Nimrod Grounded

[EdSett100]

I understand that only ONE Nimrod has been modified (ducts and seals), and a new series 10 seal is being used. What was wrong with the old series 1?

It contains the wrong amount of carbon. I can't remember from the brief to aircrew if was too much or too little. Suffice to say, that a number of them have been found, on routine removal, to be split or similarly damaged due to incorrect carbon content. The damaged seals were not leaking at the time of discovery. Seems like the MOD was supplied with dud seals from the turn of the century. This adds weight to the probability of a fuel coupling leak on XV230, due to either misalignment (XV235 incident) or seal failure, rather than a 1 Tank blow-off.

[EdSett100]

DV:

It is true that the duct replacement program stems from the incident involving XV277, but the statement from BAES that certain ducts within the system were "life expired" goes back to June 2005, in is not a recent event. MOD did not accept that there was a problem until early 2008, almost 3 years later. Between June 2005 and 2nd Sept 2006, Nimrods flew with the cross-feed duct activated and with "life expired" ducting in the system. Since then Nimrods have continued to fly with suspect parts of the hot air system.

I wasn't aware that BAeS had inspected all of the HP air ducts and pronounced them lifex as early as Jun 05. Are you confusing the examination of the SCP system with the HP air system? The SCP system was certainly examined and declared dangerous the day after the XV227 incident, resulting in the immediate banning of its use. BAeS later (Jun 05?) confirmed the SCP was lifex.

The completion date of 31st May, 2009, was set by the Nimrod IPTL at the inquest, when he agreed that the system was not ALARP, but he was moving towards it. I am not surprised that IPT do not want to go beyond this point, because if it is not ALARP it is not safe.

IMHO Your last few words are not quite correct. ALARP, in the context of Nimrod risk analysis refers to the degree of risk of losing the aircraft due to a hazard caused by a single failure. Hickmans use of the term "ALARP" was misplaced and has led to a lot of confusion. Yes, in terms of the hazard presented by the old ducts, the risk of a single failure was not as low as practicable. They are lifex and they need to be replaced and, arguably, it is practicable to change them at the first opportunity, hence it can be said that the risk of a duct failure is not as low as practicable until the duct is changed. But, importantly, that is only in reference to the ducts, NOT the AIRCRAFT. The risk to the aircraft, created by a single duct failure (for whatever reason, including lifex) can be mitigated by the structure around the ducts and well practised crew procedures. Granted, there were no crew drills for a duct failure in the bomb bay, due to a lack of detection capability, and that part of the system is now out of operation in the air. Therefore, although the duct failure risk is not as low as reasonably practicable, the risk to the aircraft of a catastrophic or critical failure is bordering on negligible due to mitigation. This high degree of mitigation provides the control required for safe operation even in the event of pipe burst at the most critical time. Therefore, regardless of what Hickman said at the inquest, there is no legal need to drive towards ALARP then, now, or in the future. A HP air duct might be about to fail, according to Qinetiq, but the structure and the crew can handle it, safely.

With regards to the hazard risks in the engine bay and wing areas, I must ask if you have had time to read up on Hazard H66 and the QinetiQ report of Feb 2008. (We have talked about this on the other thread).

Yes, I read Hazard 66 some time ago, but the discussion was inactive and I thought it sensible to leave it so. Now, due to "Bob" its back in the headlines. I haven't been able to read Qinetiq's report, but I know the conclusion and I don't have any argument with it. It centres, quite rightly, on the age and condition of the pipework and they have upgraded the hazard accordingly. However, I'm led to believe that QQ did not comment on how the loss of the aircraft due to a pipe failure is mitigated by airframe structure, warnings and drills. Is there anything in H66 that you want to know more about? Please believe me, the loss of a hydraulic system (we have 5), an electric supply (we have 4), an air conditioning system (we have 2), and airframe de-icing system (we have 2; each capable of supplying everywhere) or a CDSU cooling pipe (I don't know why they mentioned that, but we have 4, anyway) an engine fuel fire (we have detection and extinguishants) all due to a single hot pipe failure is not a problem. Even our least experienced crews will deal with the problem very effectively. It has been practiced regularly since the day the aircraft first flew. Its a formal Basic Training Requirement to be able to deal with a hot pipe failure in an engine compartment. But it appears that Hickman doesn't want to account for our training in his narrow decision making process. On that basis, every max weight take off is dangerous because if an engine fails, the crew procedure is not accounted for as the only mitigation against a crash.

Meanwhile, the troops on the ground will not know where the next bullet is coming from. I wonder what the Army chiefs would think if they find out that we are not flying one their most valued air assets because we are "worried" about an insignificant problem.

Finally, detectors, fire suppression etc do not mitigate a hazard, they mitigate the accident. QinetiQ's words, not mine.

Agreed. And to summarize, we can easily avoid the accident and we can live with pipe failures ad infinitum.

