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Originally Posted by brooksjg
Why 'provenance' of a false rumour could be interesting [to PBL] defeats me.
PBL |
It looks from the synoptics as if there may be a drift towards the west of the UK by 25th.
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Earthquake action continues
Earthquake activity both at Eyjafjallajokull (many) and again two at Katla (the most recent occurring in the last 4 hours, while not very big at 0.4 on the Richter scale, was deep at 13.7km which is concerning).
Also just found out that the last time Eyjafjallajokull erupted it lasted for 14 months.... so this could be a long thread. :{ - GY |
What better risk analysis can you have than 50 years of records and millions of flights? The undisputable facts are that NO ONE has been killed in the whole history of aviation by ASH. Maybe its becuase aircraft have always avoided flying through dust, certainly when they do, in certain concentrations its got very very expensive and dangerous. And VA is not the same from all eruptions, some, like this, are far more damaging. |
Yet more earthquake activity at Katla
Another quake directly under Katla of 0.9 magnitude at a shallower depth 4.8km.
A bunch under Eyjafjallajokull. -GY |
What better risk analysis can you have than 50 years of records and millions of flights? The undisputable facts are that NO ONE has been killed in the whole history of aviation by ASH. You are trying to do a risk analysis on something which to date statistically has shown NOT to be a risk. What is done is to review much more common outcomes which fortunately for the passenger and crew are measurable degradation in safety (all nicely tided up in the definitions under 25.1309 and the Industry wide CAAM report published by the FAA. Therfore even sucessful outcomes (the plane landed safely and the passengers changed their underwear) become part of the data. And nobody takes credit for events where nothing happened in millions and millions of hours but instead simply looks at the statistical probability that "any" degradation of safety (according to measured definitions) may happen that contains Volcanic Ash as an ingredient. I keep saying that the volcanic conditions that we speak of today "will" result in some measurable degradation of safety but no more than the typical risk that we operate within everyday for all other causes (risk is never zero but it is managed within acceptable limits) Most readers have no idea of what risk is allowed to underly each and every flight and the variable contributions of the causal factors versus time. Just because you identify a newly recognized causal factor "du jour" doesn't mean that you have to manage it to zero to justify to keep flying. |
Originally Posted by peter we
(Post 5706956)
And VA is not the same from all eruptions, some, like this, are far more damaging.
Or do you mean that the response to the ash cloud was far more damaging (to the tune of a couple of billion) ? |
an F-18's engine is like a ramjet when compared to todays hi-bypass engines; no wonder it picked up a load of VA!
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Precisely ! The F18s would have been manoeuvring at high speed, high thrust, with no engine bleed worth speaking of, and probably at medium/low level. Under these circumstances they would have almost inevitably been damaged by ash ingestion.
Your average high-bypass commercial turbofan, on the other hand, operates at lower speed and relatively constant thrust, with air bleed. Our manuals tell us that in the event of an ash encounter we reduce speed and increase air bleed (and get the hell out of there). The British government and authorities at the time of the original ash closure also mentioned an RAF Typhoon that had allegedly been damaged by ash. No doubt that was also manoeuvring at high thrust, low level, which bears no resemblance to the civil jet environment. |
Seismic activity has increased in the last few hours
Frequent but weak tremors in the area around our beloved Volcano in the last few hours, extending also to the proximity of Katla. Hopefully I am just over reacting and it does not mean anything at all.
The increase in seismic activity is objectively a fact in the last few hours but it seems normal activity intensity-wise, the location instead is a bit more worrying as epicentres seem to be moving towards Katla crater, but it could mean nothing, hopefully:uhoh::uhoh: |
Originally Posted by PBL
(Post 5706656)
The "refutation" and "lack of re-refutation" have no more status than the original rumor. For hobbyists, this might be enough. For many professional purposes, it does not suffice.
