"Are we talking hours, days or weeks? No idea really."

Apparently Icelandic volcanoes don't have as much gas as those in the Caribbean and other places, so it won't be years (of ash/dust thrown up).

The worry is that it will stop and start or that Katla may start up as well.

This is going to be messy...

Metcheck.com - Atlantic Jet Stream Forecast - [Updated on 15 April 2010 at 20:00] - Weather Feeds - Live Data - Long Range Weather Forecasts

My point exactly.

And as I fly hardware with spinning wings over my head, I tend not to exceed 7000 ft. So closing off the entire airspace without any concrete information about concentration levels and when they are considered to be dangerous and why, is pretty annoying.

I don't advocate finding the nearest ashcloud and drive straight through it, but after all sorts of knee jerk reactions to terrorism, illnesses and perceived threats, I am loathe to accept at face falue the simple closing of large areas of airspace "because we know it is safer".
Show me the proof, or at least show me the theory behind the caloculations. Stopping all SAR and HEMS because someone says we should not be flying to me is an overreaction when not substantiated by scientific evidence.

And what if it takes more than 4 days? What if it is 2 weeks? Are we then going to differentiate in which concentrations are safe enough to fly and which are not because the economy cannot sustain a total shutdown? What sort of evidence will we be using then?

I can understand not putting high speed IFR traffic into a risk area, but I do not believe that the entire airspace from the ground up towards the stratosphere contains enough ash to become a significant problem, and especially not in VFR/VMC conditions.

Did you actually bother looking for any information?
I'm guessing no. Otherwise you would have found this page that details the basics (very basics) of how the London VAAC operates:
Met Office: Volcanic ash detection tool
You would also have found this page, which shows the last known ash spread (top left) anf projected spread for the next few hours:
http://metoffice.com/aviation/vaac/d...1271354037.png

You'll notice that there is currently ash over London, even though the inability of our eyes to detect IR light means we can't see it.

By searching google scholar or a similar database you'd also find literally thousands of papers and articles on the subject of ash dispersion, ash detection, the effects of ash upon aircraft and countless related topics.
e.g.:
volcanic ash advisory - Google Scholar

The fact that it's on top of your island rather than on top of some godforsaken pacific island.:ok:


(edit) And for those wanting proof: The theory and calculations behind volcanic ash detection are available through google scholar, although you may need to go to a library to gain access to the actual journal articles.
The data required for detection (AVHRR) is freely available from NASA. You can download it yourself, although unless you have a fancy satellite dish you will have to put up with a day or so delay from real-time.
Then you'll have all you need to calculate the ash spread yourself.

There is certainly very rough, to the touch, brownish coloured contamination on cars in this area.

Quote from NATS

All of scandinavian airspace is closed...

My flight tomorrow to palma is delayed... =(

Not to turn this into a spotter thread but radarvirtuel is showing a lonely CL601 Challenger over the London area (G-FBFI).

I thank that is a point, so whilst some are denigrating the UK authorities, other countries are taking the same precautions. So are all these other nations wrong as well?

There may be a clue in the silence
 

S76, I disagree and I take my clue from the silence from the airlines themselves. Not a peep from Cryan or Squeezy, let alone the network airlines. They cannot be happy - expenses through the roof and refunds flowing out the door - but they aren't going to risk the reputations, their employees, or their expensive aeroplanes just because someone hasn't proved its unsafe. Fear of litigation could be part of it, but I give them credit by thinking that isn't their sole, or most important motivation. Ask BA, ask KL, ask any of the other reported 90 odd volcanic dust incidents over the last 20 years?

Better safe than sorry? You betcha.

These virtual Radar sites are only as good as info put in as G-FBFI =G-CHAI
This went to biggin hill VFR just before 1900 this eve from Oxford . possibly
its off home again.

TONY

Really? Where is that written?

I think the European aviation industry needs to come up with some drastic measures that need to be brought in during times of crisis such as this.

It's fair to say that a good 25-33% of flights from this country that are heading southbound could still take place virtually risk free at a lower level. I'm not saying my numbers are correct but an example might be: A departure out of Gatwick could trod along 100 nm south at 6000ft before being out of the risk zone and then climbing higher and proceeding normally. Clearly this means temporary changes to airspace classification across borders which would affect GA but thats a lot better than having commercial traffic at a complete standstill for a month!

Just an idea, don't shoot me down!

Sky news just showed some of the procedure if flown into a volcanic cloud (in a flight simulator).

Very informative (even for SLF like me).

And the BBC'S coverage is mostly about the live debate...

