Kawasaki P-1

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Kawasaki P1 - RIAT 2015 (20142197773).jpg
Kawasaki P-1
Role Maritime patrol aircraft
National origin Japan
Manufacturer Kawasaki Aerospace Company
First flight 28 September 2007
Introduction 2013[1]
Status In service
Primary user Japan Maritime Self-Defense Force
Produced 33
Unit cost

2015 MOD Budget: 20 units (¥350.4 billion) / US$140.8 million each[2]

2014 MOD Budget: 3 units (¥ 59.4 billion) / US$167 million each[3]
Variants Kawasaki YPX

The Kawasaki P-1 (previously P-X, XP-1) is a Japanese maritime patrol aircraft developed and manufactured by Kawasaki Aerospace Company. Unlike many maritime patrol aircraft, which are typically conversions of civilian designs, the P-1 is a purpose-built maritime aircraft with no civil counterpart and was designed from the onset for the role. It has the distinction of being the first operational aircraft in the world to make use of a fly-by-light control system.

The P-1 has entered service with the Japan Maritime Self-Defense Force (JMSDF) as a replacement for the P-3C Orion. On 26 March 2013, the JMSDF took delivery of the first two operational P-1 aircraft.[1] Export customers are also being sought for the type as part of a general loosening of Japanese military export restrictions.


Observing that its fleet of P-3C aircraft had been in service for sometime, the JMSDF began searching for a replacement maritime patrol aircraft. Since other similar aircraft abroad did not meet the JMSDF's requirements, the development of a purpose-built indigenous aircraft became the primary consideration. The Japanese Defense Agency (JDA) submitted the domestic development of a P-X maritime patrol aircraft as part of its April 2001–March 2006 Five-Year Defense Plan.[4] In 2001, following its earlier proposal, the Kawasaki Aerospace Company received prime contractor status for the P-X program, as well as the adjacent C-X program for a new-generation cargo aircraft; this selection occurred almost 30 years since the previous large-scale domestic development of an aircraft in Japan.[4]

The P-X shares some components with the C-X, later designated as the Kawasaki C-2, another indigenously-developed aircraft to replace the Kawasaki C-1 and C-130H Hercules cargo aircraft. The P-X and C-X designs were originally independent, it was decided that having common components to both designs would be useful.[5] The JDA mandated that the two aircraft share identical body components;[4] common components include the cockpit windows, outer wings, horizontal stabilizer, and other systems. Internal shared parts include the auxiliary power unit, cockpit panel, flight control system computer, anti-collision lights, and gear control unit.[4] Due to the different roles of the two aircraft, they remain distinctly separate. The sharing of development resources had allowed for a large reduction in overall development costs which, when including the C-2, were reported as being 345 billion Yen ($3 billion) in 2007.[6]

In addition to a level of commonality with the C-2, one proposed derivative of the P-1 is a civilian airliner, the proposed project has typically been referred to as the Kawasaki YPX.[7] If development is pursued, the YPX would make extensive use of technology and components of the P-1, such as the wingbox, empennage, and fuselage.[8][9]

An indigenously produced turbofan engine, the IHI Corporation F7, was also developed to power the P-X.[10] By April 2004, the JDA had completed a successful evaluation of five XF7 research engines, by which point it was viewed as being the sole candidate powerplant for the P-X program.[11] In May 2005, the IHI Corporation received a contract for an additional seven XF-7 test engines from the JDA following the completion of initial tests in December 2004, four of these engines were to equip the first flight test aircraft.[12] The Full Authority Digital Engine Control (FADEC)-equipped F7 engine had a bypass ratio of 8:1, which was reported as being substantially higher than rivals such as the General Electric CF34-8E.[13][10]