PBL CEN10RA135 Note the date of the incident - it's pre iceland VA. I doubt there have been two uncontained failures like this on the same type in less than three months (or rather, if there had I think it would have been bigger news and we'd know). PBL: From this incident note and your professional contacts you may be able to confirm the details and tie in the photos - in which case the date and location rules out VA. This may be as close as the rest of us amateurs get to an official statement (reported statement form Cessna): Engine Damage Not Caused by Volcanic Ash: AINonline. |
Latest update from the Iceland Met Office and Institute of Earth Sciences indicates that the explosive activity has died down considerably.
Articles < Seismicity < Icelandic Meteorological office :8:8:8 |
at high thrust, low level, which bears no resemblance to the civil jet environment And how can you say "no doubt" at low altitude and high thrust? |
I keep saying that the volcanic conditions that we speak of today "will" result in some measurable degradation of safety but no more than the typical risk that we operate within everyday for all other causes (risk is never zero but it is managed within acceptable limits) Most readers have no idea of what risk is allowed to underly each and every flight and the variable contributions of the causal factors versus time. Just because you identify a newly recognized causal factor "du jour" doesn't mean that you have to manage it to zero to justify to keep flying. This is a well written and thought ;) If you want zero risk DONT Fly. There are far more PROVEN risky elements to flight than Ash yet ASH has cought the public imagination hyped by the media amd reacted to by a whole host of back watching Burocrats and quangos. We have had many fatal landing and takeoff accidents in strong winds and shear conditions even within the "accepted operational levels" but do we have a long thread like this one demanding all takeoffs and landings should only be with zero wind? Ash which has NO fatality record throughout aviation history has been hyped into a monster or bad wolf which is out to get you. Maybe its becuase aircraft have always avoided flying through dust, certainly when they do, in certain concentrations its got very very expensive and dangerous. And VA is not the same from all eruptions, some, like this, are far more damaging. Volcanic eruptions are nothing new. Jet aircraft 20+ years ago had hardly any sophisticated equiptment and NO fancy computer generated Ash Prediction charts. Maybe they flew through low level ash concentrations and never knew about it. If you cannot see it it wont hurt you. Volcanic Ash really isnt a new phenomina! Our MEDIA HYPE driven, paranoid, liability and blame culture IS!!! Oh well off to bed so I can dream of shooting and killing a few million birds to save us from Bird flu! but more likely to save us from ingesting them in our jet engines a real ignored threat. Pace |
Originally Posted by if789
This looks to be an official note on the incident - I think someone already posted it ealier:
CEN10RA135 The pictures show an aircraft with a D-reg (can't see other letters), with engine, rear fuselage and tail markings identical to those on pictures on the WWW of some other Citations from Eisele Flugdienst. So I can call up the BFU, or indeed the company, and find out. PBL |
I guess that a whole lot of the 'Ash Emergency' reporting from the Meeja generally is examples of 'Never let a Few Facts get in the way of a Good Story'.
Even the Flightglobal story reporting no significant damage to the F-18 engines, with a by-line of 23/4/10 was followed the very next day in the same magazine with 'Europe's volcanic ash response: was it adequate?' which mentioned the original 'reported' F-18 damage but not, strangely enough :rolleyes: , the previous day's 'no damage' story. I haven't ploughed through the literally 100s of VA references just in Flightglobal to try to judge their attempts to balance what was published but my guess is that they were also to some degree cheerleaders on the 'High VA risk - We're all gonna die' bandwagon. Given Flightglobal's position as an industry-specialist publication and particularly its own masthead (Serious about Aviation), this is disappointing. It would be a bit of a stretch to envisage a conspiracy in which someone hijacked the NTSB website and planted a faked-up story about the Citation CJ incident so as to place it well before VA became an issue!!! |
BrookSJG
That is the sickening thing with the media they create the story they want and either ignore the facts or worse falsely make one thing appear to be another. There are people who have had their lives ruined by the media by pretending something is true and painting a false picture to influence readers into believing it is true. Some of these people have been accused of horrendous crimes. When the courts find them not guilty that report gets a half inch column in the depths of the media report. It is the same with this charade very damaging to aviation and made up of selective and false reporting designed to generate unfounded fear in the public. These people including a select few in this forum should be ashamed of themselves as all they achieve is damaging an industry and peoples livelyhoods by their false representations. Worst is most dont even know what they are talking about. Pace |
Interesting to see the nature of this ash, note the chunky structure.
