Nimrod Information
Join Date: Jul 2003
Location: Lincs
Posts: 695
Likes: 0
Received 0 Likes
on
0 Posts
AC Ovee,
I'm sorry to inform you that you are wrong my dear chap.
The principles you quote are correct and plausable, but the fact remains that the Nimrod bomb bay could, and should have beeen fitted with a fire extinguishant, especially on the MR4, and thats most people are banging on about now. I hate to say it, but to retro fit the bomb bay on the MR2 is probably not worth it given it's short time left in service.
The Nimrod bomb bay is unique in that it is heated as you say by ducted air from the engines, and MR4 is just the same. That said, the heating can be switched off, and in an emergency (unless SOPs have changed) was regularly switched off. At this point, one of the boys down the back would look down the old periscope and check the bay for a fire, smoke or fumes, and the captain would thereafter decide on the best course of action.
But why do you feel that you could not flood the bomb bay at this point with an extinguishant? lets say some form of inert gas? Reason = Cost £££££££
There is no other reason at all. High pressure inert gas is used throughout avaiation for such an event. I would expect the same to go for civilian jets.
But the simple, blunt, distasteful and disturbing reason is because it will cost money, and thereby lies the problem.
Now Mr Safeware has come up with all this statistical nonesence about reasonable risk, acceptable risk blah, and those at MOD and BWOS will have looked at these figures and gone for them in a big way, saying 'hey, we can save a few quid here chaps' Lets not bother with the bomb bay fire senario, because in all the years of Nimrod, we have only had a handful of incidents, and lost only 2 aircraft (I'm including the St Mawgan jet that was eventually cat 5) so as Safeware says, its an 'acceptable risk' (I say bollox it is!)
What The Winco and others are saying is that MR4 should be made as safe a is humanly possible for todays standards, and I agree entirely with them. If XV230 had been fitted with a bomb bay fire-fighting system, who knows whether it would have survived or not? It might have just bought the guys a few more minutes to get the jet on the ground. If that had been the case (and we will never know) does anyone still think its an 'acceptable risk'??
Safeware, your comments read like those of a polititian. Maybe you are one, I don't know. But I find some of your comments in bad taste, especially given the fact that Nimrod 4 is regarded as a 'new jet' by the those who will fly it. It now appears it will be using old parts and old technology, clearly a move to save on costs, and not using state of the art fire fighting kit. That is a shameful and unacceptable way to conduct things, but I suppose the bean counters will be rubbing their greasy little hands, pleased with themselves at having saved a few extra pounds for the asylum seekers, and not bothered that the lives of RAF aurcrew have been put in danger.
Thank God I'm no longer on the fleet.
KInd regards to all
TSM
I'm sorry to inform you that you are wrong my dear chap.
The principles you quote are correct and plausable, but the fact remains that the Nimrod bomb bay could, and should have beeen fitted with a fire extinguishant, especially on the MR4, and thats most people are banging on about now. I hate to say it, but to retro fit the bomb bay on the MR2 is probably not worth it given it's short time left in service.
The Nimrod bomb bay is unique in that it is heated as you say by ducted air from the engines, and MR4 is just the same. That said, the heating can be switched off, and in an emergency (unless SOPs have changed) was regularly switched off. At this point, one of the boys down the back would look down the old periscope and check the bay for a fire, smoke or fumes, and the captain would thereafter decide on the best course of action.
But why do you feel that you could not flood the bomb bay at this point with an extinguishant? lets say some form of inert gas? Reason = Cost £££££££
There is no other reason at all. High pressure inert gas is used throughout avaiation for such an event. I would expect the same to go for civilian jets.
But the simple, blunt, distasteful and disturbing reason is because it will cost money, and thereby lies the problem.
Now Mr Safeware has come up with all this statistical nonesence about reasonable risk, acceptable risk blah, and those at MOD and BWOS will have looked at these figures and gone for them in a big way, saying 'hey, we can save a few quid here chaps' Lets not bother with the bomb bay fire senario, because in all the years of Nimrod, we have only had a handful of incidents, and lost only 2 aircraft (I'm including the St Mawgan jet that was eventually cat 5) so as Safeware says, its an 'acceptable risk' (I say bollox it is!)
