Volcanic ash stops flights

[wolram]

http://www.guardian.co.uk/world/2010/apr/15/airports-closed-volcanic-ash-iceland

[Andre]

That's quite a spectacle:

http://www.icelandviking.com/wp-content/uploads/2010/03/eyjafjallajokull-volcano-eruption-2010.jpg

source (http://www.icelandviking.com/volcanoes/eyjafjallajokull-volcano-eruption/)

which also states:
Throughout history, Katla always erupted after Eyjafjallajokull, the only question is when and how strong her eruption will be. Geologists not only from Iceland, but certainly from all over the world tend to agree that if Katla goes off, the eruption could have global consequences.

Aircraft don't like Volcanoes as we discussed before (http://www.physicsforums.com/showthread.php?t=249594).

[Borek]

Aircraft don't like Volcanoes

You can't say for sure. Could be volcanoes don't like aircrafts and they do what they can to ground them.

Edit: so far, so good. http://www.ruv.is/katla/

[matthyaouw]

Foor anyone interested Johann Smari has some fantastic photos of the event.

http://www.flickr.com/photos/smari/4476784097
http://www.flickr.com/photos/smari/4488053300/

[AppleBite]

Does anyone know where one can find satellite images of the ash cloud?

[wolram]

Does anyone know where one can find satellite images of the ash cloud?
Im not sure if the (cloud) would show up.

[AppleBite]

Well, I've found some predictive maps, like this one:

http://www.telegraph.co.uk/travel/travelnews/7592867/Volcanic-ash-cloud-latest-news-from-British-airports.html

But looking for one where on can see how the winds are directing the ash

[cristo]

All flights in and out of the UK and several other European countries have been suspended as ash from a volcanic eruption in Iceland moves south.

Up to 4,000 flights are being cancelled with airspace closed in Norway, Sweden, Finland and Denmark among others.

The UK's air traffic control service (Nats) said no flights would be allowed in or out of UK airspace until 0700 BST on Friday amid fears of engine damage.

The airspace restriction was the worst in living memory, a spokesman said.

http://news.bbc.co.uk/1/hi/uk/8621407.stm

I have to say, it's eerily quiet with no planes overhead!

[turbo]

http://news.bbc.co.uk/1/hi/uk/8621407.stm

I have to say, it's eerily quiet with no planes overhead!Very quiet in New England just after 9-11, too. Only military planes. It's odd what you get used to. I hope that volcano settles down soon - that's a pretty wide-spread disruption.

[Evo]

Satellite maps of Iceland Volcanic ash.

http://news.bbc.co.uk/2/hi/europe/8622978.stm

http://esciencenews.com/articles/2010/04/15/new.satellite.image.volcanic.ash.cloud

[lisab]

From one of Evo's links:

http://i39.tinypic.com/wm1rb5.jpg

Any PFers in that area seeing ash fall? Any other signs - perhaps an unusual sunset color?

[Andre]

We are waiting for that

It has just been decided that the Netherlands air space is closed to all air traffic.

[Borek]

Any PFers in that area seeing ash fall? Any other signs - perhaps an unusual sunset color?

Sun is already low here so I went to the attic to check - and I found our roof window facing north is covered with ash. But it is less than 10 feet from the chimney, so I don't blame Icelandic volcano. So far Sun doesn't look unusuall. But then I am on the border of the marked area.

[Count Iblis]

You can listen to the latest information for aircraft on Shannon Volmet on 5505 KHz. If you listen to Shanwick ATC on e.g. 5616 KHz, you'll hear that ATC is constantly asking pilots if they aware of the situation.

[Andre]

Anyway nothing unusual here, the sunset is pretty standard in a bit hazy weather conditions and only a few cloud.

[Count Iblis]

There is something else worth seeing today after sunset. Venus, Mercury and a very young cresent Moon in one line. Venus is easy to see with the naked eye. You can use a binocular to locate Mercury. Just look at Venus and then move to the north-west. When Venus moves out of the field of view in a typical 8 by 40 bino in the upper left corner, Mercury will enter in the field of view.

Then knowing where Mercury is in the sky, you should be able to spot it with the naked eye.

[Borek]

Venus, Mercury and a very young cresent Moon in one line.

Planets in one line, volcanoes erupting, in 2012 world will come to an end, I tell ya.

[wolram]

http://news.bbc.co.uk/1/hi/uk/8623364.stm

From the BBC.

[billiards]

Nothing of note here (London) from what I could see, then again, I live on the east side of a hill so my view of sunset is lame.

[brewnog]

Rubbish. I was supposed to be going to Ireland for the weekend. Booo!

[Frame Dragger]

Better no flights than glass forming in your turbines...

@turbo-1: No kidding! I used to work a bit at Hanscom AFB, and the old fighter-interceptors were going nonstop.

[lisab]

Planets in one line, volcanoes erupting, in 2012 world will come to an end, I tell ya.

And did anyone notice that the name of the volcano, Eyjafjallajoekull, is an anagram of: Jell-La, A Jay, Flu Joke! Which means...well...ok I don't know. But it will all become clear to us, I'm sure, as the fateful day approaches.

[mheslep]

We are waiting for that

It has just been decided that the Netherlands air space is closed to all air traffic.
Andre, don't these ash plumes concentrate mainly at high altitude, and thus wouldn't it be possible to have some aviation traffic fly at 8-12,000 ft for awhile, weather permitting? Edit: Or, could some of the jumbos climb over at ~45,000?

[Andre]

Andre, don't these ash plumes concentrate mainly at high altitude, and thus wouldn't it be possible to have some aviation traffic fly at 8-12,000 ft for awhile, weather permitting?

I'm not sure about the logic of the spreading of the ash in three dimensions, but in the flying business, safety desicions are normally very conservative and pragmatic solutions like that are usually out of bounds.

[mgb_phys]

Planets in one line, volcanoes erupting, in 2012 world will come to an end, I tell ya.

See we told you the icelanders were terrorists (http://news.bbc.co.uk/2/hi/7662827.stm) what's more a weapon of MASS destruction than a volcano!

The US could do more to help though - can't you pacify volcanoes by throwing people from Virginia into them?

No reason why a little volcano should stop British flights (http://en.wikipedia.org/wiki/British_Airways_Flight_9)

[mheslep]

I'm not sure about the logic of the spreading of the ash in three dimensions, but in the flying business, safety desicions are normally very conservative and pragmatic solutions like that are usually out of bounds.Sure, but aviation flys around bad weather every day, weather that would be very dangerous if flown through. The trick here would be localizing the plume similarly. Maybe that can't be done.

[Andre]

Sure, but aviation flys around bad weather every day, weather that would be very dangerous if flown through. The trick here would be localizing the plume similarly. Maybe that can't be done.

Yes, thunderstorms are clearly visible on weather radars which are operating in frequency ranges, optimized for reflecting water. Volcanic dust is usually dry.

No reason why a little volcano should stop British flights (http://en.wikipedia.org/wiki/British_Airways_Flight_9)

That link states:

The crew decided to fly the ILS, Instrument Landing System, however, the glideslope was inoperative, so they flew the localizer as the first officer monitored the airport's DME (Distance Measuring Equipment). He then called out how high they should be at each DME step along the final track to the runway, creating a virtual glide slope for them to follow. It was, in Moody's words, "a bit like negotiating one's way up a badger's arse".

A bit off track but If you'd happen to fly an older generation jet without ILS, you would not know better than this is daily standard operation procedure, except that, flying solo, you don't have a first officer calling out altitudes and distances.

Anyway, Nobody is stopping the KLM (http://en.wikipedia.org/wiki/KLM_Flight_867) either

[Borek]

Air space over northern Poland closed.

Getting to Kraków for funeral will be tricky.

[jtbell]

From http://www.cnn.com/2010/TRAVEL/04/15/iceland.flights/index.html?hpt=T2

The prime minister of Norway was among those stranded by the closure of European air space.

Jens Stoltenberg, who was in the United States for President Obama's nuclear summit, is running the Norwegian government from the U.S. via his new iPad, press secretary Sindre Fossum Beyer said.

[mgb_phys]

Looks like the only thing flying over europe are some friends of mine at http://arsf.nerc.ac.uk/ especially funny because the better funded group at www.faam.ac.uk with a jet can't fly because it's being painted !!!

[Count Iblis]

Good that there were no jet planes when this happened (http://en.wikipedia.org/wiki/La_Garita_Caldera)

[Borek]

Space over Poland closed, with exception of Kraków and radom.

I wonder - do we know of a plot of number of volcanic eruptions and amount of ash ejected in the past? Yes, I am thinking about the subject that we can't discuss. Was the average amount of ash flying in the last 50 years different from the average? I don't want to start a discussion, but if someone can fill my curiosity, that'll be great.