Eyjafjallajökull ash under a petrographic microscope in crossed-polarized light at ~40x. Image by Erik Klemetti. http://i726.photobucket.com/albums/w...b-400x300-.jpg Eyjafjallajökull ash under a petrographic microscope in crossed-polarized light at ~100x. Image by Erik Klemetti. http://i726.photobucket.com/albums/w...x300-49461.jpg |
Icelandic Met Office reporting marked decrease in activity:
The eruption activity is minimal and therefore no significant ashfall is expected. The volcano is still being monitored and an ashfall forecast will be issued if neccessary. |
VA forecast accuracy
Now that the dust has settled (at least for the moment!), has anyone seen any proper explanation (especially from the Met Office) for the overall lack of accuracy of VA Forecasting and, in particular, for the error(s) that led to the sudden and very obvious revision between 0600 and 1200 last Monday (17th May)?
Quite apart from the disruption caused by lack of inbound flights to LGW and other short-term problems, there was also a potential risk (already mentioned above) from reassignment of certain areas of the North Sea from 'white' to Black in the same revision. Superficially, it looked like inaccuracies in weather forecasting had been allowed to 'bleed through' into the VA Forecast, with no later corrections being applied as real weather data superseded the forecasts. I have no actual evidence of this but unless something like this occurred, how could such a major restatement of the position of the ash cloud ever be required? - unless, of course, there were other problems with the model that only came to light over the weekend 15/16th May. |
BillS
No, visibly is exactly what the report is saying... there is visibly only steam production, and other signs show that the eruption calmed down... How long, it's impossible to know, though. You can hardly see it on the cameras. Let's hope this is it!
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I have no actual evidence of this but unless something like this occurred, how could such a major restatement of the position of the ash cloud ever be required? - unless, of course, there were other problems with the model that only came to light over the weekend 15/16th May. |
There was nothing wrong with the model or the forecasting, they were obviously told to change it The Powers That Be can (easily) change the specified minima/maxima for any given situation, so long as the new value remains inside other legal / regulatory limits that may apply. They already did this - by going from 2000 to 4000 micrograms/cube (with additional caveats). They did not need to get the VA forecast 'adjusted' as well. IMHO it would have been extremely foolhardy to even try to do so: someone could easily have other, more accurate evidence and/or might want to saddle the originator of the request/order with all the responsibility (and potential blame). In this situation, a leak to the media would be a virtual certainty! For a recent example of this, see Climate Change 'emails scandal' at the University of East Anglia. A bit of tinkering with climate data and months later, after an external enquiry and at least one Severely Career-Limiting Move, they're still chipping brown solids off the fans! Especially with this recent example to learn from, I'm surprised the Met Office has so far failed to come clean about the forecast! So why were the limits and the VA forecast both adjusted, at very similar times?? (I still favour cock-up over conspiracy but have no better information myself.) That said, it's also quite entertaining to watch the various regulators' heads popping above / below the parapet, depending on whether they reckon they'll catch blame (or have to take responsibility!) if ultimately something goes legs-up. |
Peter - there most certainly did appear to be a forecasting error. As brooksjg and I have pointed out, there was a sudden shift of the 'black ash' area from over the middle of England out into the 'clear area' where unsuspecting a/c had been happily toddling along.
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Think about it. The VAAC issue one forecast every 6 hours, and if we examine these forecasts since the beginning of the 'ash crisis', let's say 60 days ago, then there is only this one obvious error on May 17th.
60x4=240 forecasts. One of which is wrong, that's 0.4% of the total. Not a bad accuracy level, to be honest. Forecasts will always be slightly wrong. The forecast you see on something like the VAAC is merely the most probable outcome. The prediction system typically generates a number of possible forecasts and assigns a probability to each that determines how likely it is to occur. Perhaps on the 17th there were two with very similar probabilities, and the VAAC staff got unlucky and chose the wrong one. Or perhaps they chose one that was very likely, but for some reason one of the more unlikely predictions turned out to be true. |
Not that simple, Simon (as they say.:)). The 'incorrect model' went on for days, drifting the ash down to where it wasn't. Suddenly when a huge fuss erupted - bingo!
