Incident at Castle Martin 14-06-2017

Caecilius

LE
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To date the only Challenger destroyed by incoming tank fire was one hit by the fire of another Challenger.

FFS, you're advocating a flapper's charter.
That's the second time you've accused people of flapping because they've decided to return fire faster. Given that you haven't faced incoming fire from opposing armour (or from anything?), I suggest you get back in your f*cking box and stop judging soldiers who have.

Probably the major reason CR2 hasn't been destroyed is because we managed to hit opposing tanks faster than they could hit ours. Hits from the wrong angle from almost any main armament will comfortably K Kill any tank in the world, no matter how much applique armour you bolt to the front so increased rate of fire increases survivability.

Safety angle prescribed by SASC is a 'training only' safety rule., governing where you point the weapon, not how you operate it.
The argument I was responding to was the suggestion that safety standards should apply equally on ops and training. Where you're allowed to point your weapon is a clear instance where that standard differs.
 
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Caecilius

LE
Kit Reviewer
Book Reviewer
Well.. there are only so much you can do IMHO.. as the man says, and with no intention or wish to malign the dead.. "It is impossible to make things foolproof, as fools are so ingenious". This episode in my opinion comes into the same category as inspecting fuel levels with a lighter or playing Russian roulette with an automatic pistol..
I'm inclined to agree with this. The guys in question were experienced gunnery instructors so they will have been told not to store bag charges outside the bins countless times and will have releatedly instructed students on the correct stowage. People will choose to ignore safety rules and do things they know they shouldn't - sometimes that will be justified, sometimes it won't.

In this case they did something that carries a tiny risk of going wrong, but tragically did so on one of the occasions where another event realised that risk.
 
In a previous life in a quaint Scottish town, I worked on an experimental version of the gun prior to it's issue as the L30 CHARM system.

The vertical breech mechanism consists of a beautiful and marvellously engineered split sliding-block breech mechanism.

For them that's unfamiliar, the upper sliding block holds the obturation assembly, comprising a bolt vent axial (BVA) and an obturator ring. Those of you familiar with the neoprene obturator pad on an M109 will be able to visualise the similarity.

The BVA is basically a mushroom shape; the stem of the mushroom goes through the front face of the vertically sliding breech block and a counterbore machined into the end of the stem of the BVA provides a chamber where the live vent tube is loaded.

So in effect, the obturator ring is fitted under the mushroom head of the BVA and provides a rearward seal during combustion of the propellant in the main charge. Back in the day, each MBT had two serial numbered sets of obturators on board.

Action;
When the breech is closed, the upper block travels upwards and forwards due to the forward-sloping sliding grooves in the breech ring. During it's last movement, the upper breech block secures the BVA and obturator ring into a tapered seating at the end of the chamber. The upper block is locked for firing after the lower breech block travels upwards, wedging itself between the inner rear face of the breech ring and the rear face of the upper block. The sound is a delightfully unforgettable thunk-kerchunk.

The ammunition system is made up of three parts; projectile, main charge and combustion is initiated by means of an electrically fired vent tube. The vent tubes are magazine-fed and automatically fed into the rear of the BVA. On firing, the vent tube is expelled into the firing hole bored concentrically down the centre of the BVA, igniting the primer pad on the rear end of the main charge.

As combustion of the main charge occurs, force is applied to the front face of the BVA. The BVA is forced rearwards and squeezes the obturator to an extent that it makes a perfect seal between the firing chamber and atmosphere, encouraging all pressure behind the projectile, which now commences it's forward travel down the barrel.

I hope my dusty recollection will be of use to those that have an interest in things mechanical. More so, I sincerely hope that someone more enlightened than I will reveal the solution to the original dilemma of being able to make ready the experimental gun without an obturator ring in place and how it was overcome. Particularly in a training environment where, in maybe a competetive moment, a young thruster hurriedly assumes that soomcoont has fitted the obturator.

