Development of the Nimrod MRA.4
Work on the Nimrod MRA.4 airframe was initially contracted out to FRA/Serco at Hurn Airport. Accordingly, on February 14th - 16th 1997 the fuselages of the three reserve MR.2s (XV234, XV242 and XV247) were flown by HeavyLift An-124 from Kinloss to Bournemouth.
On July 29th 1998 it was announced that Raytheon Systems Company had been selected to by Boeing to provide 299 Model 960 computers for the Nimrod 2000 program, in a deal worth about $30 million. The Model 960 is a repackaged version of the Compaq AS/500 Alpha workstation.
On September 9th 1998 it was announced that Aerosystems International had been awarded a contract valued in excess of £4.5m by MoD(PE) to supply Link 11 datalink systems for ten Nimrod MR.2s. The first aircraft was to be delivered in early 1999, with the rest by July 1999. Presumably the rest of the fleet will get Link 11 as they go through the MRA.4 upgrade.
In March 1999 it was announced that Nimrod MRA.4's in-service date (when the seventh aircraft was delivered) was likely to slip to early 2005. The delay was blamed on "resource and technical difficulties...at BAe". The first aircraft was expected to fly at the end of 2002 and be delivered to the RAF in late 2004. Programme cost was given as £2.4bn (at September 1998 prices).
FRA lost the subcontract from BAe (October 1999) to do the MRA.4 airframe conversions. In December 1999 all work was transfered to BAE Systems/Woodford.
In 2000 a new-build MRA.4 was proposed by BAE Systems as a contender in the US Navy's Multimission Maritime Aircraft (MMA) program. This seems to have caused BAe to take its eye off the RAF's requirements, thus causing further delays.
Final assembly of the first Nimrod MRA.4 (ZJ516) began in early September 2000 with the delivery of the first completed wing from BAE Systems/Chadderton to Woodford.
CAE was awarded a contract in October 2000 by Boeing to upgrade the Nimrod MRA.4's magnetic anomaly detection system. This upgrade allowed the MRA.4 to fly with the latest software for the AN/ASQ-504(V) Advanced Integrated Magnetic Anomaly Detection System
On December 19th 2001 the first MRA.4 (ZJ516) was officially "powered up" at Woodford. It was fitted with the full new mission system.
In March 2002 the UK MoD announced a reduction in the the order for the Nimrod MRA.4 from 21 to 18. This was aimed at providing seventeen operational and one sustainment aircraft. Although the MoD official reason was that the increased availability and capability of the MRA.4 made a reduction in numbers possible, a three-aircraft cut in a fixed-price contract effectively provided BAE with compensation for the program cost increases it had been forced to absorb. Another posible explanation is that it was a cost-cutting measure forced on the MoD by HM Treasury.
In October 2002 the Nimrod MRA.4 was withdrawn from the MMA program after failing to attract a US-based production partner.
In late 2002 the Nimrod MRA.4 programme was hit by further delays, with the maiden flight of the first aircraft being put back by more than a year (to the end of 2003), after it emerged that the type's new wings were not strong enough and did not fit the fuselage properly. The problem was that the new wings had been manufactured using precise CAD/CAM techniques, but the Nimrod fuselages were built using much less sophisticated technology and differed in size by as much as 4 inches. This meant that BAE Systems had to modify each set of wings individually to make them fit.
On February 19th 2003 BAE Systems and the UK MoD announced that they had agreed changes to the contract structure for the Nimrod MRA4 programme. Under the terms of the agreement, the current contracts for design, development, production and support on the Nimrod programme were to be revised. These revisions separated the Design and Development phase of the programme from the Production phase. Design and Development were to be completed under new Target Cost Incentive Fee (TCIF) arrangements.
BAE Systems took an exceptional charge of £500 million to cover the increased costs of the programme (in addition to the £300m made in 2000), while the MoD made a contribution of £270m. The change from a fixed-price contract to TCIF allowed BAe to reduce its risks and protect itself from cost overruns, while at the same time introducing incentives for improved performance. (Why a fixed-price contract was awarded in the first place is known only to the civil servants in the MoD; and why did the company agree to it?). This change was probably the only way that the MoD could prevent BAe Systems from simply walking away from the contract.
The difficulties in the Nimrod programme stemmed principally from issues associated with delays in design causing an increasing concurrency between design, development, and production. Accordingly, production work on the remaining Nimrods in the MRA4 programme was halted, and was not due to resume until significant risk reduction had been accomplished. The first three aircraft which were in build at the time were to be used as development aircraft. This put the aircraft's in-service date back to 2009 - now defined as the delivery of the sixth production aircraft.
In late 2003 both PA-1 and PA-2 reached "weight on wheels" and other key milestones. On April 17th 2004 one of PA-1's BR710 engines was started for the first time, and all four were started two days later.
PA-1 (ZJ516) started low-speed taxi trials on June 12th 2004. It finally made its maiden flight on August 26th 2004 from Woodford, with programme CTP John Turner at the controls. It landed at BAE's Warton flight-test facility after an 110-minute flight to begin an extensive flight trials programme.
PA-1 was to be used mainly for aerodynamic testing and envelope clearance and expansion, while PA-2 (ZJ518, ex-XV234) was to be used for mission systems testing and weapons clearance. PA-2 (ZJ518) made its maiden flight on December 12th 2004, having started ground runs in October.
