Lockheed P-3 Orion

The Lockheed P-3 Orion is a four-engine turboprop anti-submarine and maritime surveillance aircraft developed for the United States Navy and introduced in the 1960s. Lockheed based it on the L-188 Electra commercial airliner. The aircraft is easily recognizable by its distinctive tail stinger or "MAD Boom", used for the magnetic detection of submarines.

Over the years, the aircraft has seen numerous design advancements, most notably to its electronics packages. The P-3 Orion is still in use by numerous navies and air forces around the world, primarily for maritime patrol, reconnaissance, anti-surface warfare and anti-submarine warfare. A total of 734 P-3s have been built, and during 2012, it joined the handful of military aircraft including the Boeing B-52 Stratofortress and Boeing KC-135 Stratotanker that have served 50 years of continuous use by the United States military. The U.S. Navy's remaining P-3C aircraft will eventually be replaced by the Boeing P-8A Poseidon.

Origins
In August 1957, the U.S. Navy called for replacement proposals for the aging twin 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 antisubmarine warfare. Modifying an existing aircraft was expected to save on cost and allow rapid introduction into the fleet. Lockheed suggested a military version of their L-188 Electra, which was still in development and had yet to fly. In April 1958 Lockheed won the competition and was awarded an initial research and development contract in May.



The prototype YP3V-1/YP-3A, Bureau Number (BuNo) 148276 was modified from the third Electra airframe c/n 1003. The first flight of the aircraft's aerodynamic prototype, originally designated YP3V-1, was on 19 August 1958. While based on the same design philosophy as the Lockheed L-188 Electra, the aircraft was structurally different. The aircraft had 7 ft less fuselage forward of the wings with an opening bomb bay, and a more pointed nose radome, distinctive tail "stinger", wing hardpoints, and other internal, external, and airframe production technique enhancements. The Orion has four Allison T56 turboprops which give it a top speed of 411 knot comparable to the fastest propeller fighters, or even slow high-bypass turbofan jets such as the A-10 Thunderbolt II or the Lockheed S-3 Viking. Similar patrol aircraft include the Soviet Ilyushin Il-38 and the French Breguet Atlantique, while Britain adapted the jet-powered de Havilland Comet as the Hawker Siddeley Nimrod.

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. Paint schemes have changed from early 1960s gloss blue and white, to mid-1960s gloss white and gray, to mid-1990s flat finish low visibility gray with fewer and smaller markings. In the early 2000s, the scheme changed to a gloss gray finish with the original full-size color markings. Large size Bureau Numbers on the vertical stabilizer and squadron designations on the fuselage remained omitted.

Further developments


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.

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 insuffiently strong engine mounts, unable to dampen 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. 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.

Sales of airliners were limited as the technical fix did not completely erase the "jinxed" reputation, turboprop-powered aircraft were soon replaced by faster jets. 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. 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.

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 is due to enter service in 2013.

Design


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, 127 mm Zuni rockets, and various other sea 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.

The P-3 is equipped with a magnetic anomaly detector (MAD) in the extended tail. This instrument is able to detect the magnetic anomaly of a submarine in the Earth's magnetic field. The limited range of this instrument requires the aircraft to be near the submarine at low altitude. Because of this, it is primarily is used for pinpointing the location of a submarine immediately prior to a torpedo or depth bomb attack. Due to the sensitivity of the detector, electromagnetic noise can interfere with it, so the detector is placed in P-3's fiberglass tail stinger (MAD boom), far from other electronics and ferrous metals on the aircraft.

Crew complement
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). Data for U.S. Navy P-3C only.

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

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).

Engine loiter shutdown
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 port 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.

United States


Developed during the Cold War, the P-3's primary mission was to track Soviet Navy ballistic missile and fast attack submarines and to eliminate same in the event of full scale war. 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 squadron in California provided P-3 training for the Pacific Fleet, while the squadron 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 Texas 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 U.S. Navy P-3 or other P-3 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 (PLAN) J-8II jet fighter-interceptor resulted in an international dispute between the U.S. and the People's Republic of China (PRC) called the Hainan Island incident.

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 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 in Washington.

In January 2011, the U.S. Navy revealed that P-3s have been used to hunt down "third generation" narco subs. This is significant because as recently as July 2009, fully submersible submarines have been used in smuggling operations.

Cuba
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.

Vietnam
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. 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 26 (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 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 AAA fire from the same source as the April incident.

Iran


Iran used P-3Fs in the Tanker War during the Iran-Iraq War. They were one of the most successful squadrons of the IRIAF during the war. A total of four P-3Fs remain in service.

