The BAe Nimrod MRA4 and Boeing P-8 Poseidon


The Nimrod MRA4 in flight. Originally named Nimrod 2000, this project died of ambition.

Britain is an island nation and history has shown that, to survive, it needs to control the seas around it. For centuries that was the job of the Royal Navy, but with the rise of aviation during the 20th century the Royal Air Force began to play a part as well. The importance of air power became obvious during the existential struggle of the Battle of the Atlantic, when Coastal Command’s patrol bombers played a major part in the fight against the U-Boats that came so close to strangling the UK’s supply routes. After the war new technology – the Shackleton maritime patrol aircraft – was brought in to deal with the new threat of the USSR’s submarines. Then, in 1967, the RAF decided to bring maritime patrol into the jet age.

The Nimrod family of maritime military aircraft served the RAF for over forty years, in various marks and roles, with the MR2 being the workhorse of the anti-submarine warfare and maritime surveillance squadrons. Entering service in 1969, the five operational squadrons were deployed in critical roles during the Cold War, the Falklands War, both Iraq conflicts and over Afghanistan. The R1 variant was an exceptional but little-known air electronics success story that was the last operational Nimrod to be withdrawn from service in 2011. Right up to its retirement it was one of the most capable electronic intelligence platforms in the world, but its ageing airframe made it unsafe.

Developed from the De Havilland Comet 4 airliner, the Nimrod was the first all-jet maritime reconnaissance and anti-submarine aircraft in the world, revolutionising the deployment time to target areas and greatly increasing the patrol and loiter time in theatre. Compared to its predecessor, the Shackleton MR2, the Nimrod provided near-airline comfort for crews on long patrols.

Nimrod MR2

The Nimrod MR2 was reliable and effective, but problems increased as they aged.

However, the success of the Nimrod MR2A was in some ways responsible for a series of futile attempts to develop an all-British range of airborne early warning and electronic warfare aircraft. In the 1970s the decision was taken to modify a number of Nimrods into AWACS-type systems to provide long-range radar cover to the UK and deployed British forces. Unfortunately it didn’t work. The Nimrod airframe turned out to be too small to support a radar like that of the American E-3 Sentry. Rather than use the more compact system AN/APS-125 system from the E-2 Hawkeye it was decided to use two huge and powerful British-built radars, each capable of scanning 180 degrees, fitted at the nose and tail. A moment’s thought would seem to suggest that an airframe too small to carry one large radar might have some issues carrying two (and, more importantly, their associated cooling systems.) Despite spending over a billion pounds over ten years this turned out to be the case. The radars overheated dangerously. The cooling system was upgraded. The undercarriage collapsed under the increased weight. The undercarriage was reinforced. The airframe was now too heavy to take off. The end result was a plane that could either fly or not catch fire, but not both at once. The Nimrod AEW3s were scrapped and, in 1991, Britain bought the E-3 Sentries they’d turned down in 1976.

Sadly this wasn’t the last costly and embarrassing catastrophe involving the elegant but ageing Nimrod. As years passed the increasing age of the fleet began to show up in maintenance – and, worryingly, safety – problems. BAe Systems proposed a complete rebuild of 21 aircraft to create the Nimrod 2000 – later named the MRA4 as the 2000 deadline slipped past – which would combine maritime reconnaissance and electronic surveillance roles. These were to be almost brand-new aircraft; the plan was to strip MR2s down to the fuselage, refurbish them and fit all-new wings, modern fuel-efficient engines and completely new flight control systems and mission electronics. Using refurbished fuselages would be cheaper than building new ones and would also class the project as an upgrade, which for political reasons was more desirable than buying new airframes. The new wings and other components would be designed and built with the latest computer-aided techniques, ensuring modern standards.

Nimrod MRA4

The MRA4 flew extremely well – if the wings fitted.

That was all very well, but the fuselages had been designed and built by men in brown dust coats who’d laid them out on a factory floor with a chalk line. The first one was stripped down, carefully measured and the dimensions used to design the new parts. Several hundred million pounds later it was discovered that no two of the fuselages were exactly the same; in fact the difference between the longest and shortest was nearly five inches and other dimensions were just as variable. This hadn’t mattered when the aircraft were first built because all the parts had been hand-fitted by those industrious men in brown coats, but it certainly mattered now. The new parts wouldn’t mate up with the fuselages. BAe managed to waste a total of £3.6 billion proving this before the plug was pulled and the project cancelled; in 2010 the airframes were scrapped, and that was the end of the Nimrod. Annoyingly, if new fuselages had been built using the original plans and modern techniques the project would most likely have gone flawlessly.

However it didn’t, and an island nation was left with the same maritime patrol capability as Switzerland or Afghanistan. The government argued that the gap could be filled by other systems, but as these systems turned out to be C-130s and transport helicopters nobody was very convinced. Now, once again, it’s likely that a failed Nimrod conversion will be replaced by an off the shelf US design that could have been bought in the first place.

The Boeing P-8 Poseidon, like the Nimrod, is based on a militarised airliner. Rather than the Comet, however, it’s built around the latest generation of the 737, the most popular jet airliner in history. Mainly because it uses a proven and reasonably modern airframe the P-8 project is on time and on budget, and there aren’t any problems getting the wings to fit. It’s also highly capable. BAe Systems are a major subcontractor and the aircraft available to the UK will have essentially the same sensors and mission electronics as the MRA4 would have had. The Fleet Air Arm and RAF are both looking at the P-8 as a possible solution. A decision on acquiring them could be taken in the 2015 defence budget. That’s great, but we could have had them already.

P-8A Poseidon

Boeing P-8 Poseidon. The future of maritime reconnaissance?