[dorlomin]

Does anyone know the VEI of this erruption?

[D H]

The US could do more to help though - can't you pacify volcanoes by throwing people from Virginia into them?
Correction #1: People from right next door to Virginia. Elected officials only; plain old ordinary citizens don't count.

Correction #2: You also missed the tossing of PF annual award winners into the volcano as a placative effect.

[dorlomin]

Glacier flood water from iceland (http://www.youtube.com/watch?v=9sryalI57oo)

[BobG]

I never realized Iceland was such a picturesque place. I think that's my new dream vacation destination.

http://upload.wikimedia.org/wikipedia/en/thumb/c/c3/Gullfoss-Iceland-20050724.jpg/800px-Gullfoss-Iceland-20050724.jpg Gullfoss

http://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Skogafoss_from_below.JPG/800px-Skogafoss_from_below.JPG Skógafoss

http://upload.wikimedia.org/wikipedia/commons/thumb/0/06/Iceland_Dettifoss_1972-4.jpg/434px-Iceland_Dettifoss_1972-4.jpg Dettifoss

[cristo]

Rubbish. I was supposed to be going to Ireland for the weekend. Booo!

Surely you can get to Ireland without flying!

[Frame Dragger]

@BobG: I had no idea either, but apparantly that's where the Lord of The Rings movies were filmed. That would explain the vistas, but not why the movies were unwatchable. :biggrin:

Anyway, like California, isn't there always a big catch to that kind of natural beauty? :yikes:

[mgb_phys]

@BobG: I had no idea either, but apparantly that's where the Lord of The Rings movies were filmed.
No, that was New Zealand

Anyway, like California, isn't there always a big catch to that kind of natural beauty? :yikes:
In Iceland? - occasional volcanoes and the ever present danger of Bjork encounters.

in New Zealand - no volcanoes and even the sheep are pretty tame.

[Frame Dragger]

No, that was New Zealand


In Iceland? - occasional volcanoes and the ever present danger of Bjork encounters.

in New Zealand - no volcanoes and even the sheep are pretty tame.

Oooooohhhh... heh.. no offense... well... a lot of people! :redface: Right, New Zealand = tastey lamb and people who will hang you by your ankles if you compare them to flightless birds. Iceland = "Uh.. didn't you know, that uh, Iceland is GREEN, and uh, Greenland ICEY. SHAZAM!" from a 15 year old.

Bjork... she's... interesting, in a "run you poor swan, RUN!" and "DON'T SAY 'Welcome To Bangkok!'" way. On the upside she's... ah... scary?

EDIT: Oh, and mgb... why are the sheep tame? What have you been doing to the poor.... lambs?! "Tame" or "Tramatized"? :biggrin:

[zoobyshoe]

in New Zealand - no volcanoes and even the sheep are pretty tame.

You could be pecked by a kiwi, though.

[Frame Dragger]

You could be pecked by a kiwi, though.

Too true mate, too true, still, better than steppin' on an inland Taipan, am I right?! *sound of unamused crickets*... right?!

Ehhh....

[Borek]

http://www.physicsforums.com/showthread.php?t=395467

[Frame Dragger]

I would just add that flying low = GAS GUZZLER.

[Frame Dragger]

http://www.physicsforums.com/showthread.php?t=395467

Oh... can a mentor merge the threads?

[lisab]

http://www.physicsforums.com/showthread.php?t=395467

:rofl: Clicking that now brings you...here. It's like walking through a door into the room you just left. Took me a minute to get my bearings and figure out what happened.

[mgb_phys]

EDIT: Oh, and mgb... why are the sheep tame? What have you been doing to the poor.... lambs?! "Tame" or "Tramatized"? :biggrin:
Well compared to the island next door, where even the sheep are venomous.

Oh, New Zealand does have a few volcanoes but they are relatively polite and well behaved.
Cute note at the bottom of the NZ geological survey's web page
They have a link for questions, but note that "The Institute cannot determine exactly when the next eruption will occur"

[Count Iblis]

Can propellor planes fly safely throught the ash?

[mgb_phys]

Can propellor planes fly safely throught the ash?

Most large propeller planes are turbo-props so have exactly the same engine as 'jets'.
However the ash is mostly at 20-30,000 ft so it's perfectly safe for anything to fly under it, small planes, turboprops, jets and helicopters.
But it's risky if you have to climb or descend through the cloud, or if the cloud moves - and you don't want to be the one explaining to the lawyers of a 747 full of victims why you ok'ed it.

[Frame Dragger]

Well compared to the island next door, where even the sheep are venomous.
Oh, New Zealand does have a few volcanoes but they are relatively polite and well behaved.
Cute note at the bottom of the NZ geological survey's web page
They have a link for questions, but note that "The Institute cannot determine exactly when the next eruption will occur"

I KNOW! Evolution took a really nasty turn when even the damned PLATYPUS (male) is venemous! For god's sake, the Aussies have a tick that can paralyze and kill you. A TICK. That makes Rocky Mountain Spotted Fever, and Lyme sound like a cool breeze!

[Frame Dragger]

Most large propeller planes are turbo-props so have exactly the same engine as 'jets'.
However the ash is mostly at 20-30,000 ft so it's perfectly safe for anything to fly under it, small planes, turboprops, jets and helicopters.
But it's risky if you have to climb or descend through the cloud, or if the cloud moves - and you don't want to be the one explaining to the lawyers of a 747 full of victims why you ok'ed it.

Yeah, a glass shell on your engine is really a pretty dire scenario, given the glide ratio of a 747 being somewhere between a brick and a brick with wings. :eek:

[mgb_phys]

given the glide ratio of a 747 being somewhere between a brick and a brick with wings. :eek:
The glide ratio of a 747 is 1:15 -so giving you about a 100mi glide from cruise altitude (http://en.wikipedia.org/wiki/Ba_flight_9)

Better than helicopters which seem to turn into wood chippers at the slightest provocation.

[brewnog]

Surely you can get to Ireland without flying!

I could have got a ferry but that would have cost a shedload and involved another shedload of driving. Gone to Yorkshire instead, much better!

[Frame Dragger]

The glide ratio of a 747 is 1:15 -so giving you about a 100mi glide from cruise altitude (http://en.wikipedia.org/wiki/Ba_flight_9)

Better than helicopters which seem to turn into wood chippers at the slightest provocation.

A joke mgb... that was a joke. I for one would rather strap a rocket to my *** and pray for divine guidance than go into a helo, no arguments here.

[Borek]

I have just seen sunset - red, but not unusually red. I was driving home, got here about 5 minutes too late to take pictures.

[Frame Dragger]

I have just seen sunset - red, but not unusually red. I was driving home, got here about 5 minutes too late to take pictures.

Well, it sounds as though this ash and other particulates will be airborne for days... I'd say you'll get some more chances, and it may look more spectacular once the particles settle a bit into the lower atmosphere and mix with water.

[mheslep]

...
I wonder - do we know of a plot of number of volcanic eruptions and amount of ash ejected in the past? Yes, I am thinking about the subject that we can't discuss. Was the average amount of ash flying in the last 50 years different from the average? I don't want to start a discussion, but if someone can fill my curiosity, that'll be great.
For comparison, material ejected:

Recent:
Mount St Helens: 1.2 km^3
Pinatubo: 10 km^3

Past epics:
Yellowstone Caldera: 1000 km^3
Toba, Indonesia: 2800 km^3
La Garita Caldera: 5000 km^3

http://en.wikipedia.org/wiki/Caldera
http://en.wikipedia.org/wiki/Pinatubo

[Frame Dragger]

For comparison, material ejected:

Recent:
Mount St Helens: 1.2 km^3
Pinatubo: 10 km^3

Past epics:
Yellowstone Caldera: 1000 km^3
Toba, Indonesia: 2800 km^3
La Garita Caldera: 5000 km^3

http://en.wikipedia.org/wiki/Caldera
http://en.wikipedia.org/wiki/Pinatubo

Yellowstone... that's the one that probably reduced the effective human pop of the world to less than 20K (EDIT: About 80K years ago that is), right? Ahhh, thanks, I have my nightmare all lined up for tonight now! :wink:

That said... damn.

[Andre]

The biggest recent event was Mt Tambora in 1815, (http://en.wikipedia.org/wiki/Mount_Tambora) 160 km3.

[Frame Dragger]

The biggest recent event was Mt Tambora in 1815, (http://en.wikipedia.org/wiki/Mount_Tambora) 160 km3.

Well, I imagine that scared the living daylights out of pretty much EVERYONE... and more than 70,000 dead... that is absurdly nasty.