What The Winco and others are saying is that MR4 should be made as safe a is humanly possible for todays standards, and I agree entirely with them. If XV230 had been fitted with a bomb bay fire-fighting system, who knows whether it would have survived or not? It might have just bought the guys a few more minutes to get the jet on the ground. If that had been the case (and we will never know) does anyone still think its an 'acceptable risk'??
Safeware, your comments read like those of a polititian. Maybe you are one, I don't know. But I find some of your comments in bad taste, especially given the fact that Nimrod 4 is regarded as a 'new jet' by the those who will fly it. It now appears it will be using old parts and old technology, clearly a move to save on costs, and not using state of the art fire fighting kit. That is a shameful and unacceptable way to conduct things, but I suppose the bean counters will be rubbing their greasy little hands, pleased with themselves at having saved a few extra pounds for the asylum seekers, and not bothered that the lives of RAF aurcrew have been put in danger.
Thank God I'm no longer on the fleet.
KInd regards to all
TSM
Join Date: Mar 2006
Location: wilts
Posts: 1,667
Likes: 0
Received 0 Likes
on
0 Posts
Further to TSM's post a couple of thoughts. Firstly the Nimrod bomb bay is protected by fire extinguishant on certain occasions.
"Regarding the bomb bay fire extinguisher issue. The Nimrod has a 'trooping role' and in order to be used in that manner 6 extended range fuel tanks would be fixed in the bomb bay. With this fit 10 fire extinguishers would also be fitted. However, in the normal fit we do not have either the extended range tanks or the fire extinguishers fitted. That means that day to day there is no fire protection in the bomb bay. However, the bomb bay fire drill calls for all stores to be jettisoned, and to my knowledge there has only been one actual bomb bay fire in the life of the ac. This was caused by an electrical fault causing a flare to ignite when power was supplied to the weapons carrier."
I am sure it doesn't take the brains of a rocket scientist to work out how many would be required for an empty bomb bay.
Secondly, when the Nimrod was originally designed nobody expected it to do AAR. So, if AAR is the weakest link and it is not possible to safely protect the bomb bay then bloody well stop doing AAR and stop letting the likes of AOC2Gp overrule safety decisions.
Furthermore, if hot air is the likely reason for the ignition, (The theory has now been explained to me), TSM is quite correct in that some fire extinguishant may well habe bought the boys enough time to get the aircraft on the deck.
Finally, OBIGGS is a one shot system if it fails to put the fire out in the duration of the nitrogen charge, then the fire could come back. PROBIGGS is a constant nitrogen producing system. But guess what, it costs money.
"Regarding the bomb bay fire extinguisher issue. The Nimrod has a 'trooping role' and in order to be used in that manner 6 extended range fuel tanks would be fixed in the bomb bay. With this fit 10 fire extinguishers would also be fitted. However, in the normal fit we do not have either the extended range tanks or the fire extinguishers fitted. That means that day to day there is no fire protection in the bomb bay. However, the bomb bay fire drill calls for all stores to be jettisoned, and to my knowledge there has only been one actual bomb bay fire in the life of the ac. This was caused by an electrical fault causing a flare to ignite when power was supplied to the weapons carrier."
I am sure it doesn't take the brains of a rocket scientist to work out how many would be required for an empty bomb bay.
Secondly, when the Nimrod was originally designed nobody expected it to do AAR. So, if AAR is the weakest link and it is not possible to safely protect the bomb bay then bloody well stop doing AAR and stop letting the likes of AOC2Gp overrule safety decisions.
Furthermore, if hot air is the likely reason for the ignition, (The theory has now been explained to me), TSM is quite correct in that some fire extinguishant may well habe bought the boys enough time to get the aircraft on the deck.
Finally, OBIGGS is a one shot system if it fails to put the fire out in the duration of the nitrogen charge, then the fire could come back. PROBIGGS is a constant nitrogen producing system. But guess what, it costs money.