A touch more than .4% - and that is assuming that the previous ash disposition charts were all spot on! |
60x4=240 forecasts. One of which is wrong, that's 0.4% of the total. Not a bad accuracy level, to be honest. |
Yes - not necessarily one 'incorrect' forecast - a whole series of totally consistent forecasts, over at least 3 days, showing movement South / South-eastward and gradual expansion of the cloud's area.
I'm just digging back through the raw mapping data to try to understand better what happened...... |
Frankly, as I've said before, I thought the whole event has been handled very well. There will undoubtedly be review and analysis of what could have been done better, and of course with 20/20 hindsight there will undoubtedly be room for improvement.
However that does not change the fact that a response to an unforeseen event - the possibility of a major volcanic ash cloud disrupting the worlds busiest intercontinental air routes, has been handled very quickly, considering the coordination required, with minimal disruption to the travelling public. Well done to the industry as a whole! You are in a better armed state to face the next challenge when it arrives. |
You are in a better armed state to face the next challenge when it arrives Realities are that a (small) volcano has stopped erupting for now and the big one (Hekla) has yet to start. Meantime, we still have no quick, accurate means to locate and measure volcanic ash in the atmosphere, and therefore depend on computer modelling, which in turn depends on accurate data from forecasts and actual weather in the recent past. As was demonstrated last week, modelling can fail and each time it does the unnecessary financial cost to the industry is very large and/or aircraft could be damaged. Not much of a moment for congratulations. And to say that we're 'better armed' only applies to defensive reaction time when ash is predicted, with little improvement in prediction accuracy or avoidance of the problem. There must be potential improvements in sensors and other detection strategies but little evidence at the moment of any concerted effort being applied. Sorry to rain on the parade but that's the way it is. |
Brookes:
Meantime, we still have no quick, accurate means to locate and measure volcanic ash in the atmosphere, and therefore depend on computer modelling, which in turn depends on accurate data from forecasts and actual weather in the recent past. As was demonstrated last week, modelling can fail and each time it does the unnecessary financial cost to the industry is very large and/or aircraft could be damaged. Not much of a moment for congratulations. And to say that we're 'better armed' only applies to defensive reaction time when ash is predicted, with little improvement in prediction accuracy or avoidance of the problem. There must be potential improvements in sensors and other detection strategies but little evidence at the moment of any concerted effort being applied. Sorry to rain on the parade but that's the way it is. Meanwhile, in Two weeks from the start of the event, the airframe manufacturers, engine manufacturers, airlines, regulators, lawyers, vulcanologists, meteorologists and insurers of many nations worked together to produce a set of operational protocols that worked. I'm sorry if they weren't to your liking, but the fact is that they are an achievement and can be deployed again if necessary. Bear in mind that the consequences of a major part of the Transatlantic fleet, for want of a better word, getting their engines seriously damaged by Ash ingestion would have been months of cancelled flights as there is not enough engine overhaul capacity on this planet to deal with an emergency workload of that magnitude. We cater for the odd bird strike, not 200+ airliners needing four overhauled engines at five minutes notice. Please try and understand that that is the logistical nightmare behind the need for regulation and prohibition. |
If you want to attempt to forecast where ash is, then your industry can pay for it So what about ash detection? Seems that the only really effective method is to fly an aircraft along a track where VA might be and use lidar and / or sampling to check what's there. Cost? Really doesn't matter! NOT doing this results in potentially unnecessary shutdowns of airspace, airports and sometimes the whole of UK air transport, with calculable cost x per hour or day. So long as the cost of an accurate forecasting / alerting system is less than a fraction of x, it's worth doing. (fraction calculated from the probabilities of future eruption(s) and of false VA alarms.) Risk? You can't ask people to deliberately fly research aircraft into high risk areas when there is no accurate VA data. However, there is a suitable platform for doing just this, at negligible risk to people. Predators with all sorts of fancy sensors (and Hellfires!) are already flying reliably in various places. Why not rip out as much of the expensive bits as possible from some Predators (or another suitable UAV), plus whatever classified bits have to go, mount instead some suitable LIDAR, SO2 sensor and whatever other sensors and samplers would be useful, plus civil transponders, and use them as a picket line somewhere off NW Scotland / Ireland? Flying orbits using (say) 4 aircraft round the clock at various heights in an otherwise-vacant bit of airspace would yield very accurate data on what was heading towards UK. If all else failed, monitoring the in- and post-flight engine condition of the engines would also provide good data. Why not? - We'd only need to fly the picket line as such when we knew that an eruption was happening. We know where the risk will be coming from. Rest of the time, the UAVs could be used for (military) training in the use of the UAV platform and occasionally checking that the system worked with a quick trip close to a volcano. OK - would not prevent disruption altogether but would minimise it. And much better than doing nothing proactive! |
Originally Posted by brooksjg
Risk? You can't ask people to deliberately fly research aircraft into high risk areas when there is no accurate VA data.