Iraq
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 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 the Navy’s Space & Naval Warfare Systems Command (SPAWAR), "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.

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.

Afghanistan
Although the P-3 is a Maritime Patrol Aircraft, armament and sensor upgrades in the Anti-surface Warfare Improvement Program (AIP) have made it suitable for sustained combat air support over land. Since the start of the current war in Afghanistan, U.S. Navy P-3 aircraft have been operating from Kandahar in that role. Royal Australian 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.

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

Pakistan
Three P3Cs, delivered to the Pakistan Navy in 1996/97 were operated extensively during the Kargil Conflict. After the crash of one P-3 the type was grounded due to loss of complete crew, nonetheless these were maintained in armed state in flyworthy condition throughout the escalation period of 2001/02. In 2007, the P-3C aircraft were used by the Navy to conduct signal intelligence missions, airborne and bombing operations in a Swat offensive and the final operations in North. The precision and strategic bombings were carried out by the P-3C aircraft as well as conducting intelligence management on Taliban and al-Qaeda operatives in 2007.

On 22 May 2011, two out of the four Pakistani P-3C aircraft were destroyed in an attack on PNS Mehran Base while parked on the hardstand, during an attack at the Mehran Pakistani Naval Air Base in Karachi. 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. In February 2012, the U.S. delivered two additional P-3C Orion aircraft to the Pakistan Navy.

Somalia


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

Libya
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.

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 two smaller craft fired on merchant ships in the port of Misrata, Libya. The Orion fired AGM-65 Maverick missiles on the Vittoria, which was subsequently beached.

Civilian uses


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 ex-USN 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.

Variants
Over the years, numerous variants of the P-3 have been created. A few notable examples are:


 * WP-3D: Two P-3C aircraft as modified on the production line for NOAA weather research, including hurricane hunting.
 * EP-3E Aries: 10 P-3A and 2 EP-3B aircraft converted into ELINT aircraft.
 * EP-3E Aries II: 12 P-3C aircraft converted into ELINT aircraft.
 * 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.
 * CP-140 Aurora: Long-range maritime reconnaissance, anti-submarine warfare aircraft for the Canadian Forces. Based on the P-3C Orion airframe, but mounts the more advanced electronics suite of the Lockheed S-3 Viking; 18 built
 * CP-140A Arcturus: Three P-3s without ASW equipment for Canadian Aurora crew training and various coastal patrol missions.
 * P-7 proposed new-build and improved variant as a P-3 Orion replacement later canceled.
 * Orion 21 proposed new-build and improved variant as a P-3 Orion replacement; lost to the Boeing P-8 Poseidon.

Operators
This list of P-3 Orion operators is a list of Lockheed P-3s that were used by Patrol Squadrons of the U.S. Navy and foreign governments. The P-3 has seen continuous use for over five decades since its introduction in 1962 as an Antisubmarine warfare and Antisurface warfare patrol aircraft.



Military operators

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

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 (infra-red and visual), magnetic anomaly detectors, identification friend or foe systems, and acoustic detectors.
 * 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
 * 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


 * Brazilian Air Force – 12 P-3AM(Upgraded) in 2008. Integrated with the CASA FITS (Fully Integrated Tactical System)utilized in antisubmarine warfare.
 * Brazilian Air Force – 12 P-3AM(Upgraded) in 2008. Integrated with the CASA FITS (Fully Integrated Tactical System)utilized in antisubmarine warfare.


 * Royal Canadian Air Force – 18 CP-140 Aurora (P-3 Orion airframe with S-3 Viking electronics suite) and three CP-140A Arcturus (CP-140 Aurora without full ASW suite)
 * Royal Canadian Air Force – 18 CP-140 Aurora (P-3 Orion airframe with S-3 Viking electronics suite) and three CP-140A Arcturus (CP-140 Aurora without full ASW suite)


 * 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.
 * 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.


