As an aside ..... why are Imperial and metric units of measurement being used at the same time ? .....

(LBS and KG)

Hobie,
The 2 aircraft use different units of measurement on their gauges.

Oh $$$$$$ ...... :(

Nimrod salute
 

To hell with the politics;
I salute all Nimrod crews past & present & todays solo Nimrod overhead Chelmsford en-route to the Mall was for me a very moving tribute albeit for the Falkalnds 25 today, but very appropriate to this thread for all the lost crews - I salute them all, one & all, Aircrews of honour to the very end.
Godspeed to them all & their families & loved ones everywhere.

Well, Old Timer, your thoughts are appreciated. However, the aircrew is only one element of the team that gets the jet to where it is needed. Today is a Sunday and the Nimrod doesn't fly on Sundays, unless operationally (or ceremoniously) needed. We don't have the human resources, any more. OK, the aircrew are not overworked at the moment, while at home, so a bit of weekend flying (yesterday included) is nothing to complain about. In fact it was a good reason to fly. However, the groundcrew supporting the two flights this weekend went into work in addition to their normal work routine. And its Father's Day, today. Again, pride in our our predecessors in the Falklands and the "Proud to be British" sentiment when Trooping the Colour and showing off our Service, suggests no complaints from my groundcrew colleagues, but we must never forget that we are all in the same team.

Please pause for thought this Fathers Day for the 18 children whose fathers were on XV230 Crew 3 and will never come home.

Today is not a good day for any of the families.

We will remember them XXXXXxxxxxxxxx

Seven tons of Avtur in a bomb bay?
 

I have refrained from joining in this thread despite some rather suspect facts being banded about.

However the following by nigeglib:

“One of the Nimrods recently landed with 7 tons of fuel sloshing around in the bomb bay, another fuel migration and one which could have seen a repeat of Afghanistan.
I will dig out the Parliamentary answer and compare.”

I could not ignore. (That’s not a personal dig at you nigeglib, many facts quoted by various people have been wrong).

7 Pints perhaps, 7 gallons at a stretch but 7 tons? That’s nearly 16,000lbs, that’s a lot of petrol. The bomb doors would not take it (that’s a guess), however, the fuel would leak out before that amount could collect.

And that’s the problem with repeating stories without understanding their context. Especially incident signals; unless you are the recipient and understand the engineering aspects, all they do is create uncertainty and alarm.

We all care about the problem because we are or were involved in military flying and to us it is a big issue, but we must let the wheels of investigation turn, we will not find the answers otherwise. If they fail to produce a plausible answer and take action to reduce the risk, then is the time to take up the pen.

From my handle those that know the Nimrod will realise I have flown on them from the early days, have many tanking sorties in my log book and knew some of the guys on 230. I too want to know the answers as much as the next man (oh yes, and woman), but feel too much speculation is pointless at this stage.

Time for my cocoa.

TSM,
I couldn't decide if you were condescending or hard of thinking. Clearly I don't fly Nimrod for a living, and those that do have my utmost respect. And the families who lost loved ones have my deepest sympathy.
I don't think that all aircraft are inherently unsafe, but all aircraft carry an element of risk. And I didn't say that it isn't necessary to put fire extinguishant or suppressant in the bomb bay. In my last post I explicitly said To re-cap for you what I did say:
There are 3 levels of risk - Intolerable, Tolerable and Broadly Acceptable. Where risks are tolerable, it is for the duty holder to weigh up the benefits of introducing a safety system against the implications of doing so, ie a judgement of "reasonable practicality". I'm not in a position to judge, based on objective examination of the evidence, whether the argument being made is sound.

As for Mr Boeing and Mr Airbus, I believe that they make aircraft that are tolerably safe. Why only tolerably safe? Because even the certification specifications against which civil aircraft are made do not demand absolute safety:
So, where a civil aircraft is certified (and btw, don't try and ask them for a "safety case") against a technical hull loss probability of 1 in 10 million per flying hour and your pilot is exposed (rounded for simplicity) to 1000 hrs flying hours pa then the level of risk for an individual pilot is in the tolerable zone. Society tolerates this level of risk because of the benefits of air travel.

sw

Safeware,

I must admit that I too am a little bemused at your reply now. First you say that ALL aircraft are dangerous to one degree or another, only to retract that statement by saying that they you don't think they are. So what's it to be?

Before you go and give me another patronising and very lengthy explanation about duty of care, aircraft certification, tolerable, intolerable and acceptable levels of risk, and goodness knows what else, let me just put my cards on the table and explain that with almost 15,000 hours of flying in my log book (Lots in the military and quite a few on Nimrod) I do know just a little bit about aircraft and how they operate, and would rarther you didn't reply as if I were someone who graduated from Cranwell yesterday. Neither am I being condescending!

