Icelandic volcanic ash alert

[nking]

Anyone in Scotland seeing the effects? http://news.bbc.co.uk/1/hi/uk/8621407.stm

[steve]

Our planes have been cancelled. Seems a bit odd as they don't go very high. I guess they're not taking any chances. Weather is overcast, no obvious signs of ash.

[EvilV]

'Elf 'n safety', Steve. Same syndrome that cancelled all the London buses in 2009 because an inch of snow had fallen on London. Soon, the UK will go into hibernation whenever a snowflake, fleck of dust or hot day is forecast.

If anyone wants to see the cloud erupt from Iceland, for a short time, this set of moving satellite images will show it. You can see the eruption at about 8.00 hrs and it builds until about 10.00. Because this link shows recent images, it will be superseded as time passes by new ones. There is a small red caption on the image pointing out where to look.

http://sat24.com/Region.aspx?country=eu ... &type=loop

[geoffw]

We often get 'dust' on our card parked on the drive that is clearly 'alien' ....... Summer highs pull it up here from the Sahara I understand.

Yesterday morning and again this morning there was a similar deposit so maybe it is there in the air. I don't think at this distance any of us are going to see a 'cloud' of dust.

EDIT: As the grounding of aircraft - I for one think - better being called a fool for doing it than being blaimed by the 'hindsight' brigade in the aftermath of an accident!

[hills]

I saw on one of those air crash investigators episodes that volcanic ash really stuffs up planes engines and they can't see it on the radars.

[Gina]

BBC News and BBC 1 are broadcasting a special programme about this as I type. Since volcanic ash can "kill" aero engines in seconds. I think the precautions are well founded.

[Great Cornholio]

As an airline pilot I can explain the bad things ash clouds do to planes. I only fly in the United States and parts of Canada so lucky for me I'm not affected by the ash cloud (good for me since I only get paid once the door is closed and the parking brake is released).

Ash clouds (nor any clouds) for that matter can be "painted" by our radar. Only precip or ground can be painted by the radar. Ash clouds have almost caused many crashes before. The ash cloud will cause a jet engine to stop really quick. The most common problem seems to be a compressor stall (air reverses flow and flows out of the front of the engine instead of the back) which in turn will lead to a flame out (engine quits). The ash will even clog the fuel nozzles in the engines. I'm not sure exactly why the ash is so bad for the engines as thats never been told to me, but my guess would be that the ash "sand blasts" some of the compressor blades (rotating pieces) and stator vanes (stationary pieces between sets of rotating pieces) just altering their shape just a bit, or the ash bonds to the same parts also altering the shape. Jet engines are built with extremely small clearance between moving and non-moving parts...think 1/1000 of an inch neighborhood. The main thing a jet engine does is compress air and control the pressure of the air inside the engine to keep it efficient and flowing in the proper direction. Any change in the engine and the air may not behave normally and the engine will lose power or fail. If we find ourselves in ash we go to idle thrust open as much "bleed air" as possible to lower the diff press across the engine to try to keep it from having a compressor stall and do a 180 degree turn to get out of the ash since ash clouds can last for thousands of miles. Thats just the stuff it will do to the engines.

The rest of the plane will get sand blasted so the paint will come off. Not really a big deal. The windshields may get sand blasted to the point where you can not see out of them. The airspeed, vertical speed, and altimeter all use this thing called a pitot static system which basically senses air pressure. The ash can clog the pitot tube which would lead to the plane showing a slower speed than it is doing...or going all the way to zero if totally clogged, or if the static port becomes clogged then all three (airspeed, vert speed, altimeter) will provide erroneous and false information and could lead to a crash. The rubbing of the ash across the plane will also cause lots of static electricity to build on the plane which could cause problems with the electrical system and even possibly cause a lightening strike which could also have bad results from small holes in the plane to exploding a fuel tank, to frying the electrical system.

As you can see ash is very bad...so we don't go anywhere near it.

[EvilV]

One of the things volcanic ash does in a jet engine is melt, turn to a sort of glass / slag and stick on internal parts of the engine, blocking up ducts.

Having said that, and also bearing in mind the know problems, the AMOUNT and density of dust in a particular location is fundamental to creating a problem. This cloud as far as it affects the UK and Europe is very sparse. Some of the flights looking for particles over the northern UK came across no particles. The famous Speedbird 9 event in June 1982 off Jakarta, flew right intoa dense plume which blasted the windscreens to frosted glass, stripped off the paint and filled the engines with melted slag which stuck on the internal parts until the engines cooled when it then fell off and allowed them to be restarted. It's all about how much ash there is. This event is an absolute disaster. There are many tens of thousands of people stranded all over the world, and this volcano could carry on like this for years. Since it is to the west of the UK and northern Europe and in latitudes of prevailing westerlies, I predict that the current over-cautious stance will change pretty quickly, before the aviation industry in Europe goes belly up.

