homeland security missions. "Slicks" are P-3s with an optical sensor turret in the nose which often work with the AEW ships.
  • CP-140 Aurora: Longe-range maritime reconnaissance, anti-submarine warfare aircraft for the Canadian Armed Forces. Based on the P-3C Orion airframe, but mounts the more advanced electronics suite of the S-3 Viking.
  • CP-140A Arcturus: Three CP-140s without ASW equipment installed for Aurora crew training and various coastal patrol missions.
  • P-7 proposed new-build and improved variant as a P-3 Orion replacement later cancelled.
  • Orion 21 proposed new-build and improved variant as a P-3 Orion replacement; lost to Boeing P-8 Poseidon.


Military operators

Civilian operators

Specifications (P-3C Orion)

See also




  • Winchester, Jim, ed. Military Aircraft of the Cold War (The Aviation Factfile). London: Grange Books plc, 2006. ISBN 1-84013-929-3.

External links

Search another word or see P-3_Orionon Dictionary | Thesaurus |Spanish
Copyright © 2015, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature