P-3C Orion maritime patrol aircraft is manufactured by Lockheed Martin. Credit: Alaniaris.
The P-3C aircraft is powered by four Allison T56-A-14 turboprop engines. Credit: Mark Wagner.
The P-3C aircraft was commissioned in 1969. Credit: Asuspine.

The P-3C Orion land-based maritime patrol and anti-submarine warfare aircraft is operational in the airforces of ten countries. More than 700 P-3 aircraft have been built by Lockheed Martin.

More than 400 aircraft are operational with 21 operators in 17 countries including the US, Argentina, Australia, Brazil, Chile, Greece, Germany, Canada, Japan, New Zealand, Norway, Pakistan, Portugal, Taiwan, Spain and Thailand.

The aircraft carries the US Navy designation P-3, the Canadian Forces designations CP-140 Aurora and CP-140A Arcturus, and the Spanish Air Force designation P.3.

P-3A was first operational in the US Navy in 1962. The P-3C first entered service in 1969 and has been continuously upgraded and updated with new avionics systems and mission equipment.

The US Navy’s P-3C aircraft are being replaced by the advanced Boeing P-8 Poseidon. The US Navy airborne patrol squadron VP-40 began the transition of P-3C Orion to the Boeing P-8A Poseidon maritime patrol aircraft in November 2019. The final transition was completed in May 2020.

P-3C Orion upgrade programmes

“The P-3 Orion is a land-based maritime patrol and anti-submarine warfare aircraft.”

In 1975 an improved navigation system, expanded computer memory, and tactical displays were provided under the Update I programme. In 1976 the Update II programme provided an infrared detection system and sonobuoy reference system and the aircraft were fitted with the Harpoon missile. The P-3C aircraft to the Upgrade III standard, delivered in 1984, were equipped with advanced anti-submarine warfare avionics including the IBM Proteus AN / UYS-1 acoustic processor.

Update IV programme improvements, mainly directed towards the provision of advanced signal processing capabilities, were implemented during the 1990s to meet the threat of new generation fast, quiet and deep-diving submarines. The aircraft are equipped with Raytheon AN / APS-137(V) multi-mission surveillance radar.

International upgrade programmes

International upgrade programmes included 18 aircraft of the Royal Australian Air Force upgraded to AP-3C standard. The upgrade involved the installation of an Elta Electronics EL / M-2022(V)3 maritime surveillance radar and a FLIR Systems Star SAFIRE II thermal imager. Deliveries concluded in March 2005.

Eight aircraft upgraded for the Royal Netherlands Navy have been sold to the German Navy. The upgrade included new Electronic Support Measures (ESM), radar and acoustic sensors, new data management system and new communications suite. EADS CASA is upgrading nine aircraft of the Brazilian Air Force. This upgrade included Thales integrated cockpit avionics and the EADS CASA FITS mission system.

New Zealand selected L-3 Communications to upgrade six P-3K aircraft with new mission systems. The upgrade also included new communications and navigation equipment.

“The P-3A was first operational in the US Navy in 1962.”

Pakistan purchased seven upgraded ex-US Navy P-3C aircraft and ordered the upgrade of two Pakistan Navy aircraft. The upgrade included Inverse Synthetic Aperture Radar (ISAR / SAR), Electronic Support Measures (ESM) and communication systems. The first was delivered in January 2007.

Kawasaki Heavy Industries, based in Kobe, Japan, manufactures the P-3C aircraft in Japan under a licensed agreement. Kawasaki is the prime contractor to the Japan Maritime Self-Defence Force (JMSDF) for the supply of up to 110 P-3C aircraft. Ishikawajima-Harima Heavy Industries (IHI), based in Tokyo, manufactures the engines.

Crew stations

The aircraft is flown by a crew of ten on missions up to 14 hours long. The flight deck accommodates the pilot, the co-pilot and the flight engineer.

The main cabin is configured as a mission operations room for the tactical coordinator, the navigator and communications operator, two operators for the acoustic sensor suite, the electromagnetic sensors systems operator (responsible for the operation of the radar, electronic support measures, infrared detection system and magnetic anomaly detectors), the ordnance crew member and the flight technician. Circular protruding windows in the main cabin give the crew a 180° view.

Anti-submarine warfare systems

P-3C’s anti-submarine warfare systems include the AN/ARR-78(V) sonobuoy receiving system supplied by Hazeltine Corporation of New York, the AN/ARR-72 sonobuoy receiver supplied by Fighting Electronics Inc of New York for the operation and management of buoys, two AQA-7 directional acoustic frequency analysis and recording sonobuoy indicators, and an AQH-4 (V) sonar tape recorder.

The sensor suite also includes an ASQ-81 magnetic anomaly detector and an ASA-65 magnetic compensator. Sonobuoys are launched from within the main cabin and from the external hardpoints.

“The P-3C Orion maritime patrol aircraft can carry weapons in the bomb bay and on ten underwing pylons.”

The airborne electronic surveillance receiver, ALQ-78(V) is carried on a pylon under the wing fairing. The system is supplied by Lockheed Martin based in New York and has also been manufactured under licence by Mitsubishi in Japan.

ALQ-78(V) automatically operates in search mode, its target primarily being submarine radars. When a submarine radar signal is detected the system is switched to direction-finding mode and the received signals are characterised.


The aircraft can carry weapons in the bomb bay and on ten underwing pylons. The bomb bay is in the underside of the fuselage forward of the wing. It is capable of carrying a 2,000lb mine such as the mk25, mk39, mk55 or mk56. Alternative ordnance includes 1,000lb mines, depth bombs, torpedoes, or nuclear depth bombs. The underwing pylons can carry 2,000lb mines, torpedoes, rockets, rocket pods and 500lb mines.

The US Navy P-3C aircraft are equipped to carry the Harpoon AGM-84 anti-ship and stand-off land attack missile. During the late 1990s, the US Navy P-3C Orions armed with the Harpoon were deployed in Yugoslavia. US Navy P-3Cs are also being upgraded with the WESCAM 20 multi-sensor system, which includes thermal imager and CCD sensors.

In February 2004, the Boeing SLAM-ER standoff land attack missile completed integration on the US Navy P-3C Orion.


The aircraft is equipped with four Allison T56-A-14 turboprop engines rated at 3,661kW. Each engine drives a four-blade constant-speed propeller, type 54H60-77 supplied by Hamilton Standard. There are five fuel tanks, one in the fuselage and four integral wing tanks with a total fuel capacity of 34,800l.