If this is considered acceptable why not fly samplers in the areas where the ash 'isn't' to confirm the forecast? |
Sunfish: We cater for the odd bird strike, not 200+ airliners needing four overhauled engines at five minutes notice. Please try and understand that that is the logistical nightmare behind the need for regulation and prohibition. |
Brooks:
Part of the purpose of my last post was to highlight that the industry has done nothing except react 'passively'. Whether this reaction was adequate or technically sound is debatable. Anyway, we have some breathing space while the volcano(es) go(es) quiet and we await the next eruption - expert opinion suggests there will be one, possibly soon. So what about ash detection? Seems that the only really effective method is to fly an aircraft along a track where VA might be and use lidar and / or sampling to check what's there. Cost? Really doesn't matter! NOT doing this results in potentially unnecessary shutdowns of airspace, airports and sometimes the whole of UK air transport, with calculable cost x per hour or day. So long as the cost of an accurate forecasting / alerting system is less than a fraction of x, it's worth doing. (fraction calculated from the probabilities of future eruption(s) and of false VA alarms.) Risk? You can't ask people to deliberately fly research aircraft into high risk areas when there is no accurate VA data. However, there is a suitable platform for doing just this, at negligible risk to people. Predators with all sorts of fancy sensors (and Hellfires!) are already flying reliably in various places. Why not rip out as much of the expensive bits as possible from some Predators (or another suitable UAV), plus whatever classified bits have to go, mount instead some suitable LIDAR, SO2 sensor and whatever other sensors and samplers would be useful, plus civil transponders, and use them as a picket line somewhere off NW Scotland / Ireland? Flying orbits using (say) 4 aircraft round the clock at various heights in an otherwise-vacant bit of airspace would yield very accurate data on what was heading towards UK. If all else failed, monitoring the in- and post-flight engine condition of the engines would also provide good data. Why not? - We'd only need to fly the picket line as such when we knew that an eruption was happening. We know where the risk will be coming from. Rest of the time, the UAVs could be used for (military) training in the use of the UAV platform and occasionally checking that the system worked with a quick trip close to a volcano. OK - would not prevent disruption altogether but would minimise it. And much better than doing nothing proactive! Your accountants will perhaps chafe a little while these expensive standards gather (non - volcanic) dust sitting on the shelves waiting for the next Icelandic eruption, and if it's a big one from Katla, and the wind is in the wrong direction, then all your little cheese paring standards aren't going to be much use are they? In my opinion, the reaction of the regulators was measured, proportionate, prompt, cost efficient and minimised both risk and disruption to the public to a bare minimum. SSK: It is NOT the job of the Regulator to regulate on issues of commercial judgement, which this is. Safety - yes. Logistics - no. A single engine failure is a matter for your airline. An epidemic of engines all turning up at the "Hospital" at once is a matter of public concern regarding provision of RPT services and hence regulatory action. To put it another way: An ounce of prevention is worth a pound of cure. Saying "No" and grounding you until we are relatively certain you are safe is the simplest, cheapest and most direct safety action. |
regulations about avoiding ash clouds in real time while maintaining separation standards with other aircraft all doing the same thing I NEVER suggested anything of the sort. My observation is that the VAAC forecasting can be inaccurate, as was especially obvious on 17th May. There is some technology (UAVs with suitable sensors) that could be used if the airlines wish to avoid losing revenue due to unnecessary shut-downs when in fact there is not enough VA to be a problem (although 'tolerable' ash density presumably still awaits final agreement...) or it's in places where it can have no effect. A way this could be funded is via contributions from companies at risk of major losses due to VA - it's a business calculation for them what measures would be cost-effective. From where I'm sitting, it looks like an excellent investment in the absence of any other improvement to the forecast.... How my suggestion could refer to aircraft playing officially-sanctioned 3D Blind Man's Buff I'm unable to explain! I was only suggesting a method to improve VA mapping, nothing to do with subsequent use of the resulting maps. |