Anyways, the countryside and fishing in the quaint Scottish town were amazing. Being an excellent shot, I put my name down to take part in the annual unit shooting competition. Against the advice of my comrades and in true spirit of admiration for the Emperor himself, I happened to beat the donkey-walloping if-you-ain't-cav-you-ain't Colonel. Shortly after, I was made up on posting back to the fatherland, bockholz and zenf. Happy with that.
 
The yanks have very strange drills, as anyone will attest if they have experienced the US Marines CQB drills from the 90's "I'm the rabbit, I'm the rabbit, long wall, long wall" as he leads a caterpillar of 6 guys into the house. Thank fvck bad guys don't use grenades.
I'm watching some yanks do some house clearances at this very moment. It's quite entertaining and clearly they have a massive budget for blank ranks.
 
I have the feeling that the real problem here is that the coroner, under what pressure I know not, has come to a technical conclusion that it was an equipment "design fault"!
Most weapons simply won't fire if you miss a bit out; this one did so it is a design fault in that sense.

I found myself wondering how many other times crews have fired the gun without the BVA fitted; realised afterwards and gone "oh ****" and then chalked it up to experience, rather than embarrass themselves by asking an armourer "how the **** was that possible"?
 
Action;
When the breech is closed, the upper block travels upwards and forwards due to the forward-sloping sliding grooves in the breech ring. During it's last movement, the upper breech block secures the BVA and obturator ring into a tapered seating at the end of the chamber. The upper block is locked for firing after the lower breech block travels upwards, wedging itself between the inner rear face of the breech ring and the rear face of the upper block. The sound is a delightfully unforgettable thunk-kerchunk.

The ammunition system is made up of three parts; projectile, main charge and combustion is initiated by means of an electrically fired vent tube. The vent tubes are magazine-fed and automatically fed into the rear of the BVA. On firing, the vent tube is expelled into the firing hole bored concentrically down the centre of the BVA, igniting the primer pad on the rear end of the main charge.

As combustion of the main charge occurs, force is applied to the front face of the BVA. The BVA is forced rearwards and squeezes the obturator to an extent that it makes a perfect seal between the firing chamber and atmosphere, encouraging all pressure behind the projectile, which now commences it's forward travel down the barrel.
.
Thanks for that, I was wondering about the differences between Chief/Chall.
 
My point is that the enquiry seems to have come down on the side of "equipment design fault" as the cause, when in fact the incident was the direct result of the equipment not being prepared or inspected correctly..

I would be interested to know of any other BL breech mechanism that prevents the gun being fired as a result of a missing component.. I know the old Chieftain breech ( I forget the L number) had a blow out pin that stopped the breech closing if there was an excessive gas leak on the first obturating ring, but this was because this could happen during normal use and had an override facility if needed. It would not AFAIK, prevent the breech closing or the gun firing if the obturator was not actually fitted...!

Guns are by definition, dangerous, pressure bearing bits of equipment. You are meant to do function checks before firing on all types of weapon to ensure they are fit for use. We are at least three or four generations away from QF tank gunnery and one would expect the function of the BL MBT armament to be well understood.

Obviously not..!

My worry is that attention will now swing towards a hardware based solution to this specific issue, which will no doubt come up with an elegant (and probably extremely expensive!) solution. What concerns me is that it will not actually address the real problem which is more to do with people rather than equipment, and in the turret rather than with the chain of command.

This tragic incident may just get through the thick skulls of those who have allowed their professionalism to slide, and act as a marker for the future! Whatever the learned Coroner thinks, or says, this should never have happened, and we all know that the Emperor got paid this time...!

Don't let it happen again.. never ever forget that living is optional!
 
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I have the feeling that the real problem here is that the coroner, under what pressure I know not, has come to a technical conclusion that it was an equipment "design fault"!

Well.. there are only so much you can do IMHO.. as the man says, and with no intention or wish to malign the dead.. "It is impossible to make things foolproof, as fools are so ingenious". This episode in my opinion comes into the same category as inspecting fuel levels with a lighter or playing Russian roulette with an automatic pistol..

