Nimrod crash in Afghanistan Tech/Info/Discussion (NOT condolences)

[Distant Voice]

Oil Can: What is exactly wrong with the brakes? The seals in the hydraulic lines are leaking.

DV

[OilCan]

DV

Roger.... in that case...

Option 2) Replace the leaking seals then re MOT.

[tucumseh]

Winco

The one and only absolute FACT here, is that an aircraft caught fire, was destroyed, and many of our friends died (unnecessarily IMHO)

I could mention some other absolute, 100% verifiable facts.

• In Nov 2007 ACM Sir Clive Loader stated in the BoI report that Airworthiness regulations were not implemented properly. This repeated similar, and in one case even more damning, statements in previous BoI reports; in addition to HCDC hearings, PAC Audit reports and internal MoD Audit reports.
• In Dec 2007 Des Browne accepted this and acknowledged liability.
• In 1991, 1992, 1993…………………….. MoD(PE), DPA, DLO, AML and AMSO 2 Stars and above were told this. None denied it; all ignored it.
• In September 2005 Adam Ingram, when Min(AF) was told it, in writing. And denied it, in writing.

Perhaps if ANY of these people had listened………..

[Chugalug2]

Whether your depressing list is based on wickedness, incompetence or merely "obeying orders", tuc, it tells me that what goes around comes around. If after all the BoIs, Inquests, Reviews, Statements and Platitudes this corrupt system is allowed to pick up where it left off we will have more accidents, more deaths and more destroyed lives and all needlessly! The MOD is not to be trusted with Military Airworthiness which must be removed from its control forthwith, and placed into the hands of an independent authority similar but separate from the CAA, ie an MAA.

[tucumseh]

wickedness, incompetence or merely "obeying orders"

All of the above, plus a healthy dose of greasy poling and gong hunting.

[ShortFatOne]

MAA vs CAA?

Whilst I tend to agree with many of you erudite people in your general summation of the pros and cons of an independent MAA (and would probably vote for one) can I just plays devil's advocate for 2 seconds?

The Boing Boing 777 that pancaked into LHR. No definitive word on what caused @100 Tonnes of commercial airliner to swandive towards the green & brown stuff, yet not a word from CAA about grounding the fleet just in case it happens again and this time is unfortunate enough to land in Mrs Miggins' pie shop.

Why?

Winco,

I hope you are well, I apologise for our 'misunderstanding'several months ago.

[OilCan]

Nige, forgive me, I’m not clear on the difference,

We’re worried about Nimrods falling out of the sky when we know what happened to XV230 and something is being done,

Yet

We’re not worried about B777s falling out of the sky and nobody has a Scooby.

Thankfully there were no fatalities on the B777, but a few hundred yards shorter would have pushed Nimrod to the back page!!

..please don't tell me it's because the b777 was ALARP and therefore 'Safe'.

[Winco]

SFO

I am very well indeed, thank you. No apology needed Sir. I have read all of the posts on this forum many times, and with the benefit of hindsight and a clearer head, I think we have all been guilty one way or another of maybe 'overstating' our cases. How is the MR4 progressing? Are you able to offer us any good news on the project?

Best wishes

The Winco

[SirPeterHardingsLovechild]

DV

Roger.... in that case...

Option 2) Replace the leaking seals then re MOT

No stock of the seals
Brake pipes are corroded too
Not enough trade cover on shift to carry out functionals
Instruction manual out of date (just for Tucumseh)
Distracted by trivia
Management putting the pressure on
Shift change in a couple of hours
Someone else's problem

[dunc0936]

I have not read through the whole thread, however are these airframes totally knackered and in need of scrapping, or just in need of a danm good service (i.e. money spent on them) and some good tlc???

sorry for sounding very siomple

Duncan

[OilCan]

Old Fat One

MoD = easy target.....just like the NHS. (8 words)

..and I think Duncan has......a cunning plan.




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[dunc0936]

Well looking at this from a laymans position, the solutions do seem very simple, though it would mean spending a bit of money, in the long run the RAF would have a platform they could be really be proud of and it would stll be 100% british


Duncan

[Brian Abraham]

I have not gone back through the thread so please excuse if I'm doubling up. From Avweb today.