P-1 with its US equivalent, the Boeing P-8 Poseidon in 2014

In April 2004, Japan and US extended discussions on potential cooperative efforts on the P-X and US Navy's Multi-mission Maritime Aircraft (MMA) programmes; options ranged from terminating the P-X program to participate in the US-led MMA program to incorporating some of the MMA's technology onto the P-X to reduce costs.[14] The Japanese Defence Ministry ultimately opted to persist with the P-X program, stating that: "there was a possibility that foreign aircraft would not satisfy the required capability and there was a possibility that foreign aircraft would not meet the required period of introduction...it is necessary to domestically develop the aircraft".[15] In addition to the P-1, studies were also conducted into the use of ship-based UAVs to support maritime aviation activities.[16]

Since 2014, Japan has been making approaches to other nations for prospective export sales of the P-1.[17][18] Japanese officials have claimed that the P-1 is a more capable, albeit more expensive, aircraft than the Boeing P-8 Poseidon; in comparison to the P-8, the P-1 has a greater range, a larger bomb bay, and has been purpose-built for the maritime patrol mission.[17] Prior to 2015, the P-1 was being procured at a typical rate of one or two aircraft deliveries per year; in 2015, this changed to a bulk order for 20 P-1s as part of a measure to cut the aircraft's unit costs.[19][20]


IHI F7-10 engines of a P-1, 2013

The Kawasaki P-1 is a purpose-built maritime patrol aircraft equipped with four engines. Similar to the Hawker Siddeley Nimrod, S-3 Viking and P-8 Poseidon, the P-1 is powered by turbofan engines, specifically four podded IHI F7-10 turbofan engines set underneath the low-set wings.[17] The low-wing loading adopted for the P-1 results in a flight profile with better maneuverability and stability at low-speed, low-altitude flight. The use of four engines allows the aircraft to continue its mission in the event of a single engine failure as well as greater operational survivability, the high-bypass engines provide for quiet and fuel-efficient operation.[17] Due to its engines, the P-1 benefits from reduced transit times in comparison to turboprop-powered competitors.[21]

The P-1 is equipped with many newly developed technology and features, particularly in terms of its avionics and missions systems.[21] One such key feature is the use of a fly-by-light flight control system. This has the effect of decreasing electro-magnetic disturbances to the sensors in comparison to more common fly-by-wire control systems. The P-1 is the first production aircraft in the world to be equipped with such a flight control system.[17] Various onboard systems are provided by Honeywell, who is the largest non-Japanese supplier to the project, such as the auxiliary power unit, environmental and pressurization control systems, ram air turbine, sonobuoy dispensers and elements of the avionics.[22][23]

A P-1 on approach to land, 2014

The P-1 is equipped with various sensors to enable the aircraft to perform its primary purpose of detecting submarines and surface vessels; these include the Toshiba HPS-106 active electronically scanned array (AESA) radar which uses a total of four antennas to provide 360 degree coverage, and Infrared/Light detection systems for surface detection. The P-1 is also furnished with a CAE Inc.-built magnetic anomaly detector (MAD) embedded into the aircraft's tail,[21][24] along with deployable Sonobouys, which is used for the detection of submerged submarines.[19] Sophisticated acoustic systems are also used for this purpose.[19] The P-1 has an artificial intelligence (AI) system to assist TACCO operations; similar to the SH-60K, this advanced combat direction system directs the TACCO operator to the optimal flight course to attack a submarine.[25]

A large bomb bay housed within the main fuselage, similar in size to that of the Hawker Siddeley Nimrod's, contains the bulk of the aircraft's munitions,[17] the bomb bay is supplemented by a total of eight external hardpoints mounted on the wings.[26][27] Weapons available on the P-1 include torpedos, mines, depth charges, air-to-surface missiles (ASMs) (such as the US-built Harpoon), or bombs.[19] Armaments are managed by a Smith Aerospace-built stores management system, which includes a newly developed Universal Stores Control Unit (USCU) capable of accomidating hundreds of different munitions, including future ones and precision weapons.[28] Multiple radar warning receivers provide all-round awareness of missile threats, which is combined with a defensive countermeasures suite.[21]

Operational history[edit]