[mheslep]

Yellowstone... that's the one that probably reduced the effective human pop of the world to less than 20K (EDIT: About 80K years ago that is), right? ...640,000 ya. No Homo sapiens in N. American then, or anywhere else. Early Neanderthals may have seen the funky sunsets in Africa.

[Borek]

About ash amount plot:

The biggest recent event was Mt Tambora in 1815, (http://en.wikipedia.org/wiki/Mount_Tambora) 160 km3.

I am not thinking about single events, I am thinking about average. There is no doubt that ash in the air is an important climate changing factor and I wonder how this factor evolved in time. Sure there will be a spike after huge eruptions so they are important, but they don't tell everything.

About sunset:

Well, it sounds as though this ash and other particulates will be airborne for days... I'd say you'll get some more chances, and it may look more spectacular once the particles settle a bit into the lower atmosphere and mix with water.

Thay said in Polish TV that the amount of ash over Poland is at peak at the moment and weather (wind/air circulation) simulations suggest it should go down in the next few days. Could be you are right about visible effect beinbg more prominent later, no idea.

[mheslep]

About ash amount plot:



I am not thinking about single events, I am thinking about average. There is no doubt that ash in the air is an important climate changing factor I think the ash itself has a very short lived impact on weather. The aerosols, especially SOx, have longer term impacts (couple years) as I understand it.

[Andre]

I am not thinking about single events, I am thinking about average. There is no doubt that ash in the air is an important climate changing factor and I wonder how this factor evolved in time. Sure there will be a spike after huge eruptions so they are important, but they don't tell everything.


There would be a lot to tell about, given these volcanic marker data (ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/chem/volcano.txt) but that has to wait until these dark ages are over.

[Andre]

This was our volcanic ash sunset. Edit: more in this thread (http://www.physicsforums.com/showthread.php?p=2675095)

I was not too impressed but the slight haze could have been caused by the volcanic ash

http://i43.tinypic.com/15j6yp.jpg

[Frame Dragger]

There would be a lot to tell about, given these volcanic marker data (ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/chem/volcano.txt) but that has to wait until these dark ages are over.

"The King is dead, long live the King!" Eh? I don't think our age gets lighter from here on... :sad:

Beautiful picture however, whatever the cause.

[Galteeth]

Many news reports have been talking about the risk of Katla erupting. How much of a risk/concern is this?

[Frame Dragger]

Many news reports have been talking about the risk of Katla erupting. How much of a risk/concern is this?

It's certainly due for an eruption, but I don't know that it means it will soon. This seems to be on the HuffingtonPost, which may be a lot of things, but not a really great source for science. There is no seismological data or gas emissions to indicate increased activity.

Then again, it's either right on time for an eruption, or about 50 years OVERdue. In essence, it's a safe bet for a reporter and a story that will reach print.

[ViewsofMars]

Hi everyone.:smile: I just wanted to briefly share with PF's audience two recently published pamphlets by The International Volcanic Health Hazard Network . "They are now avaiable in English, Japanese, French Spanish, Portuguese and Swahili with Italian versions being available shortly."
http://www.ivhhn.org/index.php?option=com_content&view=article&id=55&Itemid=61

Please note that following at the bottem of the pamplet:
"Document was written by Dr Claire Horwell of the University of Cambridge, UK, with assistance from staff of the United States Geological Survey and GNS Science, New Zealand. The IVHHN is grateful to the Leverhulme Trust, UK, for funding associated meetings, and to the following people for reviewing this guideline document:
- Dr Bob Maynard, Department of Health, London, UK;
- Steve Brantley, USGS Hawaiian Volcano Observatory, Hawai'i, USA;
- Dr David Johnston, GNS Science, Lower Hutt, New Zealand;
- Dr Peter Baxter, Institute of Public Health, University of Cambridge, UK;
- Dr Carol Stewart, Wellington, New Zealand.
- Scott Barnard, University of Canterbury, Christchurch, New Zealand"

Here are the two pamphlets in English:

1. GUIDELINES ON PREPAREDNESS BEFORE, DURING AND AFTER AN ASHFALL
This document has been prepared by the International Volcanic Health Hazard Network
(IVHHN), Cities and Volcanoes Commission, GNS Science and the United States
Geological Survey (USGS) to promote the safety of those who experience volcanic
ashfall.

It details procedures to follow if warning of a volcanic ashfall is given, recommends
what to do during ashfall, and what methods are most effective for cleaning up
volcanic ash after the event.
[Please read on . . .]
http://www.ivhhn.org/images/pamphlets/Preparedness_Guidelines_English_WEB.pdf

2.THE HEALTH HAZARDS OF VOLCANIC ASH
A guide for the public
This document has been prepared by the International Volcanic Health Hazard Network
(IVHHN), Cities and Volcanoes Commission, GNS Science and the United States Geological
Survey (USGS) to promote the safety of those who
experience volcanic ashfall.

This guide explains the potential health effects of volcanic ash and gives details on how to
protect yourself and your family in the event of a volcanic ashfall.
[Please read on . . .]
http://www.ivhhn.org/images/pamphlets/Health_Guidelines_English_WEB.pdf

A few news articles about the most recent Iceland volcanic erruption that is having a major effect for those who live in Europe. My sincerest and warmest wishes for "better weather" in the near future to those who are affected and take good care of yourself and loved ones. :smile:
http://news.bbc.co.uk/2/hi/europe/8624748.stm
http://www.boston.com/bigpicture/2010/04/icelands_disruptive_volcano.html
http://news.bbc.co.uk/2/hi/uk_news/8626765.stm
http://www.guardian.co.uk/world/2010/apr/17/volcano-disruption-flights-grounded-ash
http://www.nasa.gov/topics/earth/features/iceland-volcano-plume.html
http://www.irishcentral.com/news/news_from_ireland/Health-fears-as-volcano-ash-set-to-fall-on-Ireland-91151034.html

[tiny-tim]

Why can't planes fly lower ? :confused:

(years ago, a plane flew through an ash cloud, all its engines stopped, it plummeted thousands of feet, and the engines restarted when it reached clear air again)

[Matterwave]

Why can't planes fly lower ? :confused:

(years ago, a plane flew through an ash cloud, all its engines stopped, it plummeted thousands of feet, and the engines restarted when it reached clear air again)

From my very limited knowledge of planes, I think the air-altitudes are all split up for different purposes. The commercial flights have a specific range of altitudes they fly at, it may not be easy to allow them to fly at different altitudes.

Furthermore, there could be sound pollution from airplanes flying too low...or other safety hazards...

I'm not sure myself haha.

[Borek]

Other things ignored - low flight means high fuel consumption, shorter range and higher costs.

[Andre]

Optimum flight level is the tropopause (http://en.wikipedia.org/wiki/Tropopause). The jets I flew would use typically 2500 lbs/per hour at the tropopause versus maybe 6-7000 lbs/hr at low level to maintain 480 knots true airspeed.

Best cruising speed is a complex function of air density and air temperature. An important parameter for the engines is combination of temperature and the mach number which are directly related and making it perform best at lowest temperature. This is at the tropopause and above, which is typically at some 33,000 feet, however with big variations.

Going higher means less dense air at rougly the same temperature, however the reduction in drag is offset by reduced engine performance due to the lack of oxygen.

So the ash is below the best altitude for cruise flight, however I have no idea about the effects of low concentration ash during climb or descent in those layers.

[tomkeus]

I'm watching this entire situation and I'm amazed at incompetence bureaucrats across Europe demonstrated handling this situation.

Apparently, flight bans all over Europe were issued based on computer simulations run by UK Met Office. Although I understand that, because it is better to be safe than sorry I cannot understand why hasn't anyone in Europe took actual measurements or test flights after that. It took initiative of KLM and Lufthansa to get actual planes in the air for people to start talking that ban should be partially lifted based on real and not computer generated data.

Lack of action of flight regulating bodies and meteorological organizations to deploy balloons or flying labs or other measurements across Europe may prove to have cost Europe billions of euros.

Now, office eggheads probably realized that they've dropped the ball handling post-ban situation so they will probably stick with the total ban for some time yet in order to save their public face.

[cristo]

Apparently, flight bans all over Europe were issued based on computer simulations run by UK Met Office. Although I understand that, because it is better to be safe than sorry I cannot understand why hasn't anyone in Europe took actual measurements or test flights after that.

Err.. firstly the simulations were not just done by the Met Office in the UK; simulations have been done by many other European equivalents. In fact, once professor whom I saw interviewed yesterday say that there was a remarkable level of agreement between the different simulations. Secondly, planes have been up there collecting data, and test flights continue to be done. However, it makes sense that such flights are done by suitable aircraft to try and gauge the situation, and not by just seeing whether a commercial airliner can fly through the ash.