Coroner: UK Nimrod Fleet Not Airworthy

A coroner who led an inquest regarding the September 2006 midair explosion of a Nimrod sea control aircraft has said the aircraft "like every other aircraft within the Nimrod fleet, was not airworthy," but the UK Ministry of Defense (MoD) does not have to comply the coroner's recommendations and likely won't. An RAF Board of Inquiry in December 2007 delivered a report that declared aging parts and lack of fire-suppression systems as contributing factors but in the end apparently served as a spark for investigations initiated by parents of some of the deceased fliers. Of all the parents, Graham Knight stood out for claiming to have e-mails from high-ranking officers that detailed problems with fuel leaks prior to the 2006 explosion and noted a 2005 recommendation from BAE Systems that fire-detection systems be installed on the aircraft. The assistant deputy coroner who led the inquest is now calling for the entire Nimrod fleet to be grounded, according to Defense Industry Daily. The UK MoD has taken measures it believes are satisfactory and will continue to fly the plane.

The UK MoD says it will continue to fly the Nimrod but has stopped air-to-air fueling and has ceased use of the "very hot air systems" in flight. According to the MoD, these measures remove the dangers in design noted by the coroner and along with enhanced maintenance and inspection procedures effectively ensure safe operation of the aircraft.

[dunc0936]

Still a old aircraft that either needs a major overall or replacing as follows

1) complete new design of airframe to put the exsiting kit inside, or buy off the shelf, Boeing/Airbus

2) Get Bae to build completely new airframes i.e. start the production line up again, and carry on with the Nimrod, because if it is such a crap aircraft as some people have said then why has it lasted so long?

I peronally believe that it is more of a case of lack of money to service them correctly and upgrade them when needed

Just a thought

Duncan

[Wader2]

Originally Posted by dunc0936

I have not read through the whole thread, however are these airframes totally knackered and in need of scrapping, or just in need of a danm good service (i.e. money spent on them) and some good tlc???

sorry for sounding very siomple

Yup, spot on, knackered, scrapping or a damn good service

Well looking at this from a laymans position, the solutions do seem very simple, though it would mean spending a bit of money, in the long run the RAF would have a platform they could be really be proud of and it would stll be 100% british

Yup, spot on again. Indeed we have been spending a bit of money, over the last 15 years or so, giving it a damn good service, new wings and undercarriage even, and a new avionics suite.

Still a old aircraft that either needs a major overall or replacing as follows

1) complete new design of airframe to put the exsiting kit inside, or buy off the shelf, Boeing/Airbus

2) Get Bae to build completely new airframes i.e. start the production line up again, and carry on with the Nimrod, because if it is such a crap aircraft as some people have said then why has it lasted so long?

I peronally believe that it is more of a case of lack of money to service them correctly and upgrade them when needed

Just a thought

Duncan

Well we could have gone for Boeing or Airbus but 15 years ago it was deemed far better (ie cheaper) to go for a damn good service.

Well not completely new airframe but essentially the bits that were recycleable, such as the fuselage seemed a good idea at the time.

Now however for a personal opinion. Many years ago I used to wonder how our cousins could take an aircraft, like the B52, and do a root and branch refurbishment, new avionics etc, and keep the old airframe in use for ever - same with the KC135. OTOH the Vulcan could have been extended for years with improved avionics etc.

It all boils down to money and need. The cousins had both whereas we needed the money to buy TSR2/F111/F4/Buccaneer/Tornado etc.

Even the cousins ran out of money when it came to re-engining the B52 with 4 turbo fans vice 8 jets.

At the time new was not an option and, as ever, the Treasury is king. Also the Nimrod 3 AEW fiasco is too recent to follow suite with Numrod 4 MRA one even if it is a different Government (or perhaps because it is a different Government).

[EdSett100]

DV,

Sorry, but the QinetiQ report sets the risk as being tolerable (see para 1 of conclusions).

You must be reading a different document to the one I've seen. Putting aside the document, and whomever wrote it (I recognise the authors, incidentally) for the moment, can you explain to me, how a risk is tolerable when it doesn't exist? The reason I say it doesn't exist is this (my apologies to the grannies for the egg sucking lesson):

Lets say that a pipe containing a hydrocarbon liquid, anywhere, at any time, leaks; maybe even sprays out of the pipe. That, in itself, is not a fire hazard. A health hazard, maybe. Therefore, with no fire hazard, there is no risk.

