The definitive account of why the Nimrod MRA4 project went so drastically wrong


In February 1965 the Mk1 Nimrod was selected to replace the Shackleton as the UKs MPA and a fixed price contract for thirty-eight production aircraft was agreed in January 1966. Progress was rapid and on 28 June 1968, the first new-build production Nimrod Mk 1 had its maiden flight and in the late 1970s the Mk1 was upgraded to the MR2.

Hindsight is a wonderful thing and nobody realised when Michael Portillo,  the then Secretary of State for Defence, placed the UKs MR2  replacement contract in the mid 1990s with BAE  as prime contractor that BAE had vastly underestimated the difficulty of what they proposed to do in developing and building the Nimrod MRA4 and to put it simply didn’t understand what they were letting themseves in for.

In my view the reason for this fatal underestimation is quite simple:

 By the time BAE took part in the competition to replace the Nimrod MR2 in the mid 1990s almost 30 years had passed since the MK1 had been designed and built in the late 1960s. By then the corporate memory of the Mk1 design and build had largely disappeared with most of the original team having retired or moved on to other jobs and with numerous company reorganisations also taking their toll on the staff with the corporate memory.

If the corporate memory had been retained then the BAE led bid team would have been briefed during the bid stage that the old MR2 wings and fuselages  had been constructed before the days of CAD / CAM and were built in jigs and then mated by tradesmen hammering & filing the metal to fit as necessary.

As a result each fuselage was slightly different, in some cases by up to 4 inches. Thus the embarrassing failure of the new wing designed on a modern CAD and manufactured with great precision to fit to the old fuselage wouldn’t have happened. The BAE team at Woodford then found that the new wing was flawed, which resulted in the project being put on hold while another wing design was developed.

The MRA4 would have been almost a brand new aircraft as only the parts of the old MR2 fuselage that were being refurbished and retained were the fuselage pressure cell and empennage – everything else including the cabin pressure floor, bomb bay area, wings and undercarriage were newly designed and manufactured. Speaking with the benefit of hindsight a complete rebuild would have avoided these problems.
The Nimrod, the Mk 1 was designed and developed by Hawker Siddeley who had absorbed De Havilland in 1960 the company who designed the Comet. De Havilland had its headquarters at Hatfield and lost its separate identity in 1963 and was then merged into British Aerospace in 1978 as part of Hawker Siddeley. The Hatfield site then closed in 1993.


To arrive at the Nimrod Mk1 Hawker Siddeley (formerly Avro) at Chadderton simply added an under fuselage pannier to the proven Comet 4C airframe . The pannier produced a large increase in space for operational equipment and weapons. The existing Rolls-Royce Avon engines were replaced with more fuel efficient, Spey turbofan engines to provide good endurance. To minimise costs a lot of the Mk1 mission avionics were similar to those in the Shackleton.
Starting in 1975, 35 Mk1 aircraft were upgraded to MR2 standard, being re-delivered from August 1979 The upgrade included extensive modernisation of the aircraft’s electronic suite. Changes included the replacement of the obsolete ASV Mk 21 radar used by the Shackleton and Nimrod MR1 with the new EMI Searchwater radar,[N 2] a new acoustic processor (GEC-Marconi AQS-901) capable of handling more modern sonobuoys, a new mission data recorder (Hanbush) and a new Electronics Suite.
Woodford became part of BAE Systems as a result of the £7.7 billion merger of British Aerospace (BAe) and Marconi Electronic Systems (MES) in November 1999. The aerodrome and factory became known as BAE Systems Woodford until it was sold in late 2011.
When the final decision was made in 2010 to cancel the MRA4 project it was said by MOD that there still a large number of safety and design flaws outstanding. I am not competent to comment on these but there were rumours that the RAF preferred to protect the budget for their fast jets rather than an MPA based on a 1950s airliner the Comet.
In January 2011 it was reported by the Financial Times that when the decision was taken to scrap the aircraft, “[The MRA4] was still riddled with flaws…. Safety tests conducted [in 2010] found there were still ‘several hundred design non-compliances’ with the aircraft. It was unclear, for example, whether its bomb bay doors functioned properly, whether its landing gear worked and, most worryingly, whether its fuel pipe was safe.” According to Air Forces Monthly magazine, “significant aerodynamic issues and associated flying control concerns in certain regimes of flight meant that it was grounded at the time of cancellation and may not have been signed over as safe by the Military Aviation.

Various Tory ministers have rubbished the MOD for the MRA4 procurement debacle. Howerver, in hindsight perhaps the only thing MOD could have done differently would have been to cancel the contract a long time ago and redo the competition as BAEs abilty to complete the contract to any acceptable time and budget  was non existent. As BAE were the UKs largest defence company no doubt the MOD thought that they had to support them which they did by bailing them out in the early 20 th century when the ASTUTE  project aso went wrong and BAE could have gone out of business or would have had to have been nationalised for a while as Rolls Royce were.