It took initiative of KLM and Lufthansa to get actual planes in the air for people to start talking that ban should be partially lifted based on real and not computer generated data.


The problem here is that off the back of these flights one can only show that a plane can fly through the ash. However, the KLM test flight was once flight for around one hour. This is not really good enough to say that the European airspace should be opened and service resumed as normal. Aircraft make many journeys in a day, and so will be flying through this ash over and over again, which will presumably bear a toll on the engines. Then there's the issue of how often should the engines be checked: after every flight like with the test flights, or at the end of every day?

Alternatively, you could just stick two fingers up like the Russians and Ukrainians but, well, that's not really too sensible, is it?

[sophiecentaur]

Other things ignored - low flight means high fuel consumption, shorter range and higher costs.

That doesn't seem too much of a hardship compared with the Total Loss at the moment. Plenty of people would be prepared to pay a 'low altitude surcharge' in order to get home on time.
It would mean that priority transport could still get through. If long haul were not possible at low altitude, the majority of long haul flights could still be made a full altitude.

It would need the Air Lanes to be temporarily re-planned in the affected area as well but that problem would not be as great if the total number of flights were a lot less during an emergency.
I wonder if this event has prompted anyone to think of devising an emergency low-altitude plan for the eventuality of this happening again - somewhere in the World.

[Frame Dragger]

That doesn't seem too much of a hardship compared with the Total Loss at the moment. Plenty of people would be prepared to pay a 'low altitude surcharge' in order to get home on time.
It would mean that priority transport could still get through. If long haul were not possible at low altitude, the majority of long haul flights could still be made a full altitude.

It would need the Air Lanes to be temporarily re-planned in the affected area as well but that problem would not be as great if the total number of flights were a lot less during an emergency.
I wonder if this event has prompted anyone to think of devising an emergency low-altitude plan for the eventuality of this happening again - somewhere in the World.

Did you not read Andre's post? We're not talking about a little boost in fuel, we're talking about a HUGE increase, and a subsequent DECREASE in range. It's cheaper and easier to fly around an ash cloud than below it, not to mention that ANY crash at this point would be instantly blamed on negligence by the airlines.

The difference in fuel is the difference between a profit, and a loss. When you add the HUGE decrease in range, there is no way for it to be feasible. Keep in mind also that people don't want jets roaring overhead at 10-12,000 feet, nor would any government's military allow that.

This has happened, it will happen again, and there is no contingency other than boats. That's real life.

[Borek]

I wonder if this event has prompted anyone to think of devising an emergency low-altitude plan for the eventuality of this happening again - somewhere in the World.

1821 eruption of Eyjafjallajökull lasted over half a year.

[sophiecentaur]

Did you not read Andre's post? We're not talking about a little boost in fuel, we're talking about a HUGE increase, and a subsequent DECREASE in range. It's cheaper and easier to fly around an ash cloud than below it, not to mention that ANY crash at this point would be instantly blamed on negligence by the airlines.

The difference in fuel is the difference between a profit, and a loss. When you add the HUGE decrease in range, there is no way for it to be feasible. Keep in mind also that people don't want jets roaring overhead at 10-12,000 feet, nor would any government's military allow that.

This has happened, it will happen again, and there is no contingency other than boats. That's real life.
Interesting. I have taken in all you have written. I'm not sure the military would have a say in the matter if the GBP insisted. . . . (LOL).
I searched and scanned through the thread but could find no actual figures and it is the actual number that count in a problem like this. Which number is the post, so I can look at it?

[Frame Dragger]

Interesting. I have taken in all you have written. I'm not sure the military would have a say in the matter if the GBP insisted. . . . (LOL).
I searched and scanned through the thread but could find no actual figures and it is the actual number that count in a problem like this. Which number is the post, so I can look at it?

Never underestimate the efficacy of SAMs... :wink:

Optimum flight level is thetropopause (http://en.wikipedia.org/wiki/Tropopause). The jets I flew would use typically 2500 lbs/per hour at the tropopause versus maybe 6-7000 lbs/hr at low level to maintain 480 knots true airspeed.

Best cruising speed is a complex function of air density and air temperature. An important parameter for the engines is combination of temperature and the mach number which are directly related and making it perform best at lowest temperature. This is at the tropopause and above, which is typically at some 33,000 feet, however with big variations.

Going higher means less dense air at rougly the same temperature, however the reduction in drag is offset by reduced engine performance due to the lack of oxygen.

So the ash is below the best altitude for cruise flight, however I have no idea about the effects of low concentration ash during climb or descent in those layers.

EDIT: For the record, the effect of ascent and descent to form a measure of glass on the engines, and while it may or may not be fatal or damaging (it usually takes quite some time for engines to fail from volcanic ash, and you can get out if it if you're lucky) it would certainly be terrible for the engines in the long run, and any crash would be hailed as grossly negligent. Outrage over a plane crash due to a desire to travel... I can see the news stories, lawsuits, and criminal case now.

[ViewsofMars]

I'm adding on to my previous message which I think was extremely important!:biggrin:

I also want to share a wonderful website to explore by John Seach. He has a very impressive bio. I wouldn’t mind going on a trek with him.:wink:
http://www.volcanolive.com/john.html

On his website today, Sunday 18th April 2010:
Eyjafjallajokull volcano, Iceland
Ash emissions are continuing from Eyjafjallajokull volcano in Iceland. Winds are blowing the ash over Europe, causing flights to remain grounded. All flights to and from Britain have been cancelled until at least 7pm today. Ashfall has been reported in Britain. Five million travelers are stranded, waiting for flights to resume. Some may be waiting for more than a week to find available seats. If flight disruptions continue into this week there will be a shortage of some food products in Britain, which normally come in by air from east Asia and Africa. The grounding of flights has already cost the British economy about £1 billion, with £230m losses for every day of further disruption. The initial eruption of Eyjafjallajokull volcano last month was basalt, while the new eruption under the glacier last week involved andesite.
http://www.volcanolive.com/news.html


An article on BBC from today which brings added concern:

Ash cloud puts lives of bone marrow patients at risk
The ban on air travel in much of Europe is putting the lives of people waiting for bone marrow transplants at risk.
[Read on . . .]
http://news.bbc.co.uk/2/hi/uk_news/8628078.stm

More links :
http://www.nytimes.com/2010/04/18/world/europe/18ash.html
http://news.bbc.co.uk/2/hi/europe/8627720.stm
http://news.bbc.co.uk/2/hi/uk_news/politics/8628253.stm
http://news.bbc.co.uk/2/hi/europe/8627720.stm

They seem to be comparing this event worse than 911 as far as closing
down air space.

[Frame Dragger]

I'm adding on to my previous message which I think was extremely important!:biggrin:

I also want to share a wonderful website to explore by John Seach. He has a very impressive bio. I wouldn’t mind going on a trek with him.:wink:
http://www.volcanolive.com/john.html

On his website today, Sunday 18th April 2010:



An article on BBC from today which brings added concern:



More links :
http://www.nytimes.com/2010/04/18/world/europe/18ash.html
http://news.bbc.co.uk/2/hi/europe/8627720.stm
http://news.bbc.co.uk/2/hi/uk_news/politics/8628253.stm
http://news.bbc.co.uk/2/hi/europe/8627720.stm

They seem to be comparing this event worse than 911 as far as closing
down air space.

Oh yeah, nature always wins in those situations. Frankly, this is pretty impressive and clearly medical services have a lot of work to do. Perhaps ground-effect (on water) airplanes can be a viable solution for these kinds of emergencies, but not for mass transit.

[sophiecentaur]

@Framedragger

I read that post but the info is very sparse and doesn't really prove anything about low altitude, low speed flight economics. Clearly it's not what modern jets were designed for and their economics are on a bit of a knife edge.
Andre may well know what he's talking about but we normally expect more info or a reference rather than just accepting an 'assurance'.

I can't help thinking that planes stack for an hour or more around Heathrow and Gatwick and that is all accounted for in the flight plan. Is that so very different from a slow trip to Paris or Brussels?
It would be nice to see just how 'unthinkable' it is. The present situation is far from 'thinkable' too.
Is there a knowledgeable Engineer on the forum who can give information (without hyperbole) about this? I'd love to know the real situation.
After all, we wouldn't rely on what the Press have to say about anything else in our lives.

[ViewsofMars]

" After all, we wouldn't rely on what the Press have to say about anything else in our lives."

Well sophiecentaur, I'm not Framedagger, but your comment is merely *your* opinion. Many press releases are made by scientists. And, public officials do consult with scientists and engineers as well as with news reporters.:smile:

I surely wouldn't wish to dismiss the fact that it wasn't a fabricated story just so the press could impress the public with lies. If planes aren't being flown it's for a darn good reason. Please remember that public safety comes first.

