New eruption starting in Iceland? (merged)

[TURIN]

Those diagrams are assuming the eruption continues at the same intensity.

I was under the impression the eruption ceased between 2 and 3 zulu this morning.

[PhilW1981]

Yes but the ash at the upper levels had already been emitted, started heading towards Canada and the change in wind direction sees it headed back our way, if I am interpreting the charts correctly.

[flying lid]

Where does Eurocontrol come into all this ? No mention thus far.

Where is Joe Sultana ??

Mr Joe Sultana, Chief Operating Officer, Directorate Network Management | EUROCONTROL (http://www.eurocontrol.int/bio/mr-joe-sultana-chief-operating-officer-directorate-network-management)

In April 2003, Mr Sultana was appointed as Head of Business Division Network Capacity. Subsequently, he was assigned additional responsibility for the Dynamic Management of European Airspace Network (DMEAN) Framework Programme. In October 2006, Mr Sultana became EUROCONTROL’s Head of Airspace, Network Planning and Navigation Division.

On 1 June 2008, Mr Sultana moved to the Central Flow Management Unit (CFMU) as Head of Operations and on 2nd Jan 2009 became the Deputy Director CFMU responsible for Network Operations and Information Management.

Joe Sultana was appointed a Director of the Agency, holding the position of Chief Operating Officer in the Directorate Network Management with effect from 1 January 2011.

One (silent) big cheese. Where is Joe Sultana - is he a pPRUNE'er !!!???

Lid

[Al Murdoch]

That's never a real name...

[TURIN]

MOL on CH4 news now.

Talking some sense but mostly bowlarks.

[mona lot]

Did MOL mention that his flight "into the ash cloud" was restricted to VMC by the CP?

[TURIN]

He avoided mentioning lots of things. Sidestepped the remark from the newsman about his aircraft being tracked by radar and not flying through the 'contaminated' area.

PR and BS all in one package. Genius.:suspect:

[victorc10]

It is fine drawing predictive maps created by computer simulations. But there doesn't seem to be any form of verification of the concentrations? Also in order to create predictions and draw maps, there must be an initial input into the simulation, where does this value or values come from? As a former scientist and current flight deck crew, I have never seen such poor science.

[The SSK]

Where does Eurocontrol come into all this ? No mention thus far.

Where is Joe Sultana ??

Mr Joe Sultana, Chief Operating Officer, Directorate Network Management | EUROCONTROL (http://www.eurocontrol.int/bio/mr-joe-sultana-chief-operating-officer-directorate-network-management)

In April 2003, Mr Sultana was appointed as Head of Business Division Network Capacity. Subsequently, he was assigned additional responsibility for the Dynamic Management of European Airspace Network (DMEAN) Framework Programme. In October 2006, Mr Sultana became EUROCONTROL’s Head of Airspace, Network Planning and Navigation Division.

On 1 June 2008, Mr Sultana moved to the Central Flow Management Unit (CFMU) as Head of Operations and on 2nd Jan 2009 became the Deputy Director CFMU responsible for Network Operations and Information Management.

Joe Sultana was appointed a Director of the Agency, holding the position of Chief Operating Officer in the Directorate Network Management with effect from 1 January 2011.

One (silent) big cheese. Where is Joe Sultana - is he a pPRUNE'er !!!???

Lid

Oh dear, Flying Lid ('retired engineer'), Joe Sultana is closer to the heart of this issue than you will ever be. If there is ever going to be a satisfactory resolution, a core group of experts, of which he is part, will be at the centre of it. Google EACCC (European Aviation Crisis Coordination Cell) which has convened every day since the start of this event.

But then, mocking someone because of their name is never going to help your credibility.

[kazzie]

Just a question for the Pro's!

I see the charts for Friday are not looking good for the UK, But a I right in saying the high density ash will be between FL200-350. If so then would you be able to fly at lower altitudes (FL150 for example) and then climb once clear of the danger area? I know that would mean using ore fuel and restrictions in traffic and so on, But would it be possible?