And so we leap into another set of unintended consequences..
Most weapons simply won't fire if you miss a bit out; this one did so it is a design fault in that sense.

I found myself wondering how many other times crews have fired the gun without the BVA fitted; realised afterwards and gone "oh ****" and then chalked it up to experience, rather than embarrass themselves by asking an armourer "how the **** was that possible"?
did they have access to the design documents run on the weapon or any of the other studies done whilst writing procedures etc.?

when i first heard about this i was surprised that the weapon could be fired in a configuration which could potentially kill the crew but thinking about it i assumed that some form of HAZOP activity would've identified the issue and stated that procedures would be used to mitigate the risk. if this is the case then it is not a fault with the design.

if the design team failed to identify that the weapon could be fired in such a configuration then they should be in the dock themselves...
 
That's the point it is either acceptable or not, this 'it's OK on Ops but not in training' does not make sense. It is either highly dangerous or it is not.
Depends on the risks you face. That doesn't just apply to tanks.
 
if the design team failed to identify that the weapon could be fired in such a configuration then they should be in the dock themselves...
Totally unrelated to tanks but on topic as a design fault
I was tasked with solving an issue that suddenly occurred on a Helicopter
The PTT in emergency mode stayed live
Further investigation revealed that it was also transmitting on the un selected radio.

It was a Design integration error - The safety case had revealed (at 5 mins to midnight) the I/C System MTBF didn't meet the CAA requirements . As a result an emergency bypass switch panel was installed (existing design as the other OEM installed radio type used on the rest of the fleet didn't conform either) .
In this hurried redesign nobody noticed theyed cocked up and set up 2 earth paths in emergency.

Almost 3 years later the fault manifested itself -
Since the system was tested on installation and tested at least once annually + whenever a modification affected the comms system - it caused some confusion.
It transpired we had a new mechanic and he had followed the test procedures - rather than do it the way everyone knew by heart as applicable to the rest of the fleet.

3 years a potentially serious fault - admittedly a mistake by design - was missed because others down the chain failed to follow the procedures produced by design that would have revealed it.

Quite possibly here peoples prior adherence to good procedure enabled the fault to go unremarked for so long.

It does seem a strange oversight to not test and ensure it cant be operated without it fitted - I wonder if it was, but the OEM design test procedure itself or the manner it was conducted was flawed.


As an aside I had the joy of explaining to my superiors why a decision made before I joined the company was made and why they would connect the system up as they did (including the error)
All the more challenging as - They didn't intend to it was a mistake wasn't an acceptable answer - but was the only conclusion possible.
 
Totally unrelated to tanks but on topic as a design fault
I was tasked with solving an issue that suddenly occurred on a Helicopter
The PTT in emergency mode stayed live
Further investigation revealed that it was also transmitting on the un selected radio.

It was a Design integration error - The safety case had revealed (at 5 mins to midnight) the I/C System MTBF didn't meet the CAA requirements . As a result an emergency bypass switch panel was installed (existing design as the other OEM installed radio type used on the rest of the fleet didn't conform either) .
In this hurried redesign nobody noticed theyed cocked up and set up 2 earth paths in emergency.

Almost 3 years later the fault manifested itself -
Since the system was tested on installation and tested at least once annually + whenever a modification affected the comms system - it caused some confusion.
It transpired we had a new mechanic and he had followed the test procedures - rather than do it the way everyone knew by heart as applicable to the rest of the fleet.

3 years a potentially serious fault - admittedly a mistake by design - was missed because others down the chain failed to follow the procedures produced by design that would have revealed it.

Quite possibly here peoples prior adherence to good procedure enabled the fault to go unremarked for so long.

It does seem a strange oversight to not test and ensure it cant be operated without it fitted - I wonder if it was, but the OEM design test procedure itself or the manner it was conducted was flawed.