[Andre]

About aircraft range and altitude. Maybe this link (http://selair.selkirk.ca/Training/Aerodynamics/range_jet.htm) helps a bit, especially this sixth graph.

http://selair.selkirk.ca/Training/Aerodynamics/graphics/altitude-jet1.gif

Notice that a fuel flow of 540 lbs/hr generates a max range speed of 200 knots true airspeed (KTAS) at sea level and 440 KTAS at 45,000 feet. Notice also that the sea level curve is much steeper, so flying faster than best range is at a greater penalty than at high altitude.

Also I expect this graph to be based on air density only since -as said- the temperature and related mach number play a big role for engine performance/efficiency and these are not linear in that altutide range due to the tropopause.

The exact numbers are not very relevant but it gives an impression of the rate of changes in range versus altitude.

[Frame Dragger]

Thanks Andre, ViewsofMars... I didn't realize that this wasn't very common knowledge re: prop vs. jet engines. *shrug*

[ViewsofMars]

"So the ash is below the best altitude for cruise flight, however I have no idea about the effects of low concentration ash during climb or descent in those layers."

Andre, you aren't a pilot are you?:smile: A simple yes or no will do. Honestly, I've known a few pilots. They wouldn't risk their life or passengers if there was risk. Have you read any articles where airline pilots are protesting the closure of air space in Europe? I haven't.

"Thanks Andre, ViewsofMars... I didn't realize that this wasn't very common knowledge re: prop vs. jet engines. *shrug*"

*Shrug* all you want FrameDragger! I said airline pilots!

[Andre]

""

Andre, you aren't a pilot are you?:smile: A simple yes or no will do. Honestly, I've known a few pilots. They wouldn't risk their life or passengers if there was risk. Have you read any articles where airline pilots are protesting the closure of air space in Europe? I haven't.

I used to be pilot but it's not a simple yes-no at all.

Obviously there is a lowest concentration at which harm is negliglible and concentrations at which major damage is inevitable. For instance, how many times have aircraft landed in dusty hazy conditions near big cities and that is clearly visible?

So it's rather impossible to say something useful here, but just suppose for arguing that the actual concentration is only 5% or 10% or 30% of the damage threshold in the regions where it counts, why the fuss then?

It's just that these things have probably never been tested because it used to be a non factor in the past, so probably nobody has a clue what the best decision is.

[Frame Dragger]

""

Andre, you aren't a pilot are you?:smile: A simple yes or no will do. Honestly, I've known a few pilots. They wouldn't risk their life or passengers if there was risk. Have you read any articles where airline pilots are protesting the closure of air space in Europe? I haven't.

I can't speak for Andre, but I'm no pilot, yet I know that volcanic ash is TRICKY. I've been trying to find a citation online, but I recall a NatGeo or Discovery program which described a plane that had flown into volcanic ash. The pilots had no CLUE what was happening, other than intermittant engine failure. They finally figured out that it was the ash vitrifying in the engines, but only once they landed. The pilots were simply bright and lucky enough to realize that they couldn't fly at their normal cruising altitude.

To be blunt, what information do you expect? It takes tiime for the glass to form, it's almost impossible to detect, and then BOOM, your engine can fail. Ascent and Descent are relatively brief compared to the time spend at altitude, and no one is willing to take that kind of risk. You don't crash test passenger jets in volcanic ash, and isolating the effect to a particular period of ascent or descent is pointless outside of a lab.

You don't fly air-breathing engines in ash, period.

@ViewsofMars: *shrug* :biggrin:
@Andre: Sorry if I stepped on your toes with this simul-post. I'll delete it if you prefer.

[lisab]

""

Andre, you aren't a pilot are you?:smile: A simple yes or no will do. Honestly, I've known a few pilots. They wouldn't risk their life or passengers if there was risk. Have you read any articles where airline pilots are protesting the closure of air space in Europe? I haven't.

""

*Shrug* all you want FrameDragger! I said airline pilots!

Haven't heard of protests, but the pilots who made these test flights (http://www.cnn.com/2010/TRAVEL/04/18/volcano.ash.test.flights/index.html?hpt=T1) must not have felt they were in danger, otherwise they would not have flown. The test flights, btw, apparently showed no ill effects from the concentrations of ash through which they flew (which I presume were quite low).

I think it's a good bet that there is a concentration of ash which is safe to fly through; what that level is isn't known. Which raises the question: is there a way to measure concentration of airborne ash? Because before we can determine what level is safe to fly through, we need a way to measure it.

[ViewsofMars]

"You don't fly air-breathing engines in ash, period.

@ViewsofMars: *shrug* :biggrin:
"

Duh, FrameDragger! :biggrin: You don't fly airplane(s) into air space that has volcanic ash. You can locate that information in several articles via link that I have provided on this page and the previous one. :wink:
---
"Haven't heard of protests, but the pilots who made these test flights (http://www.cnn.com/2010/TRAVEL/04/18/volcano.ash.test.flights/index.html?hpt=T1) must not have felt they were in danger, otherwise they would not have flown. The test flights, btw, apparently showed no ill effects from the concentrations of ash through which they flew (which I presume were quite low).

I think it's a good bet that there is a concentration of ash which is safe to fly through; what that level is isn't known. Which raises the question: is there a way to measure concentration of airborne ash? Because before we can determine what level is safe to fly through, we need a way to measure it."

Hi lisab. :) Since pilots are inside the plane, I doubt there would be volcanic ash in the air they breathe. Volcanic ash clogs up the engine of a plane. Perhaps a very short span of time in air space with ash might not cause a plane's engine to die. Of course, measuring what level is safe could result in the pilot's death. Of course, they would have to get an *ok* by the control center of an airport and present the route. Has that happened yet?

Quite frankly, I haven't located the instrument used for measuring in air space the amount of volcanic ash. Perhaps, we should go digging for that information. I'm sure it's out there in cyberspace.
---

"@ViewsofMars: "Duh"? :rofl: I don't know if you're angry or amused, but you're absolutely making me laugh in real life (with, not at). Maybe a bit of a softer touch would be helpful however? Everyone doesn't feel as rough-and-tumble online as I do."

FrameDragger, I'm a serious contender with a gentle manner. And I don't mind you
rolling on the floor laughing. Also, as you can see, I like to condense cyberspace and free it up for others. :rofl: I personally think a person should enjoy particpating in discussions. I may not always agree with everything someone has to say, but I do appreciate knowing that people are having a wee bit of fun.

[Frame Dragger]

Haven't heard of protests, but the pilots who made these test flights (http://www.cnn.com/2010/TRAVEL/04/18/volcano.ash.test.flights/index.html?hpt=T1) must not have felt they were in danger, otherwise they would not have flown. The test flights, btw, apparently showed no ill effects from the concentrations of ash through which they flew (which I presume were quite low).

I think it's a good bet that there is a concentration of ash which is safe to fly through; what that level is isn't known. Which raises the question: is there a way to measure concentration of airborne ash? Because before we can determine what level is safe to fly through, we need a way to measure it.

Sure, you could probably do these tests at JPL...I believe they had a setup to test the effect of static discharge caused by particulate matter.

The problem is: Volcanic ash is not homogenous, and just hasn't been well studied. It takes some time for glass to choke an engine, and frankly... who will take that risk with a full cabin? There is the issue I raised earlier as well, which is that there could be cumulative damage.

I would also add that pilots do things such as fly into Hurricanes, not because they feel they are in no danger, but for the same reasons they fly into Anti Aircraft Fire. They have to: it's a job they love, and there is no other way right now (that people are willing to pay for). I doubt those same pilots would do this with a 747 and a full crew-cabin.

Finally, what is a safe concentration? You could determine an average, and still run into a sticky patch, which probably means that you and all souls will be lost. Airplanes just don't have much of a fail-safe at high altitudes if the engines are glassed.

@ViewsofMars: "Duh"? :rofl: I don't know if you're angry or amused, but you're absolutely making me laugh in real life (with, not at). Maybe a bit of a softer touch would be helpful however? Everyone doesn't feel as rough-and-tumble online as I do.

[Borek]

I recall a NatGeo or Discovery program which described a plane that had flown into volcanic ash. The pilots had no CLUE what was happening, other than intermittant engine failure. They finally figured out that it was the ash vitrifying in the engines, but only once they landed. The pilots were simply bright and lucky enough to realize that they couldn't fly at their normal cruising altitude.

http://en.wikipedia.org/wiki/British_Airways_Flight_9

[Frame Dragger]

http://en.wikipedia.org/wiki/British_Airways_Flight_9

Borek you wigged genius, THANK you! :smile:

[lisab]

Sure, you could probably do these tests at JPL...I believe they had a setup to test the effect of static discharge caused by particulate matter.

