Lockheed P-3 Orion

In August 1957 the U.S. Navy called for proposals for replacement of the piston-engined Lockheed P2V Neptune (later redesignated P-2) and Martin P5M Marlin (later redesignated P-5) with a more advanced aircraft to conduct maritime patrol and anti-submarine warfare. Modifying an existing aircraft was expected to save on cost and to allow rapid introduction into the fleet. Lockheed suggested a military version of its L-188 Electra, then still in development and yet to fly. In April 1958 Lockheed won the competition and was awarded an initial research-and-development contract in May.[4]

The first Orion prototype was a converted Lockheed Electra.

Lockheed modified the prototype YP3V-1/YP-3A, Bureau Number (BuNo) 148276 from the third Electra airframe c/n 1003.[5] The first flight of the aircraft's aerodynamic prototype, originally designated YP3V-1, took place on 19 August 1958. While based on the same design philosophy as the Lockheed L-188 Electra, the aircraft differed structurally: it had 7 feet (2.1 m) less fuselage forward of the wings with an opening bomb bay, and a more pointed nose radome, a distinctive tail "stinger" for detection of submarines by magnetic anomaly detector, wing hardpoints, and other internal, external, and airframe-production technique enhancements.[4] The Orion has four Allison T56 turboprops which give it a top speed of 411 knots (761 km/h; 473 mph) comparable to the fastest propeller fighters, or even to slow high-bypass turbofan jets such as the Fairchild Republic A-10 Thunderbolt II or the Lockheed S-3 Viking. Similar patrol aircraft include the Soviet Ilyushin Il-38, the French Breguet Atlantique and the British jet-powered Hawker Siddeley Nimrod (based on the de Havilland Comet).

The first production version, designated P3V-1, was launched on 15 April 1961. Initial squadron deliveries to Patrol Squadron Eight (VP-8) and Patrol Squadron Forty Four (VP-44) at Naval Air Station Patuxent River, Maryland, began in August 1962. On 18 September 1962 the U.S. military transitioned to a unified designation system for all services, with the aircraft being renamed the P-3 Orion.[4] Paint schemes have changed from early 1960s gloss seaplane gray and white to mid-1960s/1970s/1980s/early 1990s gloss white and gray, to mid-1990s flat finish low-visibility gray with fewer and smaller markings. In the early 2000s the paint scheme changed to its current overall gloss gray finish with the original full-size color markings. However, large-size Bureau Numbers on the vertical stabilizer and squadron designations on the fuselage remained largely omitted.[6]

P-3 Orions from Japan, Canada, Australia, Republic of Korea and the United States at MCAS Kaneohe Bay during RIMPAC 2010.

In 1963, the U.S. Navy Bureau of Weapons (BuWeps) contracted Univac Defense Systems Division of Sperry-Rand to engineer, build and test a digital computer (then in its infancy) to interface with the many sensors and newly developing display units of the P-3 Orion. Project A-NEW was the engineering system which, after several early trials, produced the engineering prototype, the CP-823/U, Univac 1830, Serial A-1, A-NEW MOD3 Computing System. The CP-823/U was delivered to the Naval Air Development Center (NADC) at Johnsville, Pennsylvania in 1965, and directly led to the production computers later equipped on the P-3C Orion.[7]

Three civilian Electras were lost in fatal accidents between February 1959 and March 1960. Following the third crash the FAA restricted the maximum speed of Electras until the cause could be determined. After an extensive investigation, two of the crashes (in September 1959 and March 1960) were found to be caused by insufficiently strong engine mounts, unable to damp a whirling motion that could affect the outboard engines. When the oscillation was transmitted to the wings, a severe vertical vibration escalated until the wings were torn from the aircraft.[8][9] The company implemented an expensive modification program, labelled the Lockheed Electra Achievement Program or LEAP, in which the engine mounts and wing structures supporting the mounts were strengthened, and some wing skins replaced with thicker material. All the surviving Electras of the 145 built at that time were modified at Lockheed's expense at the factory, the modifications taking 20 days for each aircraft. The changes were incorporated in subsequent aircraft as they were built.[8]

