Ash clouds threaten air traffic
The Reverend
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The reason being that we avoided flying in visible volcanic ash. Airmanship.
Last edited by HotDog; 25th Apr 2010 at 12:16.
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Hot Dog
So if somebody flew into the Icelandic volcanic cloud at night, it would have been OK?
The problem is that UK airspace was closed down for an ash cloud that could not be seen 1000 miles from the eruption.
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Why is there a persistent removal of posts from anyone who comments that the ill effects of ash have always involved 'visible' ash clouds (sometimes not appreciated or seen due to night - but always sufficiently dense to by visible or obscure stars)?
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I'm still amazed at the IMO totally unbalanced view so many are taking about this whole thing. I also accept that I am heavily leaning in a particular direction too and am at risk of being blind to the inaccuracies of my own logic. But, I have heard it stated more than a few times that previous ash encounters have not resulted in a single accident and even the ones that included engine flamouts, had engines sucessfully restarted and a safe landing completed.
Imagine a design fault which had caused over reported 100 incidents (and likely many more unreported) leading to damage and a combined total of hundreds of millions of dollars in reapir bills. One year alone had 23 incidents. 7 incidents involved engine failure including two with all engine loss but none resulted in accidents. The occurence of the issue could be loosely forecast but it was difficult to narrow down the exact conditions under which it would occur. The fact that 100 issues had occured at all suggests that inadvertent and unexpected recurrence was both possible and likely. Are you really telling me that the public and the industry would accept an amendment to the regulations to allow continued flight of affected aircraft as long as they don't enter flight conditions which were already known to guarantee the problem would arise? And all because the industry itself was compaining that they would lose money and risk collapse if they were not allowed fly?
Of course not. The authorities would be firm and insist that the manufacturer(s) involved do something about it immediately, and would only allow flight if they were sastified, using hard proof from tests and unquestionable technical confirmation that the issue had been resolved or at least could be guaranteed to not recur under all but the most rare and easily avoidable conditions.
Now, of course, that's a stupid comparison, but really if you think about it, it is effectively what this ash thing is about. Safe airspace was designated using a best guess method. Many aircraft, including some civilian machines continued (some yet to be confirmed) to have issues. Does that not say the best guess wasn't good enough? Nope. Cause it'd be too painful and difficult to say "Whoops. Got it wrong. Let's try again." And as always seems to happen, the problem quickly goes away by itself, nobody was hurt, no aircraft fell out of the sky (if I hear another pilot say "what's the problem? I don't see aircraft falling out the sky" I'll punch him.) and it can all be quietly put to bed, even though all the evidence suggests it didn't quite go as smoothly as was originally hoped.
I tell ya, sometimes this industry and the people in it make me dizzy, with all their declarations that they can not be shaken from accepting the lessons of the past and that commercial pressure shall never be allowed influence judgement when it comes to issues that can cause damage or affect safety regardless of the cost. But of course, that only applies when it suits them. A la carte professionalism I suppose you'd call it.
Imagine a design fault which had caused over reported 100 incidents (and likely many more unreported) leading to damage and a combined total of hundreds of millions of dollars in reapir bills. One year alone had 23 incidents. 7 incidents involved engine failure including two with all engine loss but none resulted in accidents. The occurence of the issue could be loosely forecast but it was difficult to narrow down the exact conditions under which it would occur. The fact that 100 issues had occured at all suggests that inadvertent and unexpected recurrence was both possible and likely. Are you really telling me that the public and the industry would accept an amendment to the regulations to allow continued flight of affected aircraft as long as they don't enter flight conditions which were already known to guarantee the problem would arise? And all because the industry itself was compaining that they would lose money and risk collapse if they were not allowed fly?
Of course not. The authorities would be firm and insist that the manufacturer(s) involved do something about it immediately, and would only allow flight if they were sastified, using hard proof from tests and unquestionable technical confirmation that the issue had been resolved or at least could be guaranteed to not recur under all but the most rare and easily avoidable conditions.
