RAF to scrap twin-seat Typhoons
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Broadly correct in terms of total fleet costs, but probably not in this case.
The costs of operating a bespoke bunch of 2 seater Typhoons must be considerably greater than the very (relatively) simple Hawk T1. twice the number of engines, hugely increased fuel burn and so forth.
There are sufficient spare Hawk frames to maintain the Reds up to the OSD. Not so with this finite number tranche1 2 seat Typhoons ?
The costs of operating a bespoke bunch of 2 seater Typhoons must be considerably greater than the very (relatively) simple Hawk T1. twice the number of engines, hugely increased fuel burn and so forth.
There are sufficient spare Hawk frames to maintain the Reds up to the OSD. Not so with this finite number tranche1 2 seat Typhoons ?
Ignorance on your part does not constitute a crisis on mine.
PDR
Last edited by PDR1; 1st Feb 2018 at 07:01.
I'm with Rhino power on this! Those who use words such as 'stochastic' in everyday speech are the sort of people who use biz-speak drivel such as "And, if we actually think outside the box and facilitate an idea shower with stakeholders, taking action forward together, we must be able to develop the holistic, cradle-to-grave approach of our challenges. Perhaps if we touch base offline and conversate the pre-plan when you have a window. Remember, my door is open on this issue, I’m still optimistic that, working with our strategic partners, the issues and challenges will feed through the service delivery pipeline."
Disagree stochastic is a precise term that would never get used in management speak. Of course with such a high percentage of RAF on here maybe it's best to limit the vocabulary to the level of a Janet and John book.
I'm with Rhino power on this! Those who use words such as 'stochastic' in everyday speech are the sort of people who use biz-speak drivel such as "And, if we actually think outside the box and facilitate an idea shower with stakeholders, taking action forward together, we must be able to develop the holistic, cradle-to-grave approach of our challenges. Perhaps if we touch base offline and conversate the pre-plan when you have a window. Remember, my door is open on this issue, I’m still optimistic that, working with our strategic partners, the issues and challenges will feed through the service delivery pipeline."
Not knowing something isn't a crime - it just creates an opportunity to look it up and expand your understanding of the world around you. The crime is having such a blinkered outlook that when you encounter something you haven't seen before you start jeering and bleating to mummy about the nasty man who is using words that aren't found in the vocabulary of one with a single-digit reading age.
So the "crime" is being "actively ignorant" - childishly refusing to learn stuff.
PDR
Anyway, whether stochastic or not, I think I conclude on balance that the loss of a few Tranche 1 twin stick airframes doesn't make it onto my current list of most-worrying defence issues.
I do just wonder if the remaining pool of airframes, especially the 100 or so Tranche 2 and 3s, is quite big enough to rotate them through the front line out to 2040. Once upon a time there might have been a prospect of a small top up batch, but possibly not in the current climate.
I do just wonder if the remaining pool of airframes, especially the 100 or so Tranche 2 and 3s, is quite big enough to rotate them through the front line out to 2040. Once upon a time there might have been a prospect of a small top up batch, but possibly not in the current climate.
I'm with Rhino power on this! Those who use words such as 'stochastic' in everyday speech are the sort of people who use biz-speak drivel such as "And, if we actually think outside the box and facilitate an idea shower with stakeholders, taking action forward together, we must be able to develop the holistic, cradle-to-grave approach of our challenges. Perhaps if we touch base offline and conversate the pre-plan when you have a window. Remember, my door is open on this issue, I’m still optimistic that, working with our strategic partners, the issues and challenges will feed through the service delivery pipeline."
Run that one up the flagpole and see how it flies.
A huge expense in EVER having a twin seat version in the first place. It was only done because no one had the guts or the hard evidence to prove that the synthetics would be good enough to meet the modern safety case.
Oh, and to allow certain of the high priced help to get to fly it without putting in the hard hours (and clogging) ground school.....
Oh, and to allow the marketing campaigns a chance to do the same.
Tarnished
Oh, and to allow certain of the high priced help to get to fly it without putting in the hard hours (and clogging) ground school.....
Oh, and to allow the marketing campaigns a chance to do the same.
Tarnished
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Stochastic or Not?
Perhaps I can help a bit here. (I'm an engineer, too).
I'd agree (sorry PDR1) that using the word 'stochastic' is really asking a bit too much of the average pilot. As an engineer, I always made sure that when I was explaining technical matters to ANY audience, I did so in a way that they could understand. That said, there's never any excuse for lack of manners and sarcasm, from either side. Forums like PPrune should be informal, but rude? No.