A P-1 just prior to landing, 2014

On 31 August 2007, the Japanese Ministry of Defense revealed that they will procure four production airframes. The request in the FY2008 budget is 67.9 billion yen, or about US$566 million, the unit price for each aircraft at US$141.5 million.[29][30] In 2013, the ministry ordered two units for ¥44.5 billion. These P-1s were reported to possess increased detection/discrimination capability, flight performance, information processing capability, and strike capabilities as a successor to the existing P-3C fixed-wing patrol aircraft.[31]

In June 2007, Kawasaki rolled out the XP-1, a prototype for the P-X program.[32][33] The rollout had been delayed for three months due to the discovery of defective rivets provided by a US supplier which required remedial repairs to be performed.[34] On 28 September 2007, the XP-1 conducted its maiden flight from Gifu Air Field, Kakamigahara, Gifu, Japan; this flight lasted about one hour and ended successfully.[35] The P-X was redesignated XP-1 at this time. By March 2010, Kawasaki Heavy Industries had delivered four XP-1 maritime patrol test aircraft to Japanese Ministry of Defense; the company also stated its aim for type certification to be achieved in time for the formal delivery of the first two aircraft by the end of March 2012.[36]

On 8 August 2011, the Japanese Ministry of Defense announced that two aircraft used for ground testing had developed tears in various parts of the craft, including the fuel tank and central part of the fuselage.[37] In response, modifications to reinforce the affected areas were planned.[37] By October 2012, the problems had been reportedly resolved.[15] On 26 March 2013, Japan's Maritime Self-Defense Force took delivery of its first pair of P-1s, ahead of a planned two years of test flights.[38] On 14 May 2013, these aircraft were grounded after one developed an unstable combustion condition in some of its engines during mid-flight.[39]

In January 2015, it was reported that Tokyo was holding a series of defence talks with the United Kingdom to ascertain a possible sale of P-1s to the Royal Air Force to replace their recently retired fleet of Hawker Siddeley Nimrod patrol aircraft. The proposal was part of a wider initiative to lower restrictions on Japanese military exports. It was claimed that Britain may consider jointly manufacturing the type, and that the nation could retain rights over related radar and sensor technologies.[40] A pair of P-1s were present for the 2015 Royal International Air Tattoo, one aircraft performing a flying display while the other was on static display; this was the first time that any Japanese military aircraft had performed in European flight display.[41][42] In the aftermath of its UK appearance, the P-1 proceeded to an airbase close to Ambouli International Airport, Djibouti, to continue with operational trials within tropical and desert climates.[43][19]

Specifications (XP-1)[edit]

View of the underside of a P-1 inflight, note the open bomb bay
Rear view of a P-1 at Iwakuni Air Base, Japan, 2014
A P-1 landing at RAF Fairford, England, 2015

Data from flightglobal.com[36][44]

General characteristics



  • Hardpoint: 8 wing stations in total (2x on each wing and 2x on each wing root) and eight internal bomb bay stations
  • Bombs: 9,000+ kg (20,000+ lb)
  • Missiles: AGM-84 Harpoon, ASM-1C, AGM-65 Maverick
  • Sonobuoys: 30+ Pre-loaded, 70+ Deployable from inside
  • Other: MK-46 and Type 97 and new (G-RX5) torpedoes, mines, depth charges


  • Radar: Toshiba, Active Electronically Scanned Array radar system
  • Sonar: NEC, multi-static sound navigation system sound
  • Anti-submarine systems:SHINKO ELECTRIC CO.LTD., Advanced combat direction system
  • Other: Mitsubishi, Electronic countermeasures (CMD, RWR, MWS, ESM)

See also[edit]

External video
Footage of the P-1's first flight in September 2007
Video of P-1 taxing, taking off, and landing
A P-1 performing an flight display at RIAT 2015
Related development
Aircraft of comparable role, configuration and era
Related lists