On June 13th 2005 BAE Systems announced that flight trials of the MRA.4 were proceeding
well. Aircraft PA-1 was joined in mid-December 2004 by the
second aircraft, PA-2, which was allocated the task of testing the mission system.
The intensive flight trials programme
will continue for the rest of this year and well into 2006.
By June 2005 PA-1 and PA-2 had accumulated a total of 30 flights and around 70 hours of flying time. The longest flight to date was 4 hours and 12 minutes, with the aircraft achieving a top speed of 250 knots, and an altitude of 31,800ft. Initial stall trials had also been completed successfully.
The RAF was closely involved in all flight trials, and a number of RAF personnel have been seconded to the MRA.4 programme for several years. Evidence of this partnership approach is amply illustrated by the fact that by the fifth flight of the MRA.4, RAF personnel had already flown in every position in the aircraft.
In mid-July 2005 BAE Systems announced that PA-1 and PA-2 had accumulated a total of 70 hours of flying time over 40 separate missions, with the longest flight lasting 4 hours and 35 minutes, with the aircraft achieving a top speed of 250 knots. Initial stall trials had successfully been completed and the aircraft has flown at its maximum operating altitude of 35,000ft.
In early August 2005 PA-2 left the UK for the first time, flying to Sicily for preliminary hot weather trials.
On August 11th 2005 BAE Systems announced that Nimrod MRA4 PA-2, flown by a joint BAE Systems/RAF crew, had successfully completed hot weather trials at Sigonella, Sicily. Despite punishing daytime temperatures reaching 40°C, PA-2 passed this latest series of development testing with flying colours.
On the same date it was announced that development aircraft PA-1 and PA-2 had completed more than 100 flying hours between them, with the longest flight to date being of 4 hours and 35 minutes duration. Three sorties had been flown by Nimrod MRA.4 on the same day for the first time, with one of them being the first to be captained by an RAF pilot.
On August 29th 2005 the third Nimrod MRA4 development aircraft, PA-3 (ZJ517, ex-XV242), successfully completed its first flight. It took off from BAE Systems/Woodford at 16:45 and landed at Warton after a 75 minute sortie. PA-3 is the first development aircraft equipped to test the whole mission system.
In late November 2005 the Nimrod MRA.4 structural test specimen wingset and fuselage were delivered to BAE Systems Brough from Woodford. The wingset is referred to as "PA56", and was originally destined for PA04; the fuselage 'tube' which is required to make the testing representative, is probably from AEW.3 XV263 (8967M).
On September 29th 2006 Nimrod MRA4 PA-2 arrived at Eglin Air Force base in Florida after
its first transatlantic flight. Because full fuel and navigation system clearances were not available,
the transatlantic deployment took place over three legs and three days – Warton to Lajes (three hours
42 minutes), Lajes to Brunswick, Maine (six hours 38 minutes) and Brunswick to Eglin (four hours 26 minutes).
In the second half of October 2006 PA-2 spent ten days at temperatures as low as -40°C (-40°F) in the McKinley Climatic Laboratory at Eglin AFB. The aircraft also completed high-temperature trials at the same facility, operating in temperatures up to 44°C (110°F) and 100% relative humidity.
ZJ518 returned to BAE Systems/Woodford on November 16th 2006, via the Azores.
The MRA.4 fleet's 200th flight was made from Warton on February 20th 2007 by ZJ519, which was the 89th flight made by that aircraft.
At the end of May 2007 Nimrod MRA.4 ZJ517 (PA-3) visited its future home at RAF Kinloss. It was flown by a joint RAF and BAE Systems crew and captained by test pilot Flight Lieutenant Si Bowell. After a successful sortie, the aircraft landed at Kinloss and was serviced by a team of BAE systems ground engineers from Warton. After leaving for Warton the following day, the MRA.4 undertook a three-hour long sortie, which involved testing of the avionics systems.
Nimrod MRA.4 ZJ518 (PA-2) made an appearance at the Royal International Air Tattoo at RAF Fairford on July 14th 2007, and carried out a number of flypasts before making a steep (and very quiet) climbout.
In late July 2007 Nimrod MRA.4 PA-2 successfully released a Stingray torpedo for the first time over the Aberporth range during its 75th flight. The release was the latest in an ongoing series of safe separation trials to prove the MRA.4's new stores release system. Radically redesigned from that of the Nimrod MR.2, the system ensures that the weapons are programmed and released correctly. The release of sonobouys had already been proved successful, with future testing programmed for further checks of the torpedoes and the release of search and rescue equipment
On February 18th 2008 Nimrod MRA.4 PA-1 arrived at Nashville International Airport, Tennessee, after a journey of over 4500 nautical miles with overnight stops in the Azores and Bermuda. Once at Nashville, preparation of the aircraft for icing trials included fitting the under wing pylon with specialised probes for characterising the icing conditions in terms of droplet size and water content.
The flights will demonstrate the performance of the airframe and engine intake anti-icing systems, windscreen heating and air data probe heating and demonstrate the aircraft handling characteristics in these conditions. In addition, the trials will demonstrate the aircraft’s continuing maturity by operating it overseas.
PA-1 made its last flight on March 9th 2010, and is in storage at Woodford. PA-2 made its last flight on March 5th 2010 and is also at Woodford.
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