Now, of course, that's a stupid comparison, but really if you think about it, it is effectively what this ash thing is about. Safe airspace was designated using a best guess method. Many aircraft, including some civilian machines continued (some yet to be confirmed) to have issues. Does that not say the best guess wasn't good enough? Nope. Cause it'd be too painful and difficult to say "Whoops. Got it wrong. Let's try again." And as always seems to happen, the problem quickly goes away by itself, nobody was hurt, no aircraft fell out of the sky (if I hear another pilot say "what's the problem? I don't see aircraft falling out the sky" I'll punch him.) and it can all be quietly put to bed, even though all the evidence suggests it didn't quite go as smoothly as was originally hoped.
I tell ya, sometimes this industry and the people in it make me dizzy, with all their declarations that they can not be shaken from accepting the lessons of the past and that commercial pressure shall never be allowed influence judgement when it comes to issues that can cause damage or affect safety regardless of the cost. But of course, that only applies when it suits them. A la carte professionalism I suppose you'd call it.
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Hi,
The problem is the confusion and misuse of a principle does not apply to all situations ...
The confusion between the foresight principle and the precautionary principle.
The precautionary principle is often used for situations that require only a foresight principle ..
It's semantic .. but nevertheless the words have their importance given the different actions taken by the principle employed.
We are now living in a society driven by fear .... and this is not innocent ....
The media called for governements to destroy millions of birds over bird flu.
65000 deaths predicted over the mexican flu (345 actual)
And now this
I hope the airlines do sue
65000 deaths predicted over the mexican flu (345 actual)
And now this
I hope the airlines do sue
The confusion between the foresight principle and the precautionary principle.
The precautionary principle is often used for situations that require only a foresight principle ..
It's semantic .. but nevertheless the words have their importance given the different actions taken by the principle employed.
We are now living in a society driven by fear .... and this is not innocent ....
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jcjeant
I cannot disagree with what you are saying but this has happened so many times now that many are questioning the science.
Even global warming which so many claim is created by man and with the same scare tactics is under a big ? Yet it will cost the UK £18 billion and no doubt crucify our industry even further.
I am sure in a few weeks this latest expensive exercise will disappear into a distant memory until the next HUGE scare arises generated by the science in whatever field.
Oh well maybe the Hadron Collider another media generated scare with backing by some scientists will have turned us all into a black hole so none of us will have to worry
Pace
I cannot disagree with what you are saying but this has happened so many times now that many are questioning the science.
Even global warming which so many claim is created by man and with the same scare tactics is under a big ? Yet it will cost the UK £18 billion and no doubt crucify our industry even further.
I am sure in a few weeks this latest expensive exercise will disappear into a distant memory until the next HUGE scare arises generated by the science in whatever field.
Oh well maybe the Hadron Collider another media generated scare with backing by some scientists will have turned us all into a black hole so none of us will have to worry
Pace
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Imagine a design fault which had caused over reported 100 incidents (and likely many more unreported) leading to damage and a combined total of hundreds of millions of dollars in reapir bills. One year alone had 23 incidents. 7 incidents involved engine failure including two with all engine loss but none resulted in accidents. The occurence of the issue could be loosely forecast but it was difficult to narrow down the exact conditions under which it would occur. The fact that 100 issues had occured at all suggests that inadvertent and unexpected recurrence was both possible and likely.
Bird strikes, we know broadly when and where they occur, they are estimated to cost aviation £1.2bn pa., have a recent history of causing complete and unrecoverable loss of power, and have caused fatal accidents and the loss of airframes in non-fatal accidents. (at least everyone so far involved with ash encounters has been able to get the engines going again!) Should we stop civil aviation during bird migration season? No of course not. We should take sensible mitigation steps. That is all people seem to suggesting - not that ash is not a problem - just the approach of closing down Europe was out of proportion to the risk.
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Hi,
Indeed the approach was to apply the precautionary principle.(all grounded)
When the "corridors" were put in force it was the foresight principle applied.
This principle was to apply immediately .. and the costs and disturbances will not be what they are today ...
not that ash is not a problem - just the approach of closing down Europe was out of proportion to the risk.
When the "corridors" were put in force it was the foresight principle applied.
This principle was to apply immediately .. and the costs and disturbances will not be what they are today ...
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What is the volcanic cloud density that is 'safe' and when is it not safe to fly, and, should an encounter occur, what is the safest course of action?"
We all know that flying in thick dense volcanic ash clouds as seen bellowing out of the volcano source would be a very serious encounter.