  1. ^ a b "KHI gives MSDF first P-1 antisub patrol aircraft". The Japan Times. 27 March 2013. 
  2. ^ "Defense Programs and Budget of Japan: Overview of FY2015 Budget." Japanese Ministry of Defense, January 2015.
  3. ^ "Defense Programs and Budget of Japan Ministry of Defense: Overview of FY2014 Budget." Japanese Ministry of Defense, December 2013.
  4. ^ a b c d "Sky-High Expectations for Japan’s P-X and C-X Aircraft." Kawasaki Heavy Industries Scope Quarterly Newsletter, No.73. October 2007.
  5. ^ "P-1&C-X development reference paper." TRDI Defense Technology Symposium, 2007. pp. 4-6.
  6. ^ "中日新聞:<蜜月の終焉> ミライズに固執:防衛利権 蜜月の構図(CHUNICHI Web)." Chunichi Shimbun, 2008.
  7. ^ Perrett, Bradley (15 August 2008). "Kawasaki Studies Advanced, Lightweight Competitor to CSeries". Aviation Week and Space Technology. McGraw-Hill. 
  8. ^ "FARNBOROUGH 2008: Japan eyes slice of CSeries market." Flight International, 15 July 2008.
  9. ^ Govindasamy, Siva. "Kawasaki talks civil." Flight International, 23 September 2008.
  10. ^ a b Sobie, Brendan. "IHI backs GE's CF6 engine proposal." Flight International, 27 May 2003.
  11. ^ Sobie, Brendan. "Japan amends five-year plan as priorities change." Flight International, 18 May 2004.
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  13. ^ "Japan reveals novel XF7 engine design features." Flight International, 11 October 2005.
  14. ^ "Japan extends talks with USA." Flight International, 13 April 2004.
  15. ^ a b Waldron, Greg, "IN FOCUS: China crisis adds urgency to Japanese air force modernisation." Flight International, 8 October 2012.
  16. ^ Waldron, Greg. "Japan's defence budget places premium on airpower." Flight International, 19 December 2013.
  17. ^ a b c d e f "Tim Huxley: Japan’s P-1 leads defence export drive." IISS Defence and Military Analysis Programme, 11 September 2015.
  18. ^ "DUBAI: Kawasaki talks up its aerospace portfolio." Flight International, 8 November 2015.
  19. ^ a b c d e Gady, Franz-Stefan. "Japan Seeks To Export its New Sub-Hunting Plane." The Diplomat, 9 July 2015.
  20. ^ Waldron, Greg. "Japan defence budget calls for 20 P-1s, 5 V-22s." Flight International, 14 January 2015.
  21. ^ a b c d Gardner, Richard. "Rising sun breaks cover on Japanese defense industry ." SAE International, 24 July 2015.
  22. ^ "Contracts." Flight International, 18 May 2004.
  23. ^ Minnick, Wendell. "Honeywell to Outfit Japan P-1 Maritime Aircraft." Defense News, 16 February 2016.
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  25. ^ P-1&C-X project reference paper p. 13. in TRDI Defense Technology Symposium 2007
  26. ^ P-1 & C-X development reference paper, pp. 12-13.
  27. ^ Policy assessment's outline paper about P-1's production
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  29. ^ Policy assessment's reference paper about P-1 production
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  37. ^ a b Waldron, Greg (8 August 2011). "Kawasaki XP-1 develops cracks in ground testing". Flightglobal.com. Archived from the original on 8 August 2011. 
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  39. ^ "New MSDF patrol jets grounded since May". The Japan Times. 21 June 2013. 
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  41. ^ "Japan Makes Air Tattoo History." Royal Air Force Charitable Trust, 7 July 2015.
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  43. ^ "P-1哨戒機のジブチで運用試験実施 及び英国ロイヤル・ンターナ 及び英国ロイヤル・ンターナ 及び英国ロイヤル・ンターナショナル・エアタトゥーへの 参加 について." Japanese Ministry of Defense, 7 July 2015.
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External links[edit]