Duration of the event
 

I have not seen much focus by the media on the duration of this event.

Even if it just goes on for a few weeks, the effects could be major for Northern Europe.

As has been observed, the event could last years.

What would be the effect of a long and continuous ash fallout for aviation (even at low altitudes)?

I think we're into the realms of science fiction style solutions in that scenario.

Interesting times ahead perhaps.

I have read theories on this thread that these erruptions can lead to ash clouds hanging in the air for years.

However from recent violent eruptions I am of the understanding that these large ash clouds are associated with the initial 'explosion'. That initial explosive release of pressure that has been building up for years. Once the mountain has blown its top and that pressure has been realeased, the violence will subside.

I am no geologist, but I think this whole drama of airspace closures will be behind us in a few days.

However with the small margins airlines operate under these days, I hope all will recover from a couple of days sitting on the ground. :bored:

DB :ok:

I recognise the problem of dealing with public perception of danger, but I do feel that the reaction to this problem seems to have erred strongly toward risk aversion rather than risk management.

The ash plume is a three dimensional and largely predictable pattern. In the military we had algorithms for managing flow patterns (eg downwind chemical hazard); we could then operate around the threat. It wasn't difficult science. Why doesn't NATS have the same approach? It seems to me that they have taken an overweening approach.

More pertinently enormous areas of operating airspace appear to have been closed down, but not by operators. Operators deal daily with operating hazard - it seems odd to me that nobody is equating ash with dust/sand that forms a routine risk assessment in many parts of Africa and Asia.

Just a thought. But many correspondents might like to dwell on what they are told to do (and readily accept) by people who never step out of the bunker - and what the rest of us routinely manage as part of our daily approach to life.

Cash flow, or lack of it , took it's toll on airlines after Sep 11. Lets hope this is no longer than 2-3 days. Obviously the European based airlines are going to be the worst hit due to the fact that is their home base.

I hope you're right ! But.........
 

Desert Budgie

Wish I could share your optimism my friend. However, from a purely scientific basis I cannot. For example, your comment:
"However from recent violent eruptions I am of the understanding that these large ash clouds are associated with the initial 'explosion'. That initial explosive release of pressure that has been building up for years. Once the mountain has blown its top and that pressure has been realeased, the violence will subside. I am no geologist, but I think this whole drama of airspace closures will be behind us in a few days."

Here's the rub - in the case of a truly violent eruption (think Mount St. Helens) you would perhaps be correct and stand a reasonable chance of measuring the problem in days. These event usually occur with "Composite" or "Cinder Cone" type volcanoes that build up energy over long time periods, then suddenly release it very quickly in an explosive manner.

Unfortunately, the Iceland event is a "Shield" type volcano and these types behave differently, releasing their energy -heat, lava, ash, gas, etc.- over a longer, much less violent manner. Think of it like the difference between bursting a balloon with a pin versus letting the air out slowly.
Also, Iceland sits on the north end of the Mid-Atlantic Ridge, which has always made it a bit extraordinary geologically speaking. Said ridge is huge, spanning both northern-southern hemispheres of the Atlantic. It's one of the most energetic regions on the planet, spewing lava, gas & ash along its length constantly. Iceland just happens to be the part of it above sea level.

Per my previous post, and in-line with Skyhook One's post above, I think one should look at the long-term, do the science and engineering, and start trying to manage and/or plan around this problem. I sincerely hope I'm wrong. We're planning a family trip to the UK this summer !

Regards,
LoboTx, geologist at large

volcanic ash advisory latest map from met office website. Received at 0031 on 16 April 2010

http://www.metoffice.gov.uk/aviation...1271374304.png

Doesn't look promising for the airspace to open tomorrow however there maybe a chance for Irish airspace. I suppose we will have to wait until 0330z for the latest update from NATS

I think this is all a bit overdone.

We know that the ash that BA009 encountered was too much.

Is that all we know?

How much, for example, is of no significance? (in ppm)

How much is the level over, say, London today? in ppm or some other unit.

If it had happened during the Battle of Britain... blah blah blah:}

I'm glad the subject has been studied by scientists.

So what is the maximum SAFE concentration of ash?




Zero? :rolleyes:

I have just walked back from t'pub under a clear, starlit sky. There is no way that an aircraft would encounter volcanic ash tonight (25 miles from LHR). This is a massive over-reaction.