It is NOT the job of the Regulator to regulate on issues of commercial judgement, which this is. Safety - yes. Logistics - no. It is not the job of the Health Department to monitor your personal health either, but when an epidemic potentially occurs the Health Department rightly steps in. A single engine failure is a matter for your airline. An epidemic of engines all turning up at the "Hospital" at once is a matter of public concern regarding provision of RPT services and hence regulatory action. Just because some suggest that there is an epidemic on the horizon does not mean that it will actually occur (SARs etc.). So like other concerns watching, measuring and a measured response in avoidance seems to be the best action all of which is being practised. |
Sunfish
To put it another way: An ounce of prevention is worth a pound of cure. Saying "No" and grounding you until we are relatively certain you are safe is the simplest, cheapest and most direct safety action. Frankly Sunfish you do not have a clue what you are talking about. Do you not think that the Airline industry would not jump at the so called "cheapest" option as you declared? The biggest flaw in computer mapping of VA is that VA density is no more consistant than any cloud. You could take an area of 10,000 sq miles of ash contaminated air estimated as being within the approved density levels and there would be NO consistancy in that area. Some patches would be way below other patches would be way above. Any particles in the air of enough area and density will show to the naked eye in a cloud or mist form. The only practical and accurate way to avoid flying into dense ash is to avoid flying into visible cloud especially pollution coloured cloud. Stick in clear air by using the normal CB avoidance of requesting a left or right deviation is the only practical and reliable way of keeping clear of dense ash which "could" cause you an inflight engine problem and of course avoiding flying at night. As to minute density areas of ash which are in thin mist form or not visible then the only practical way is to check those aircraft for pollution damage on a regular basis. As for your doomsday scenario forecast of 100s of engines needing major maintenance that is equally fanciful and not showing any evidence to date. Until the day that qualified engineers start reporting such damage I am afraid that your comments will stay in the fanciful and in your dreams bin. If that ever happens and I doubt it then I will take my hat off to you and say that Sunfish was right. I would also like to ask you what your background and knowledge is that justifies your wild assumptions? Yes I do think the current VA forecasting is seriously flawed and innacurate and that also is proving to be true. Please also differentiate between what is a threat to flight and a threat to bank balance. The threat to bank balance will be best determined by the airlines as probably will the threat to flight by pilots and airlines and engineers not some burocrats, politicians or quangos with their own agendas and back covering foremost. Pace |
Nothing I have said is wild or fanciful. I've watched the build of plenty of engines and I assure you it does not happen overnight. Do you know for example what tip grinding is? Do you know how many tip grinding lathes are around? Have you ever seen people at the bench individually hand finishing blades and vanes?
Do you understand that when the evidence of which you speak appears, it is too late for that engine? Don't you understand that engines take a long time to build? Do you understand the consequences of being wrong and not applying the precautionary principle? I do not think you do. |
Originally Posted by brooksjg
There is some technology (UAVs with suitable sensors) that could be used if the airlines wish to avoid losing revenue due to unnecessary shut-downs ....
PBL |
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