Actually, I had to look up 'stochastic', and I got this (fairly clear) definition:
Situations or models containing a random element, hence unpredictable and without a stable pattern or order. All natural events are stochastic phenomenon. And businesses ... are stochastic systems because their internal environments are affected by random events in the external environment. Stochastic is often taken to be synonymous with probabilistic but.... stochastic conveys the idea of (actual or apparent) randomness whereas probabilistic is directly related to probabilities and is therefore only indirectly associated with randomness.
So, as I read it, 'stochastic' refers to random events, as opposed to 'probable' events. However, that does rather cut across PRD1's statement that:
'...the foundation of all the analyses is reliability data, and reliability data is statistical*, based on the probability of events occurring in fleets over large numbers of missions/years or whatever.'
I absolutely agree with PDR1 on that last statement. Where I would, very respectfully, part with him would be an assertion that an ILS/LSA analysis is 'stochastic'. In my experience, it's normally probability based, but if the newer analyses have found a way to include randomness then, hey, fill yer boots.
OK, explanation for non-experts (like me). Any ILS/LSA analysis for a new aircraft (or any new system) has to use a large number of assumptions and predictions, particularly those associated with anticipated usage and the predicted reliability of components and systems. So here's the unvarnished truth - any initial spares/support package is liable to be really, really wrong. What smart project managers do is take the output from from ILS/LSA analyses and apply a good stiff dose of common sense to it. Then ensure that when the stuff enters service, it is subjected to formal fault reporting, with a comprehensive 'blacklist' to make sure that key (high cost and/or mission critical) components assessed as U/S are properly investigated to find out what went wrong.
Then, they regularly adjust their support/spares packages to make sure that what they're sending to the front line matches what is actually happening. Here's the problem. Many PMs now working in DE&S don't even know what a 'blacklist' is, never mind a defect reporting form. So kit enters service without the essential feedback loop to adjust the spares provisioning. This is not an opinion, I've seen it happen on multiple (and recent) programmes.
To the subject. Dismantling aircraft for spares is only ever economic when you have surplus aircraft you don't need any more. And even then it's marginal, given the costs to actually remove the kit, get it reconditioned and certified, repackaged and reloaded on to the ILS system. Oh, and the parts you get out of this process are 'part lifed', unless you pay for them to be reset to zero hours. That said, given the state of the MoD budgets these days, even a marginal pay back is worth it. Yeah, strip the mothers.
This also shows that the Typhoon fleet is now too big for the job it's now required to do. The T1 buy was probably driven by the same 'broad brush' (i.e. bum) calculations I saw being used to justify Harrier T10 numbers on JFH. That, plus a realisation that sim hours can be far more useful that burning holes in the sky (or providing a handy 'hack' for the CO to fly around in).
Best regards as ever to all those juggling the fleets, it's never easy with less money,
Engines
I'd agree (sorry PDR1) that using the word 'stochastic' is really asking a bit too much of the average pilot. As an engineer, I always made sure that when I was explaining technical matters to ANY audience, I did so in a way that they could understand. That said, there's never any excuse for lack of manners and sarcasm, from either side. Forums like PPrune should be informal, but rude? No.
Actually, I had to look up 'stochastic', and I got this (fairly clear) definition:
Situations or models containing a random element, hence unpredictable and without a stable pattern or order. All natural events are stochastic phenomenon. And businesses ... are stochastic systems because their internal environments are affected by random events in the external environment. Stochastic is often taken to be synonymous with probabilistic but.... stochastic conveys the idea of (actual or apparent) randomness whereas probabilistic is directly related to probabilities and is therefore only indirectly associated with randomness.
So, as I read it, 'stochastic' refers to random events, as opposed to 'probable' events. However, that does rather cut across PRD1's statement that:
'...the foundation of all the analyses is reliability data, and reliability data is statistical*, based on the probability of events occurring in fleets over large numbers of missions/years or whatever.'
I absolutely agree with PDR1 on that last statement. Where I would, very respectfully, part with him would be an assertion that an ILS/LSA analysis is 'stochastic'. In my experience, it's normally probability based, but if the newer analyses have found a way to include randomness then, hey, fill yer boots.
OK, explanation for non-experts (like me). Any ILS/LSA analysis for a new aircraft (or any new system) has to use a large number of assumptions and predictions, particularly those associated with anticipated usage and the predicted reliability of components and systems. So here's the unvarnished truth - any initial spares/support package is liable to be really, really wrong. What smart project managers do is take the output from from ILS/LSA analyses and apply a good stiff dose of common sense to it. Then ensure that when the stuff enters service, it is subjected to formal fault reporting, with a comprehensive 'blacklist' to make sure that key (high cost and/or mission critical) components assessed as U/S are properly investigated to find out what went wrong.