However, it will become a fire hazard if there is any potential for it to ignite.

Oxygen abounds in the atmosphere, so the liquid needs only some form of ignition in its environment. Fuel is ignited only by heat (heat accelerates or provides the combustion/oxidisation process, otherwise known as fire). A spark contains heat, which is the only reason that a spark will ignite fuel. Some hydrocarbons are very volatile and vulnerable to oxidisation and require only a little amount of heat (or a small spark); gasoline is a good example. Clearly, an aircraft, unlike a car cannot stop if there is a fire on board, so jet-engine fuel has to be resistant to accidental/easy ignition. Kerosine fits the bill. Kerosene, unless atomized, is very difficult to ignite. Atomization of kerosene occurs under very high pressures only. Kerosine vapour will spontaneously ignite (flash point) at approx 45C. Kerosine liquid will ignite at different temperatures dependant on the time that it is subject to that heat, bearing in mind that it will vapourise under heat and, due to any air local currents, move away from the heat source (convection). Therefore, in order for us to deliberately ignite kerosine, we need either a huge spark (with sufficient heat) or an existing heat source. In a jet engine the latter is achieved by constant combustion, whereby we simply add more fuel to the existing hot fire. However, we still need to start that combustion process and to do that we have to generate lethal voltages to produce very powerful sparks in the igniters in the engine combustion chambers. Furthermore, the kerosine has to be atomised before it gets to the spark. Once it has lit, we have constant combustion and the ignitors can be switched off. If you believe we are overdoing it with the atomising process, we experience engine running problems with carbonised burners which do not atomise the fuel properly. The 7% lower flight idle RPM on the No 4 engine during the descent on XV230 was a classic example of carbonised burners (Mick Bell, my old friend: a fuel leak, not. A 1000 gall/hr fuel leak at flight idle would result in a flame out because the flight idle fuel bleed would be starved; I think you forgot that bit)

Conclusion1: Kerosine cannot be accidentally ignited by a low voltage spark. Therefore, in this aspect: no risk

It can only be accidentally ignited by a very hot surface or a very powerful spark. Outside of the engine bay ignition system, in all aircraft , incl Nimrod, there is no possibility of a spark of that magnitude occuring unless it is caused by a massive electrical failure. It would have be a failure so significant that the circuit protection devices will switch off that circuit before it reaches the magnitude required to ignite kersosine. We have been discussing fuel safety here, but electrical safety requirements in aircraft have always insisted that circuits are protected by high quality insulation, protected against arcing and sparking by fast acting cut-outs and good maintenance practice.

Conclusion 2: Although kerosine can be ignited by HE energy sparks, there has to be a triple failure in an aircraft for this to occur: the fuel must have leaked (1st failure), a nearby HE electrical system (200 volts?) must have failed in its isolation (2nd failure) and the associated circuit protection has not acted in time to stop the fuel igniting. Single point failure risk due to a HE spark in a Nimrod: none, because we do not have any 200V power supplies anywhere near the fuel pipes. The designer wasn't that stupid.

We've discussed hot pipes ad nauseum. But, to add to the growing knowledge in this forum, please note that, with the exception of the crossfeed pipe, all HP air pipes are inside fire zones. The crossfeed valves are inside the hotter (fire) zones of the outboard engines. Therefore, approx one third of the crossfeed pipe (ie the pipe between the valves) is inside a fire zone with the appropriate protection. We do not, now, open that pipe, except to start the engines. While that pipe is open we limit the engine speed such that the pipe's external temperature does not exceed the degree required to ignite fuel or hydraulic liquid that might come into contact with it. The IPT has sponsored tests to ensure that we are below that ignition temperature. We are not guessing and using our "gut feelings", here. We might be under-resourced, but we are professional and we will do the right thing and we will not assume we are right.

Conclusion 3: the kerosine on a Nimrod cannot now possibly ignite due to coming into contact with a hot surface. Fire risk: none.