Go figure.......

As has been said multiple times, those images are available. I posted one this morning, someone else psoted one this afternoon.
After a post mentioning the BBC I just went and checked their website. They have a large satellite image of the ash as their primary image. What more do you want?

And the reason most science is not explained publically is because 99.999% of people don't care. Just about every science major project in the last 10 years will have an informative website detailing their objectives. Just about every library in every country in europe has access to scientific journals whereby anyone can see just what the scientists are doing. Again, what more do you want?

KL867
 

I've dug out the NYT article from Dec 89 KL867

This incident happened despite the KL crew knowing there was an ash-cloud in the vicinity, but There's also a mention of the BA and SQ incidents here.

Edited to Add. There is also this comment: That's how it was in 1989, thankfully we no longer leave it up to the individual airlines ...

The fact of the matter is that there is an uncertain amount of risk associated with flying through a volcanic dust cloud. Probably most aircraft would be unaffected, but there is a chance that something would happen in a small number of scenarios.
The two or three well known instances have survived by good airmanship and luck. They could very easily have gone the other way.

So who is willing to take the chance? Is it 1/10,000, is it 1/100,000? What is an "acceptable" level of risk, and who determines that.
Who would take the responsibility if the 1/100,000 chance went wrong?
In this age of litigation at the drop of a hat the legal liability would be horrendous.

No doubt this huge disruption will spur new research into the effects of volcanic dust and the forecasting of danger zones, but in the meantime we have to err on the side of caution.

@ Peter We, thank you.

Over cheshire today , looking directly upwards the blue sky had a dirty grey tinge to it, but looking either side it appeared much bluer - guess its a bit of parallax. and our cars are covered in a fine grey ash.
Frankly I'm glad my husband is not flying.:D
Not so glad to have to return to work this weekend though if it has all cleared away!;)

louby

Volcano ash vs dust up there anyway.
 

I recommend Simonpro's replies. I'm neither an atmospheric scientist, nor an engine engineer, but I think there is definitely cause to worry about flying through a spread-out dust cloud, as well as a BA9/KLM867-style eruption plume.

Any rock-like material will melt onto hot turbine parts, which are some of the hottest and most carefully-shaped surfaces that are engineered. If a random coating of volcanic glass improved jet engine performance, one would have been fitted in the factory. Piston engine/turbocharger surfaces are much cooler, and so I doubt they would suffer.

No rock ash is good, but there is a background level, definitely from meteorites and averaged volcanic emissions, and perhaps from wind-uplifted sediment, with which aircraft engines cope all the time.

Meteorite particles rain down at the rate of a few hundred thousand tons per year, over the whole earth (Access : Space Density of Dust in the Stratosphere : Nature 4838 (1962) p. 269). This gives a hard lower limit to the amount of meltable particles in the stratosphere.

Iceland currently seems to be chucking up a few tons of ash per second into the stratosphere - a rate that is about a thousand times higher than from the meteorites, and concentrated geographically (Satellites Providing Rapid Estimates Of Iceland Volcano Emissions - Science News - redOrbit).

Volcanos that went off during the last few years also contribute to the background level of stratospheric ash. I can't immediately find a number for this, but individual volcanos seem to make a factor <10 difference to lidar measurements of particle density in the stratosphere, so it's probably not hugely greater.

With a few volcanos a year throwing ash up for a few days each, and a couple of years needed for it to rain back down, that would imply something like an average of one-to-ten million tons of volcanic ash in the stratosphere at any time, likely a factor of 10 more than from meteorites, especially at aircraft heights in the lower stratosphere.

A diffuse, drifting cloud of volcanic ash from Iceland does seem to be a real risk. It is reasonable to expect levels of turbine-clogging ash over the UK to be up by a factor of at least a hundred from the background at the moment. Where a safe line can be drawn, I don't know, but Eurocontrol seems to be confident that it's below where we are now.

Let me tell how does it look from airline office:
1. We have no idea how danger it is really. All we know is similar to what Joe Public knows (like BA009 story). We are neither educated nor qualified to quantify the risk in the way like "BA009 was 100 km from volcano and it is ended up badly, so we should be ok if we are at least 200, 400 or 500 km from there".
2. We have spoken to local MET office. Actully they have no clue either. All they know is what you can read on internet. Not a big suprise, given most European countries are active volcano-free.
3. We don't want to get a bad PR from the press, who will say "airline XXX is putting revenue on top of safety and asking a clearance to resume the flights".
4. Neither we want PR like "airline XXX forced pilots to depart VFR and low level to boost the revenues".