Article from Navy Lookout.

The axing of the troubled Nimrod MRA4 project in 2010 SDSR has left Britain unable to properly patrol its waters and left a serious gap in anti-submarine capability. In 2015 the government tacitly admitted its mistake and announced the plan to purchase nine Poseidon P-8A Maritime Patrol Aircraft (MPA) from Boeing in the United States. In the first part of this article we will look at the programme and infrastructure behind its introduction into service, and the aircraft itself.

Background

Although the US Navy operates its own aircraft, by a historical anomaly the RAF have always owned the UK MPAs – a critical naval capability. This arrangement will continue as only the RAF has the facilities and experienced personnel needed to support the next generation. Since the 1950s, the RAF operated the Shackleton and then the Nimrod MR1 and MR2 maritime patrol aircraft which were largely successful in this role. The planned successor to the Nimrod MR2 was another Nimrod, the MRA4. The tale of woe that led to the eventual cancellation of the MRA4 is long, complicated and depressing and has been discussed in much detail elsewhere.

In broad terms the decision to build a ‘new’ aircraft utilising existing ancient Nimrod airframes was disastrous. This and many other factors, meant that by 2010 the project was £789 million over-budget and over nine years late. It should be noted that a production aircraft was flying in 2009 and the first aircraft had been delivered to the RAF. Although there were still serious flaws, it was not perhaps as unsafe or hopeless as government claimed at the time. Anyway, the MRA4 was cancelled and the airframes were chopped into pieces with extraordinary haste, effectively throwing away the £4Bn already spent on the project.

Enter Posiedon

The P-8A Poseidon has been in development since 2004 intended to replace the venerable turboprop Orion P-3. The P-8 airframe has little in common with the Nimrod or the P-3, being based on a modern, and extremely successful commercial airliner, the Boeing 737-800. On 25 March 2016 the US government approved the sale of nine P-8s to the UK. Although the Japanese P-1 was given cursory consideration, the P-8 was always the strong favourite and is being procured as a direct government sale. Controversially no competition was held and the purchase is not subject to the MoD’s single source regulatory framework. Given the urgency of the situation, this was perhaps sensible. Although expensive, the P-8 is the simply best available option and ease of interoperability with the US Navy is always desirable. The US Navy is buying at least 117 aircraft, Australia 12, India 9 and Norway 5, so the UK will benefit from a multinational development programme and economies of scale.

Having shot itself in the balls with the MRA4 debacle, the UK aerospace industry is in no position to complain about this major foreign purchase. Fortunately, as part of the P-8 deal, Boeing has agreed to expand its UK workforce from 1,300 to 4,000 and is opening a major new aircraft repair and maintenance hub at Boscombe Down. UK industry will also have opportunities to be involved in training and support work for the P-8.

On 11 July 2016, the UK signed a $3.87 billion contract with Boeing for the 9 aircraft and elements of their support which will be delivered in 3 batches. The schedule calls for the first two aircraft to be delivered in 2019, with three more in 2020 and the final four in 2021. It will be at least 12 years after the end of the Nimrod MR2 (which at one time numbered 35 aircraft) before the re-establishment of a ‘full strength’ squadron of 9 P-8s.

Regenerating on the front foot

There were those, including some in the RAF, who were not especially enthusiastic about the P-8 and hoped that the focus could be steered away from maritime and instead obtain a more generic ISTAR Multi-Mission Aircraft and/or long range UAVs. However the RAF did have the foresight not to make all its Nimrod aircrew redundant in 2010. The Seedcorn exchange programme has seen around 30 RAF personnel serving aboard US, Canadian, Australian and New Zealand aircraft on 3-4 year tours. UK personnel have already accumulated more than 1,000 hours of flying time on US Navy P-8s and even have won various awards in international anti-submarine warfare competitions. This demonstrates the wealth of skill that the Nimrod force had acquired and will be able to contribute to bringing the P-8 into service. The RAF has also persuaded personnel who previously served on Nimrod to assist with the P-8 introduction. 12 have recently re-joined the RAF and more are set to re-join in the future.

The P-8 will be based at RAF Lossiemouth in North East Scotland. (The Nimrod’s former Scottish base was at RAF Kinloss which has since been converted to an Army base). Despite the ongoing complaints by nationalists about lack of defence investment in Scotland and worries over the future of the Union, the UK government is set to invest further in new support infrastructure including new runways and hangars. Boeing will also set up a P-8 maintenance hub at Lossiemouth and is investing £100M and will create around 100 new jobs. An extra 600 personnel are expected to be stationed at the base by 2020.

