Nimrod XV230

[walbut]

I recently read Tony Blackman's book on the Nimrod and coincidentally saw him on television a couple of weeks ago in the programme on the British aviation industry. This prompted me to have a look at his website and in addition to publicising his books, there is some interesting information on the accident to Nimrod XV230 which supplements the associated section in the book. This suggests that the Haddon Cave Review's conclusion on the root cause of the fire was probably incorrect. The subsequent rapid rundown of the fleet, at least partly done on the grounds of airworthiness may have been premature, as the more likely cause of the fire could have been addressed relatively easily. For those of you interested here is a link to the website:- Tony Blackman's Page

[The Old Fat One]

In first before the usual suspects hijack this thread...

I like TB's book on the Nimrod (well I would...I'm in it!). It is good read for anybody unsure of the aircraft and its role. But it is not really what I would call an authority on the subject...and I don't think the author would claim it as such.

As to the statement..

This suggests that the Haddon Cave Review's conclusion on the root cause of the fire was probably incorrect.

Haddon Cave did not make any such conclusion. He merely agreed with the Board of Inquiry. They did not make any such conclusion either. What follows is a direct quote from the Board.

In summary, therefore, whilst the BOI was unable to determine positively the exact source or causes of the fire
which led to the loss of XV230 and its crew...

In the BOI report this is followed by a list of the probable causes.

As to you last assumption, that the retirement/rundown of the fleet was premature..I'm afraid not. This aircraft was due to be replaced in the mid nineties and its basic design was always suspect. Hardly surprising when you consider from whence it came.

It was good bit of kit in the seventies and eighties, after that it all went horribly wrong. As has just been posted elsewhere on here...the replacement program for the Nimrod MR2 began in 1992, so calling its retirement in 2009 "premature" is a bit of a stretch.

[dervish]

TOFO


I agree with almost everything you say but think you're a bit unfair having a swipe at the "usual suspects". If you're referring to the few on pprune who had the balls to stand up and be counted when the whole of MoD was against them, we would all do well to remember what they have achieved for aircraft safety.

But if you're referring to those who are actually to blame, then I apologise.

BTW, what's happening on the legal side? No news of prosecutions?

[The Old Fat One]

To clarify

There are plenty of threads to discuss some of the safety issues surrounding the Nimrod and other aircraft. There are some good discussions and contributions on them (and some not so good). I feel it is selfish and discourteous to other users to have the same discussions on every thread with Nimrod in the title...so I got my tenpenneth in first. Not having a go at anybody, it's a free world...well almost.

Maybe the OP wants it to go that way...who knows? I thought predominantly it is a thread about TB's Nimrod book/website and my main point was to correct the assertion that the HC Inquiry attributed a source for the fire...which it did not.

[GOLF_BRAVO_ZULU]

Originally Posted by The Old Fat One

the replacement program for the Nimrod MR2 began in 1992, so calling its retirement in 2009 "premature" is a bit of a stretch.

I think Mr Blackman's salient point is the continuation; "and the cancellation of the MRA4". Leaving aside the massive departures from Flight Safety requirement and MoD indifference to existing Standards, he makes a good point. It's also arguable that the MK2 still had sufficient fatigue life and capability to "fill the gap", albeit with revised operating procedures. Accepting that Mr B really highlights a probable flaw in the BoI, it wasn't picked up by the thorough Judge H-C.


All in all, it's regrettably too late. Sentiment and MoD indifference (or some other word starting with "in"), combined with the opportunity to make a quick "saving", doomed the aeroplane in its existing and intended form.

Thank you The Old Fat One for drawing attention to TheVulcan's latest book.

[betty swallox]

OFO,
I'm struggling with your statement that the design was always suspect???!!
And that it all went wrong in the 90's??!! I flew her lots then, and she was just fine!

[dervish]

TOFO

Understood. Unfortunately there are also those who try to rewrite history with every thread so I wouldn't call correcting them "hijacking".

And I still agree with what you said. I know nothing about the Nimrod but I've read both the evidence to Hadden Cave and his report and still can't understand where he got many of his conclusions from. I'll go away now and read Mr Blackman's words.