TSM
I’m sure Safeware can speak for himself, but what he says is undoubtedly true. Like most of us, he doesn’t make up the rules, but knows them inside out. And uses them positively, for your benefit.
It is the experience and dedication of people like Safeware, who are prepared to fight the beancounters and other sycophants, that provides you with aircraft that, invariably, exceed the required safety standards.
These standards are deemed satisfactory at the time. However, as technology progresses, new requirements emerge and legislation changes then it is quite a different thing to MAINTAIN safety and airworthiness through life. This needs significant investment but, as I have said before, is largely ignored by many in MoD who think it a waste of money. With respect, and I fully agree with most of what you say, your ire should be aimed at others.
Make no mistake, there are those in MoD, both Service and civilian, who don’t give a flying **** about you. They see ANY problem affecting Time or Cost, including safety and airworthiness, as a hindrance to their advancement. As for Performance, word has come down from on high that Customers (Sponsors and Users) must be prepared to trade out more performance (which MAY save on time and cost, but very often doesn’t). As performance includes safety and airworthiness, you would think this edict would carry a suitable caveat. It doesn’t. So, these people happily quote it and accept aircraft and equipment off-contract that don’t come within a country mile of the very minimum standard Safeware speaks of. Luckily, they are in the minority but, increasingly, hold senior posts. But luck shouldn’t come in to it. Successive generations have quickly learned how to get the ticks in boxes – and it’s most definitely NOT by sticking ones head above the parapet on issues like this.
I’m sure Safeware can speak for himself, but what he says is undoubtedly true. Like most of us, he doesn’t make up the rules, but knows them inside out. And uses them positively, for your benefit.
It is the experience and dedication of people like Safeware, who are prepared to fight the beancounters and other sycophants, that provides you with aircraft that, invariably, exceed the required safety standards.
These standards are deemed satisfactory at the time. However, as technology progresses, new requirements emerge and legislation changes then it is quite a different thing to MAINTAIN safety and airworthiness through life. This needs significant investment but, as I have said before, is largely ignored by many in MoD who think it a waste of money. With respect, and I fully agree with most of what you say, your ire should be aimed at others.
Make no mistake, there are those in MoD, both Service and civilian, who don’t give a flying **** about you. They see ANY problem affecting Time or Cost, including safety and airworthiness, as a hindrance to their advancement. As for Performance, word has come down from on high that Customers (Sponsors and Users) must be prepared to trade out more performance (which MAY save on time and cost, but very often doesn’t). As performance includes safety and airworthiness, you would think this edict would carry a suitable caveat. It doesn’t. So, these people happily quote it and accept aircraft and equipment off-contract that don’t come within a country mile of the very minimum standard Safeware speaks of. Luckily, they are in the minority but, increasingly, hold senior posts. But luck shouldn’t come in to it. Successive generations have quickly learned how to get the ticks in boxes – and it’s most definitely NOT by sticking ones head above the parapet on issues like this.
Join Date: Feb 2007
Location: Scotland
Age: 49
Posts: 134
Likes: 0
Received 0 Likes
on
0 Posts
I think maybe a crucial point is being missed here.
Spending money fitting fire protection to the Nimrod bomb bay MR2 or MRA4 is surely like buying a gold plated bucket to catch water from a leaking roof. Fix the roof and you don't need the bucket!!!
Stop the fuel escaping into the bomb bay in the first place and the need for bomb bay fire pretection is reduced. I accept that I have simplified the process slightly but surely fixing the source of the leak is a more sensible approach.
Spending money fitting fire protection to the Nimrod bomb bay MR2 or MRA4 is surely like buying a gold plated bucket to catch water from a leaking roof. Fix the roof and you don't need the bucket!!!
Stop the fuel escaping into the bomb bay in the first place and the need for bomb bay fire pretection is reduced. I accept that I have simplified the process slightly but surely fixing the source of the leak is a more sensible approach.
Join Date: Sep 2006
Location: Bridgwater Somerset
Posts: 459
Likes: 0
Received 0 Likes
on
0 Posts
Information Please
Could someone please please tell me where on a Nimrod MR2 is Fuel tank 7 fitted. I understand there have been problems in this area in the past.