Sales of Electra airliners were limited, as Lockheed's technical fix did not serve to completely erase the aircraft's "jinxed" reputation, in an era in which turboprop-powered aircraft were being replaced by faster jets.[10] In a military role where fuel efficiency was more valued than speed, the Orion has been in service over 50 years after its 1962 introduction. Although surpassed in production longevity by the Lockheed C-130 Hercules, 734 P-3s were produced through 1990.[2][11][12] Lockheed Martin opened a new P-3 wing production line in 2008 as part of its Service Life Extension Program (ASLEP) for delivery in 2010. A complete ASLEP replaces the outer wings, center wing lower section and horizontal stabilizers with newly built parts.[13]

In the 1990s, during a U.S. Navy attempt to identify a successor aircraft to the P-3, the improved P-7 was selected over a navalized variant of the twin turbofan-powered Boeing 757, but this program was subsequently cancelled. In a second program to procure a successor, the advanced Lockheed Martin Orion 21, another P-3 derived aircraft, lost out to the Boeing P-8 Poseidon, a Boeing 737 variant, which entered service in 2013.

The crew complement varies depending on the role being flown, the variant being operated, and the country that is operating the type. In U.S. Navy service, the normal crew complement was 12 until it was reduced to its current complement of 11 in the early 2000s when the in-flight ordnanceman (ORD) position was eliminated as a cost-savings measure and the ORD duties assumed by the in-flight technician (IFT).[1] Data for U.S. Navy P-3C only.

Officers:

• three Naval Aviators
  • Patrol Plane Commander (PPC)
  • Patrol Plane 2nd Pilot (PP2P)
  • Patrol Plane 3rd Pilot (PP3P)
• two Naval Flight Officers
  • Patrol Plane Tactical Coordinator (PPTC or TACCO)
  • Patrol Plane Navigator/Communicator (PPNC or NAVCOM)

NOTE: NAVCOM on P-3C only; USN P-3A and P-3B series had an NFO Navigator (TACNAV) and an enlisted Airborne Radio Operator (RO)

Enlisted Aircrew:

• two enlisted Aircrew Flight Engineers (FE1 and FE2)
• three enlisted Sensor Operators
  • Radar/MAD/EWO (SS-3)
  • two Acoustic (SS-1 and SS-2)
• one enlisted In-Flight Technician (IFT)
• one enlisted Aviation Ordnanceman (ORD position no longer used on USN crews; duties assumed by IFT.)

The senior of either the PPC or TACCO will be designated as the aircraft Mission Commander (MC).

Once on station, one engine is often shut down (usually the No. 1 engine – the left outer engine) to conserve fuel and extend the time aloft and/or range when at low level. It is the primary candidate for loiter shutdown because it has no generator. Eliminating the exhaust from engine 1 also improves visibility from the aft observer station on the left side of the aircraft.

On occasion, both outboard engines can be shut down, weight, weather, and fuel permitting. Long deep-water, coastal or border patrol missions can last over 10 hours and may include extra crew. The record time aloft for a P-3 is 21.5 hours, undertaken by the Royal New Zealand Air Force's No. 5 Squadron in 1972.