The fact is that if Mr Boeing finds something that is 'dangerous' on my current aircraft, and it can be replaced or retro-fitted to overcome that danger, then its done. That is because there is a danger to the aircraft and therefore the pax (and me!) Remember the door on a 747/200 that detached in flight? the chances of it happening again were minute, infintisimally small, but the whole fleet were checked and the mechanism replaced. Any ideas how many 747/200 there were at the time? Well I don't know either, but there was a hell of a lot more than a hand full of Nimrods I can assure you. As a follow on, all future 747s (and probably many others types) were fitted with the new mechanism, without question.

Niimrod has been an outstanding aircraft and has served this country wonderfully, but it is sadly out of date and we need to move on with up-to-date aircraft. If we are going to stick with the MR4 then it needs to be brought up to date, not only with avionics and weapons sytems, but with the basic airframe needs, and that means a reliable and competant fire suppression sytem that covers the whole aircraft. It is farcical to think that the bomb bay on this aircraft does not have even a single fire extinguisher! It is ridiculous to put all your weapons in one basket, but not be able put out a fire in that location. I wonder which baffoon dreamt that one up?

You begin to sound like a politician Safeware! Your comment of 'Mr Boeing and Mr Airbus, I believe that they make aircraft that are tolerably safe' I think is inaccurate and false. I would say that they both make aircraft that are as safe as they can possibly be for the year 2007. In 5 years time, they may well be regarded as 'intolerably safe' as standards increase and safety improves, but at the moment they are as safe as they can be made. NIMROD IS NOT! And thereby lies the problem.

The RAF, (as it has had to do for many years now), will have to make do with what they get and like it! I know that MR2s are unsafe, the aircrew at Kinloss know it and so do some of the groundcrew it would appear. It is wrong of you to seemingly defend this level of danger as being within your 'tolerable' limits. Try telling that to the families of those we have lost.

The Winco

The Winco,

I take your personal point of criticism of Safeway 'patronising and very lengthy explanation' may I make a counter point?

These are open fora where others are reading and learning too. Some of us follow every post, others dip in from time to time. In other words, Safeway may be patronising on a one-to-one basis or had he posted in a PM. Here I think it was not unreasonable.

Wader,
Thank you for coming to the assisstance of Safeware, but you have also failed to see my point Sir.

We all know how the MR4 project will be seen - the RAF will get a new replacement for Nimrod MR2, updated Avionics, better Sonics, better Radar, more powerful engines and a whole miriad of other goodies. and the public will think that all is great in Maritime once more.

What the public will not be told however, is that the aircraft will NOT have foam in the wings, it will not have state of the art fire suppressant. Infact, it won't even have a single fire extinguisher located in the bomb bay. Now forget all about tolerable, intolerable and acceptable levels of risk; this is basic, simple fire precaution/fire fighting stuff. There is nothing more simple than a fire extinguisher is there?

So all this Red Herring stuff about aircraft certification, and that is all it is, has no bearing whatsoever on the fact the the MR4 will still have a 1940s/1950s fire fighting capability, and that cannot be right.

As for the AAR. As I have said, 25 yerars ago it was acceptable, but I'm not convinced that the very same system cannot be improved upon for the inclusion into MR4. Even the Tristar has double thickness pipes throughout, Nimrod MR4 DOES NOT? Why not? Why are you appearing to defend such appalling penny-pinching and cost-saving measures that affect aircraft and therefore aircrew safety?

My point about Mr Boeing is but a simple one. He will make the aircarft of taoday as safe as it is possible to make an aircraft today. In 5 years time it may be out of date, but today it is spot on. Nimrod MR4 will be 10, 20 30 years out of date as soon as it roles out. Not the engines, and not the avionics, but on the fire safety/suppressant side and the AAR side also.

Please try to understand that I am in no way having a go at anyone on this forum, but we have to look at what MR4 is; a (very) old design, with a few gucci bits of kit bolted on but an aircraft that still retains an out of date and (potentially) dangerous lack of fire fighting capability and AAR ability.

The Winco

Further to the Winco's post, Mr Boeing provides 215 minutes worth of fire extinguishant in the FWD/AFT Cargo hold of a 747. Mr Boeing is also fitting state of art fuel tank protection to the latest Boeing airliners coming off the line. There have been about 5 attributed fuel tank explosions in airliners in the last 25 years or so. The RAF has had probably 4 in the last 30 months in it's tiny inventory. (anyone see the video of the J on the strip, did you check out the port wing?)

Needless to say civil airliners don't get shot at (with the exception of DHL, which also suffered a fuel tank explosion) and don't do AAR. What does that tell you about cost benefit analysis in the RAF just now?