[Duncan D'Sorderlee]

TOFO,

I'm also a little bit surprised that, notwithstanding the issues with earlier marks of Comet (I think that's where you are coming from), the design pedigree of the Nimrod was always in doubt. Like Betty, I flew the jet in the 90's; I thought - and still think - that we were world beaters!

Have I got the right end of the stick?

I concur with your comments re the BOI; John Nelson and his team did, in my opinion, a fantastic job considering what they had to work with.

Duncs

[walbut]

I did not make the post in order to start another Haddon Cave thread, just read the book, came across the website by chance and, knowing the interest on PPRuNe thought it was worth pointing out.

With regards to TOFO's original points about the book, I also found it very interesting, particularly the personal stories covering the operational life of the aircraft. However I had hoped to find out more about the engineering background of the project. I spent my life working as an aircraft development engineer, mostly on another long running project, and I find it interesting to see how other people tackle similar engineering problems to the ones I faced.

Nimrod as a project was unusual, maybe even unique, in that it went through 3 major metamorphoses, Comet to Nimrod MR, Nimrod MR to AEW and Nimrod MR to Nimrod MRA4. The first transformation was undoubtedly a success and resulted in a very capable aircraft delivered in a reasonable timescale and cost. The second was a complete failure with the primary mission systems failing to perform, despite the expenditure of a huge amount of cash and the sacrifice of a significant proportion of the fleet. The third was a partial success in that the end product worked, but it was only achieved at a huge price in engineering redesign, cost and timescale overruns. These drove up the unit cost and reduced the planned fleet size. In the end I think someone decided that the subsequent life cycle cost of operating such a small bespoke fleet with some lingering legacy engineering issues would be untenable.

I would be interested to find out more about these phases of the aircraft life, i.e. its development rather than its operational life. Making major changes to a design is not easy and deciding at what point its easier to start afresh with a completely new design is always a contentious issue with both customer and contractors all having there own opinions and vested interests. I think there is perhaps scope for another Nimrod book in there, written from a design engineer's perpective rather than a pilots. After all, engineers lead lives which can be just as interesting and exciting as pilots.

[Party Animal]

its basic design was always suspect

TOFO,

I'm with Betty and D'D on this one. Are you saying that operators of the MR1/MR2, who flew the aircraft in the 60's/70's/80's/90's/00's thought the design was suspect?? Having served on 42/CXX/201/206/236 since the mid eighties, I can't ever remember anyone having concerns over the basic design of the aircraft prior to the end of 2006, even with the exposed refuelling pipes running down the centre of the aircraft.

I've also made the comment in the past that when BAe unveiled the MRA4 model during Fincastle 95 (it was kept under wraps at the back of the OCU), most of my peer group seemed happy and excited by the thought of it - as oppossed to a new P3 (LM bid) or an upgraded P3 (Loral bid). Obviously, hindsight is a wonderful thing and yes I know, not everyone thought the MRA4 was the best.

I also think the replacement programme for the MR2 started in the mid 80's. I remember lots of glossy blurb on the P7 (LRAACA - stretched P3) doing the rounds in 87 and I think MoD had started the paperwork to join in with the USN on the programme and this is what we would have had if the US didn't withdraw from the programe early on.

Walbut - back to the thread and thank you for the link. It's a fascinating read. You forgot the R1 by the way in your comment later on!

[The Old Fat One]

I'm also a little bit surprised that, notwithstanding the issues with earlier marks of Comet (I think that's where you are coming from), the design pedigree of the Nimrod was always in doubt. Like Betty, I flew the jet in the 90's; I thought - and still think - that we were world beaters!

Have I got the right end of the stick?

I'm struggling with your statement that the design was always suspect???!!

For sure guys, she was a great bit of kit. I'm reflecting on the history (writ large if you will) of the airframe...end to end.

Amongst the basic flaws, well known from the comet...

