The Japanese territorial waters cover a vast area around the Japanese islands. For example, Okinawa in the South to Chitose in the North is a distance of around 1400 miles in a direct line. To oversee and protect those waters the Japanese Maritime Self Defence Force (JMSDF) has utilised a fleet of around 100 Lockheed P-3 Orions since 1984. However, since 2013 the JMSDF has started to replace these ageing aircraft with its own indigenous built modern aircraft – the Kawasaki P-1 Maritime Patrol Aircraft (MPA).

The P-1 is a four engine MPA powered by IHI F7-10 turbofan engines low slung on the wings, which allows the aircraft to be more manoeuvrable and stable at low altitude and speeds. The engines are quiet and highly efficient, meaning the aircraft has a reduced transit time compared to the turbo-propped Orion, a longer on-station loiter time, and submarines find it harder to acoustically detect the P-1  – a huge benefit in Anti Submarine Warfare. Currently, a total of 60 to 80 P-1s are expected to be procured by the JMSDF, but it has also been rumoured to eventually be in possession of circa 100 airframes.

Back in 2001 the Japanese Defence Agency (JDA), as part of its five year defence plan, looked to develop its future cargo and maritime aircraft projects, namely the P-X (P-1) and C-X (now the C-2), which were subsequently awarded to the Kawasaki Aerospace Company. Although both the P-X and C-X projects were independently designed it was later decided by the JDA that both aircraft should have commonality with regard to components, to reduce costs. The P-X and C-X projects would share parts such as outer wings, horizontal stabiliser and cockpit windows, along with the Auxiliary Power Unit (APU), Flight Control System Computer, anti-collision lights and gear control units.

The prototype P-1, designated XP-1, was rolled out in June 2007, but the first flight was delayed as defective rivets were encountered and had to be replaced. The XP-1 frame number 5501 (now 9501) eventually took to the skies on its one hour maiden flight on 28th September 2007 from the Test and Evaluation centre airfield at Gifu. By 2010 four aircraft had been delivered to the Japanese Ministry of Defence for evaluation, and subsequently, the JMSDF took delivery of its first two aircraft on the 26th March 2013.

Pitched directly against the Boeing P-8A Poseidon, the JDA has been looking to sell the P-1 to other nations who are looking to replace their ageing MPA fleets, although with little success at the time of writing. The JMSDF and Kawasaki sent two P-1’s to the Royal International Air Tattoo in 2015 (5503 & 5504) on a ‘good will’ visit at the time the UK was looking for a replacement MPA platform, although the Japanese denied it was a direct sales pitch, the UK eventually opted for The Boeing P-8. The cost of the P-1 comes in slightly more expensive with an average price of $150m, compared to the P8 at $125M, which is probably a good reason why the P-8 is forging ahead with sales to Australia, the United Kingdom, India, Norway, South Korea and New Zealand so far.

The P-1 does have many benefits over the P-8A, and on paper is a much more capable aircraft in the MPA role. It has the ability to shut down two of its four engines whilst on station therefore giving it the benefit of extended loiter time (a range of over 8000km) whilst operating at low level, saving fuel and reducing emissions. The wing area of the P-1 is over 170 m2 compared to the P-8A which has around 125 m2, which means it can operate at both high and low level, unlike the P-8A which has to operate at higher levels (the lower wing loading on the P-1 increasing manoeuvrability at low altitude). The P-1 has a lower Maximum Take Off Weight (MTOW) at 5 tonnes lighter, whilst matching the P-8A’s engine output and the cockpit windows are also larger on the P-1 giving the pilots a much better field of view.

Both aircraft have the ability to carry 10 tonnes of ordnance, the P-8A on 11 hard points, and the P-1 on 16. In addition to the 107 sonobuoys carried (37 external tubes plus 70 internally) the P-1 can carry an impressive array of weaponry; AGM-84 Harpoon, AGM-65 Maverick, ASM-1, various torpedoes including the Mk46, depth charges and mines.

With a plethora of sensors fitted, the Kawasaki P-1 is purpose built for the maritime patrol mission, compared to the Boeing 737 airframe based P-8A. The crew consists of two pilots and up to 11 mission specialists – depending on the employment of the aircraft – to operate the variety of systems fitted onboard. The Toshiba HPS-106 Active Electronic Scanned Array (AESA) radar utilises four antennas fitted to the aircraft to give nigh on 360 degree coverage, although there is a blind spot directly behind the aircraft. Along with the previously mentioned MAD boom fitted at the rear of the aircraft the P-1 is fitted with a Fujitsu HAQ-2 Forward looking infra-red (FLIR) detection system for aiding surface ship recognition. The Tactical Coordination officer (TACCO) is aided by use of an advanced artificial intelligence (AI) system, the Mitsubishi Electric HYQ-3 Combat Direction System, similar to that fitted in the SH60K which reduces workload on the TACCO and provides attack solutions to ease in the prosecution of submarines. Electronic Support Measures are provided by way of a Mitsubishi Electric HLR-109B ESM unit.

As of February 2019, 20 aircraft had been delivered (5501 – 5520) to the JASDF at NAF Atsugi. Two squadrons operate the aircraft – 51 Hikotai; known as Air Development Squadron 51 or VX-51, and 3 Hikotai; known as Air Patrol Squadron Three which is part of Fleet Air Wing 4.

Based at the sprawling Naval Air Facility Atsugi, the P-1’s share the base with a number of other units and types. The United States Navy relocated the majority of its Carrier Air Wing Five (CVW 5), which embark onboard the nuclear-powered Aircraft Carrier USS Ronald Reagan, to Iwakuni Air Base during 2018, however three rotary units remain; Helicopter Maritime Strike Squadron 51 (HSM-51) flying MH-60R Seahawks, Helicopter Strike Squadron 77 ‘Sabrehawks’ again flying MH-60R’s and Helicopter Sea Combat Squadron 12 ‘Golden Falcon’ flying the MH-60S Seahawk.

A large number and variants of P-3s also operate from the base with Fleet Air Wing 4 and VX-51, along with SH-60J/K & USH-60K. Air Transport 61 are also hosted at NAF Atsugi, flying Lockheed C-130R Hercules and King Air LC-90s.

Air Patrol Squadron Three was formed in 1961 at the Kanoya air Base and originally equipped with Lockheed P2V-7 Neptunes. In 1962 the squadron was moved to Shimofusa Air Base where it remained until Christmas day 1973, when it moved to its current base at Naval Air Facility Atsugi.

In 1974 the squadron received its first Kawasaki P-2J, a Japanese built variant of the Neptune which they flew until 1984 when the more capable Lockheed Orion replaced them. The P-2s were retired the following year.

In 2008 Air Patrol Squadron Three merged with another NAF Atsugi based unit, Air Patrol Squadron Six. After the arrival of the first P-1’s to Air Patrol Squadron Three during March 2015, the squadron became the first all P-1 operating squadron just over two years later, in August 2017.

During our visit in November 2018 the following P-1 frames were seen: 5506, 5507, 5508, 5509, 5510, 5513, 5514, 5515, 5516, 5517, 5518, 5519.

The Kawasaki P-1 is without doubt a through and through MPA, built specifically for the role. It has a huge arsenal at its disposal, high performance suite of sensors and with a great range and the ability to operate both at low and high levels depending on the mission, it is surely only a matter of time before Kawasaki achieves international sales with the aircraft.

AeroResource would like to thank the JMSDF staff, PAO and Embassy staff for their time and assistance in making this visit possible.