P-3B of VP-6 near Hawaii

US P-3C Orion of VP-8

Changing a tire on a P-3C

Developed during the Cold War, the P-3's primary mission was to localize Soviet Navy ballistic missile and fast attack submarines detected by undersea surveillance systems and eliminate them in the event of full-scale war.[16][17] At its height, the U.S. Navy's P-3 community consisted of twenty-four active duty "Fleet" patrol squadrons home based at air stations in the states of Florida and Hawaii as well as bases which formerly had P-3 operations in Maryland, Maine, and California. There were also thirteen Naval Reserve patrol squadrons identical to their active duty "Fleet" counterparts, said Reserve "Fleet" squadrons being based in Florida, Pennsylvania, Maryland, Michigan, Massachusetts (later relocated to Maine), Illinois, Tennessee, Louisiana, California and Washington. Two Fleet Replacement Squadrons (FRS), also called "RAG" squadrons (from the historic "Replacement Air Group" nomenclature) were located in California and Florida. The since-deactivated VP-31 in California provided P-3 training for the Pacific Fleet, while VP-30 in Florida performed the task for the Atlantic Fleet. These squadrons were also augmented by a test and evaluation squadron in Maryland, two additional test and evaluation units that were part of an air development center in Pennsylvania and a test center in California, an oceanographic development squadron in Maryland, and two active duty "special projects" units in Maine and Hawaii, the latter being slightly smaller than a typical squadron.

Reconnaissance missions in international waters led to occasions where Soviet fighters would "bump" a P-3, either operated by the U.S. Navy or other operators such as the Royal Norwegian Air Force. On 1 April 2001, a midair collision between a United States Navy EP-3E ARIES II signals surveillance aircraft and a People's Liberation Army Navy J-8II jet fighter-interceptor resulted in an international dispute between the U.S. and the People's Republic of China (PRC).[18]

More than 40 combatant and noncombatant P-3 variants have demonstrated the rugged reliability displayed by the platform flying 12-hour plus missions 200 ft (61 m) over salt water while maintaining an excellent safety record. Versions have been developed for the National Oceanic and Atmospheric Administration (NOAA) for research and hurricane hunting/hurricane wall busting, for the U.S. Customs Service (now U.S. Customs and Border Protection) for drug interdiction and aerial surveillance mission with a rotodome adapted from the Grumman E-2 Hawkeye or an AN/APG-66 radar adapted from the General Dynamics F-16 Fighting Falcon, and for NASA for research and development.

The U.S. Navy remains the largest P-3 operator, currently distributed between a single fleet replacement (i.e., "training") patrol squadron in Florida (VP-30), 12 active duty patrol squadrons distributed between bases in Florida, Washington and Hawaii, two Navy Reserve patrol squadrons in Florida and Washington, one active duty special projects patrol squadron (VPU-2) in Hawaii, and two active duty test and evaluation squadrons. One additional active duty fleet reconnaissance squadron (VQ-1) operates the EP-3 Aries signals intelligence (SIGINT) variant at Naval Air Station Whidbey Island, Washington.

In January 2011, the U.S. Navy revealed that P-3s have been used to hunt down "third generation" narco subs.[19] This is significant because as recently as July 2009, fully submersible submarines have been used in smuggling operations.[20] As of November 2013, the US Navy began phasing out the P-3 in favor of the newer and more advanced Boeing P-8 Poseidon.

In May 2020, Patrol Squadron 40 completed the transition to the P-8, marking the retirement of the P-3C from U.S. Navy active duty service. The last of the active-duty P-3Cs, aircraft 162776, was also delivered to the Naval Aviation Museum in Pensacola, Florida. Two Navy Reserve squadrons and Air Test and Evaluation Squadron 30 continue to fly the P-3C, with final phaseout of the aircraft expected in 2023.[21]

In October 1962, P-3A aircraft 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.

Beginning in 1964, forward deployed P-3 aircraft 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. 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 VP-26 was downed by anti-aircraft fire in the Gulf of Thailand with the loss of the entire crew. Two months earlier, in February 1968, another one of VP-26's P-3B aircraft was operating in the same vicinity when it crashed with the loss of the entire crew. Originally attributed to an aircraft mishap at low altitude, later conjecture is that this aircraft may have also fallen victim to anti-aircraft artillery (AAA) fire from the same source as the April incident.[22]