[PhilW1981]

The Met office have updated the long range forecast this evening and Friday now doesn't look so problematic. The forecasts I posted earlier are now out of date.

[Pace]

Lord Spandex masher

How many passengers lives are you going to risk while you do this?

Your quote !!! If I loose just one life with my attitude as you put it! Then i will be the first in the history of aviation to loose a life due to ash as to date none have been lost in millions of flights and covering an era when there were no sophisticated systems. Then it was all just pure piloting and common sense an attribute that seems in short supply nowadays.

Why dont you put your efforts into arguing for closing down masses of airspace in the bird migration season. Now there there is a proven and demonstrable risk.

The Met office have updated the long range forecast this evening and Friday now doesn't look so problematic. The forecasts I posted earlier are now out of date.

Surprise!!! surprise!!! and we are supposed to have confidence in this so called science :ugh:

The press have been having a field day with charts printed of these predictions and doom and gloom of how passenegers holdays and flights will be ruined!!!

Pace

[fireflybob]

Glad to see this is all blowing over at last - just hope I've retired before the next debacle and the lack of preparedness by all!

[Lord Spandex Masher]

Dear Pace,

If I loose just one life with my attitude as you put it! Then i will be the first in the history of aviation to loose a life due to ash as to date none have been lost in millions of flights

Yes you would. However, there have been many lives within a gnats cock of being lost because of volcanic ash encounters. You're willing to put your passengers in that position deliberately?

You do also realise that BAW009 lost twenty thousand feet trying to recover? So do tell us brave aviator what would happen had they lost all engines at nineteen thousand feet. Splat. Luckily that hasn't happened...yet.

Simply stating that no lives have ever been lost due to VA encounters doesn't make it an intelligent thing to do.

[Pace]

Lord Spandex Masher

You do also realise that BAW009 lost twenty thousand feet trying to recover? So do tell us brave aviator what would happen had they lost all engines at nineteen thousand feet. Splat. Luckily that hasn't happened...yet.


We have all seen pictures of Volcanic source eruptions. Massive CB like mountains in the sky!

There was a superb shot of one of these eruptions with a single engines PA28aircraft flying by.

No pilot would fly into such a mass as without doubt such dense ash would stop his engines.

I have no problems with that! I do have problems with concentrations which are so low that they are not visible to the naked eye in the form of ash mist or cloud.

Would such low levels which are categorised as high levels by the authorities down a jet? IMO NO!! could such low levels shorten an engine life? possibley yes?

Is that a safety descison to fly in INVISBLE ash! IMO NO!

is that an economic financial decision? Possibly yes!

IMO there has to be some common sense and less of this burocratic nonsense and self protectionism nvolved.

As to my flight today to the South of France? back at FL380 beautiful weather over france, some benign looking cloud over southern UK. Windy but good flight, lovely weather and engines happy :D I doubt I will be the first in aviation history to loose a life flying in ASH!

[Defruiter]

Kazzie,

From what I gather, any danger areas that are created due to ash start from the surface, regardless of the fact that the ash cloud may be FL200+. Techincally, that means flying through a danger area. (Unless this has now been changed? It's what I was briefed on at work a couple of days ago)

[JammedStab]

At least some deviations in northern Canada as well in the Baffin Island area due to some of the ash flowing westward. It altered my flight plan today.

[bullet190]

Pace,

I think most if not all pilots here know the engines are not going to just stop when flying through even a red sector of ash. There is a big difference between that and the ash cloud BAW009 flew through.

My concern though is that by flying through a low density area of ash I am causing a small amount of damage to the turbine sections, bearings, small amounts of glass stuck to the blades etc
After the days work, then what ?........I hand it over to a colleague to do the next shift.

Can a quick inspection by an engineer detect these small amounts of damage without the time for a bore-scope ? I doubt it.

I know where your coming from Pace but it's the hidden danger that concerns me.