Lack of cabin size. This was why the 707 was picked over the comet by the US airlines. It had major downstream ramifications in the AEW project, because it was so hard to squeeze all the kit in (plus it's cooling systems). Kinda ironic that the AEW project was kicked into touch in favour of a 707 based AWACs.

Lack of endurance. Even the MR1, with it's clean lines, struggled to make nine hours. The MR2 was much worse as it gathered up so many "bolt-on-bits" which screwed up the drag. In the end the old lady didn't have the legs (not talking MRA4 here...well aware that had new donks)

Prehistoric flight control system. I showed the Lockheed Chief Engineer around the kite circa 1993. His comment as he peered down the bays..."hell, havn't seen hydraulics like these since I rebuilt my ol' man's tractor".

Build standards originated in the 1960s...you guys are well aware of the affect that had on the MRA4 project (or to give the name it had when the contract was signed...Nimrod 2000).

Lets nail it down. The MR1 and MR2 were great bits of kit operated by great crews throughout the cold war. They had no equal.

The MR2 should have been replaced in the 1990's by a P3 variant. The AEW/Nimrod 2000 project were both a crock of crap, which many, many knowledgable operators predicted. Loyalty (and because it became the only game in town) meant many kipper fleet people stuck with it to the end. All of them should tell it as it now...they were all totally shafted. As was the British taxpayer.

Where does the blame lie? All over the shop. Does it matter? Not really...unless we ever need an MPA capability again. Then it might.

[The Old Fat One]

I've also made the comment in the past that when BAe unveiled the MRA4 model during Fincastle 95 (it was kept under wraps at the back of the OCU),

The MRA4 did not exist as a concept until the contract was restructured circa 2001. What you saw in 1995 was a marketing "solution" to a staff requirement and it was called Nimrod 2000. Otherwise known as a blatant lie...because that "solution" was never, ever going to be delivered on time and on budget.

It is the job of marketing men to big up their solution and trash talk the opposition.

For the record, I walked round the actual Nimrod 2000 mock-up at BAe in May 1998 when I did the "introduction to Nimrod 2000 course". It was empty.

Why was it empty? Because Boeing (who were doing the mission system) had just picked up their trainset and gone home as they were ****ed off with the way BAe where running the project. BAe were sitting around scratching their heads wondering what to do next.

Guys, I understand the loyalty, but this is all now a matter of public record...and we don't have an MPA. Time to take the rose-tinted specs off maybe?

PS

And by the way, by talking about the MRA4 as existing in the nineties, you are proving how effective the smoke and mirrors stunt pulled by BAe in circa 1999 was.

The taxpayer signed a contract in 1996 with BAe to deliver 21 Nimrod 2000 with an in service date about 2001 at a total cost of £2.1 billion.

In 2010 the contract was terminated at a cost of around £3.6 billion with the square root of **** all delivered.

All the rest is just bull crap.

[tucumseh]

I’ll leave it to others to dissect the technical description of what happens in a Nimrod during re-fuelling as it is a rather specialist subject, but it seems Blackman has had the help of experienced BAE engineers and I’m in no position to contradict anything he says.


However, he makes a number of fundamental errors when describing the process by which airworthiness is maintained. I made 7 notes but the two significant ones are;

1. (page 3) It is unfair to say reports were ignored by BAE when they were the authors. This implies BAE had the contractual authority to develop, trial and install a mod at will. The design was Under Ministry Control (UMC), which is the very first fact you have to ascertain before launching into a Design Authority. Just because they are the DA doesn’t give them authority to do what they want to the design. Such work must be carried out under MoD contract; the same contract that failed to maintain the Safety Case. (By the way, this process is so poorly described in the latest MAA documentation as to be totally useless). Therefore, the evidence points to MoD failure. He (Blackman) says the report (into discharged fuel) was sent to the MoD’s RTO, but this is meaningless. The important person is the MoD’s Technical Agency, as it is he who prioritises, tasks and signs off. The question here is – Was the TA informed? Then, follow that line. The salient point here is that we know this contract was not implemented properly by MoD as the Nimrod IPT (under Gp Capt Baber) did not inherit a continuous contract to maintain the Safety Case, but had to let one. The fact his staff managed it incompetently is a different issue. The important factor is he had to let such a task in the first place. Also, that under the RAF Chief Engineer the process I describe (TAs, maintaining build standards) was run down from 1991-on. That is, instead of continuous assessment of safety, the system had degenerated into “Don’t bother, but if something happens have a quick look”. And even then, funding was routinely refused.