Aircraft overview

Although based on the 737-800ERX, the P-8A is a very different aircraft. The wings are based on the 737-900 but have been substantially re-designed to cope with the stress of more low altitude flying than a commercial jet and to provide four hard-points for weapons. The fuselage has been substantially redesigned with a bomb bay and additional fuel tanks replacing luggage holds. The airframe life will be around 25 years or 25,000 flying hours in tough high and low conditions over the sea and is able to operate in icing conditions or extreme temperatures.

A variety of additional sensors and antenna are mounted externally, all linked to the sophisticated mission systems. It is these sensors and electronics that are the real cost-drivers for an aircraft with a price tag of around £350 Million (Before support and weapons costs are added). The computing and data fusion abilities of the aircraft are what set it apart from other MPAs. The P-8 has the world’s most powerful onboard sonobuoy data processing capability and has space for more sonobuoys than any other MPA. The P-8 was also designed from the outset to be able to control and monitor data from the MQ-4C Triton Broad Area Maritime Surveillance (BAMS) unmanned aerial vehicle. Although a highly desirable force multiplier and rumours about UK Triton orders prior to SDSR 2015, the MoD has no plan or funding in place for such a purchase.

The aircraft is powered by two CFM56-7 turbofans, one of the most widely used jet engines in the world, with over 30,000 manufactured as of 2016. Most MPAs have four engines which provide a measure of redundancy when operating for long distances away from land. However the CFM56 is exceptionally reliable with shutdown rates around three per million flight hours. In the three years the P-8A has been in service it has yet to have an in-flight engine shutdown. Electrical power is provided by a 180KVA generator on each engine and a standard 90KVA back-up APU. With a total of 450KVA available, there is more than enough to support the mission systems with plenty of capacity for additional equipment to be fitted in future.

The P-8 has an endurance of around 10.5 hours at an economical cruising speed of around 500 knots at high altitude, with an approximate unrefuelled range of 4,500 miles. Operating at low level, the aircraft can fly in a fuel efficient regime at 180Knots, just 60m above the sea. Crews are trained to refuel their own aircraft so the P-8 can land at civilian airports and utilise standard commercial jet fuelling facilities if required. Unfortunately, when first delivered, only US tanker aircraft will be able to conduct in-flight refuelling with the UK P-8. The RAF Voyager tanker is fitted with a probe and drogue system rather than the flying boom used by the USAF. It is possible the aircraft could be modified in future to address this problem.

In US Navy service the Poseidon is operated by nine aircrew which includes the flight commander, two pilots, two tactical coordinators, two anti-submarine weapon systems operators and two electronic warfare weapon system operators. There is no dedicated flight engineer.

Although the process is far too slow, the UK has retained just enough skills and is putting the right infrastructure in place to gradually re-enter the MPA game. By selecting the P-8, the RAF will have the best platform available to conduct maritime patrol, anti-submarine warfare and search and rescue.

P-8A, the high flyer

MPAs have historically operated at medium or low altitude over the sea. This requirement primarily comes from the need to be able to drop sonobuoys or weapons accurately. Dropping an ASW homing torpedo with a small parachute required the MPA to descend a low as 100ft. Based on the 737, a commercial airliner designed to cruise efficiently at around 30,000 ft, the P-8A is intended to operate predominately at much higher altitudes than legacy MPAs. Low flying uses more fuel and demands a more rugged airframe able to cope with the thicker, more turbulent air. Contrary to popular belief, the P-8 airframe has been strengthened for this regime and can perform well at low altitude. During the first part of its life in service with the US Navy, it has been operating predominantly down low. This is partly because the adapted weapons and sensors needed for use at high altitude are not yet available.

There are considerable advantages that will come when the P-8A is able to routinely fly at higher altitude, including greater fuel efficiency. With just 9 aircraft available, the time on station dictated by fuel consumption will be particularly important for the UK P-8s, especially as the RAF cannot provide its own air-air refuelling for them. Aircrew also suffer less fatigue in the smoother air at altitude.

Increasingly sensitive sonar means the noise of low-flying aircraft can be detected by submarines at times. Various attempts have been made to develop submarine-launched anti-aircraft missiles, and it is only a matter of time before they are perfected and become a lethal threat to aircraft at low-level or helicopters. For search & rescue and surface surveillance missions, flying at higher altitude also vastly increases the sea surface area that can be surveyed by the multi-mode radar, electro-optical/infrared camera. The USN is developing the Multi-Static Active Coherent (MAC) system which uses dispersed active and passive sonobuoys, greatly enhancing submarine detection capability. This new generation of sophisticated sonobouys with modern batteries are able to work for longer, have GPS to track their exact position and allow one aircraft to handover monitoring to another aircraft or ship. The powerful onboard processing capabilities of the P-8A are intended to interact with widely dispersed sonobuoy fields from high altitude.