[foxfire42]

Pace, I think most if not all pilots here know the engines are not going to just stop when flying through even a red sector of ash. There is a big difference between that and the ash cloud BAW009 flew through. My concern though is that by flying through a low density area of ash I am causing a small amount of damage to the turbine sections, bearings, small amounts of glass stuck to the blades etc After the days work, then what ?........I hand it over to a colleague to do the next shift. Can a quick inspection by an engineer detect these small amounts of damage without the time for a bore-scope ? I doubt it. I know where your coming from Pace but it's the hidden danger that concerns me. not only that but I SUSPECT that it is the case that with volcanic ash that there will be a concentration at which it's still safe to fly but not economic. In that situation it seems right, to me, that airlines can choose not to fly even though to fly would be safe. Planes aren't cheap and to chose to expose some to conditions known to cause damage (which may or may not be at a higher concentration than the current red zone) may be an expensive decision. On the 'test flights' I'd feel they were intended more for science than PR if they had instruments measuring the (small) levels of ash they were flying through. The ash isn't going to be uniform through the red zone (or any other) and ISTM that what is needed is an accurate measure of the concentration flown through and the subsequent damage (or lack of thereof). I'd have thought only by calibrating the conditions flown through with the effect on the plane can sensible limits be set. Knowing only one (and AFAIK the 'test flight' are only measuring the latter) doesn't seem very useful IMVHO

[dfstrottersfan]

The ash cloud id mapped on here - a convenient way of following its progress



Flightradar24.com - Live Flight Tracker! (http://www.flightradar24.com/) it works best in firefox

[maxrpm]

No this is not the ash cloud. This is a simulation.

[WetFeet]

Now, instead of a very coarse contour plot, labelled with emotive terms like "low", "medium" and "high", why not produce a fine grained plot with many different numerical values and then allow airlines to generate a safety case relating to the level that they are prepared to accept (if any of this is really necessary vice "see/sense and avoid", in any case)?

The Norwegian met office have a graphic showing more levels, rather than just low, medium and high. Don't know how accurate they are though.

Forside - met.no (http://www.met.no)

[Ace Rimmer]

He does exist! I've had the dubious pleasure of taking part in the telecons of the EACCC over the last few days - and assure you that Joe Sultana was playing a key role in each and every one.

[Herman the Navigator]

Brilliant, thanks wetfeet!

I think this conclusively shows that it's actually very straightforward to draw detailed contour plots (and that 1970s style arguments about computing power are a bit old hat).

Trust the Norwegians to quietly and competently do it better and more precisely. They say: "Dette er tilleggsinformasjon til VAAC-bulletinene, som utstedes av Volcanic Ash Advisory. SNAP-modellen gir en beregning lenger fram i tid, fram til 66 timer, samt større oppløsning i tid og rom" <translating> "This is additional information to the VAAC bulletins, which are published by Volcanic Ash Advisory. The SNAP model calculates further forward in time, up to 66 hours, and greater resolution in time and space".

So, the Norwegians have a different model from the UK - I hope someone's talking to them to draw on their experience and not doing the traditional "not invented here". In fact, wouldn't it be wonderful if someone (from, oooh, let's say the regulators) called all the chemists, meteorologists, atmospheric physicists, jet engine engineers, flight ops professionals, etc. together in a multi-disciplinary team to sort this out once and for all. And, it's no good saying "that's TFD" - if you can't finish don't start, with "zero tolerance", which was never actually "zero" but a 0.2 mg limit because that was chosen as the model cutoff (quite arbitrarily, as far as I can tell)...

For the scientifically inclined, here's plenty to chew on:

http://www.skybrary.aero/bookshelf/books/1162.pdf

including a paper: "IMPACT OF VOLCANIC ASH FROM 15 DECEMBER 1989 REDOUBT VOLCANO ERUPTION ON GE CF6-80C2 TURBOFAN ENGINES". This states that the KLM Redoubt encounter was at a range of 150 nm and that the estimated ash concentration was 2 grams per m3 i.e. 500 times denser than what is currently being claimed to be dangerous.