This isn't a tolerable risk. Its a non existant risk.
(in the case of single point failures)

The copy of the QQ report, that I have read, fully supports my assertion. It states in the Summary:

"Principally, the key factor in the Very High and High risk assessments has been the proximity of a hot surface relative to the fuel system.....It is considered that these areas of risk are addressed as part of ongoing inspections or aircraft limitations, specifically, limited use of bomb bay heating, HP Bleed Air cross feed and the SCP"

These are the facts that I referred to in my previous post.

DV, I'm keen to know more about the document you refer to. The one I have refers to the only analysis that QQ has done in recent years.

I'm also prepared to discuss HP air pipes and any perceived associated risks.

Ed
ps. I had a pprune name faff over the weekend, so I've changed my name (slightly). Do not write privately to edset100; I will not receive it; edsett100 works.

[EdSett100]

DV:

Ed Sett 100; You said,

Quote:
I do not care one jot what the politicians, air officers and IPTL's say to the media or the Coroner, I care only about what my colleagues and I know to be the facts
Up until now I have always respected your views. I have not always agreed with them, but I have respected them. However, this statement takes your credibility rating to zero.

You can't tell me that you believe politicians. Air Officers read from prepared briefs and don't take supplementary questions because they do not have the depth of specialist knowledge. I don't have any problems with that. Someone has to talk to the media. Its a shame that those who have the depth of knowledge required to answer the questions at the core of the matter are not trusted to stand up and speak for the organisation. Its not so much that I don't care what our air officers say. Its simply that they do not go to the depth that interests me or the media. Consequently, the media digs elsewhere and, regrettably, sometimes they come up with the wrong answers or use a dodgy source.

Regarding the Coroner's questions: I'm led to believe that the more coherent and relevant evidence from the RAF relating to the system failures came from the operators and the maintainers. Inconsistencies and prevarication from the IPT leadership in the witness box led to the mess in which we now find ourselves. I was wrong to say that I do not care about their words and terminology, because what they said has led us to this point.

All the facts were examined,

Oh, no they were not. The only facts that were examined, and they were all available, were the ones that the Coroner wanted to examine.

and the end game was "ground the aircrart". Now if you, or any other member of MOD can present sound evidence supporting your "gut feeling" claim, then do so.

I refer you to my previous post about fuel fire risks. No gut feelings are used and I don't think I have ever indicated that I, or my colleagues, have any such feelings in this subject.

[Distant Voice]

Edsett100: I have a copy of your QinetiQ report (Nimrod Fuel System Zonal Hazard Assessment), dated Sept 2007, but you need to read the report to which Des Browne referred. This is the Nimrod Fuel System Safety Review Report, dated Oct 2007. The September report is mentioned in this all embrasing report.

On the question of high energy electrical sources (200v), you will find several listed in Exhbit 62 to BOI report; 4 in No.7 tank dry bay area, and 14 in the Rib 1 area.

DV

[tucumseh]

EdSett


Your post displays impressive knowledge and I don’t pretend to know anything about the intricacies of the Nimrod design. But I’m afraid I don’t agree with your conclusions.

You can’t say the risks don’t exist – you identified them. The probability of occurrence may be incredible (e.g. caused by “massive electrical failure”) but as the outcome would be catastrophic that results in a Class C risk – Tolerable if ALARP. Most of what you write is an excellent risk assessment and could be cut and pasted into the Risk Register as evidence of proper management, competency and existence of corporate knowledge – all airworthiness requirements. Your mitigation plan may indeed be “do nothing” as you have assessed the risk as ALARP.

Importantly, the audit trail is maintained and if, sometime in the future, someone tries to put an ignition source next to a kerosene line in “Location xx”, then the chances increase of the conflict being spotted. (Because you will have entered key words like “Location xx” and “fire” in the RR and future designers will tap that into the database and your work will pop up with a flag). Your successors will benefit from this retention of corporate knowledge, as required by JSP553.

Just my way of looking at things. I believe what I describe is very close to what ACM Loader was referring to when he said the regs weren’t implemented. Certainly Air Cdre Baber acknowledged similar data errors in the Hazard log.

[SirPeterHardingsLovechild]

Edsett

Kerosine vapour will spontaneously ignite (flash point) at approx 45C.

Er...I think you're wrong there.

I'll revisit this point. But while I'm away, could someone repeat the estimated temperature of the bleed air in the ducts.

About 30 pages ago I was uneasy about the ignition source