Then, they regularly adjust their support/spares packages to make sure that what they're sending to the front line matches what is actually happening. Here's the problem. Many PMs now working in DE&S don't even know what a 'blacklist' is, never mind a defect reporting form. So kit enters service without the essential feedback loop to adjust the spares provisioning. This is not an opinion, I've seen it happen on multiple (and recent) programmes.
To the subject. Dismantling aircraft for spares is only ever economic when you have surplus aircraft you don't need any more. And even then it's marginal, given the costs to actually remove the kit, get it reconditioned and certified, repackaged and reloaded on to the ILS system. Oh, and the parts you get out of this process are 'part lifed', unless you pay for them to be reset to zero hours. That said, given the state of the MoD budgets these days, even a marginal pay back is worth it. Yeah, strip the mothers.
This also shows that the Typhoon fleet is now too big for the job it's now required to do. The T1 buy was probably driven by the same 'broad brush' (i.e. bum) calculations I saw being used to justify Harrier T10 numbers on JFH. That, plus a realisation that sim hours can be far more useful that burning holes in the sky (or providing a handy 'hack' for the CO to fly around in).
Best regards as ever to all those juggling the fleets, it's never easy with less money,
Engines
Blimey and there's me thinking for years that ILS stands for Instrument Landing System!
My late F-i-L was an engineer at RAE Farnborough, or Boffin as I used to call him. He didn't have much of a sense of humour either - seems to be an engineer characteristic according to TP son at Airbus!
My late F-i-L was an engineer at RAE Farnborough, or Boffin as I used to call him. He didn't have much of a sense of humour either - seems to be an engineer characteristic according to TP son at Airbus!
Ecce Homo! Loquitur...
Brian, exactly what I thought the first time I heard ILS in a Systems Engineerung environment - now I are one....
I can recall being told by an engineer that when describing FMICW to pilots, when it got to the parts when they processing involved processes such as fast Fourier transforms he tended to describe it as as FM (f***ing magic) or WMM.....
I'd agree (sorry PDR1) that using the word 'stochastic' is really asking a bit too much of the average pilot. As an engineer, I always made sure that when I was explaining technical matters to ANY audience, I did so in a way that they could understand.
1. The "infanty mortality" phase - early failures are presumed to be mostly due to manufacturing defects, and the probability of a manufacturing defect remaining present in-service decreases exponentially with time/usage/cycles etc. That's actually the technical purpose of burn-in testing (aka "Production Reliability Acceptance Testing"*)- to get the item through the infant mortality phase so that the probability of manufacturing defects remaining was acceptably low.
2. The "Wear-out" phase - the back end of the item's life when stuff is starting to exhibit wear/degradation. The probability of this happening is exponential with respect to time/cycles/usage etc. There are types of equipment that don't have a wear-out characteristic, but they are much rarer than most people think.
3. The bit between the two which is misleadingly called the "constant failure rate" phase. In this phase you expect to see a failure rate which looks fairly similar when measured over a long enough period - failures per year, failures per 100,000 cycles or whatever, so that when plotted it looks like a flat(ish) line. In this period we say the failures are "random" when what we actually mean is "the time between each failure is random". The total time covering any 100 failures may be a nearly constant figure, but those 100 failures will be randomly clustered into clumps rather than being evenly-spaced through the period.
All three of these phases model well using the exponential probability distribution. So we have an initial exponentially decreasing phase, then a flat-line phase, then an exponentially increasing phase. The probability of a failure at any time is given by the sum of the three phases, and when you sum the three probability densities you get a plot that looks like a bathtub (the infamous "reliability bathtub curve" - that's where it comes from).
HTH,
PDR
* yes, we do know what that looks like as an acronym. Blame the Americans - they put it in the mil-spec
A huge expense in EVER having a twin seat version in the first place. It was only done because no one had the guts or the hard evidence to prove that the synthetics would be good enough to meet the modern safety case.
Oh, and to allow certain of the high priced help to get to fly it without putting in the hard hours (and clogging) ground school.....
Oh, and to allow the marketing campaigns a chance to do the same.
Tarnished
Oh, and to allow certain of the high priced help to get to fly it without putting in the hard hours (and clogging) ground school.....
Oh, and to allow the marketing campaigns a chance to do the same.
Tarnished
Again, a stop could have been made at production ordering, but was their sufficient confidence in simulator training then?
As a counter, the US decided around the same time not to develop a two seat version for the F-22.
In some ways, the issue is compounded by the fact these 16 aircraft were intended to be a much smaller part fo the Typhoon fleet than they are, when our original buy was scheduled to be 230 aircraft