When Mt St Helens blew in 1980, the actual plume was shown on the met charts and we planned around it. Some ash covered most of North America but it didn't cause any problems.

On 24/2/90 I operated LHR-ANC. There was a large plume to the north of the airfield (Mt Redoubt), so we flew past the airfield and approached from the south (KLM had previously decided to fly through the plume).

My point is that it is still possible to operate during volcanic activity, so long as the major plume is avoided. To close an entire airspace in absolutely clear conditions has dubious logic.

Dave

Skyhook One:

barbiesboyfriend:

I'm sorry to have to tell you that it is not overdone.

First stage turbine blades in jet engines are operating in a gas stream well above their melting point.

They are cooled by an internal flow of cooling air that exhausts through hundreds of very tiny holes, providing what is called "film cooling".

Volcanic ash in the cooling air melts and clogs these holes. The result is blades overheating and failing. Failure = no thrust.

As far as I know, the only data on "How much" ash will cause this condition is supplied by Two or Three accidental flights through ash.

I don't believe anyone wants to risk aircraft or passengers in test flights to prove some theory about acceptable levels of airborne ash, or others about ash concentrations or flow patterns. As far as we currently know, the acceptable level is zero ash.

The blades look something like this, and they are very, very expensive.

http://www.pilotfriend.com/training/...o/images/6.gif

A lot of talk here about ash damaging/clogging engines, but what
about the toxicity of the upper atmosphere? If there are large amounts
of sulphur etc then that's going to be drawn in to the packs and the
air con. So whilst the ash particulate size/dispersal may not be a hazard
in a couple of days (falls due to gravity) what about the noxious gasses?
Who wants a lung full of that? :eek:

A4

What would you do?
 

It's apparent that a lot of people are very sceptical about whether the relatively thin dust cloud over the UK would bring down a plane.

You may be right, it may not bring down a plane. But you may be wrong. Who knows?

But consider this, if you had to make the decision whether or not to let the 500,000-600,000 people who's flights were disrupted today, get on board their aircraft and give it a go regardless, what would you do? Would you send your own family up there to try it out? I for one would not take that risk! The absolute number one priority of any airline and regulator is quite rightly safety.

Factor into it that airlines (mine included) would not want to risk causing any damage to their billions of pounds worth of equipment by flying it through that dust that can cause very real damage to an aircraft, even if it doesn't bring it down.

I say well done NATS for having the balls to make a difficult decision :D

UK Airspace now closed until 1900 local at the earliest...

'However, flights in Northern Ireland and the Western Isles of Scotland to and from Glasgow and Prestwick may be allowed up to 1300 (UK time) today, subject to individual co-ordination. North Atlantic traffic to and from Glasgow, Prestwick and Belfast may also be allowed over the same period'

"I have just walked back from t'pub under a clear, starlit sky. There is no way that an aircraft would encounter volcanic ash tonight (25 miles from LHR). This is a massive over-reaction."

Next time you're outside, have a quick look at the ozone layer and see how that's holding up, would you?

I said much earlier on this thread that I had been in the Indian Ocean/Indonesia incident when the a/c lost all four engines simultaneously. This was daytime - bright sun "clear" visibility - yet all four engines stopped. Restart was achieved only at a much lower altitude as the glassification dislodged. It was slow - one engine at a time. Just because you can't see the bl**dy stuff from the ground doesn't mean it isn't there!

Some hours ago listening to a very famous Vulcanologist i took 2 main ideas...
First, when this "Lil Bad Boy" had his last "euphoria" was around the beginning of 1821 and last until 1823..Ouchhhh:ooh:
Second, this "lil Boy here" has a brother some miles to the north, but with one "little detail"...shouldnt bother him cause this one its the double size...and if this one already can does such messy, one could really imagine what a double sized vulcano could do...!!????:confused:

Not all aircraft have this vulnerability
 

I hope someone does some work soon to base the closures on the actual conditions in combination of the vulnerability of the aircraft type for the flight.

I'd like to see charter operators, with piston engined equipment, make the money they should as soon as it can be determined that it is safe for them to do so.

BA9 Was at night
 

@ Royalist

History shows that the incident happened at night in darkness...

Thank God for the CAA in closing the airspace. No need to waste our breath arguing with the passengers. Perhaps this may have saved some press-on-itis operators from an incident or accident. :ok:

Royalist,

your memory seems to be failing you:

http://www.ericmoody.com/Page1.pdf

Top of right hand column:

"...the night was moonless but clear..."