I am checking out the latest order for 5xJ Hercs from RNAF. I understand that LM is fitting nitrogen gas inerting equipment as standard on the latest Hercs. Maybe this is the way ahead, cut out the customer from the decision making.

“Maybe this is the way ahead, cut out the customer from the decision making”.


That’s precisely what the MoD want, I believe. They’re not allowed to “solutionise” anymore by specifying what they want. In turn, this leads to (a) further dumbing down, as the people capable of specifying are considered dinosaurs and ignored, and (b) an inability to act as an intelligent customer.

While not wishing to excuse some of the acquisition blunders of the past, many stem from politics. But the above policy has resulted in a noticeable increase in real schoolboy howlers which are wasting hundreds of millions (and that’s just on a single project I could mention). The outcomes are mixed. Some companies simply deliver the wrong thing in ignorance. Some knowingly deliver the wrong thing, and stand back waiting for the blank cheque to fix it. Others try to educate the MoD. They’re the ones who suffer.

Winco

All that you say is true; however, there is one missing fact. Mr Boeing and Mr Airbus will recoup his extra costs over the production run of the ac. If Mr Boeing and Mr Airbus does nothing, he might not sell any more ac, he goes out of business. The Ministry cannot recoup costs and therefore a cost benefit analysis will establish that 2 bomb bay fires over 36 years will justify the non inclusion of fire suppression. Had the first one not occurred in the circuit at St Mawgan, they too might have had an unfortunate end.

Like it or like it not that is how we build military ac. Change the spec and BAES will charge the earth and the costs will have to come from somewhere within the defence budget because this government does not see defence as a priority.

Its not called penny pinching, it's called affordability.

The Nimrod is not Typhoon, therefore is not a priority.

Don't get me wrong, I am in your gang, but alas MOD PE, DPA, DE & S or whatever they chose to call themselves this week, are not.

"It is farcical to think that the bomb bay on this aircraft does not have even a single fire extinguisher! It is ridiculous to put all your weapons in one basket, but not be able put out a fire in that location. I wonder which baffoon dreamt that one up?"
Just wondering what sort of fire extinguisher puts out fires in magnesium, HE or ( out of date but i can't remember the new stuff ) OTTO? No fire suppression in the bomb bay is a bit of risk analysis really. Stores jettison would be the best way of putting out the most likeley source of fire in that location, IMHO.




ps;while I have 42 posts, I would just like to clear the air by stating I never served on the 'monday-to-friday-beach-bum-squadron' :rolleyes:

thunderbird7

"Just wondering what sort of fire extinguisher puts out fires in magnesium"

Can I refer you to my posting on 16th June 2007, 16:21 #499

And also:

Fires can be extinguished with a MET-L-X powder extinguisher for fires involving combustible metals - magnesium, sodium (spills and in depth), potassium, sodium-potassium alloys uranium and powdered aluminum

Just remember what happened to the DHL A300 which was hit by a MANPAD system a couple of years ago:

To pick on a point raised previously, actually the ‘stuff about certification’ is important. It’s the airworthiness system in MoD not working as intended that’s at the root of things. Pick any in service IPT and you’ll find the same issues under the rug.

Commercial Aviation

What Mr Boeing and Mr Airbus do is meet the certification requirements in force at the time when the application is made for type certification. They will satisfy mandatory requirements to get the certification from the regulator (minus whatever aspects they can ‘grandfather’ if the aircraft is based on an older one). This is a world away from designing to be as safe as it can ‘possibly be’. No commercial organisation does that. If they say they do its just PR.

The industry functions on the basis that the regulatory compliance ensures an adequate level of safety. There is also a requirement within the regulations themselves to demonstrate safety against a numerical target. As Safeware said previously good luck finding a fully comprehensive example of that being done. The Safety Case concept is not applied in the industry.

Then, once the aircraft is sold to customers, the manufacturer has a requirement to respond to any in service data showing that the design is not meeting the designed level of safety. This is also required by regulation.

The prescriptive regulations prevent anybody from doing anything outrageously stupid for commercial reasons. Shortfalls in designs are fixed after sufficient incidents accrue to force the hand of the parties involved. The regulations also evolve slowly over time in response to technology changes.

MoD

The Military situation is rather different since MoD is its own regulator. This means that the manufacturer proceeds in sole reference to the contracted requirements and the direction it gets from the customer. MoD is full of standards and design criteria. Some are out of date, some are good. However its all entirely dependent on whatever makes it into the contract. That’s under the control of the IPTL.

The regulation JSP 553 provides the baseline criteria for airworthiness. In recent years the move has been away from safety by compliance with specific technical requirements of the kind found in EASA regulations towards safety cases. Basically, ‘do it any way you want just convince us the risk is tolerable’.