Regards
Ed Sett

[nigegilb]

Ed Sett, so do you agree with my summary that the AIRCRAFT has been ALARP these past few months and that the new standard WEF 01 Apr is effectively ALARP with bells and whistles-ALARP PLUS?

[drustsonoferp]

Nige

Yes, perhaps I should clarify my own post. I understand that some of the evidence presented to the Coroner was considered by the RAF/MoD to be inaccurate. Quite whether the RAF/MoD have informed the Coroner of any alleged inaccuracy I have no idea. Quite why the RAF/MoD did not send an even more knowledgeable/senior witness to correct any alleged inaccuracy I can only guess. From my experience of these things it is most useful, from the Ministry's point of view, to keep the damage away from the higher military echelons and God forbid, the Politicians.

There can be a world of difference between senior and well informed. The inquest put a lot of focus on seniority. Questioning on engineering that requires considered thought, close evaluation of documentation etc is not something best done with individual witnesses on the spot in a court room. It is an environment that, imho is almost guaranteed to give inaccurate results.

[FrustratedFormerFlie]

MOD admits only 1 Nimrod with modification completed

Article from Press and Journal (Aberdeen) 13 March

[KeepItTidy]

"The MoD is facing a £20million claim for compensation from relatives of those who were killed in the crash"

I shocked and in disbelief that the family members are after this sort of cash. I am in utter shock .. I will leave the keyboard now as I dont want to say anything I will regret ............ I really am astounded as I thought a substantial payout was done not so long after the crash but for a few more million each

[Distant Voice]

Ed Sett;

The June 2005 BAes report, to which I refer lists the following;

(a) 15 ducts - engine to cross feed cocks

(b) 12 ducts - between cross feed cocks

(c) 7 ducts - downstream of 5-way duct pressure reducing valve.

Note: Many of the above had already been identified in an earlier "quick look" report, dated 7th Jan 2005.

Ducts listed under (a) and (b) are now being replaced in the duct replacement program, four yeras after they were dclared "life expired".

Hope that helps.

DV

[Lazer-Hound]

BBC NEWS | Scotland | North East/N Isles | Only one RAF Nimrod 'fit to fly'

[KeepItTidy]

Like I said I smell Shiite , WTF does the BBC know

Im not even going to start at this utter complete bullcrap

[nigegilb]

drustsonoferp, not sure the Inquest should be blamed for placing a great deal of focus on seniority. The Coroner would have wanted to have heard evidence from the people who had responsibility for decision making. I am sure Tuc has a view on this, since the IPT system came into being a lot of the specialist engineering knowledge and experience has either been lost or overridden.

The MoD and RAF would have had a degree of flexibilty as to who was forwarded to give evidence. I happen to know that a number of presonnel have been "moved on", "retired" etc since the Inquest. I spent a lot of time at the Herc Inquest it was very obvious, even to the layman who were the strong witnesses, who were struggling, who were being economical with the truth. I am sure the Coroner formed his own opinion on the reliabilty of the witnesses.

I do understand your underlying point. For a long time I did not believe the Nimrod was ALARP, EdSett's answer was most helpful in understanding this issue.

[EdSett100]

Ed Sett, so do you agree with my summary that the AIRCRAFT has been ALARP these past few months and that the new standard WEF 01 Apr is effectively ALARP with bells and whistles-ALARP PLUS?

I agree completely. I would add that it has been ALARP ("as safe as it needs to be"' as CAS clearly stated at the time) since 4 Sep 06.

Ed

[Tappers Dad]

Ed Sett,

If it is, and always has been ALARP how come they can't fly them. In the letter sent to me by Bob Ainsworth on March the 10th 2009 he said that the Nimrod fleet remains airworthy as long as the ones that haven't had the ducts done don't take off.

I'm confused !!!!

[EdSett100]

DV:

Ducts listed under (a) and (b) are now being replaced in the duct replacement program, four years after they were declared "life expired".

Do you have documentary evidence that BAeS signed a report declaring those pipes LIFEX in Jun 05? I was led to believe that they made their report in 2007. If so, I could understand, to some degree, why only one aircraft has had the new pipes fitted so far, in response to that report. I believe they have to be tailor-made for each aircraft. I still stand by my assertion that the Duct Replacement Programme should never have compromised flying operations, anyway.

Today we were informed by the BBC that only one of our aircraft is airworthy. Who the hell is releasing this rubbish to the media? We are losing our way, here, big time.

Ed Settt

[Distant Voice]

Ed.

The report that have was issued by BAES in reply to PDS task 06-3487. An ealier report from BAES, dated 7th Jan 2005, identifying the same ducts, was in reply PDS Task 16-3468. Neither report, nor the one issued in 2007 (but prepared in 2006) was made available to the BOI for XV230.

DV

[JFZ90]

I may have this wrong but I read the story as :

5 aircraft have had their ducts done, but it seems only 1 aircraft of those aircraft has had fuel seals changed (is this MoD info?)