[peter we]

The ash plume has resided, looks like the eruption in Grímsvötn 2011 is over. There is however some ash floating around in the air, might cause local disruption here and there in the coming hours, over Iceland and elsewhere but that should be the end of it.

Today, there is glorious weather in Reykjavik, sunny and ca 12C. The darkness encroaching on the city and the whole of Southern Iceland has disappeared and the mood of the country improved

Sigrún Davíðsdóttir's Icelog (http://uti.is/)

Trust the Norwegians to quietly and competently do it better and more precisely.
What exactly would showing a few spots of clean air surrounded by ash achieve?
Last time I looked, the purpose of flying is to get from A to B, not circle in a 10 mile patch of clean air.

[Pace]

Bullet

I understand your arguement too. We talk about Volcanos and ash as if it is some sort of new phenomina which has hit us and which scientists are quickly trying to find a solution to to save us from this new threat.

Infact the problem has been around in various corners of the globe for as long as aviation has existed.

The only difference from the 60s and 70s is that back then no one would have known whether they had flown through invisible ash and probably wouldnt have cared anyway.

Nowadays we do care or should I say the masses of government departments who see a new target for their attention care as do our huge liability driven society.
The science is far from perfect as shown by numerous non aviation scares in the past. (we are all going to die from bird flu etc and all the media hype surrounding those episodes)

There is a risk in flying. Proven safety holes have to be identified and plugged.
Against that there also has to be a level of common sense or the industry gets bogged down by burocracy, huge expenses and overregulation.

Unlike many threat areas which are killers but which we seem to accept and live with to date throughout the history of aviation ASH has not killed anyone.

We have to trust the science and that is the big ?mark

Pace

[Herman the Navigator]

Good! So, what happens now? Do the regulators just shrug their shoulders and say, "nothing more for us to do". Or will they take very positive action to get a proper resolution? Or will the politicians force them to take their responsibilities seriously?

Who knows?

[Herman the Navigator]

What exactly would showing a few spots of clean air surrounded by ash achieve?
Last time I looked, the purpose of flying is to get from A to B, not circle in a 10 mile patch of clean air.


Have we touched a raw nerve?:)

My argument for a more detailed contour plot was that it would allow those who wish to to make a safety case for areas where concentrations are >4mg per m3. At present this limit is "The Edge of the World" (quite appropriate when you think about the "science" involved) and no one can possibly make a safety case (as the regulators claim they have been expecting to receive) for areas that could have a concentration slightly above 4 mg per m3 or any arbitrarily large concentration >4mg per m3.

[Sober Lark]

Statistically the biggest danger Vulcan poses to aviation has been CFIT and not ash.

Closing airspace is an overreaction to a low probability risk. It creates unnecessary travel disruption and falling airline shares.

When you over exaggerate risk who gets scared and who benefits?

[Postman Plod]

With the best will in the world, what use is a contour plot operationally, when a simple graphic will in fact do, and be much easier to read? The only thing the contours and colours add is prettyness for those who don't need it, detail for those who need it! If you can't fly in concentrations of ash above 400micrograms, then thats all you need to know! People always want flashy pictures.... :P

What you need to remember though, and what has been mentioned numerous times, is that meteorology is an inexact science (its not bad science in any way, but the atmosphere is a complex beastie!) I don't know what those Norwegian charts represent - I don't read Norwegian and I can't see anything other than a single image! However the dispersal pattern of whatever it represents doesn't look too dissimilar to those on the Met Office VAAC charts. Some agencies will produce much more "optimistic" charts, and others much more "pessimistic". Just because one chart shows you what you want to see now, doesn't mean it will show you what you want to see later - you have to accept that the atmosphere changes dynamically, and that each model run will be different.

and if it helps, the meteorological community do talk to each other, and are highly collaborative.

and finally, every Met organisation in the world is most likely capable of producing pretty contoured output like the Norwegian Met Office.