Of course, if within range of enemy warships and land batteries equipped with medium/long range anti-aircraft missiles (such as the lethal Russian S300/400 series) the aircraft becomes far more vulnerable than at low altitude. The increment 3 P-8A does not have a full set of robust countermeasures such as radar jammers and decoys needed to protect it from modern SAM systems.

Buying all-American aircraft and kit

It is clear from MoD statements that the UK will be buying the P-8A directly “off the shelf” with no modifications and no plan to integrate UK weapons. The platform has successfully evolved in a series of increments, with capabilities added over time. The UK will get aircraft fitted to Increment 3 standards, identical to those being delivered to the US Navy. Initially, the UK will have to purchase a stock of US Mk 54 torpedoes. Performance is classified, but the British-made Stingray Mod 1 Torpedo is probably slightly superior to the Mk 54. Both weapons experienced development problems, but the Stingray is now very mature, while there are still question marks about the Mk 54 in demanding environments.

A British company, Ultra Electronics is the world leader in sonobuoy manufacture and is continues to work with QinetiQ in conducting research and development supporting the Merlin ASW platform. There will be little UK-supplied sonobuoy and acoustic processing input into the P-8A, at least initially. The sonobuoy is a British invention but the P-8A will not benefit from the considerable UK expertise available in this field. The P-8 processors and dispenser are not fully compatible with UK sonobuoys, so US stocks will have to be acquired. The UK will have to support the cost of two parallel inventories of, sonobuoys and torpedos, but there may be some operational advantages of commonality with US equipment. RAF, US and Norwegian P-8As will all be able to share a common pool of stores and spares held RAF Lossiemouth, Keflavik Air Base (Iceland) and other US bases.

In order to be effective at higher altitude, the US is developing two specific enablers. Boeing has the contract to build a glider kit for the Mk 54 torpedo, the High Altitude Anti-submarine warfare Weapon Capability (HAAWC). HAAWC integrates an air-launched accessory (ALA) kit with a GPS guidance system and folding wings. This will allow the launch of the weapon from 30,000ft under operator control so the torpedo can be put into the water with precision and at the considerable distance from the aircraft that launched it.

BAE Sytems in the US is developing the High Altitude ASW (HAASW) Unmanned Targeting Air System (UTAS). This is a small dispensable drone equipped with a Magnetic Anomaly Detector (MAD) that can be dropped from the P-8A weapons bay at high altitude. Previous MPAs (and India’s P-8i) have a MAD boom on the tail of the aircraft which require the aircraft to fly at low level over the suspected contact. Small changes in the earth’s magnetic field are detected if there is a submarine present. MAD has only a short detection range but is a useful tool for localising and confirming the presence of a submarine if no active sonar emitter is available. UTAS will enable this to be done by the P-8A at high altitude without the need to descend.

P-8 Operations

The table below shows the missions the P-8A will be expected to carry out when it enters service plus some additional roles that it could be equipped for. With just 9 aircraft, it is clear the force will be in great demand and raises some interesting questions about how is tasking will be prioritised. A continuous ASW watch over northern waters and GIUK gap would be desirable with an aircraft available to respond to SAR emergencies. Keeping at least two aircraft in the air or at very high readiness would probably require the entire squadron and leave limited options for other tasks. The more numerous Nimrod MR2s were frequently used to provide overwatch and co-ordination for UK military operations around the world. The RAF has an inadequate number ISTAR aircraft and there maybe be pressure to take the P-8A away from its primary maritime patrol duties.

_{*FCASW – Future Cruise and Anti-Ship Weapon. An Anglo/French missile in development, but unlikely to be operational before 2030.}

Conventional wisdom suggests that a lone MPA will struggle to detect a modern submarine, and should be considered as just one of the essential parts of the ASW matrix that include seabed arrays, ships and other submarines.

A Cold War submarine captain I know once suggested to me that he feels the only way a MPA could find a properly operated SSN was if it bumped into it. “MPA radar is a good deterrent, which makes you keep your head down,” he explained, “but the only time one SNN I commanded was detected by a sonobuoy was when we passed about 20 feet away from it and the contact was fleeting.” Cold War-era British MPAs fared better against the Russians, however. “Nimrods used to get away with it when tracking earlier Soviet submarines,” the SSN captain also observed, “but they were pretty hopeless against a Victor III. Against an Akula, I would have given them hardly any chance at all.” (Iain Ballantyne blog)

The P-8A has some classified capabilities, that are subject to much speculation but may give it the edge in ASW. It is known that it has a hydrocarbon sensor that can detect trace amounts of exhaust from ships, or more importantly conventional submarines snorting (recharging their batteries using their diesel engines). Such leading edge technology, including MAC sonobuoys and powerful onboard processors, justify the high financial cost of the P-8A. This investment may well be vindicated, particularly when up aginst a new generation of very quiet Russian submarines.