On 2 August 1990, Iraq invaded Kuwait and was poised to strike Saudi Arabia. Within 48 hours of the initial invasion, U.S. Navy P-3C aircraft were among the first American forces to arrive in the area. One was a modified platform with a prototype system known as "Outlaw Hunter". Undergoing trials in the Pacific after being developed by Tiburon Systems, Inc. for NAVAIR's PMA-290 Program Office, "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 move from Basra and Umm Qasr 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 7 January 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. A total of 55 of the 108 Iraqi vessels destroyed during the conflict were targeted by P-3C aircraft.[23]

The P-3 Orion's mission expanded in the late 1990s and early 2000s to include battlespace surveillance both at sea and over land. The long range and long loiter time of the P-3 Orion have proved to be an invaluable asset during Operation Iraqi Freedom and Operation Enduring Freedom. It can instantaneously provide information about the battlespace it can see to ground troops, particularly the U.S. Marines.[1]

Although the P-3 is a Maritime Patrol Aircraft, armament and sensor upgrades in the Anti-surface Warfare Improvement Program (AIP)[24] have made it suitable for sustained combat air support over land.[24] In what became known as the "Decade in the Desert", Navy P-3C crews patrolled combat zones in the middle east and southwest Asia.[25] Since the start of the current war in Afghanistan, U.S. Navy P-3 aircraft have been operating from Kandahar in that role.[26] Royal Australian Air Force AP-3C Orions operated out of Minhad Air Base in the UAE from 2003 until their withdrawal in November 2012. During the period 2008–2012, the AP-3C Orions conducted overland intelligence, surveillance and reconnaissance tasks in support of coalition troops throughout Afghanistan.[27]

The United States Geological Survey used the Orion to survey parts of southern and eastern Afghanistan for lithium, copper, and other mineral deposits.[28]

Several U.S. Navy P-3C Orions, and two Canadian CP-140 Auroras, a variant of the Orion, have participated in maritime surveillance missions over Libyan waters in the framework of enforcement of the 2011 no-fly zone over Libya.[29][30]

A U.S. Navy P-3C Orion supporting Operation Odyssey Dawn engaged the Libyan coast guard vessel Vittoria on 28 March 2011 after the vessel and eight smaller craft fired on merchant ships in the port of Misrata, Libya. The Orion fired AGM-65 Maverick missiles on Vittoria, which was subsequently beached.[31]

A U.S. Navy F-14 Tomcat escorts an Iranian P-3F Orion over the Indian Ocean – 1981

Lockheed produced the P-3F variant of the P-3 Orion, for Iran. Six examples were delivered to the former Imperial Iranian Air Force (IIAF) in 1975 and 1976.

Following the Iranian Revolution in 1979, the Orions continued in service, after the IIAF was renamed the Islamic Republic of Iran Air Force (IRIAF). They were used in the Tanker War phase of the Iran–Iraq War and were operated by one of the most successful squadrons of the IRIAF during that conflict. A total of four P-3Fs remain in service.

A Pakistan Navy P-3C Orion in Quetta, in October 2010

Three P-3C Orions, delivered to the Pakistan Navy in 1996 and 1997 were operated extensively during the Kargil conflict. After the crash of one, the type was grounded due to the loss of an entire crew; nonetheless, the aircraft were maintained in an armed state and airworthy condition throughout the escalation period of 2001 and 2002. In 2007, they were used by the navy to conduct signals intelligence, airborne and bombing operations in a Swat offensive and Operation Rah-e-Nijat. Precision and strategic bombing missions were carried out by the Orions, and in 2007, intelligence management operations were conducted against Taliban and al-Qaeda operatives.[32]

On 22 May 2011, two out of the four Pakistani P-3Cs were destroyed in an attack on PNS Mehran, a Pakistani Naval station in Karachi.[33] The Pakistani fleet had been readily used in overland, counter-insurgency operations. In June 2011, the U.S. agreed to replace the destroyed aircraft with two new ones, with delivery to follow later.[34] In February 2012, the U.S. delivered two additional P-3C Orion aircraft to the Pakistan Navy.[35]