[Sonorguy]

And this lovely notion of " no-one has died from flying in Volcanic Ash" is typical Dead Body Economics. have you an acceptable number in your head ...would 200 be a good number or bad number?

'Dead Body Economics', as you call them, are the basis of all risk management calculations where that activity has the potential to be fatal. To be brutal the 'acceptable' number is the point where the costs associated with fatalities become unsustainable. For instance 2,500 road deaths a year is clearly 'acceptable' in the UK or we wouldn't be able to drive. This doesn't stop us from trying to lower the number though.

If the acceptable number was zero then we wouldn't allow people to drive cars, swim, ski or any number of potentially fatal activities.

[Calendar]

Quote:
The Met office have updated the long range forecast this evening and Friday now doesn't look so problematic. The forecasts I posted earlier are now out of date.
Surprise!!! surprise!!! and we are supposed to have confidence in this so called science :ugh:

The press have been having a field day with charts printed of these predictions and doom and gloom of how passenegers holdays and flights will be ruined!!!


So you'd rather that the forecasts were left the same, despite the fact that the situation has now changed?:hmm: Where is the sense in that??:rolleyes: What a ridiculous thing to say.:mad:

[WillDAQ]

And this lovely notion of " no-one has died from flying in Volcanic Ash" is typical Dead Body Economics. have you an acceptable number in your head ...would 200 be a good number or bad number?

About 100,000? That's roughly the number of people killed by civil aviation thus far... the entire industry spends it's time working out the acceptable level of risk of people dying.

[cwatters]

If I was an airline boss who wanted to minimise cancellation claims from passengers I would do everything possible to make darn sure they knew the cancellations wern't anything to do with my company. I'd want to be seen to be on the passengers side against anyone else I can find. Who cares if they are innocent. I'd also like to be seen as the only airline really trying to keep flying.

[MagnusP]

So much for MOL's "mythical" ash. The following BBC article shows particles taken from a car windscreen in Aberdeen.

BBC News - Ash cloud particles examined by Aberdeen scientists (http://www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-13559108)

[Postman Plod]

Could the science be better? Yes - no doubt! Is anyone willing to pay for the science, and invest in the capability? That is the question... You'd like to think so - this is the second time in 2 years this has happened, but as Herman the navigator says, will the regulators just shrug their shoulders and say "nothing more for us to do"?

I guess we have moved on slightly from last year, but its clear that more can still be done, and we weren't quite ready for this eruption!

[cuthere]

Ah Herman: think this conclusively shows that it's actually very straightforward to draw detailed contour plots (and that 1970s style arguments about computing power are a bit old hat).

If only the Met Office knew that all they had to do to deflect criticism was to to pretty up their charts and make them look more detailed......regardless of accuracy, and regardless of the ICAO/WMO/CAA stipulations of what they, as a VAAC, have to produce.

As an aside the Norwegian Met Service has nowhere near the computational power of the Met Office, so just because they have spangly charts doesn't mean they're better, though if that's all it takes to placate you, then I do worry.

[Sober Lark]

'dead body economics' - but unlike the effects of ash at least one can say the financial consequences of a loss are a known factor.

You can already see the raw data they are using as the basis for some forecast, decision or judgment is being tweaked. Collecting reliable data will take a long time and during this process of course you get a lot of garbage in, garbage out. Translated this comes out as fly above, fly below, don't fly at all. Getting this forecast accurate will take years. In the meantime let each company make their own decision rather than a third party making a blanket ban.

[Herman the Navigator]

Ah Herman:

If only the Met Office knew that all they had to do to deflect criticism was to to pretty up their charts and make them look more detailed......regardless of accuracy, and regardless of the ICAO/WMO/CAA stipulations of what they, as a VAAC, have to produce.