2. On page 4 he says;
Nimrods had refuelled safely for many years without any problems but of course the Victor K2 and the VC10 were being used with a relatively low refuel rate. The accident occurred using the Tristar having a significantly higher refuel rate than the Victor
And then;
Summing up, the accident was not due to inherently bad design of the Nimrod which had performed splendidly for forty years but due to the installation of the Air to Air refuelling modification without adequate flight testing, particularly at high fuel flow rates, at high aircraft AUW and using the TriStar as a tanker with its higher refuelling rate

This is a perfect example of systems integration failure, and the flawed notion of “it works in one aircraft, it’ll work in others” or “It works on the bench, it’ll work in the aircraft”, leading to lack of functional safety. (See Tornado/Patriot, Sea King ASaC, Chinook etc). This is really basic stuff but MoD no longer teach it, or require staff with, for example, airworthiness delegation to understand it. Again, this can be traced in systemic terms to the 1991 decision to chop funding and run down airworthiness.

What he’s saying is the “system” of Nimrod + VC10/Victor was (allegedly) functionally safe, but Nimrod + TriStar was not. So the Nimrod design was unsafe in certain applications. If this lack of functional safety was not addressed in the MRA4 design (I don’t know), a part of any cost appraisal regarding retention of MRA4 would be the cost of ensuring Nimrod was safe within this “system” or, for example, reverting to VC10 or Victor delivery pressures. This was discussed in detail on the main Nimrod thread and expanded in evidence to Haddon-Cave; he never mentioned it.



This failure to ensure functional safety against a new usage (i.e. reconcile the aircraft Build Standard, Statement of Operating Intent and Usage (SOIU) and the Safety Case) became prevalent in MoD in the 90s, with (surprise) the Nimrod 2 Star in MoD(PE) ruling a number of times that there was no obligation to ensure an aircraft was functionally safe before offering it to the Service, along with a (false) declaration that is WAS safe. The Chief of Defence Procurement, with airworthiness delegation direct from SoS, upheld this twice in 1999, after being warned of the aforementioned Tornado failure.



One other point; he misunderstands the aircraft Release process, seemingly pointing a finger at Boscombe. His error diverts attention away from the failure whereby ACAS seemingly ignored (illegally) the limitations recommended by Boscombe and endorsed by CAR. Again, this is exactly what happened on Chinook Mk2.

No apologies for bringing this up (TOFO!) because it illustrates the need to understand this basic background before commenting on any accident. Blackman’s main thrust, however, is perfectly accurate. Haddon-Cave completely ignored irrefutable evidence presented to him, completely failing to explore key areas. Omitting this evidence made many of his conclusions seem plausible; in fact, they were wholly contradicted by the evidence. As I always say, one must ask why he did this and who it protected.



And the above probably explains (dervish), to a large extent, why no legal action was taken against BAeS, QQ or the two IPT officers. But it doesn’t explain why that investigation did not proceed to the next obvious stage; if BAeS, QQ and the IPT were “innocent”, and given offences were definitely committed, then someone must be guilty. Again, who did this decision not to investigate protect? The same people.

[tucumseh]

TOFO - Your #11. Fully agree, except;

Where does the blame lie? All over the shop. Does it matter? Not really...unless we ever need an MPA capability again. Then it might.

It does matter, because in MoD aviation is a small world. When you have a single 2 Star with management oversight of several huge programmes, and he formally rules that functional safety is unnecessary, then that ethos and the subsequent failures become systemic. Today, I look at the senior DE&S staff list at AbbeyWood and mentally link names to fatal accidents. Invariably, these staffs were brought up under that 2 Star's tutelage and enjoyed his patronage.

