Why is volcanic ash so dangerous for planes ?

Source : metro

In June 1982, a British Airways Boeing 747 jumbo jet flight from Heathrow to Auckland flew into a cloud of volcanic ash caused by the eruption of Mount Galunggung in Java, Indonesia. At first the crew were unaware of the exact nature of the problem but within minutes all four engines had failed. With cockpit windscreen visibility seriously reduced, the plane managed to glide far enough out of the ash cloud for three of the four engines to restart. The crew, who were to receive various awards, made light of a number of difficulties in landing at Jakarta and put down safely. It was later discovered that as the ash cloud was dry it did not show up on the weather radar designed to detect the moisture in clouds. The cloud sandblasted the windscreen and clogged the engines which restarted when enough of the molten ash broke off after solidifying.

I thought it was interesting to have an explanation : to-day, most of the northern european planes (including Spain) are stuck on ground.

And ... this is for a SINGLE volcano.
Imagine if a lot of volcanos were suddenly erupting ?
Think of the military consequences ...

I saw this explanation while looking for a link for another thread:

However, air traffic restrictions have very properly been applied, resulting in closure of airports and airspace.

“This is because if volcanic ash particles are ingested into a jet engine, they accumulate and clog the engines with molten glass.”

Emergency procedure manuals have been changed in the wake of various volcanic ash incidents.

In 1982, a British Airways plane dropped to within a few thousand feet of the ground after flying into an ash cloud over Indonesia.

Dr Rothery said: “Previously, when engines began to fail the standard practice had been to increase power. This just makes the ash problem worse.

“Nowadays, a pilot will throttle back and lose height so as to drop below the ash cloud as soon as possible.

“The inrush of cold, clean air is usually enough to shatter the glass and unclog the engines.

“Even so, the forward windows may have become so badly abraded by ash that they are useless, and the plane has to land on instruments

Read more here:

All Aircraft should be grounded as a matter of safety.
I made this thread prior to the polish crash
www.abovetopsecret.com...
My wife described her dream and she says that its not over yet.

Also during a volcanic eruption are there any other factors effected?
Think im crazy? probably but is there some sort of effect that actually alters either the atmosphere or gravity during eruptions?

If you think this is interesting, you should learn what it does to you if you would inhale it. It's glas where they talk about.

Thanks for posting. I didn't know that.

in one of my posts in this thread, I spoke of the military consequences of tha flying ashes of the Icelandic volcano.

Just have a look on what follows ...

Several NATO F-16 fighters suffered engine damage after flying through the volcanic ash cloud

A senior Western diplomat says several NATO F-16 fighters suffered engine damage after flying through the volcanic ash cloud covering large parts of Europe.
The official declined to provide more details on the military flights, except to say that glasslike deposits were found inside the planes' engines after they patroled over European airspace.
Last week, two Finnish Air Force F-18 fighter-bombers suffered similar damage while flying through the ash plume that has paralyzed air traffic over much of Europe. Both landed safely, but their jet engines will require expensive overhauls.
Volcanic ash tends to stick to a jet engine's interior parts, such as the turbines, where it melts to form a glassy coating. This restricts air flow and heats up the engine, leading to engine failure.

Air travel by Zeppelins not sounding so bad now, is it?

I wonder if this would impact Helicopters...??? Or propeller driven aircraft?

reply to post by Gazrok


Most helicopters, and some propellor driven aircraft use jet engines to provide power, so it most certainly would affect them.

Here are pictures of an F/A-18 Hornet engine after flying through the ash cloud. Finland had 5 Hornets flying in an exercise shortly before the airspace was closed, and released pictures from a borescope of one of the aircraft.

reply to post by Gazrok


I'm sure any aircraft that uses a propeller will be fine. Their motor would probably not get hot enough to melt the dust to glass.

Just al guess tho.

[edit on -05:001658 April363 by Sinter Klaas]

here is why -

www.newscientist.com...

and heres previous problems that have been logged by boeing -

www.boeing.com...



[edit on 20-4-2010 by grantbeed]

Aparrently after all it's not bad for planes any more. We were wrong. We now know what level is safe, and where those levels exist in airspace. All within a few days and a few test flights through unknown-density regions. Isn't that just lovely?

news.bbc.co.uk...

Hmmmmmmmmmmmmmmmmmmmmmmmmmm.

I hope some kind of plan to deal with buildup over the course of several flights exists.

reply to post by d60944


We shall soon see - just like the NATO F16 pilots did (and F18's) who now need to have expensive engine overhauls.

I really hope they DO actually perform regular checks on engines following this action, judging by the pics floating around the net of the F18 engines it doesn't look like its easy to miss!

I am not an aviation expert, but how can anyone seriously assume that a 45minute test flight is grounds to declare the blanket ban on flights wrong?

Originally posted by argentus
I saw this explanation while looking for a link for another thread:

However, air traffic restrictions have very properly been applied, resulting in closure of airports and airspace.

“This is because if volcanic ash particles are ingested into a jet engine, they accumulate and clog the engines with molten glass.”

Emergency procedure manuals have been changed in the wake of various volcanic ash incidents.

In 1982, a British Airways plane dropped to within a few thousand feet of the ground after flying into an ash cloud over Indonesia.

Dr Rothery said: “Previously, when engines began to fail the standard practice had been to increase power. This just makes the ash problem worse.

“Nowadays, a pilot will throttle back and lose height so as to drop below the ash cloud as soon as possible.

“The inrush of cold, clean air is usually enough to shatter the glass and unclog the engines.

“Even so, the forward windows may have become so badly abraded by ash that they are useless, and the plane has to land on instruments

and getting to the real point....

the commercial airline$ do not want to replace those co$tly engine$ before they need replacement...


read between the lines


thanks for the info