Expert witness: Has bomb bay heating fault forced Nimrod retirement?
March 9, 2010 by Guest Writer · 5 Comments
By James Jones
James Jones was a Nimrod engineering officer, responsible for carrying out flight trials at A&AEE Boscombe Down (now QinetiQ), prior to aircraft entering service in 1968. In 1969, he flew in XV230 – the aircraft which crashed in Afghanistan in 2006, killing 14. Since that accident he has acted as a technical advisor to the families who lost loved ones and advised their legal counsel during the subsequent inquest. The crash also led to the Nimrod Review under Charles Haddon-Cave, QC.
A Nimrod MRA4 "ZJ518". Picture: MilborneOne
After some 40 years service the Nimrod Mk2 is due to be prematurely withdrawn from service at the end of this month.
According to Bob Ainsworth, the Secretary of State for Defence, this has got nothing to do with safety; but this is disputed. A point not mentioned in the Board of Inquiry (BOI) report in 2007, the Inquest in 2008 or the Haddon-Cave report in 2009, is that since the Nimrod accident in September 2006 the aircraft’s bomb bay heating system, as well as cross feed system, has been electrically isolated. This is a significant detail.
Information gained under FOI reveals that the air inlet temperature to the bomb bay heating mixing chamber, located just forward of the main fuel tank in the bomb bay, is well in excess of the auto ignition temperature of fuel.
In Nov 2007, during a Nimrod incident over Afghanistan, fuel was seen spraying from a coupling in the Air to Air Refuel (AAR) line, and on landing it was reported that: “The bomb bay heating mixing chamber cladding was soaked with fuel. Fuel was also observed on the pipe work on the roof of the bomb bay in the area of the mixing chamber”.
On this occasion the aircraft landed safely at Kandahar airport. Although AAR is now suspended this area in the bomb bay still contains fuel feed and fuel transfer pipe lines.
In September 2006, Nimrod XV230 was lost over Afghanistan with a crew of fourteen service personnel on board. The cause of the accident was an onboard fire, resulting from escaping fuel coming in contact with a hot air pipe. Whilst the BOI and Haddon-Cave concluded that the fuel most likely came from an external “blow off”, which then tracked back to external hot air pipe close to the trailing edge of the starboard wing, another explanation is plausible. Up until now it has never been considered because the BOI believed that mixing chamber temperature was much lower than# now reported.
Based on this latest information it is conceivable that XV230’s fire started in the bomb bay, where the first alarm was triggered, and was caused by an AAR fuel leak similar to that which later occurred in 2007. Fuel soaked cladding around the mixing chamber, in direct contact with ducting carrying hot air with a temperature in excess of the auto ignition point of fuel, could have become an ignition source and ignited fuel spraying into the bomb bay from the leak.
When it is considered that fuel leaks had been reported on a number of flights prior to the accident it is possible that the cladding was well soaked at the time of the accident. Also, examination of a drawing of the fire’s location produced by a Harrier pilot witness, shows the leading edge of the fire as being well forward of the wing trail edge, and is approximately in line with the front of main fuel tank in the bomb bay, and the mixing chamber.
It is understood that MoD did consider re-activating the heating system, in 2009, because some bomb bay release mechanisms were becoming unreliable in extreme cold conditions. However, because most of the control valves associated with the heating system were failing functional ground tests, due to two years inactivity, and no replacement valves were available, it was decided not to re-activate the system.
It remains inhibited and will never be used again.
So having spent large sums of money during 2008/9, replacing hot air ducts, fuel seals and all cross feed valves, the MoD decides to scrap the Nimrod MK2 fleet long before the replacement MK4 aircraft arrived.
The bottom line is that they need to do this because
(1) Nimrods cannot carry and release bomb bay stores due to defective release mechanisms
(2) Temperature control valves are not available, and even if they were…
(3) There is a risk that leaking fuel from the main fuel gallery could come in contact with ducting associated with mixing chamber carrying hot air in excess of auto ignition point.
With regards to the costs of the Hot Air Duct replacement Programme (HADRP) and seal replacements, mentioned above, the following information has now been revealed, under FOI: “The BAE Systems MR2/R1 maintenance contract was amended to include HADRP (Hot Air Duct Replacement Programme) and the replacement of a number of fuel seals on Nimrod MR2/R1 aircraft; these in turn necessitated changes to the MR2/R1 scheduled maintenance programme. The total cost of this contract amendment (which included the changes to the scheduled maintenance programme) was in the order of £16 million”
In the last two years the MoD has spent £16 million on a modification programme, plus £3.5 million on Haddon-Cave review for an aircraft we are going to scrap in a few weeks time, leaving a two year gap in our maritime defence capability. (Bob Ainsworth only talks about how the SAR role will be covered).
This leads to the suspicion that Nimrod’s retirement has got more to do with problems of safety and an inability to carry and release stores than anything that Bob Ainsworth claims.
As a side issue, but very important for the families who lost their loved ones in the XV230 accident, and who are still struggling to get adequate compensation for their loss, this “wasted” £19.5 million represents around £1.4 million per family.
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I have to say that I have read some of the posts on this site that have been on the edge of distasteful, I have wondered at the mentality of some, this in my view takes the biscuit, I now leave this site never to return. I do not wish to be in the same company that revels in others pain. Many fine men died because of the fight in the Falklands/Malvinas, as you would call them, these men were not fighting for oil, or for Thatcher, but for their country, many were Scottish, Welsh, Irish, English and yes Argentinian.
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@Our Wullie: I’ve removed the comment you found so offensive. It had no place here.
I hope you reconsider. Considered rational posts are very welcome here.
Stewart Kirkpatrick
Editor, The Caledonian Mercury
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I think you will find it was Exocet missiles that caused a problem in the Falklands purely because they were never seen as being used by the other side in a conflict. The Dassault Super Entendard was the aircraft!!!!! BUT the MOD is not fit for purpose look at the Chinook crash and the cover up and then a hanger full of Chinook s that they could not fly.
The Public Accounts Committee published a report examining the MoD’s programme to make airworthy eight Chinook Mk3 helicopters.
“The story of the MoD’s programme to make airworthy eight Chinook Mk3 helicopters, acquired from Boeing in 2001 for special operations work, has been one of bad decision-making to the point of irresponsibility. The consequences have included a shortage of helicopter support in Afghanistan thereby heightening the risk to the lives of British troops.
“The programme was hamstrung from the start by the appalling decision to buy the aircraft without securing access to their software source code. This meant that the MoD could not show that the cheaper, modified cockpit avionics which it had chosen met UK airworthiness standards and hence that the helicopters were safe to fly. Eight years after they were delivered, the Chinook Mk3s are still sitting in hangers and the cost of getting them into the air is probably going to top £422 million, probably by a big margin.
“The need by our forces in Afghanistan for helicopters for high risk special operations has necessitated fitting the more basic Chinook Mk2 helicopters currently in service there with a bolt-on night enhancement package. This has made the aircraft harder to fly and the use of the package has been judged a key risk to the helicopters’ airworthiness. There is a big question mark over whether it is a risk the department should accept.
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The MoD has a long and inglorious history in procurement. Chinook is a word that should haunt the big decision makers in Whitehall and is a reminder of the horrendous double standards that the two “main” parties function with when in government.
Surely the Nimrod fleet is aeons past its sell by date? It is based on De Haviland Comets that were at the cutting edge of technology when I was a schoolboy reading The Eagle more than 50 years ago.
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