There is supposed to be an element of independence built in to the system. The airworthiness reporting chain is supposedly separate. The standard IPTL letter of delegation requires (or did require, been a while since I looked) the IPTL to deliver an airworthy aircraft and calls out JSP 553 and other documents like Defence Standard 00-970 in support. The IPTL is duty bound to satisfy these requirements. That means getting adequate resources to do the job. If this cannot be done work should cease and it be escalated to higher levels of authority.

This assumes a lot. It assumes that the man in post understands his crucial regulatory airworthiness role. It also assumes he is willing to be personally extremely unpopular in the interests of safety. Possibly to the detriment of his career. It assumes the IPTL will stand up and tell other personnel of higher rank in the same organisation that they cant have the equipment needed because there is not enough money allocated to make the risk tolerable.

As there is never enough money the pressure is always to compromise something. With capability compromises the effects are immediately tangible and opposed vocally by end users. Safety compromises often are not immediately obvious and thus meet less resistance. The flexibility of a safety case approach is also its weakness if the safety culture of the organisations involved is not strong enough. Often considerable pressure is brought to bear on IPTLs to make do, this manifests in watered down safety requirements to contractors and pressure on IPT safety managers to recommend things as tolerable. The same pressure often flows down to system engineers within the manufacturers from their management eg “I spoke to IPTL x and he says that that we don’t need this extra safety feature, he cant afford to pay for it and it would slip the schedule”. From the manufacturers management perspective the customer is right, especially as he’s the regulator as well. DECs voicing their opinion on airworthiness issues to contractors management muddies the waters even further.

While on paper the system is still robust its implementation is not in many cases. The widespread resource shortages are undermining the safety culture in the organisation and its not likely to get better in the conceivable future. :*

back in my box now....

Winco,
It is obvious from your statement above that you aren't actually reading what I've written:
- I never said that all aircraft were dangerous, then changed my mind to say they weren't.

What I said was and then So I didn't say that aircraft are dangerous, but that flying carries a risk (even in a 'safe' aircraft).

I followed this with a simple and an explation of the civil safety requirements to show that even they don't expect absolute safety.

I also agree that Mr Boeing and Mr Airbus are making aircraft which, given the currently available technologies are as safe as possible, but once again, don't confuse this level of safety with an absolute absence of risk.

I have no problem with the fact that Mr Boeing and Mr Airbus fix problems when they find something "dangerous". That is also what I think Mr MOD should do with Nimrod.

All I'm trying to point out is that it isn't as simple as you make out - the wheels will be establishing THEIR argument about what THEY are doing (be it right or wrong). You seem to be missing the point that I'm not defending their position so your accusation that I "seemingly defend this level of danger as being within your 'tolerable' limits " is way off mark. What I'm trying to explain is what the CORRECT process is for management of risk.

sw

I want to make a second point about the fire extinguisher and bomb bay issue. Most successful aviation extinguishants rely on the principle of oxygen starvation and compartmentalising the aircraft by design. Tappers Dad quoted the avionic bays in other jets and a modern expanding gas. Well, yes, that system will work because the gas expands into a small, sealed bay and starves the bay of oxygen, or if it is not sealed, it will have a limited ventilation system that will account for the needs of the fire extinguishant.

The Nimrod bomb bay is not sealed in flight. The 4 doors close together for aerodynamic purposes and they leave significant air gaps around them. When the doors are closed, the bomb bay heating system continually delivers warm air into the bay. I don't know what the volumetric rate of air exchange is, but 4 distribution ducts, each the size of domestic tumble drier hoses, are delivering air into the bay. The bay does not pressurize, therefore all of that air leaves the bay at the same rate that it goes in, via the gaps around the doors. So, in the event of a fire in the bay, the heating system will be switched off to prevent further oxygen feed. If, by design, a fire extinguisher was then immediately directed into the bay, 4 tumble drier hoses worth of air and extinguishant would be sucked out of the bay through the effects of flying at 200 kts. So, the volume of designed extinguishant that has to be stored in the jet has to be capable of exceeding the amount of bomb bay heating supply, at the outset, and then continue to smother the fire for a sustained period. The heating air is supplied by the 4 engines, so its a big task for any extinguishant to exceed. Impossible, in my opinion.

The people who designed the Nimrod were intelligent and thoughtful and put extinguishers everywhere they believed they could be needed and where they would be effective. I trusted their judgement when I first found out how the aircraft was built and I still do.

Mr Winco and Tappers Dad, as much as we would wish it otherwise, please accept that the Nimrod bomb bay cannot be protected by fire extinguishers while it is empty.