Air Pollution

[Pune]

Hi everyone,
I wondered why with all this air pollution and Saharan sand in the air, no flights were cancelled as with the Icelandic volcano eruption a few years ago, any ideas?
Cheers
Pune

[deerhunter]

Hi mate, think it may have something to do with particle size and abrasiveness, just my thoughts though

[Trenchard]

Hi mate, think it may have something to do with particle size and abrasiveness, just my thoughts though

Got it in one Dave, all down to Saharan sand having a much reduced mean particle size over the volcanic ash from that Icelandic volcano no one can pronounce.

[deerhunter]

Hiya T

Comes from 40 years as a pollution control officer

[Trenchard]

I bow to your superior knowledge Dave, I still can't spell eyafjallajokoll properly though

[RichC]

If you think about it, transports land on sand runways all the time, and you see them absolutely plastered in it when reverse thrust is actuated. It becomes a problem i would imagine if there is enough of it. The Sahara desert throws sand at us everytime there is a low pressure system in the Bay of Biscay with long frontal systems, fairly common.
The volcanic ash is highly abrasive, like deerhunter has said and it sticks to the engine parts like glue also.
There is also that the sahara sand does advect north at a lower altitude. The Volcanic dust is thrown up into the higher levels under pressure.

[reheat module]

Hi mate, think it may have something to do with particle size and abrasiveness, just my thoughts though

Got it in one Dave, all down to Saharan sand having a much reduced mean particle size over the volcanic ash from that Icelandic volcano no one can pronounce.

Meteorologists have just admitted they got the sand particle theory wrong; it's not due to the wind effect within the Sahara bringing all the dust, it's actually due to someone inadvertently opening the trophy cabinet at Anfield....

[Supra]

Jeeeeeeez! I am of an age that poor grammar & spelling does affect my nasal passages, coz I wuz tort propply! Even I had to Google this one...
ad·vect (ăd-vĕkt′)
tr.v. ad·vect·ed, ad·vect·ing, ad·vects
1. To convey horizontally by advection.
2. To transport (a substance) by advection.
[Back-formation from advection.]
Very good! but some people will need counselling for this one?

[deerhunter]

I still can't spell eyafjallajokoll properly though

[Pune]

Thanks guys, informative and amusing at the same time, brilliant, thanks again.
Pune

[opsjockey]

Shouldnt this be in the General Chat forum?

[mirage41]

Well opsjockey, if it does end up down there with us of The Tuesday Club, I'll appoint you as an official hangar-on.

[Pune]

There is always one is there not!!! it's not general chat, it's a genuine question, and it has an effect on the Military

[Beaker]

Volcanic ash has a lower melting point than sand. Ash is more likely to build up and glaze onto engine components. Sand is more abrasive but less prone to build up in engines.

There is a recent-ish thread on pprune about it but I haven't got a link straight off.

[Trenchard]

Interesting info Beaker. The Tornados in Gulf War 1 unexpectedly experienced glazing of the compressors blades, yet the Jaguar was hardly affected.

[deerhunter]

There is always one is there not!!! it's not general chat, it's a genuine question, and it has an effect on the Military

[Beaker]

Found what I was looking for. "Saharan dust is made of sand, blunted by many years of rubbing up against other dust particles. It has a melting temperature of around 1350 C.
Most turbine engine tgt's are around 850 C.
Volcanic ash has a melting temp of around 600 C. it melts all over the cooling ducts of turbines thereby blocking them causing overheating and eventual failure.
The abrasive properties are an issue but not the main one."

http://www.pprune.org/passengers-slf-se ... -dust.html

http://www.pprune.org/search.php?searchid=1914230

[RichC]

Indeed hence why i said it sticks to the engine components like glue....

[Pune]

Thanks for the info' guys, I am a little wiser now, much appreciated.
Pune