The problem is: Volcanic ash is not homogenous, and just hasn't been well studied. It takes some time for glass to choke an engine, and frankly... who will take that risk with a full cabin? There is the issue I raised earlier as well, which is that there could be cumulative damage.

I would also add that pilots do things such as fly into Hurricanes, not because they feel they are in no danger, but for the same reasons they fly into Anti Aircraft Fire. They have to: it's a job they love, and there is no other way right now (that people are willing to pay for). I doubt those same pilots would do this with a 747 and a full crew-cabin.

Finally, what is a safe concentration? You could determine an average, and still run into a sticky patch, which probably means that you and all souls will be lost. Airplanes just don't have much of a fail-safe at high altitudes if the engines are glassed.

@ViewsofMars: "Duh"? :rofl: I don't know if you're angry or amused, but you're absolutely making me laugh in real life (with, not at). Maybe a bit of a softer touch would be helpful however? Everyone doesn't feel as rough-and-tumble online as I do.

Yes, good points. I would expect the ash concentration to vary some, but I wonder how much the ash itself varies? Are some types of ash more likely to glassify than others? I really don't know.

[Galteeth]

Is this eruption likely to have any short term effects on the climate?

[Frame Dragger]

Yes, good points. I would expect the ash concentration to vary some, but I wonder how much the ash itself varies? Are some types of ash more likely to glassify than others? I really don't know.

The answer is "yes". Some ash is organic or composed of non-silicates, but a LOT of it is very fine pumice, which vitrifies like *snaps fingers*. There is also glass ALREADY suspended in the ash, which rapidly melt and then fuse, forming nucelation sites for more growth.

This might be useful: http://volcanoes.usgs.gov/ash/properties.html

[Frame Dragger]

Is this eruption likely to have any short term effects on the climate?

The ash is unlikely to have much of an effect, but if this volcano released a lot of SOx, then it could have an effect for 2 or 3 years.

[tomkeus]

http://en.wikipedia.org/wiki/British_Airways_Flight_9

I'm really getting tired of people quoting BA Flight 9. It went into ash plume 150km downwind of the volcano. I don't see that this case is any argument to close down airspace 2000 or 3000km away from the Iceland.

Even after that, Indonesian authorities have closed down just the area adjacent to the volcano. They didn't proceed and shut down entire South East Asia.

I mean, we had large eruptions, even larger recently but not one caused shutdown on such large scale as in Europe. This is plain and simple irrational paranoia.

For example, engine flameouts did occur while flying through heavy rains. Does this mean we have to ground all air traffic if we have some rain sipping somewhere?

[ViewsofMars]

"The problem is: Volcanic ash is not homogenous, and just hasn't been well studied. It takes some time for glass to choke an engine, and frankly... who will take that risk with a full cabin? There is the issue I raised earlier as well, which is that there could be cumulative damage."

Frame Dragger, do you have a link (url) to substantiate your claim?

"I would also add that pilots do things such as fly into Hurricanes, not because they feel they are in no danger, but for the same reasons they fly into Anti Aircraft Fire. They have to: it's a job they love, and there is no other way right now (that people are willing to pay for). I doubt those same pilots would do this with a 747 and a full crew-cabin."

Frame Dragger, do you have a link (url) to substantiate your claim?

"Finally, what is a safe concentration? You could determine an average, and still run into a sticky patch, which probably means that you and all souls will be lost. Airplanes just don't have much of a fail-safe at high altitudes if the engines are glassed."

Frame Dragger, do you have a link (url) to substantiate your claim?

FrameDragger, I'm strickly asking for references for my own on-line library collection. (Please note that I have on the last two previous pages to this topic provided links (url's).) Thanks in advance for your help FrameDragger.o:)

[Frame Dragger]

""

Frame Dragger, do you have a link (url) to substantiate your claim?

""

Frame Dragger, do you have a link (url) to substantiate your claim?

""

Frame Dragger, do you have a link (url) to substantiate your claim?

FrameDragger, I'm strickly asking for references for my own on-line library collection. (Please note that I have on the last two previous pages to this topic provided links (url's).) Thanks in advance for your help FrameDragger.o:)

Please don't take this the wrong way, but this is something you can do with google and search terms such as "hurricane flight plane" or "composition volcanic ash". From there, you whittle down the info to something more specific, such as: "Volcanic ash troposphere remain" or "concentrations". Here is a simple search: "Composition volcanic ash"... and look at what it yields: http://www.google.com/search?hl=en&rlz=1T4DKUS_enUS306US306&q=composition+volcanic+ash&aq=f&aqi=g-m1&aql=&oq=&gs_rfai= (Google Results)

When it comes to something like QM or Relativity, I can understand wanting citations, but in this case it's probably good to do independant research, if for no better reason than having that skill at hand.

@tomkeus: Good luck selling that to your insurance company and investors if you own an airline.

[mheslep]

About aircraft range and altitude. Maybe this link (http://selair.selkirk.ca/Training/Aerodynamics/range_jet.htm) helps a bit, especially this sixth graph.

Notice that a fuel flow of 540 lbs/hr generates a max range speed of 200 knots true airspeed (KTAS) at sea level and 440 KTAS at 45,000 feet. Notice also that the sea level curve is much steeper, so flying faster than best range is at a greater penalty than at high altitude.

Also I expect this graph to be based on air density only since -as said- the temperature and related mach number play a big role for engine performance/efficiency and these are not linear in that altutide range due to the tropopause.

The exact numbers are not very relevant but it gives an impression of the rate of changes in range versus altitude.I was generally aware of these penalties, and they suggest to me a reason for temporarily raising the ticket prices to pay for more fuel and for reducing the number of flights. It doesn't explain to me, by itself, why the airspace should be completely shut down.

[ViewsofMars]

Please don't take this the wrong way, but this is something you can do with google and search terms such as "hurricane flight plane" or "composition volcanic ash". From there, you whittle down the info to something more specific, such as: "Volcanic ash troposphere remain" or "concentrations". Here is a simple search: "Composition volcanic ash"... and look at what it yields: http://www.google.com/search?hl=en&rlz=1T4DKUS_enUS306US306&q=composition+volcanic+ash&aq=f&aqi=g-m1&aql=&oq=&gs_rfai= (Google Results)

Why would I use Google? I am a science researcher. I go to either peer-reviewed articles or use U.S. Government-Science website for scientific information, or a scientist's website, etc. By the way, I already had reviewed http://volcanoes.usgs.gov/ash/properties.html
:biggrin: I was basically asking you for a website to confirm your comments. Please don't through it back on me. Why? Because it is insulting. I'm especially still waiting on your comment, "Finally, what is a safe concentration? You could determine an average, and still run into a sticky patch, which probably means that you and all souls will be lost. Airplanes just don't have much of a fail-safe at high altitudes if the engines are glassed." That isn't a scientific statement.

[tomkeus]

@tomkeus: Good luck selling that to your insurance company and investors if you own an airline.

You don't have to sell anything. Just wait for a few more days for losses to accumulate and they will be begging you get those planes airborne.

[sophiecentaur]

About aircraft range and altitude. Maybe this link (http://selair.selkirk.ca/Training/Aerodynamics/range_jet.htm) helps a bit, especially this sixth graph.

http://selair.selkirk.ca/Training/Aerodynamics/graphics/altitude-jet1.gif

Notice that a fuel flow of 540 lbs/hr generates a max range speed of 200 knots true airspeed (KTAS) at sea level and 440 KTAS at 45,000 feet. Notice also that the sea level curve is much steeper, so flying faster than best range is at a greater penalty than at high altitude.

Also I expect this graph to be based on air density only since -as said- the temperature and related mach number play a big role for engine performance/efficiency and these are not linear in that altutide range due to the tropopause.

The exact numbers are not very relevant but it gives an impression of the rate of changes in range versus altitude.

Thanks for the info on those graphs Andre. Looking at the minima on those two red curves it seems to me that the 'fuel consumption' (mpg, in motorcar terms, ignoring winds) at 45k is about twice that at sea level. (i.e. same fuel flow at just over twice the air speed) Presumably it wouldn't be quite so bad at 10k as at ground level. That would imply that the cost of flying low would only be about twice that of flying at normal altitudes. Sounds a lot more attractive than spending hundreds of pounds on hire cars, extended stays in hotels and missed business deals.

So why aren't they considering at least some flights (high priority, perhaps) at lower, safe, altitudes? Is it just an admin (ATC) problem?