Could someone please please tell me where on a Nimrod MR2 is Fuel tank 7 fitted. I understand there have been problems in this area in the past.
Join Date: Apr 2007
Location: lincoln
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
Its one fo the smallest tanks on the ac. In between the rear wing area and the fuselage (on both sides). If I can 2nd guess where you're referring to TD, and if memory serves me right, that was where the "seals were melted" (according to panorama tv) on XV227. The heat had had sufficient time to melt some of the PRC sealant in the starboard side 7 tank.
Hope this helps
Hope this helps
Join Date: Jun 2007
Location: Moray
Age: 58
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
TD, the area shown on 227 was the ground air start panel, a facility to connect a ground air starter trolley for engine starting if the aircraft's own auxilliary power unit (APU) has failed for any reason. it utilises the same ducting that the tailpack conditioning unit uses (used, now not in use!) to feed air forward. 7 tank starboard is effectively just above this panel, sandwiched in the wing-root between the fuselage and the number 3 engine jet-pipe. There is a full metal rib between the jet pipe and tank though, with a suitable airspace either side of it, and fire detection "firewire" on the jet-pipe side of the rib, indicated as No.3 Zone 2. This area has 2 shots of fire extinguishant available to it if required.
DV, MRA2 - Maritime Reconnaisance and Attack, indeed. It is (was!) a submarine hunter-killer!
Thunderbird7, it's not farcical that there was never a bomb-bay fire extinguishant system, at the time the aircraft was designed there was no system available that could deliver a sufficient volume without causing an unacceptable weight/space penalty in the eyes of the designers. There are various types of system available today, I don't deny that, but at what price? The MOD won't spend that ammount on something that's about to go out of service, but that doesn't excuse the lack of such a system on the MR4, in my opinion.
The "Range extension tanks" referred to previously have never, to the best of my knowledge, ever been fitted to an in-service aircraft. In fact, I can guarantee they have never physically existed at ISK from 1985 to the present day. I did hear that they existed (2 sets only) at Warton in the late 80's.
As for tonnes of fuel in the bomb-doors, it has happened before and will no doubt happen again. I have personal experience.
DV, MRA2 - Maritime Reconnaisance and Attack, indeed. It is (was!) a submarine hunter-killer!
Thunderbird7, it's not farcical that there was never a bomb-bay fire extinguishant system, at the time the aircraft was designed there was no system available that could deliver a sufficient volume without causing an unacceptable weight/space penalty in the eyes of the designers. There are various types of system available today, I don't deny that, but at what price? The MOD won't spend that ammount on something that's about to go out of service, but that doesn't excuse the lack of such a system on the MR4, in my opinion.
The "Range extension tanks" referred to previously have never, to the best of my knowledge, ever been fitted to an in-service aircraft. In fact, I can guarantee they have never physically existed at ISK from 1985 to the present day. I did hear that they existed (2 sets only) at Warton in the late 80's.
As for tonnes of fuel in the bomb-doors, it has happened before and will no doubt happen again. I have personal experience.
Join Date: Mar 2006
Location: wilts
Posts: 1,667
Likes: 0
Received 0 Likes
on
0 Posts
TD, I have been informed from various sources that XV230 suffered a wing root fire before the explosion. It would fit with a problem with tank 7. Further to Sooty's post, there is no reason why MRA4 could not have a fire extinguishant for the bomb bay. The bomb bay in MRA4 is now split into 2. So in theory you could have 1 extinguishing systen covering both bomb bays. All it needs is money and time to test. Something the RAF Top Brass don't appear to have. All hangs on the BoI now, because the RAF does not do "Top Brass" leadership any more.
Join Date: Aug 2004
Location: The US of A, and sometimes Bonnie Scotland
Posts: 549
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: Jul 2002
Location: somewhere, under the rainbow
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Having come late to this thread, a few comments on the recent posts I've managed to read:
"that MR4 should be made as safe a is humanly possible for todays standards"
Well, it'll never fly then. That'll be as safe as we can make it! The best you can hope for is as safe as is reasonably practicable. That puts it into a judgement call of what you can reasonably do, and indeed what is reasonable.