 * German Navy – eight P-3C (ex Dutch Navy); based at NAS Nordholz, Marinefliegergeschwader 3 Graf Zeppelin
 * German Navy – eight P-3C (ex Dutch Navy); based at NAS Nordholz, Marinefliegergeschwader 3 Graf Zeppelin


 * Hellenic Air Force - six P-3B operated jointly with the Hellenic Navy
 * Hellenic Air Force - six P-3B operated jointly with the Hellenic Navy


 * Islamic Republic of Iran Air Force – five P-3F (71ASW SQN); based at Shiraz International Airport (Shahid Douran Air Base) (Iran operates a reverse engineered version of the P-3 that was not developed by Lockheed Martin)
 * Islamic Republic of Iran Air Force – five P-3F (71ASW SQN); based at Shiraz International Airport (Shahid Douran Air Base) (Iran operates a reverse engineered version of the P-3 that was not developed by Lockheed Martin)


 * Japan Maritime Self-Defense Force – 101 P-3C, five EP-3, one UP-3C, three UP-3D
 * Japan Maritime Self-Defense Force – 101 P-3C, five EP-3, one UP-3C, three UP-3D

After Lockheed bribery scandals, the Japan Defense Agency decided to adopt the Lockheed P-3C replacing the Kawasaki P-2J in 1977. The Kawasaki Corporation assembled five airframes produced by Lockheed, and then Kawasaki produced more than 100 P-3s under license in Japan.


 * Royal New Zealand Air Force – six P-3K2 (5 Sqn); based in RNZAF Base Auckland
 * Royal New Zealand Air Force – six P-3K2 (5 Sqn); based in RNZAF Base Auckland


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


 * 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, 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. Two aircraft were destroyed in an attack by armed militants at the Mehran Naval Airbase.
 * 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, 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. Two aircraft were destroyed in an attack by armed militants at the Mehran Naval Airbase.


 * Portuguese Air Force – Five P-3C CUP+ operated by Esquadra 601 "Lobos" (Squadron 601 "Wolves"); based in Beja Air Base (BA11). They replaced six former RAAF P-3Bs upgraded to P-3Ps in the late 1980s. The last P-3P flew on October 13th 2011.
 * Portuguese Air Force – Five P-3C CUP+ operated by Esquadra 601 "Lobos" (Squadron 601 "Wolves"); based in Beja Air Base (BA11). They replaced six former RAAF P-3Bs upgraded to P-3Ps in the late 1980s. The last P-3P flew on October 13th 2011.

🇰🇷
 * Republic of Korea Navy – eight P-3Cs, eight P-3CKs; based in Pohang Airport and Jeju international airport


 * Spanish Air Force – Two P-3A HWs, four P-3B 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.
 * Spanish Air Force – Two P-3A HWs, four P-3B 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.


 * Republic of China Air Force(1966–1967) – Least known of all P-3 family. Three P-3As (149669, 149673, 149678) were obtained by 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.
 * Republic of China Navy – 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.
 * Republic of China Navy – 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.


 * Royal Thai Navy – two P-3Ts, one VP-3T; based at RTNAB U-Tapao (102 Sqn)
 * Royal Thai Navy – two P-3Ts, one VP-3T; based at RTNAB U-Tapao (102 Sqn)


 * Vietnam People's Navy - on negotiation to buy 6 P-3Cs with non-weaponised but forward looking infrared (FLIR) sensors and other systems
 * Vietnam People's Navy - on negotiation to buy 6 P-3Cs with non-weaponised but forward looking infrared (FLIR) sensors and other systems


 * United States Navy – 154 P-3Cs and EP-3Es; additional P-3A, P-3B, P-3C and EP-3J aircraft in long-term storage at AMARC The U.S. Navy plans to reduce this number to 130 by 2010. The government of Singapore has expressed an interest in buying surplus P-3C aircraft from the U.S. Navy.
 * National Oceanographic and Atmospheric Administration (NOAA) – two WP-3Ds flown by NOAA Commissioned Corps officers, based at MacDill AFB, Florida
 * National Oceanographic and Atmospheric Administration (NOAA) – two WP-3Ds flown by NOAA Commissioned Corps officers, based at MacDill AFB, Florida

Former military operators

 * Royal Netherlands Navy – Dutch Naval Aviation Service
 * Royal Netherlands Navy – Dutch Naval Aviation Service

Civilian operators

 * USA
 * 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.
 * 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, 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.
 * 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.
 * Aero Union – eight ex-USN P-3A; aircraft based at Chico Municipal Airport in Chico, California and converted into aerial firefighting platforms