As an aside the Norwegian Met Service has nowhere near the computational power of the Met Office, so just because they have spangly charts doesn't mean they're better, though if that's all it takes to placate you, then I do worry.

cuthere, I'm quite well aware that the models have a significant degree of inaccuracy. And I wasn't suggesting that the Norwegian model is necessarily more accurate. It's more the fact that by provding something more than a big red blob, passengers, pilots and airlines can get a better idea of whether the 4mg liimit is close to, let's say, the 50 mg limit or whether that sort of much higher limit would provide much better flexibility (and on a personal note would avoided me being stuck in Helsinki at the moment - long story)...

If you or anyone else can give us the full story on how and why the 4 mg limit is as it is then I'm all ears. However, I will add that even a 50 mg limit would still be 40 times less than the 2g estimate for the KLM Redoubt incident.

Thoughts?

[KBPsen]

Some insight into how the limits were developed can be found here (http://www.caa.co.uk/docs/2011/Teleconferences%20log.pdf)

[Pace]

Herman

This is the big question mark? are the limits set to ensure that jet engines run their full expected time ( An airline economic decision) or are they set at a level to ensure that an aircraft is not brought down on a particular flight?
The present limits are still a tiny fraction of the Ash density at the Volcanic cloud source and so low as to not be visible to the naked eye in mist or cloud form.

The Metoffice do a fantastic job limited by the data they have and the tools available to them as well as the mandate that is given to them.

The Friday predictions of dense ash over most of the uk had the media blazing those pictures with headlines of holidays to be ruined for millions of passengers!!!

As those computer predictions have been proved to be so inacurate then surely they should be backed up by round the clock testing of those airmasses to confirm the predictions?

No wonder the Airlines tear their hair out when the predictions change overnight.You cannot run any business with such uncertainty and its the Airlines and our industry who pay not the burocrats,regulators or backwatchers.

Pace

[Defruiter]

http://www.caa.co.uk/docs/33/SafetyNotice201104.pdf

The CAA have issued new guidance:

"As a result of insufficient assurance for the accuracy of the vertical modelling, Volcanic Ash TDAs have previously extended from surface level to the upper limit of the modelled area of high ash concentration. Therefore, although procedures for the overflight of Volcanic Ash TDAs are in place, there has not previously been the ability for operations beneath areas of high ash concentration.

With immediate effect, Volcanic Ash TDAs will be promulgated by NOTAM with an associated upper and lower vertical extent. The publication of this information has been made possible due to improvements that have been made by the Met Office during 2011 to the dispersion model that predicts the movement of volcanic ash in the atmosphere. These included improvements to the way in which the ash concentrations in vertical layers are calculated. However, in order to mitigate an area of residual modelling uncertainty, the vertical extent of the Volcanic Ash TDA will include a lower vertical buffer zone beneath the level of the high contamination area depicted on Volcanic Ash Concentration Charts. This policy has been agreed on the basis of specialist scientific advice and accounts for the meteorological and eruption strength uncertainties that are inherent in this forecast."

[Pace]

Oh well maybe by version 20 we maybe somewhere close to reality? What can we expect with only 60 years experience to date ?anyone making a predictive model for the decline of our industry and job losses in all this ?

[Herman the Navigator]

Some insight into how the limits were developed can be found here (http://www.caa.co.uk/docs/2011/Teleconferences%20log.pdf)

Thanks KBPsen! This only covers the 2 mg limit though:

"The manufacturers were clear that although they were content that 2x10-3g/m3 represented a tolerable density level for their products, any further increase in this level would require more data on, and analysis of, the effects of ash contamination on airframes and engines" - 23 April 2010. The 4 mg limit (albeit with some riders) was introduced on 18 May 2010 - the data gathering and analysis process must have gone mighty quick in the intervening 3 weeks! :E

I also agree wholeheartedly with Pace in praising the Met Office's efforts. It's not the forecasting or data that I have a problem with; it's the use the data is put to and the fact that no one seems to have thought to figure out the result of making new rules until confronted with the practical consequences...