As an aside I had the joy of explaining to my superiors why a decision made before I joined the company was made and why they would connect the system up as they did (including the error)
All the more challenging as - They didn't intend to it was a mistake wasn't an acceptable answer - but was the only conclusion possible.
i dont disagree that things can get missed (swiss cheese effect) but it seems strange to me that you have a safety critical component (which has been identified as such) and that there is then no consideration given to what might happen if the equipment is operated without that component.

i'd have expected the ye olden day version of the safety case to pick that up.
 
i dont disagree that things can get missed (swiss cheese effect) but it seems strange to me that you have a safety critical component (which has been identified as such) and that there is then no consideration given to what might happen if the equipment is operated without that component.

i'd have expected the ye olden day version of the safety case to pick that up.
I agree
As I said - its odd to miss something so fundamental - Its removed (frequently?) its safety critical the next logical step is can it be inadvertently operated if its out.
Im struggling to believe the question wasn't asked - so can only conclude that the answer was determined to be no it cant.
 
I agree
As I said - its odd to miss something so fundamental - Its removed (frequently?) its safety critical the next logical step is can it be inadvertently operated if its out.
Im struggling to believe the question wasn't asked - so can only conclude that the answer was determined to be no it cant.
If it’s been identified and then ignored then that’s criminal negligence and the designer should be in court on corporate manslaughter.

My suspicion is that the coroner has stated it as a design flaw when in fact, if it’s decided to mitigate via procedure, it’s not a design flaw but the fault of those following the procedures themselves.

Is like blaming the claymore for injuring yourself when you didn’t read what was written on the front.

I’d better wind my neck in and do read the full statement if I’m going to continue this line of argument.....

Poor bastards at any rate.
 
@Swamp_Rat, assuming the experimental L30 CHARM gun you worked on and the in service L30 on mounted on CR2 are the same, how would you have envisaged the firing sequence of the gun working given the absence of the BVA? Your description seems to indicate that the vent tube is fed into the rear of the BVA so in its absence what happens, and how are the firing circuits made? Or is the BVA not used in the manner i am imagining.

I have scoured the internet for illustrations and or videos showing the various components and loading sequences with no luck.
 
On ops it might be necessary to do something risky that you wouldnt do in training. For example the paras ditched their body armour on Herrick 4 (It's been mentioned on here before) because they favoured mobility over protection (and because they are lazy *******) would would ditch body armour when we are doing live training in the UK, not unless the CO didn't care about his career. Maybe on Ops the tankies need speed to load their guns.
 
On ops it might be necessary to do something risky that you wouldnt do in training. For example the paras ditched their body armour on Herrick 4 (It's been mentioned on here before) because they favoured mobility over protection (and because they are lazy *******) would would ditch body armour when we are doing live training in the UK, not unless the CO didn't care about his career. Maybe on Ops the tankies need speed to load their guns.
Not disputing that but I bet that was a CoC decision
 
My point is that the enquiry seems to have come down on the side of "equipment design fault" as the cause, when in fact the incident was the direct result of the equipment not being prepared or inspected correctly..

I would be interested to know of any other BL breech mechanism that prevents the gun being fired as a result of a missing component.. I know the old Chieftain breech ( I forget the L number) had a blow out pin that stopped the breech closing if there was an excessive gas leak on the first obturating ring, but this was because this could happen during normal use and had an override facility if needed. It would not AFAIK, prevent the breech closing or the gun firing if the obturator was not actually fitted...!!


I am glad to say that my memory didn't fail me. I found the turret manual online, this is the appropriate page.


View attachment 341491
 
Bone question,not a wah,I only served on Centurion,with the breech open,is it possible to see BVA is not fitted?
 
As I said to 21st, I'm not referring to regulations. It's just something that can be done if the crew wants to. It's an option available to them, just like firing within safety margin is an option available to the infantry.
No it can’t and no it’s not.

It may have occurred many years ago, but it doesn’t make it right. It’s stupid, it’s dangerous and it causes this kind of thing to happen.
 

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