[Chugalug2]

TOFO:

In first before the usual suspects hijack this thread...

You being the exception it seems! The MOD's treatment of this tragedy eerily parallels your own when you say:

Does it matter? Not really...unless we ever need an MPA capability again. Then it might.

They would not put it so succinctly but the net effect is the same. "Stove-piping" what happened as a purely Nimrod tragedy, with no implications for other fleets, serves the MOD's purposes ideally, whether intentioned or not. tuc explains it far better than I, so I'll just point out that I haven't once used the "A" word. The OP did though. Does that mean that he hijacked his own thread?

[The Old Fat One]

Come on guys at least read the thread and show some comprehension.

Neither myself nor Op are talking about HB and who is to blame for the XV230 accident.

Note Ops post...

I did not make the post in order to start another Haddon Cave thread

Pretty easy to understand no?

When I say...who is blame etc etc, I am talking purely about the "premature" retirement of the Nimrod and/or the fact that the UK now does not have an MPA capability.

Nothing in my posts above have anything to say about MOD airworthiness and/or Haddon Cave, other than correcting the error that Hc attributed a fire source.

Now I respectfully ask again... Can we keep the discussion re HC and airworthiness to the relevant thread, and keep this thread to a discussion about such things as the latent flaws which doomed the AEW/Nimrod 2000.

And note, I'm asking nicely. Maybe a moderator could make a ruling here?

PS

Tuc, nice post as usual and I agree. And it is important to keep bringing up. Just as important...the defence of the UK, which is why I'd like to keep the two discussions at arms length.

You might be able to stay objective..others cannot.

[Distant Voice]

Tony Blackburn misses out one vital investigation; the inquest. The only investigation that called for evidence to be given on oath, and the cross-examination of witnesses. The inquest concluded that "on the balance of probability" a blow off did not happen. None was witnessed by the Tri Star crew, either during refuelling or on climb out.

The fuel leak on XV235 came from a fuel coupling in the main refuelling line just forward of the bomb bay heating mixing chamber. It was observed as a spray (from port to stbd) by the crew. It certainly was not a blow-off from No.1 tank.

The Harrier pilot was the only close eye witness to the Nimrod fires and drawings produced by him, immediately after the accident and at the inquest, clearly indicate the fire source as being close to the stbd wing leading edge i.e., in line with the mixing chamber. This vital evidence (ignored by the BOI and HC) prompted the coroner to conclude that the source of the fuel "would accord with the description first given by the Harrier pilot of a fire further forward [than No.7 tank dray bay].

Contrary to what the BOI and HC thought, documentary evidence indicates that the temperature of the hot air to the input side of the mixing chamber was well above that required for auto-ignition. The evidence also suggested that due to “air blanking” caused by the Tristar refuelling tanker aircraft the system would run hotter than normal due to the reduced air flow through the primary heat exchangers located in the leading edges of both wings. The same air blanking effect is thought to have caused the Supplementary Cooling Pack to shut down during the AAR process, an event which is mention by the flight crew of XV230. It is unlikely that the shutdown was caused by the fire, as this anomaly had been observed by other flight crews prior to the accident. It is perhaps significant that the hot air feeds to the mixing chamber were immediately isolated on all aircraft in the fleet after the accident and the system never activated again. This act probably saved XV235, and not the isolation of the cross-feed hot air system associated with the SCP.

I agree that there is some commonalty between XV230 and XV235, but not for reason that Tony Blackburn gives. In my opinion the fuel leak came from a refuel coupling in the bomb, just forward of mixing chamber. However I do agree (110%) that the HC report is a rubber stamp of the BOI report, most likely because two BOI members were advisers to HC, and both were visibly upset when the Coroner rejected their blow-off theory.

Nimrod was retired because fuel couplings could not be correctly aligned (1 degree in all axis) and replacements for the life expired hot air pipes were difficult manufacture (all aircraft were different). The aircarft could no loger carry stores safely, because the bomb bay could not be heated and the release units had become defective because of several years of inactivity. £18 million was spent on a pipe/coupling modification programme that failed to save the aircraft.