A U.S. Navy P-3C Orion monitoring the hijacking of MV Maersk Alabama, 2009

The Spanish Air Force deployed P-3s to assist the international effort against piracy in Somalia. On 29 October 2008, a Spanish P-3 aircraft patrolling the coast of Somalia reacted to a distress call from an oil tanker in the Gulf of Aden. To deter the pirates, the aircraft flew over the pirates three times as they attempted to board the tanker, dropping a smoke bomb on each pass. After the third pass, the attacking pirate boats broke off their attack.[36] Later, on 29 March 2009, the same P-3 pursued the assailants of the German navy tanker Spessart (A1442), resulting in the capture of the pirates.[37]

In April 2011, the Portuguese Air Force also contributed to Operation Ocean Shield by sending a P-3C[38] which had early success when on its fifth mission detected a pirate whaler with two attack skiffs.[39]

Since 2009 the Japan Maritime Self-Defense Force has deployed P-3s to Djibouti for anti-piracy patrols,[40][41][42] from 2011 from its own base.[43] As well the German Navy is contributing assets against piracy with one P-3 from time to time.

Aero Union P-3A Orion taking off from Fox Field, Lancaster, California, to fight the North Fire

Several P-3 aircraft have been N-registered and are operated by civilian agencies. The US Customs and Border Protection has a number of P-3A and P-3B aircraft that are used for aircraft intercept and maritime patrol. NOAA operates two WP-3D variants specially modified for hurricane research. One P-3B, N426NA, is used by National Aeronautics and Space Administration (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. operated eight secondhand P-3A aircraft configured as air tankers, which were leased to the U.S. Forest Service, the California Department of Forestry and Fire Protection and other agencies for firefighting use. Several of these aircraft were involved in the U.S. Forest Service airtanker scandal but have not been involved in any catastrophic aircraft mishaps. Aero Union has since gone bankrupt, and their P-3s have been put up for auction.[44]

 Argentina

• Argentine Naval Aviation – six P-3B; based at Base Aeronaval Alte. Zar, Trelew

 Australia

• Royal Australian Air Force – 18 AP-3C, 1 P-3C
  • No. 92 Wing
    • 10 Sqn, 11 Sqn and No. 292 Sqn; based at RAAF Base Edinburgh

In 2002, the RAAF received significantly upgraded AP-3C. Also known as Australian Orions they are fitted with a variety of sensors. They include digital multi-mode radar, electronic support measures, electro-optics detectors (infrared and visual), magnetic anomaly detectors, identification friend or foe systems, and acoustic detectors.[45] The Boeing P-8 Poseidon is gradually replacing them. The P-3 Orion celebrated 50 years of RAAF service in November 2018. P-3B sold to Portugal.

 Brazil

• Brazilian Air Force – 9 P-3AM (Upgraded) in 2008 (12 ex-USN airframes purchased).[46] Integrated with the CASA FITS (Fully Integrated Tactical System)utilized in antisubmarine warfare.

 Chile

• Chilean Navy – four P-3A; based at Base Aeronaval Torquemada, Concón. Three used as patrol aircraft, one used for personnel transport. Chile plans to extend their service lives past 2030 by changing the wings, modernizing the engines, and integrating the AGM-84 Harpoon anti-ship missile.[47]

 Canada

• Royal Canadian Air Force – Canada purchased 18 P-3A in 1980. The CP-140 Aurora are operated by 404 Long Range Patrol and Training Squadron, 405 Long Range Patrol Squadron, 415 Long Range Patrol Force Development Squadron, (all three from 14 Wing Greenwood), 407 Long Range Patrol Squadron (19 Wing Comox).[48][49]
• The RCAF also operated 3 CP-140A Arcturus, P-3 aircraft purchased in 1991 without an anti-submarine warfare suite and used primarily for pilot training and long-range surface patrol. The last two were retired in 2011.