I feel that this thread should be split into two - one to deal with the safety issue and the other to discuss possible (non-hazardous) solutions.

[Frame Dragger]

:biggrin: I was basically asking you for a website to confirm your comments. Please don't through it back on me. Why? Because it is insulting.

It is responding with the understanding that you were being rude, and patronizing, and apparantly unwilling to perform your own research to confirm a statement. In short, returning your "offer" is no more insulting than it was for you to make the request in the first place. You were hardly being subtle, polite, or reasonable. I on the other hand, gave you the benefit of the doubt, a mistake I won't make twice. As for you being a "science researcher", that statement alone gives away a great deal about what you are, and are not. If you have a further issue, feel free to continue, but my new policy on PF is to disengage and report now. Keep that in mind.

[Frame Dragger]

You don't have to sell anything. Just wait for a few more days for losses to accumulate and they will be begging you get those planes airborne.

No, they won't. Those losses won't be fatal for a business, but a crash that could be blamed on negligence (can you IMAGINE the civil trials alone?!) could absolutely ruin an airline. A plane that crashes now is immediately going to do ENORMOUS damage to a company's public image, and as Pan AM could have told you, that matters when you're trying to convince people to fly in your aluminum and composite cigar with wings.

EDIT: On the bright side, we just wait those few days and see who is correct. No need for speculation when time will answer this.

[ViewsofMars]

It is responding with the understanding that you were being rude, and patronizing, and apparantly unwilling to perform your own research to confirm a statement.

Frame Dragger, that is your opinion.


In short, returning your "offer" is no more insulting than it was for you to make the request in the first place. You were hardly being subtle, polite, or reasonable. I on the other hand, gave you the benefit of the doubt, a mistake I won't make twice. As for you being a "science researcher", that statement alone gives away a great deal about what you are, and are not. If you have a further issue, feel free to continue, but my new policy on PF is to disengage and report now. Keep that in mind.

Frame Dragger, that again is your opinion. I think you are skating around to basically avoid answering that last question of mine to you! Which is absolutely not a scientific answer. Retraction from you is never an option as I can see. Furthermore, the language you have used isn't scientific by any means.

[Frame Dragger]

Frame Dragger, that is your opinion.




Frame Dragger, that again is your opinion, which is absolutely worthless. I think you are skating around to basically avoid answering that last question of mine to you! Which is absolutely not a scientific answer. Retraction from you is never an option as I can see. Furthermore, the language you have used isn't scientific by any means.

Again, you're rude, patronizing, and making vast assumptions which reveal your intial bias. You're simply not being subtle enough that anyone would miss that either, and frankly, why would anyone BOTHER to reply to you? This is my last reply in this conversation (regarding you), which you are more than welcome to see as a personal victory. I could care less.

EDIT: You know what, even a rabid dog deserves a bone. Here: "Colonel Joseph Duckworth (USAF)". Enjoy learning about how and why people fly into hurricanes. The rest, I leave in your "sceince researcher" hands.

[tomkeus]

but a crash that could be blamed on negligence

I don't think anyone reasonable would consider crash in this situation. There were no crashes caused by volcanic ash, and those famous flights everyone is talking about flew straight into the dense plume (nothing even remotely like situation we have now) unaware of what was happening.

Chances of crash happening due to current situation over Europe are so remote that it's pointless considering them anymore than regular risk of flying.

What is worth considering for airlines is potential reduction in engines lifetime and premature overhauls. That is where accumulated losses vs. risks I was talking about come into story.

[mgb_phys]

What is worth considering for airlines is potential reduction in engines lifetime and premature overhauls. That is where accumulated losses vs. risks I was talking about come into story.
The BA flight 9 flew into a dense ash cloud and it's engines were essentially destroyed in minutes - so if you fly into an ash cloud 1% as dense are your engines unaffected, affect only 1% as much, have it's life reduced by 1% or be destroyed in a few *100 minutes?

After the flight do you have to do a regular engine walk around, a standard 1000hour boroscope inspection, a 4000 hour medium inspection of a 10,000hour full stripdown inspection.

Engines for a 747 are about $5-10M each - but just to complicate matters they are rarely bought, they are on a complex leasing/support contract with Rolls Royce, what does flying through an ash cloud do to your operations contract?

[Frame Dragger]

I don't think anyone reasonable would consider crash in this situation. There were no crashes caused by volcanic ash, and those famous flights everyone is talking about flew straight into the dense plume (nothing even remotely like situation we have now) unaware of what was happening.

Chances of crash happening due to current situation over Europe are so remote that it's pointless considering them anymore than regular risk of flying.

What is worth considering for airlines is potential reduction in engines lifetime and premature overhauls. That is where accumulated losses vs. risks I was talking about come into story.

You keep saying that the risk is remote, because in the past ash hasn't hindered air travel unles you're "flying into a dense plume". Yeah, for a couple of reason I could add:

1.) How long have major commercial pressurized flights been around?
2.) How many near-misses do you think anyone is willing to take with an expensive machine?
3.) Even if there is ZERO respect for human life, each person probably represents ~1 civil lawsuit or a MASSIVE class-action.
4.) You seem to believe that the cost of NOT doing business is in any way equivalent to the cost of a single crash.
5.) Ignoring a crash; pretend the ENGINES simply start to have issues. Better yet, forget that, just imagine that a small amount of volcanic glass DOES form, but it's only discovered upon landing. See mgb's 10,000 hour stripdown.
6.) You can't easily tell how dense an ash-cloud is from radar or from the cockpit by eye. You don't make assumptions with airplanes unless you're tired of living.

EDIT: The ACI and AEA (Airport associations, aka industry groups) are petitioning against the ban. Some flights have shown safe conditions. Here is one view... followed by another:

Olivier Jankovec, director general of ACI Europe, said airports have lost close to 136 million euros ($184 million U.S.) so far. More than 6.8 million passengers have been affected, he said in a statement, adding that the effect is worse than after the September 11, 2001, terrorist attacks on the United States.

More on how stranded travelers are coping

"While safety remains a non-negotiable priority, it is not incompatible with our legitimate request to reconsider the present restrictions," he said.

"While Europe's airlines and airports consider safety to be an absolute priority, they are questioning the proportionality of the flight restrictions currently imposed," ACI Europe and the AEA said in their joint statement. "The eruption of the Icelandic volcano is not an unprecedented event and the procedures applied in other parts of the world for volcanic eruptions do not appear to require the kind of restrictions that are presently being imposed in Europe."

But an expert who has flown over Europe to check the air said he saw "dangerous" conditions.

Guy Gratton, head of the Facility for Airborne Atmospheric Measurements at Britain's Cranfield University, flew into the skies Thursday and saw "a really strange and complex set of layers of ash," with a layer of perfectly clear air suddenly giving way to a layer of ash, he told CNN. If particles of ash enter a jet engine, when they come out they can solidify on turbine blades, he said.

A group of his colleagues took to the skies Sunday, and in some places saw "quite high concentrations of ash," he said.

"I suspect it's going to be a few days yet" before it's safe to fly, Gratton added.

Oh, and look, the head of someone who DOESN'T make money or suffer in elections doesn't think it's safe. And why?.... because the layers are not homogeneous, are not easy to predict, etc.

http://www.cnn.com/2010/TRAVEL/04/18/volcano.ash.test.flights/index.html?hpt=T1

So, most think it's perfectly safe, except for those who don't. Given that, and given the amount of air traffic... do the math.

[ViewsofMars]

The BA flight 9 flew into a dense ash cloud and it's engines were essentially destroyed in minutes - so if you fly into an ash cloud 1% as dense are your engines unaffected, affect only 1% as much, have it's life reduced by 1% or be destroyed in a few *100 minutes?


Hi mgb_phys, I read on National Geographic News Watch from News Editor David Brawn's Eye on the World the following.

The giant cloud of ash called to mind the 1982 incident when a British Airways Boeing 747 flew through an ash cloud over Indonesia.

"A strange St Elmo's Fire-like light had appeared on the cockpit windscreen and sulphur-smelling smoke started filling the passenger cabin. Then, within minutes, all four engines had failed," the Telegraph reports on its website.

The plane managed to glide sufficiently out of the ash plume for three of the four badly damaged engines to restart. It had fallen 25,000 feet.
http://blogs.nationalgeographic.com/blogs/news/chiefeditor/technology/

[ViewsofMars]

Moving onto Monday, April 19, 2010 article by Martin Evans, Alastair Jamieson, Richard Alleyne and David Millward in the online newspaper Telegraph.co.uk., the article Volcanic ash cloud: British Airways fly in the face of ban.

The chaos caused by the eruption of an Icelandic volcano, now entering its fifth day, has left more than one million British travellers stranded abroad.