My instincts are that in VMC and daylight if the ash is so dispersed as to be invisible then there is no threat.
Many will demand on what scientific basis that comment is made but then NO ONE experts or otherwise seems to really know scientific or not!
We do know that the Alaska eruption circled the world 3 times before it fully dissipated.
What the eye doesnt see??? How many aircraft flew through low level density ash totally oblivious to the fact?
The new levels are a good starting point until practical experience proves otherwise.
I like MMs Comparison with bird strikes which have brought down aircraft unlike ash which to date hasnt.
Bird strikes, we know broadly when and where they occur, they are estimated to cost aviation £1.2bn pa., have a recent history of causing complete and unrecoverable loss of power, and have caused fatal accidents and the loss of airframes in non-fatal accidents. (at least everyone so far involved with ash encounters has been able to get the engines going again!) Should we stop civil aviation during bird migration season? No of course not. We should take sensible mitigation steps. That is all people seem to suggesting - not that ash is not a problem - just the approach of closing down Europe was out of proportion to the risk.
Until the science can come up with solid data or detection equiptment for aircraft practical experience and common sense are our best options.
Pace
Last edited by Pace; 25th Apr 2010 at 17:29.
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How memories are short. I find it incredulous for anyone, let alone Sir Richard, to suggest that in the first two or three days of the ash reaching/covering the UK we could have continued operations in the face of an anti-cyclone dragging volcanic ash into our airspace. We would have had to put aside good airmanship, all of our knowledge of VA and its hazards, ignored the advice in our ops/airplane and engine manufacturers manuals- and that of the ICAO led VAAC. That was never going to happen. The fact that NATS prevented IFR flight in our airspace is in truth, secondary to the above; how many airline pilots would have been comfortable getting airborne or flying through this airspace given the information they had available to them at the time? How many Chief Engineers would have had the confidence to say, it's OK let's continue operations? Who had the confidence to risk the repair or replacements of leased engine's and airframes?
It was only after the risk was assessed by regulators and OEM's that it was established that it was safe and reasonable to start flying again. And by then the ash was much more widely dispersed. And to do that in the time they did was quite remarkable.
Of course, with hindsight, the airline industry should have had this issue sorted out long- However, to those not involved in the negotiations to set safe limits of ash- we thought we had- the rule was- we don't fly into VA!
Sure, there are many lessons to be learned and we'll all do it better next time, but it is disingenuous for anyone to say or suggest that we could have just kept flying as normal or been able to pick our way through corridors free from ash.
It was only after the risk was assessed by regulators and OEM's that it was established that it was safe and reasonable to start flying again. And by then the ash was much more widely dispersed. And to do that in the time they did was quite remarkable.
Of course, with hindsight, the airline industry should have had this issue sorted out long- However, to those not involved in the negotiations to set safe limits of ash- we thought we had- the rule was- we don't fly into VA!
Sure, there are many lessons to be learned and we'll all do it better next time, but it is disingenuous for anyone to say or suggest that we could have just kept flying as normal or been able to pick our way through corridors free from ash.
Last edited by no sig; 25th Apr 2010 at 20:51.
Not a bad discussion these last (few posts ....if they survive 
)
The answer probably lies in the details.
On the surface it appears that the historical single-flight safety impact from volcanic ash (Eric Moody etal.) was the failure to look for a clear route around the (unknown to the pilot) volcanic ash cloud. The same might be said for the last weeks only the cloud patterns were known but no chance was ever given to search out a clear path.
Now that the decision to manage flights around various densities of volcanic ash has been shared, it has been shown that one can minimize the risk down to something like avoiding bird ingestions that knock you out of the sky.
The human does learn to adapt even though we may not fully understand.
I don't like the rhetoric that heaps distrust on the CEO,s They only take advice of the avaition safety experts (believe it or not).
I suppose we could always fill a room with aviation safety experts and listen to the discussions, but I suspect that this has already happened and we are just second guessing what they discussed
OTOH have we noticed many qualified aviation safety experts in the press that say the present course of action is unsafe?
To me the opinions of individuals is only that, unless you represent a larger contingent that has reviewed the issue and history.
)The answer probably lies in the details.