[andrewinpopayan]

I was in Grimsby overnight on Tuesday and it rained a little during the night. Next morning my car was covered in a fine red/orange powder, much like sirocco (sahara) dust nut wind has been predominantly N and NNW, I believe that it's Icelandic dust deposits.

[EvilV]

I found a lot of reddish dust on our cars the day before the aircraft fly ban started. I haven't seen much since, but that dust was rather unusual, first for its colour and also because it wasn't that fine.

I notice that KLM have been flying a few of their big jets around today to test the effects on their machinery. They are empty of passengers.

I expect they are beginning to worry about the long term behaviour of this volcano and its neighbouring ones. They tend to go off together when they become active, and as you all know, erupted for two years lest time they got stirred up. With generally westerly wind patters from Iceland to the UK the current level of flight restriction would be really catastrophic for the industry and for travellers.

I still assert that the TOTAL flight ban is a HUGE over reaction given the sparse density of the dust over the UK and Europe at the moment. The disruption is actually pretty serious for passengers and business, particularly freight, but I know at least three people who are stuck abroad and trying to get home overland, and so seemingly do most people I speak to about it. There are some folks I know stuck in Paris having travelled there by train from both Italy and Spain, and they are waiting for a Eurostar to the UK, with no sign of a slot yet. Apparently, John Cleese paid £3000 for a taxi to take him from Norway to London. LOL. That's the funniest one he has cracked in a long time. I'd have gone by train, myself and paid for a damned good holiday out of the change.

Frankly, I REFUSE to believe that passenger jets don't fly every day through plumes like this one is over the UK. There must be regular air routes within a thousand miles of active volcanoes all the time yet how often do you hear of a total lock down like this. Never is my answer. There is a world of difference between flying right into a plume where it starts. A thousand miles downwind is a different story.

[EvilV]

Just found this -


http://news.bbc.co.uk/1/hi/world/europe/8628323.stm

Airline organisations protest total airspace shut down in Europe. They say it is not necessary and their test flights found no effects from dust.


I was right.

"The concentration of ash particles in the atmosphere is in all likelihood so little it poses no threat to air transport," said VNV chairman Evert van Zwol."

http://www.telegraph.co.uk/travel/trave ... affic.html

[steve]

Just heard that the govt have commandeered the ferry I'm supposed to be getting on Sunday night to the UK mainland to start one of my occasional trips to the office "down south". They're using it to rescue people stuck in Norway. Hopefully it will be back doing its usual job by the weekend. Well, hopefully not, actually, I'd rather not have to go!

[EvilV]

You'll be one of very few people to claim they can't travel because their ferry has been cancelled due to the ash cloud.



I hate even typing those words 'ash cloud'. It isn't anything of the sort. What it is are tiny fragments of dust very well dispersed in the upper atmosphere. The term 'cloud' implies something altogether more dense than is being experienced as more than forty ash cloud hunting sorties of heavy jets have discovered for themselves, returning in pristine condition after braving the evil aircraft destroying cloud that belched from the bowels of Hell in Iceland, or the fevered imagination of a Met Office model, as many believe, including the senior executives of all the major European airlines.

[mcrossley]

Well airline 'executives' may have more commercial motives to get things flying than the scientists. I see the RAF grounded their Euro fighter training sorties after a single days flying resulted in ash deposit build-ups in some of the engines

[EvilV]

There would always have been hazardous areas, and as for the RAF engines, first it depends where they were flying, and second, as engineers on the radio have said, those engines are a very different proposition to a big fat turbofan.

I don't think there can be ANY doubt that the wholesale shut down of air traffic across the whole continent was an over reaction. Lord Adonis said so in no uncertain terms, thereby opening up the government to a billion pounds worth of claims. Also, the 'new guidance' on operating airlines in ash contaminated air are amazingly different to the 'zero tolerance' regulations operated before. Now it is decreed entirely safe to operate where the ash level is .002 grammes per cubic metre of air. On the day this was degreed, the ash levels over the British Isles were one twentieth of that level. At the worst time of the ash cloud, the air over the shut down European air space were only 20% of the new, declared safe level.

Of course, there can be dangerous levels. It is all a matter of judicious route planning, and judging the requirements of particular high performance engines that might have esoteric needs. This is a photo of volcanic glass attached to a turbine blade of one of the Finnish F16. However, we don't know anything about where it was when it picked up this contamination. All airlines are monitoring their engines more than usual and doing boroscope examinations of the dark recesses of turbines and combustion chambers. They would not be flying if they thought they were going to lose an aircraft or if there was the slightest chance of that.



The reaction of wholesale shutting of airspace is unique in the world in spite of airlines having to deal with on average ten volcanic eruptions every year, mostly around the Pacific Ring. While not all eruptions are ash rich, many are, so this event is far from unique in terms of its potential to pollute airlanes with dust.