Notable events, accidents, and incidents

 * 30 January 1963: United States Navy P-3A 149762 was lost at sea in the Atlantic Ocean, 14 crew killed.
 * 6 Mar 1969: USN P-3A 152765 coded RP-07 of VP-31 crashed at NAS Lemoore, California, at the end of a practice ground control approach (GCA) landing, all six crew died.
 * 28 January 1971: Commander Donald H. Lilienthal, USN flew a P-3C Orion to a world speed record for heavyweight turboprops. Over 15–25 kilometers, he reached 501 miles per hour to break the Soviet Il-18's May 1968 record of 452 miles per hour.
 * 26 May 1972: USN P-3A 152155 disappeared over the Pacific Ocean on a routine training mission after departing NAS Moffett Field, California with the loss of eight crew members.
 * 3 June 1972: While attempting to fly through the Straits of Gibraltar, en route from Naval Station Rota, Spain to Naval Air Station Sigonella, Sicily a United States Navy P-3A of Patrol Squadron 44 (VP-44) hit a mountain in Morocco, resulting in the death of all 14 people on board the aircraft.
 * 12 April 1973: A United States Navy P-3C 157332 operating from NAS Moffett Field in Sunnyvale, California collided with a Convair CV-990 (N711NA) operated by NASA during approach to runway 32R. The aircraft crashed on the Sunnyvale Municipal Golf Course, half a mile short of the runway, resulting in destruction of both aircraft and the death of all but one.
 * 11 December 1977: USN P-3B 153428 operating from Lajes Field in the Azores crashed on mountainous El Hierro (southwesternmost of the Canary Islands) in poor visibility. There were no survivors from the crew of 13.
 * 26 April 1978: USN P-3B 152724 from Patrol Squadron 23 (VP-23) crashed on landing approach to Lajes Field in the Azores. Seven of the crew were killed and the plane sank into deep water preventing recovery to assess the cause of the crash.
 * 22 September 1978: USN P-3B 152757 from Naval Air Station Brunswick Patrol Squadron 8 (VP-8) disintegrated over Poland, Maine on 22 September 1978. An over-pressurized fuel tank caused the port wing to separate at the outboard engine.  The detached wing sheared off part of the tail; and aerodynamic forces caused the remaining engines and starboard wing to detach from the fuselage.  Debris rained down near the south end of Tripp Pond shortly after noon.  There were no survivors from the plane's 8-man crew.
 * 26 October 1978: USN P-3C 159892 coded AF-586 from NAS Adak Patrol Squadron 9 (VP-9) ditched at sea after an engine fire caused by a propeller malfunction. Ten of the 15-man crew were rescued by a Soviet trawler.
 * 27 June 1979: P-3B 154596 from NAS Cubi Point, Philippines Patrol Squadron 22 (VP-22) had a propeller overspeed shortly after departure. The number 4 propeller then departed the aircraft striking the number three with a subsequent fire on that engine. While attempting an overweight landing with 2 engines out, the aircraft stalled, rolled inverted and crashed in Subic Bay just past Grande Island. Four crew and one passenger were killed in the crash.
 * 17 April 1980: USN P-3C 158213 from Patrol Squadron 50 (VP-50) while flying for a parachuting exhibition, struck overhead tram wires and crashed, killing six.
 * 16 June 1983: USN P-3B 152720 coded YB-06 from Barber's Point, Oahu, Hawai'i [NAS Barbers Point] Patrol Squadron 1 (VP-1), crashed into a mountain top in fog and low clouds, on the Napali Coast between the Hanapu and Kalalau valleys in Kauai, Hawai'i shortly after 0400 hours, killing all 14 on board.
 * 13 September 1987: A Royal Norwegian Air Force P-3B "602" is hit from below by a Russian AF Sukhoi Su-27 of the 941st IAP V-PVO. The Su-27 flew below the P-3's starboard side, then accelerated and pulled up, clipping the #4 engine's propellers. The Propeller shrapnel hit the Orion's fuselage and caused a decompression. There were no injuries and both aircraft returned safely to base.
 * 21 March 1991: While on a training mission west of San Diego, California, two U.S. Navy Orions assigned to Patrol Squadron 50 (VP-50) at NAS Moffett Field collided in midair, killing all 27 people on board both aircraft.
 * 26 April 1991: AP-3C A9-754 of the RAAF lost a wing leading edge and crashed into shallow water in the Cocos Island, one crewman was killed. Aircraft was cut up and used an artificial reef. The head investigator of this incident was RAAF FLTLT Richard Hall
 * 1 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 the Hainan Island 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.
 * 16 October 1991: P-3A N924AU of Aero Union crashed into a mountain in Montana, United States killing both crew.
 * 22 May 2011: Twenty Tehrik-i-Taliban Pakistan terrorists claiming to avenge Osama Bin Laden's death destroyed two Pakistan Navy P-3C Orions during an armed attack at PNS Mehran, a heavily guarded base of the Pakistan Navy located in Karachi. The aircraft had been readily used by the Pakistani military in overland counter-insurgency surveillance operations.