On the surface it appears that the historical single-flight safety impact from volcanic ash (Eric Moody etal.) was the failure to look for a clear route around the (unknown to the pilot) volcanic ash cloud. The same might be said for the last weeks only the cloud patterns were known but no chance was ever given to search out a clear path.
Now that the decision to manage flights around various densities of volcanic ash has been shared, it has been shown that one can minimize the risk down to something like avoiding bird ingestions that knock you out of the sky.
The human does learn to adapt even though we may not fully understand.
I don't like the rhetoric that heaps distrust on the CEO,s They only take advice of the avaition safety experts (believe it or not).
I suppose we could always fill a room with aviation safety experts and listen to the discussions, but I suspect that this has already happened and we are just second guessing what they discussed
OTOH have we noticed many qualified aviation safety experts in the press that say the present course of action is unsafe?
To me the opinions of individuals is only that, unless you represent a larger contingent that has reviewed the issue and history.
Yes it is looking like the airlines brought this on themselves. ICAO asked for their expert input on what concentrations of ash were safe to fly in, the airlines failed to respond or even attend any meetings, which left the only alternative of only zero ash is safe.
Iceland warned of volcano danger to planes “for years”
25 April 2010.
Icelandic air traffic control has often warned of the potential impact to international aviation of a volcanic eruption in Iceland; but despite this, European airlines and controllers continue to say that nothing could have predicted that an Icelandic volcano would have such a massive impact on aviation.
Norway’s Aftenposten newspaper spoke to Icelandic air traffic controller Egill Thordarson who said that volcanic ash training exercises have been taking place in Iceland four times a year for the last decade and British and Norwegian teams have joined in on more than one occasion.
Thordarson told Aftenposten that the exercises have consistently proven the potential danger of volcanic ash to aeroplanes and said he has been sending out regular weather updates to European colleagues concerning volcanic activity in Iceland for the last two years.
The journal of Norwegian pilots, Flygelederen, published a six page article on the dangers of an Icelandic eruption in December last year.
25 April 2010.
Icelandic air traffic control has often warned of the potential impact to international aviation of a volcanic eruption in Iceland; but despite this, European airlines and controllers continue to say that nothing could have predicted that an Icelandic volcano would have such a massive impact on aviation.
Norway’s Aftenposten newspaper spoke to Icelandic air traffic controller Egill Thordarson who said that volcanic ash training exercises have been taking place in Iceland four times a year for the last decade and British and Norwegian teams have joined in on more than one occasion.
Thordarson told Aftenposten that the exercises have consistently proven the potential danger of volcanic ash to aeroplanes and said he has been sending out regular weather updates to European colleagues concerning volcanic activity in Iceland for the last two years.
The journal of Norwegian pilots, Flygelederen, published a six page article on the dangers of an Icelandic eruption in December last year.
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I would ask just one who claims it is safe, "What is the volcanic cloud density that is 'safe' and when is it not safe to fly, and, should an encounter occur, what is the safest course of action?" Though the QRH tells us what to do, such a response is based upon the fact that one is already in trouble. I think stating that the shut-down was 'out of proportion to the risk' is foolish and cannot be defended on belief alone.
- No aircraft has ever encountered a loss of power that could not be recovered at lower altitude - even while flying through significant densities of ash.
- There appears not to be a single documented instance of an in flight abnormality attributable to ash with a density lower than that of visible haze - and most seem to have been in thin cloud or denser. (This is different from saying low levels of ash don't result in accelerated wear - which it quite likely does)
- Operator's in areas of volcanic activity have SOPs that allow them to continue to operate - with limitation (which curiously didn't seem to apply to Europe when the skies where opened.)
- There are risks that down aircraft every year and operators continue to operate exposed to these risks (because you couldn't operate a business if you didn't - and after all the only reason the airline industry exists is to make money serving its customers).
Well said Captainpaddy. Sort of reminds me of that old rubric that "everyone is safe until they are in a hurry" which in this case seems to be that the industry is safe until it is faced with a problem that might require a stand-down, some research, and heaven forbid--discomfiture! (and I say that in all repsect for the thousands of people who were genuinely discomfited by this eruption-disruption and had to doss down where they could for days on end)
We are safe Sir Richard seems to be saying however, but we are in an awful hurry to get things moving again...