The referenced paper also says: "It would seem sensible to consider assessing the tolerability of ash and other particulates at densities of the order of 10^-2 g/m3". I hope that work is progressing as a matter of the utmost urgency, because the new "vertical" rules will be difficult to implement effectively and would be made completely redundant by lateral shrinkage, resulting from a higher density tolerance.

[WetFeet]

Maybe this time everybody could be involved in drawing up procedures. Several years ago, when the N Atlantic ash plan was drawn up, not one airline, engine or airframe manufacturer responded to invitations to contribute. They are quite happy complaining when it all goes t**ts up though!

[lomapaseo]

I also agree wholeheartedly with Pace in praising the Met Office's efforts. It's not the forecasting or data that I have a problem with; it's the use the data is put to and the fact that no one seems to have thought to figure out the result of making new rules until confronted with the practical consequences...



we're dealing with mother nature here, ala rain, hail, birds and now ash

The rules are not made up by throwing darts at a board to guess what is enough.

They are a balance between reasonable avoidance and a practical degree of capability in the product.

Let's start with what can be reasonably avoided versus what one in 10-100 million hours of operation will encouter.

Can somebody as a volcanologist, meteroloigist, flight dispatcher, big iron pilot tell what level of ash they expect to encounter over the lifetime of the fleet ??? e.g. no more than 1 in 10-100 million hours of operation ??

Then we can ask the new engine guys developing engines available sometime 10 years from now if any of those engine can withstand that specific level of ash.

Don't be surprised if the answer comes out yes but at a 10% decrease in fuel efficiency down to B727, DC-9 levels.

OK back to the meeting rooms, now how much ash are you willing to avoid to still meet the product advancements in fuel burn forecasted for 10 years from now ?

You see the answer does not rest alone with the regulator, nor the manufacturer. In fact without stastitically viable data (not tombstone) engineers have no where to start.

BTW, today's products are pretty much frozen regarding upgrade capability to tolerate ash, so you still have another 20 years of what you experienced in the last month in Europe to contend with even if you pour development and rule making resources into the pot in the meantime.

Those are the practical consequences.:sad:

[Locked door]

We had a volcanic ash encounter over the west of Ireland today. Shanwick informed us it might be there at multiple levels. We saw distinct thin but well defined bands of what looked like brown cirrus above and below us and then for two distinct threeish minute periods had a subtle but definitely present smell of rotten eggs in the flight deck. I asked my oppo and he denied responsibility.

There were no indications of any effect on the aircraft or engines, having just landed it is now undergoing detailed inspection.

So although the a/c is probably fine, there was definitely enough for the human nose to detect. I'd love to know the actual concentrations we encountered.

LD

[sabenaboy]

Locked door,

That sounds like an interesting event.

I just read this: Latest information received from the Icelandic Meteorological Office indicate that the volcanic activity in Iceland has paused. As a result of this lower activity, UK airspace is not expected to be affected.

Volcanologists and Geologists term this quieter spell of volcanic activity as a ‘paused’ phase. However, it is typical for a volcano like this to have several ‘pauses’ as part of its overall eruption phase. Only when the volcano has been ‘paused’ for three months will it then be regarded as being dormant.

Although no ash is being emitted at the moment, while any volcanic activity continues the Met Office will continue to monitor the situation.

Therefore I wouldn't be amazed if what you encountered turned out to be something else? Pollution maybe?

Anyway, I'm sincerely interested! Please keep us updated! :ok:

[Locked door]

It definitely wasn't pollution, Shanwick passed us an ashtam, it was near where they said it would be. By the time we realised what we were looking at we were in it, and by the time we received climb clearance we were out the other side.
Ref the state of the eruption, my understanding is that the ash has been in the atmosphere for days so the current state of the volcano is not relevant.

The smell was definitely sulphur, and coincided with the discoloured layers we saw.

If I get feedback on the state of the aircraft I will pass it on.