 Germany

• German Navy – eight P-3C CUP+ (ex Royal Netherlands Navy); based at NAS Nordholz, Marinefliegergeschwader 3 Graf Zeppelin

 Greece

• Hellenic Air Force – six P-3B operated jointly with the Hellenic Navy, 1 in operable condition as of 2019, 3 additional of the planes are undergoing maintenance as of 2016 which should return them to airworthy condition, the first of which was completed in May 2019.[50]

 Iran

• Islamic Republic of Iran Air Force – four P-3F (71ASW SQN); based at Shiraz International Airport (Shahid Douran Air Base)

 Japan

• Japan Maritime Self-Defense Force – 93 P-3C, five EP-3, five OP-3C, one UP-3C, three UP-3D.[51] The Kawasaki Corporation assembled five airframes produced by Lockheed, and then Kawasaki produced more than 100 P-3s under license in Japan.[52] The Kawasaki P-1 is gradually replacing them.
  • Air Patrol Squadron 3 (JMSDF) (1984–2017)[53]

 New Zealand

• Royal New Zealand Air Force – six P-3K2 (5 Sqn); based in RNZAF Base Auckland. Operated by 5 SQN. Five were originally delivered in 1966 as P-3Bs. Another was purchased from the RAAF in 1985. All six have been upgraded by L-3 Communications Canada and now designated as P-3K2,[54] with the first upgraded aircraft delivered back to New Zealand in April 2011.[55] The New Zealand Government announced[56] they are to be replaced in 2023 with the purchase of 4 Boeing P-8A Poseidons. An interim upgrade contract worth NZ$36M has been awarded to Boeing to upgrade the underwater intelligence, reconnaissance and surveillance capability of the P-3K2,[57] with a capability similar to what is provided in the P-8.[58]

 Norway

• Royal Norwegian Air Force – four P-3C, two P-3N (333 Sqn); based in Andøya Air Station

 Pakistan

• Pakistan Naval Air Arm – ~Four P-3C; based in Naval aviation base Faisal, Karachi. Upgraded P-3C MPA and P-3B AEW models (equipped with Hawkeye 2000 AEW system) ordered in 2006,[59] first upgraded P-3C delivered in early 2007. In June 2010, two more upgraded P-3Cs joined the Pakistan Navy with anti-ship and submarine warfare capabilities. A total of nine (9).[60] Two aircraft were destroyed in an attack by armed militants at the Mehran Naval Airbase.

 Portugal

• Portuguese Air Force – five P-3C CUP+ (ex Royal Netherlands Navy) operated by 601 Squadron "Lobos", based in Beja Air Base. They replaced six former RAAF P-3Bs upgraded to P-3Ps in the late 1980s. The last P-3P flew on 13 October 2011.

 South Korea

• Republic of Korea Navy – eight P-3Cs, eight P-3CKs; based in Pohang Airport and Jeju international airport. Korean Air/L-3 Communications are upgrading the P-3C aircraft with new electronics, including new magnetic anomaly detectors, electro-optical sensors, surveillance equipment and a self-protection suite. The Navy's impetus stems from a 2010 experience in which ROK forces detected only 28% of North Korean submarines involved in exercises.[61]

 Spain

• Spanish Air Force – Two P-3A HWs, four P-3B ( ex-Norway) being upgraded to P-3M, based at Morón Air Base. The Spanish AF bought five P-3B from Norway in 1989 and it was planned to upgrade all five to M standard, however, due to budgetary constraints only four are to be upgraded, the remaining aircraft being used as spares source.

 Taiwan (Republic of China)