We are safe Sir Richard seems to be saying however, but we are in an awful hurry to get things moving again...
Do a Hover - it avoids G
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I continue to be amazed that many professionals on this thread cannot see the possibility that very low levels of certain contaminants, entering the internal cooling system of HPT blades, could result in subsequent premature failure of those blades due to a reduction in the cooling available.
John Farley
Premature compared to what
What metric should alert us and when will they know? in one month? one year??
I continue to be amazed that many professionals on this thread cannot see the possibility that very low levels of certain contaminants, entering the internal cooling system of HPT blades, could result in subsequent premature failure of those blades due to a reduction in the cooling available.
What metric should alert us and when will they know? in one month? one year??
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JF
You're so correct. The key word though, is 'could'.
We need to know if it 'will' cause the damage, or not.
At least this period of flying in low concentrations of ash will likely provide an answer.
Granted, with a little forethought, the answer to the 'how much is too much' question could easily (if at a cost) have been discovered.
We will now find out.
The cost to the airlines of the enforced stoppage must exceed by many times what the 'research', which was too dear to do, would have cost.
plus ca change.
We make money (BA forecast £600m loss this year) or we fold.
You're so correct. The key word though, is 'could'.
We need to know if it 'will' cause the damage, or not.
At least this period of flying in low concentrations of ash will likely provide an answer.
Granted, with a little forethought, the answer to the 'how much is too much' question could easily (if at a cost) have been discovered.
We will now find out.
The cost to the airlines of the enforced stoppage must exceed by many times what the 'research', which was too dear to do, would have cost.
plus ca change.
We make money (BA forecast £600m loss this year) or we fold.
Last edited by BarbiesBoyfriend; 26th Apr 2010 at 01:27.
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We will now find out
As I understand CAA and EASA directives, and current airlines reaction to them, the initial basis of ALL investigation of potential ash encounters starts with EITHER in-flight observation of ash in the air or hitting the aircraft (St Elmo's Fire, ...?) OR the strong possibility that the route DID pass through an ash cloud. Then, specific ground inspection will be done, starting with Mark 1 Eyeball examination of the aircraft for 'traces of ash'.
As has already been discussed much earlier in this thread, there's a stack of good evidence that a flight CAN pass through quite dense ash with NO in-flight indication AT ALL and nothing found visually post-flight (in particular, the NASA DC-8 incident in 2000).
Seems to me that the key problem that remains completely unaddressed is any 'backstop' testing so that even in the absence of any other evidence, ash in turbine hot section cooling systems WILL be detected and appropriate maintenance done, ideally before major damage occurs. (Don't know whether any ash removal from inside blades is even theoretically possible without tearing the whole engine apart!) Filters on bleeds from the engines provide a DEFINITE indicator of ash ingestion but as far as I know there is no organised plan to test them post-flight.
Remember that a lot of aircraft tend to fly reciprocal routes (A to B, then B to A, maybe several times in the same day). Ash encountered on multiple flights will obviously become a CUMULATIVE problem, especially if low levels of ash are unexpectedly present on a busy route and not detected by any of the current means!
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Everyone is wondering what happens when you fly through a widely dispersed ash cloud and its after effects.
Here is link to the USGS study on exactly that - the aftermath of Mt. Pinatubo in 1991 (bigger eruption than this one)Casadevall
Flying for CX at the time I remember Manila was closed for 2 weeks while the eruption was on and the ash scraped off the RWYs afterwards (55nm downwind from the Volcano).
Other than that there were various re-routes on HKG-AUS vv and in the (very busy) South China Sea.
There was some damage to aeroplanes but mostly very minor (see above report). One IFSD was reported in the 18 encounters during the aftermath.
Here is link to the USGS study on exactly that - the aftermath of Mt. Pinatubo in 1991 (bigger eruption than this one)Casadevall
Flying for CX at the time I remember Manila was closed for 2 weeks while the eruption was on and the ash scraped off the RWYs afterwards (55nm downwind from the Volcano).
Other than that there were various re-routes on HKG-AUS vv and in the (very busy) South China Sea.
There was some damage to aeroplanes but mostly very minor (see above report). One IFSD was reported in the 18 encounters during the aftermath.