"OBIGGS is a one shot system if it fails to put the fire out in the duration of the nitrogen charge....,"
Err... not quite. It Generates the Inert Gas over a period and once the required concentration is reached it should prevent a fire from starting. If the volume, e.g. bomb bay is so leaky, which it sounds like it is, that you can't build up the N2 content, then you'll never prevent a fire, which would be agood reason for not trying to use it in that environment. There are however several other systems relying on other extinguishants which could be used in that sort of environment and could be activated very (very) quickly by flame detectors or not quite so quickly by firewires.
However although I have to agree that fuel shouldn't be leaking in the first place, it should be a risk that is foreseen and measures put in place to deal with it....if these are reasonably practible.
"that MR4 should be made as safe a is humanly possible for todays standards"
Well, it'll never fly then. That'll be as safe as we can make it! The best you can hope for is as safe as is reasonably practicable. That puts it into a judgement call of what you can reasonably do, and indeed what is reasonable.
"OBIGGS is a one shot system if it fails to put the fire out in the duration of the nitrogen charge....,"
Err... not quite. It Generates the Inert Gas over a period and once the required concentration is reached it should prevent a fire from starting. If the volume, e.g. bomb bay is so leaky, which it sounds like it is, that you can't build up the N2 content, then you'll never prevent a fire, which would be agood reason for not trying to use it in that environment. There are however several other systems relying on other extinguishants which could be used in that sort of environment and could be activated very (very) quickly by flame detectors or not quite so quickly by firewires.
However although I have to agree that fuel shouldn't be leaking in the first place, it should be a risk that is foreseen and measures put in place to deal with it....if these are reasonably practible.
I think I've explained things in a simple enough manner, if any more is needed, I'm glad to help.
sw
sw
It would be fair to suggest that the risk methodology you outline is considered best practice in safety & engineering circles. Those who mock it should understand that in doing so they are therefore destroying their own credibility.
Any here actually KNOW if you could put effective fire supressant technology into a hugh drafty space like the nimrod bomb bay and what it would take? Intuitively it sounds totally impractical to me, though it would be interesting to know how it could be done (if at all).
Thread Starter
Join Date: Mar 2007
Location: Bristol Temple Meads
Posts: 869
Likes: 0
Received 0 Likes
on
0 Posts
Sorry BS, am I missing something? Your link simply supports my statement "The main roles (MRA 4 implied) are, maritime reconnaisance, anti sub warfare and SAR". Not much of that in Iraq and Afghanistan situations.
DV
DV
Join Date: Aug 2004
Location: The US of A, and sometimes Bonnie Scotland
Posts: 549
Likes: 0
Received 0 Likes
on
0 Posts
DV
You asked why the A. I pointed you in the right direction. Whilst the Nimrod's job, at present, does not qualify as attack, that's not to say the MRA4 role may be exactly the same as the MR2. Way back, when the contract was in its infancy, its fair to say that attack may have, and may will be in the future, an aspiration. Who can predict the world's affairs in a number of years. Almost impossible to say. Hence, there may be an aspiration to use it in that role, maybe not. It may be comforting to believe that there lies some forethought in this decision making.
Its also not unreasonable to understand that the world is a changed place since the contract was drawn up. But that's not to say MRA4 will not be involved in these roles you point out. Flexibility, etc, etc.
You asked why the A. I pointed you in the right direction. Whilst the Nimrod's job, at present, does not qualify as attack, that's not to say the MRA4 role may be exactly the same as the MR2. Way back, when the contract was in its infancy, its fair to say that attack may have, and may will be in the future, an aspiration. Who can predict the world's affairs in a number of years. Almost impossible to say. Hence, there may be an aspiration to use it in that role, maybe not. It may be comforting to believe that there lies some forethought in this decision making.
Its also not unreasonable to understand that the world is a changed place since the contract was drawn up. But that's not to say MRA4 will not be involved in these roles you point out. Flexibility, etc, etc.