• Republic of China Air Force(1966–1967) – Least known of all P-3 family. Three P-3As (149669, 149673, 149678) were obtained by the CIA from the U.S. Navy under Project STSPIN in May 1963, as the replacement aircraft for CIA's own covert operation fleet of RB-69A/P2V-7U versions. Converted by Aerosystems Division of LTV at Greenville, Texas, the three P-3As were simply known as "black" P-3As under "Project Axial". Officially transferred from U.S. Navy to CIA on June/July 1964, LTV Aerosystems converted the three aircraft to be both ELINT and COMINT platform. First of three "black" P-3As arrived in Taiwan and officially transferred to ROCAF's top secret Black Bat Squadron on 22 June 1966. Armed with four Sidewinder short range AAM missiles for self-defense, the three "black" P-3A flew peripheral missions along the China coast to collect SIGINT and air samples. When the project was terminated in January 1967, all three "black" P-3As were flown to NAS Alameda, CA, for long term storage. In September 1967, Lockheed at Burbank, converted two of the three aircraft (149669 and 149678) into the only two EP-3B examples in existence in the world, while the third aircraft (149673) was converted by Lockheed in 1969–1970 to serve as a development aircraft for various electronic programs. The two EP-3Bs known as "Bat Rack", owing to their short period of service with Taiwan's "Black Bat" Squadron, were issued to U.S. Navy's VQ-1 Squadron in 1969 and deployed to Da Nang, Vietnam. Later, the two EP-3Bs were converted to EP-3E ARIES, along with seven EP-3As. The two EP-3Es retired in the 1980s, when replaced by 12 EP-3E ARIES II versions.[62]
• Republic of China Navy – The Taiwan Navy obtained 12 P-3C aircraft under the U.S. government's Foreign Military Sales program in 2007 which were then modernized to provide an additional 15,000 flight hours.[63] 12 P-3Cs (Ordered, with deliveries starting in 2012), with three "spare" airframes that might be converting to EP-3E standard; based in south part of the island and offshore island.[64] In May 2014 Lockheed Martin were awarded a contract to upgrade and overhaul all 12 P-3Cs for completion by August 2015.[65]

 United States

• United States Navy – 100 P-3Cs and 14 EP-3Es in service.[66] The government of Singapore has expressed an interest in buying surplus P-3C aircraft from the U.S. Navy.[67]

 Netherlands

• Royal Netherlands Navy – Netherlands Naval Aviation Service – former operator. Sold to Portugal and Germany.

 Thailand

• Royal Thai Navy – two P-3Ts, one VP-3T, one UP-3T ; based at RTNAB U-Tapao (102 Sqn). Whithdrawn from active service in 2014.

• National Oceanographic and Atmospheric Administration (NOAA) – two WP-3Ds flown by NOAA Commissioned Corps officers, previously based at MacDill AFB, now based at Lakeland Linder International Airport, Florida
• National Aeronautics and Space Administration – one ex-USN P-3B; based at NASA's Wallops Flight Facility, Virginia used for low altitude heavy lift airborne science missions, modified to support passive microwave instruments, such as NOAA's Polarimetric Scanning Radiometer (PSR), NASA's 2-DSTAR, and the Jet Propulsion Laboratory (JPL) polarimetric scatterometer (POLSCAT) instruments.[68]
• United States Department of Homeland Security / Bureau of Customs and Border Protection / Office of Air and Marine – eight P-3 AEWs; based at NAS Corpus Christi, Texas and Cecil Field and NAS Jacksonville, Florida. Used for border patrol and anti-drug duties. Former USN aircraft, modified and equipped with the same Airborne Early Warning radar as fitted to the E-2 Hawkeye.[69]
• United States Department of Homeland Security / Bureau of Customs and Border Protection / Office of Air and Marine – 8 P-3 LRTs (Long Range Tracker). Former USN aircraft also based at NAS Corpus Christi, Texas and Cecil Field, Jacksonville, Florida. Normally operate in tandem with P-3 AEW aircraft.[70]
• MHD-ROCKLAND Services, Inc. - 5 former RAAF AP-3Cs. Aircraft are FAA Registered as L285D, and based in Keystone Heights, FL.

[71]

• Airstrike Firefighters – 1 former Aero Union Tanker 23, with plans for 6 more P-3's.[72]

• Aero Union – eight ex-USN P-3A; aircraft based at Chico Municipal Airport in Chico, California and converted into aerial firefighting platforms[73] Aero Union shut down and put its Orions up for auction in 2011.[44]