I think the MoD have implied those 5 can fly - as presumably the ducts were the Mar 09 grounding issue - hence the fuel seals are not a grounding issue -
EDIT on checking they have actually stated this explicitly - "Delays to the replacement of fuel seals will, however, have no impact on flying since our experts assess that the risk is tolerable."

The BBC has seems to have ignored this to imply that only 1 is airworthy, and stated in earlier reports that the MoD had not clarified the issue (despite the fact that I did a 10 sec search on the mod site to produce the quotes above where it seems pretty clear to me!).

Ministry of Defence | Defence News | Equipment and Logistics | Nimrods requiring safety modifications to temporarily cease flying

Hence on this occasion, the MoD appears to have had their facts completely twisted by the media to create a better story.


-----

This issue of timeliness in ALARP has been raised on this thread many times as another dimension to any ALARP assessment - but this continues to be misunderstood it seems by many on here.

A good example is that the 777 are still flying today with unmodified Trent 800 engines & its current Fuel Oil Heat Exchanger (FOHE) technology - the FAA have given operators around 6 months after a Rolls Royce modification is developed (so 6 month clock not even ticking yet - it will only start when Rolls have a fix) to get it fixed - until that time the risk of a heathrow crash repeat is quite real (noting the workarounds to minimise the risk). So is it ALARP? Well you can argue the aircraft is not really ALARP as you can improve the FOHE and fit it - but this hasn't been installed yet and can't practically be done for 6-12+ months. The FAA are content that there are workarounds to mitigate the hazard so are content that it is reasonable to keep flying as long as the mods are embodied within a reasonable time. Hence you could say they are working towards an ALARP build standard of the 777 fleet - this is where the terminology can get confusing, as it is also true to say the whole situation is ALARP, as the the risks have been minimised by outlining an timely upgrade plan. Hence you can say the risks to current 777 ops are ALARP, even though the new FOHE won't be fitted for months. Hope that makes sense, and the parallels to Nimrod are obvious.

[Roland Pulfrew]

I love some of the conspiracy theories starting to abound on this topic; they do make for amusing reading.

Please remember that tour lengths are getting shorter (for various reasons including overstretch and the rediculous size of the RAF today) so if people are getting "moved on" it's probably just that they are tourex! The only people who tend to do longer than 2 years in post are aircrew on squadrons, for anyone else (including sqn ldr+ aircrew on squadrons) it will only be about 2 years. It shouldn't come as a surprise that some people have been posted.

[Distant Voice]

Ed Sett 100: I believe that over the past year you and I have come to respect each others views and opinions. Having said that, views and opinions are one thing, evidence and statements presented by specialist is something else. And whilst it may run contrary to our views and opinions it has to be respected and taken seriously.

Whether we like it or not, hazard H66 has a hazard severity rating of CATASTROPHIC. It is currently set on the data base has having a probabilty of IMPROBABLE. Is was recommended by QinetiQ in 2008 that because there had been two duct failures this should be reset to OCCASIONAL. This would give it a HRI of "A".

According to the safety case developed by BAes a failure in this area has the "Potential for hot air leaks from the LP & HP ducting on rib 2 to impinge on the engine bay top scin and electrical wiring. The leak would also impinge on the CSDU cooling oil pipe installation together with fuel and hydraulic pipelines creating a potential for overheated systems"

So, unfortunately, I am unable to agree with you on your ALARP approach, and remind you that detection and suppression and drills do not mitigate the hazard, only the accident. If some one told you that the electrical wiring in your house was unsafe and could cause a fire would you simply go out and buy a smoke detector and extinguisher, or would you have the wiring replaced/redesigned?

DV

[Tappers Dad]

Naval Air: Nimrod Withdrawal


According to this publication two U.S. Air Force electronic monitoring aircraft (RC-135 Rivet Joint) have been leased to fill in because of shortages. The aircraft will have joint British and American crews, but will be painted in Royal Air Force colors. Britain is also buying three RC-135s from the United States, at $350 million each.

[EdSett100]

DV:

If some one told you that the electrical wiring in your house was unsafe and could cause a fire would you simply go out and buy a smoke detector and extinguisher, or would you have the wiring replaced/redesigned?

I would have the wiring replaced, as a matter of urgency. But I wouldn't move out of my only home and make myself homeless and a burden on my friends while the house is re-wired. I would switch off the electricity where I don't need it and, where it is needed, I would employ someone to watch it like a hawk, who would switch it off and deal with it, while the repairs were being carried out.

Ed Sett

[Green Flash]

According to this publication two U.S. Air Force electronic monitoring aircraft (RC-135 Rivet Joint) have been leased to fill in because of shortages. The aircraft will have joint British and American crews, but will be painted in Royal Air Force colors.

US aircraft in UK colours - so who owns it?

US and UK crews - so who tasks it? And who fix's it? ROE's?

I'm all for Combined/Joint/Coalition etc etc but I do hope someone somewhere has got the management chain well and truly nailed down! Potential for some large SNAFU's methinks.