LD

[Herman the Navigator]

It seems the regulators and forecasters have known that a problem was coming for quite some time. Found this paper last night:

Comparison of VAAC atmospheric dispersion models using the 1 November 2004 Grimsvotn eruption
METEOROLOGICAL APPLICATIONS, Meteorol. Appl. 14: 27–38 (2007)
Comparison of VAAC atmospheric dispersion models using the 1 November 2004 Grimsv[]tn eruption - Witham - 2007 - Meteorological Applications - Wiley Online Library (http://onlinelibrary.wiley.com/doi/10.1002/met.3/pdf)

Just one quote from the paper:


"One of the most important differences between the models used in this comparison is the technique used for defining the reported ash cloud. The results suggest that the criteria used by the London VAAC leads to a greater forecast extent of a plume than the concentration contours used by the other VAACs, whereas ash forecasts from Washington are the most constrained in aerial extent. Of note here, is that the London results are not based on a threshold chosen by an operator at the time, hence they are reproducible and errors cannot be directed to an individual. The use of one threshold, rather than contours of concentration, also clarifies the data for the forecaster. Given that the current ICAO guidance is to avoid all ash, it is unclear how a forecaster should deal with low concentration contours."

So the London VAAC model is known to be more pessimistic than all the others in use around the world. Aircraft are almost certainly flying elsewhere quite happily in what is known as the "Red Zone" in Europe, due to differences in the model output and interpretation. The paper also points out that the Washington VAAC uses the same intial criteria for defining the outer edge of the cloud as London VAAC. However, the Washington forecaster is allowed to use judgement and sattelite imagery to (apparently) go to levels that are 10, 100 or even 1000 times higher than the initial number. Not playing darts, as Lomapaseo suggest but very flexible nonetheless. I wonder what the London VAAC view on this is? Is the 2 mg limit effectively a 10x judgement call, for the specific case of the 2010 eruption?

Lomapaseo - I wouldn't personally want anyone to consider going back to JT8D type fuel efficiency, to guard against unexpected encounters with very high density ash (way above 4 mg per m3). I thought we were discussing the possibilities of raising the limits at the margins, to make everything a bit more flexible.... Incidentally, another paper (puff.images.alaska.edu/classes/pdf/Prata_2001.pdf) suggests (without reference) that the "US military consider mass loadings >50 mg/m3 a potential hazard to their aircraft operations".

[Pace]

Herman

That is the problem with any computer predictive software.

The metoffice are quite good at determining the movement of airmasses and I stress the word quite!

Determining the density of ash in a given airmass is not so good! Detemine that level in both the horizontal and vetical modes is even a bigger hit and miss exercise. Very much a guesstimate!

Here lies the problem because any predictive estimates which are not based on actual samples taken to back up those predictions means a lack of confidence in the system and that is what we have.

Then we have to also look at density. Yes we may call certain areas red zones which implies areas of extreme danger but are they?

Even the red zones contain relatively miniscule amounts of ash compared to the known engine stoppers which spew out of the volcano source.

Are these amounts based on ash density which will bring an aircraft down or such tiny amounts that they put a ? mark over power sources reaching their expected life spans.

Power sources reaching their expected life spans are a financial economic judgement not a flight threatening judgement.

With predictive computer generated estimates we have no confidence in those estimates without spot samples to back them up.

Secondly with the red area estimates we have no confidence that such levels will threaten an aircraft.

With the data and knowledge available we in reality have little to inspire confidence that the predictive estimates are based on anything factual.

its all well and good blaming engine manufacturers but what engine manufacturer will attach his name to a threat he doesnt need to take even if that threat is tiny ? I Stress even before we had the ability to generate computer predictions not one life has been lost to Volcanic ash in over 60 years and millions of flights.

That cannot be said of thunderstorm incursions or bird engine ingestions or even ice which appear to be risks we are prepared to accept and live with and unlike low density ash the above are proven risks while low level ash encounters are un proven risks.

But then they havent been exposed to the media hype and attention that ash has or the political pressure to be seen to be doing something even if that percieved to be doing something costs our industry £Millions and generates results which are not very factual.

Pace