DV

[The Old Fat One]

Nice post DV and pertinent.

Nimrod was retired because fuel couplings could not be correctly aligned (1 degree in all axis) and replacements for the life expired hot air pipes were difficult manufacture (all aircraft were different). The aircarft could no loger carry stores safely, because the bomb bay could not be heated and the release units had become defective because of several years of inactivity. £18 million was spent on a pipe/coupling modification programme that failed to save the aircraft.

My bolding....one of the inherent/latent/call-it-what-you-will/ flaws that showed the known risk factor when the contract was entered into in 1996....specifically build quality.

Another one...lack of internal space.

A factor in the comet V 707.
A factor in the failure of the AEW
One of the reasons the MR2 had to have an SCP

And, in addition to the cooling factor, other space considerations which would have affected the MRA4 were...

Reduced sonobuoy capacity (despite doubling the processing power)
Reduced special fits capacity (bolt on bits).
Reduced support crew capacity (MR1 29 MR2 25/25 MRA4 18)

All these and more were raised with BAe by yours truly in 1998. The BAe answer to each and every question they could not answer...

You have to understand, it is a whole new concept

The TOFO reply..Oh yeh, well was why is procured 100% against a cold war ASW spec?

[Party Animal]

TOFO,

For your record, I was part of the RAF JTT based at Warton in 98, so I saw the RMPA machinations unfold on a daily basis. It was never 'the taxpayer' that signed the contract, it was the government of the day and the threat of 5,000 people being made redundant in the NW of England is a powerful driving force behind the political decision making process. It was never going to come in on time or budget and everyone new that. You just have to accept the great procurement game for what it is.

Those of us committed to bringing the aircraft into service also knew how great the potential was for the platform to do so much more than just the traditional maritime core roles. Not rose tinted and not everything was the best. For example, the EOSDS was state of the art and better than anything on the market, when I did the operators course in Baltimore at the start of 2000. By 2003, the MX series had overtaken NG's products and what went into the Mk2 was better than what we would have got in the Mk4. As you know, the P3 is actually an older design than Nimrod, so I also don't believe that was the route we should have gone down, even if we would have had them delivered earlier.

So it's down to opinion on the platform of choice and we can all argue our own points of what road we should have followed. Back on thread though, the 230 incident seems to have exposed a whole can of worms that it seems impossible to get to the bottom of. I really don't know how the Mk 4 stood up in terms of airworthiness (sorry for the 'A' word Chug) towards the end and we will probably never know. Just like we will probably never know what really happened to 230. I thought the Mk2 had pretty much got on top of it's issues though and 'technically' was good to go on for another few years at least.

In my mind, the 2 biggest flaws were the name of Nimrod being soured by the incident and leaving a bitter taste in politico's minds and the fact that the Nimrod Force was the bottom of the RAF's priority list. I'm sure if we had been part of the FAA, the UK would still have an MPA capability.

P.S. The new sim building was delivered and everything within it, so not quite the square root of FA!

[Chugalug2]

TOFO:

... keep this thread to a discussion about such things as the latent flaws which doomed the AEW/Nimrod 2000.

I'm confused (again!). The OP says of Tony Blackman's book:

... the Haddon Cave Review's conclusion on the root cause of the fire was probably incorrect.

I take that to be the basis of this thread. If I'm wrong no doubt he will correct me. It seems from authoritative posts here that the proposition may well be correct. However, the OP suggests that if it be so:

the subsequent rapid rundown of the fleet, at least partly done on the grounds of airworthiness may have been premature,

So is not airworthiness an issue here? He seems to suggest that if the fire did not originate in the dry-bay then there was no airworthiness problem. I would certainly take issue with that (surprise, surprise!), but so I suspect would many others. Now, perhaps the book is indeed about the theme in your quote TOFO, but the OP seems to be about the seat of the fire being elsewhere than the BoI and H-C had it, and therefore about the possibility of the fleet being kept going. I say it couldn't, so do you I think, but I remain confused...