Ash cloud Fishyness

Thursday 15th april 2010 and a volcanic ash cloud from iceland has grounded all flights in and out of the uk and much of western europe. The uks aviation authority Nats has said its unsafe to fly in and out of the ash cloud because of fears that it could damage the planes jet engines.

All the while the airlines are crying out to be allowed to fly, british airways cheif executive takes to the skys to test the effects of ash on the jet engines, and big surprise, there is no effect.
After this revealing a couple of days later british airspace was once again opened, and flights returned to normal, until today.

Tuesday 4th may 2010 and its now been deemed that its unsafe to fly in ireland and in some parts of scotland again as a new ash cloud has drifted southwards towards us. But i thought we already discovered that we can fly through the ash and it has no effect on the engines.
Is it just me who thinks this whole, we can fly, we cant fly, we can, we cant attitude smells a bit fishy. i mean if i didnt want someone flying what better way to do it than to make people think it was for their benefit.

So what reason would they not want us to fly.
Terror threat?

It's for safety issues. The rather large sediements and dust in volcanic ash clouds have been proven to make Jet engines stall, infact I've heard of an incident where a pilot made the decision to fly straight through an oncoming ash cloud, next thing they know, their engines have failed, and they are now gliding through the sky, took a whole 20 minutes to start back up again apparently. I can't remember when this happen, but I know it was a few years ago.

Anyway, it's basically just for passenger and crew safety, I'm pretty sure the tourism industry doesn't want any un-necessary blood on their hands.

[edit on 4-5-2010 by Jordan_The_Maori]

Just a thunk.... Could this be related to Alleged Nasa Signal and another post?

Clear sky clear signal?

"trying to give this thread extra legs"

Originally posted by IanC99000310
Just a thunk.... Could this be related to Alleged Nasa Signal and another post?

Clear sky clear signal?

The sky isn't/wouldn't be clear, so I think we can rule that out.
I mean sure, the air traffic would be minimal, but you still got a GINORMOUSLY HUGE ash cloud hanging around in the atomosphere.

Originally posted by Jordan_The_Maori

Originally posted by IanC99000310
Just a thunk.... Could this be related to Alleged Nasa Signal and another post?

Clear sky clear signal?

The sky isn't/wouldn't be clear, so I think we can rule that out.
I mean sure, the air traffic would be minimal, but you still got a GINORMOUSLY HUGE ash cloud hanging around in the atomosphere.

Well there goes the extra legs!!!

reply to post by Damezthe2ndThat was the first thing i thought of when the ash in the sky first came to light. I think the powers that be said it was unprecidated to have uk airspace closed. But obviously the volcano must have happened so i dont know about a terror threat, however if it is true that volcanos and earthquakes are happening all the time all over the earth, why havnt i heard of airspace being closed more regularly, maybe i dont read the papers enough!

HAHA! Yeh sorry about that, but there's a lot of paranoid people on here that tend to go spaz at posts like that.

*Put the tin-foil hats away fellas.*

damned if they do and damned if they don,t get a grip folks it was a safety issue.
if a plane had come down every one would have been screaming , why the hell did they let the planes fly when there was a possibility of danger .

From the wiki article on Volcanic Ash :-

It is important to make a distinction between flight through (or in the immediate vicinity of) an eruption plume, and flight through the so-called affected airspace. Volcanic ash in the immediate vicinity of the eruption plume is of an entirely different particle size range and density to that found in downwind dispersal clouds, which contain only the finest grade of ash. The actual level of ash loading which catastrophically affects normal engine operation has not yet been established, beyond the knowledge that relatively high ash densities must exist for this to happen. Whether this silica-melt risk still remains at the much lower ash densities characteristic of downstream ash clouds is currently unclear. This is however a serious safety hazard which requires preventive risk-management strategies, in line with other comparable aviation hazards.

The same article also mentions that

Volcanic ash particles have a maximum residence time in the troposphere of a few weeks. The finest tephra particles remain in the stratosphere for only a few months

So it would seem that the heavier/denser material in the plume remains in the troposphere which extends up to around 33,000 feet, from which it normally falls back to earth within a few weeks. The lighter material can stay up in the stratosphere for months.

The stratosphere extends from around 33,000 feet above sea level to approximately 164,000 feet.
Commercial airlines typically operate between 31,000 and 37,000 feet. Most of them are certified to operate at ceilings up to around 42,000 feet.

If this is a ruse, then it's a particularly convenient one because it's extremely difficult for Joe Public to directly ascertain the quality of the air in these stratified layers more than 30,000 feet above our heads (anyone got a spare weather balloon in their garden shed?).

It seems to me, based on the history of previous aircraft incidents involving volcanic ash that the risk is very real, but that an aircraft really has to fly through a cloud of the heavier material in order for it to have a severe effect on the operation of the aircraft.

I don't yet have enough information to draw any solid conclusions, but I thought I'd share some of the information which I have gathered.