The unprecedented disruption to airline passengers, which has threatened to leave schools closed and businesses without workers after the Easter holidays, has already cost the economy £500million and is costing airlines worldwide £130million a day. Last night BA became the latest airline to challenge the necessity of the no-fly zone imposed by British air traffic authorities amid claims they had “overreacted”.

Willie Walsh, the airline’s chief executive, joined four crew in a three-hour test flight from London, over the Atlantic, to Cardiff. Today the airline will study the effects of the flight on engines before concluding whether it is safe to fly or not.

A BA spokesman said: “We would not be doing this if we did not think it was safe and didn’t have the necessary permission. We would not do anything which would jeopardise our crew or aircraft.”

The ban on flights is due to run until 7pm today at the earliest. The test flight came as Gordon Brown called a ministerial meeting amid suggestions the Government had been too slow to react. Five ministers – Lord Mandelson, Lord Adonis, Tessa Jowell, David Miliband and Lord West – lined up outside Number 10 after the talks to announce plans for Spain to be used as a transport ''hub’’ to try to get British travellers back home.

Spain’s airspace was opened up last night and plans were being made for British airline passengers to fly into Spain before being placed on naval or private ships to take them back to Britain.

With replacement bus, train and ferry services running out of capacity, the Tories earlier had proposed that ships be commandeered to get people back to Britain.

The Dutch airline KLM had earlier carried out a test flight through the ash cloud over Dutch airspace. A spokesman for the airline said: “We have not found anything unusual and no irregularities, which indicates the atmosphere is clean and safe to fly.”

Lufthansa also flew 10 aircraft from Munich to Frankfurt on Saturday with the blessing of the safety authorities.

A spokesman said: “We found no damage to the engines, fuselage or cockpit windows. This is why we are urging the aviation authorities to run more test flights rather than relying on computer models.”

Ulrich Schulte-Strathaus, the Secretary General of the Association of European Airlines, said: “Verification flights undertaken by several of our airlines have revealed no irregularities at all; this confirms our requirement that other options should be deployed to determine genuine risk”.

Last night Ryanair announced it was cancelling all scheduled flights to and from the UK, Ireland, Denmark, Finland, Norway, Sweden, Belgium, Holland, France, Germany, Poland and the Baltic States until 1pm British time on Wednesday.

Theresa Villiers, the shadow transport secretary, said: “With thousands of Britons stuck in airports overseas, it is hugely worrying that there is no end in sight for the flight ban. This crisis is costing the economy millions of pounds every day and causing huge amounts of travel misery.

''Those who are stranded abroad need reassurance from the Government that they are doing all they can to help get people home and address the crisis.”

The blanket ban was initially imposed on Thursday by Nats, the national air traffic control service.

Keith Bill, a spokesman for the pilots union BALPA, challenged Nats to prove that they have taken advice from counterparts around the world who have greater experience of ash clouds caused by volcano eruptions.

Jo Gillespie, an aviation safety expert, said: “Without having the data to back up the decision this looks like an overreaction and is hugely damaging to the already suffering airline industry.”
http://www.telegraph.co.uk/travel/travelnews/7605305/Volcanic-ash-cloud-British-Airways-fly-in-the-face-of-ban.html

[tomkeus]

I don't see how things Guy Grutton is saying are relevant for the entire continent. Ash plume is carried directly from Iceland towards the UK and the UK is most severely hit of all European countries.

What makes things tragic, everything points to entire Europe listening only to the British who are on the path of the direct impact and then just applying what they're doing to themselves. Ash info center is in the UK and their computational model just gives highest possible extent of ash plume disregarding it's density. I know for certain that Serbia and Montenegro, Croatian and Hungarian ATC closed down airspace based on UK Met's computer simulations and I'm fairly certain most of other air traffic authorities did that. No one did actual measurements. Only ones who did, were again, British who, being under highest impact, ofcourse measured high presence of ash here and there and just continue to scare the hack of the rest of the Europe without even considering that what they are measuring cannot be applied to the rest.

My point is: We have eruptions all the time There are procedures, and they certainly do not include locking down the entire continent. We had much stronger eruptions in the past but they didn't cause so much disruption in their respective areas. I mean, this volcano spewed out 150 million cubic meter of material. Met's map show that material distributed over at least couple of million cubic kilometers of atmosphere. Calculate mean concentration, and than take into account that concentration is higher in the areas closer to volcano and falls down further. I mean, the fact the people in the UK can see ash falling on the ground tells us that heavier things fall down from the sky in significant amount before reaching the continental Europe.

Basically, over greater part of closed down area ash concentration is negligible and airliners flying over Middle East or North Africa have to deal regularly with much higher presence of silicate particles in the air but no one is locking down anything down there.

Look at the Russians. They are flying without any lockdowns since this whole thing started. I didn't hear them complaining about the damage or planes falling from the sky.

[cristo]

I don't see how things Guy Grutton is saying are relevant for the entire continent. Ash plume is carried directly from Iceland towards the UK and the UK is most severely hit of all European countries.

Guy Gratton and his team flew into the cloud and took some data. Given that he is funded by the British government, it makes sense for him to primarily focus on the ash in British airspace. Just because no other data is being collected by equivalent EU entities does not mean he should be condemned for doing so.


What makes things tragic, everything points to entire Europe listening only to the British who are on the path of the direct impact and then just applying what they're doing to themselves. Ash info center is in the UK and their computational model just gives highest possible extent of ash plume disregarding it's density. I know for certain that Serbia and Montenegro, Croatian and Hungarian ATC closed down airspace based on UK Met's computer simulations and I'm fairly certain most of other air traffic authorities did that.

Really? Did you miss my post above. Here, I'll quote it for you:

Err.. firstly the simulations were not just done by the Met Office in the UK; simulations have been done by many other European equivalents. In fact, once professor whom I saw interviewed yesterday say that there was a remarkable level of agreement between the different simulations. Secondly, planes have been up there collecting data, and test flights continue to be done. However, it makes sense that such flights are done by suitable aircraft to try and gauge the situation, and not by just seeing whether a commercial airliner can fly through the ash.


No one did actual measurements. Only ones who did, were again, British who, being under highest impact, ofcourse measured high presence of ash here and there and just continue to scare the hack of the rest of the Europe without even considering that what they are measuring cannot be applied to the rest.

Are you an expert in these matters? Have you seen the data that the British researchers collected and passed on to the authorities, or the jet engine manufacturers? Did you hear the British researchers make sweeping claims applied to the entire continent?


My point is: We have eruptions all the time There are procedures, and they certainly do not include locking down the entire continent. We had much stronger eruptions in the past but they didn't cause so much disruption in their respective areas. I mean, this volcano spewed out 150 million cubic meter of material. Met's map show that material distributed over at least couple of million cubic kilometers of atmosphere. Calculate mean concentration, and than take into account that concentration is higher in the areas closer to volcano and falls down further.

Oh, I get it, the MET office are too dumb to think of this? :rolleyes:


Look at the Russians. They are flying without any lockdowns since this whole thing started. I didn't hear them complaining about the damage or planes falling from the sky.

No, not yet, but then the Russians aren't really known for their air safety. Still, I haven't seen any maps, but it's likely that Russian airspace isn't affected to the same extent; their flights over Europe have likely been above the ash cloud.

[tomkeus]

My post was probably badly worded. I wasn't accusing UK Met of anything. I was accusing everyone of listening to them and making decisions without trying to understand what is behind the data.

Besides, it is not the Met who is deciding whether to close down airspace it is ATCs and bureaucrats. Met has qualified people who are not idiots unlike guys sitting somewhere in the office thinking to themselves are they going to be elected for the next term.

By saying that Russia isn't so affected you're just confirming my arguments. Met's maps show large portion of western Russia under the cloud, same as the rest of the Europe. Maybe the ash plume is just too afraid to go over the Russian border, despite what the simulations are telling it to do. BTW, Russians don't have significantly worse passenger air safety record than any other European country. It is just unfounded myth.

Here's another example: Ecuadorans have eruption of Tungurahua for years now but they're still flying. We could learn from them a thing or two.

P.S. Latest Met's map:

http://www.metoffice.gov.uk/aviation/vaac/data/VAG_1271655414.png

[Ivan Seeking]

Apparently the eruption has virtually stopped.

[mgb_phys]

My post was probably badly worded. I wasn't accusing UK Met of anything. I was accusing everyone of listening to them and making decisions without trying to understand what is behind the data.
The problem is that the Met office can model the movement of the cloud and to an extent the density of the cloud.
What nobody knows is how dense can you fly in?
You need a graph of ash-density vs damage to engine - at the moment there are two data points, no-ash=no-danger, lots of ash = lose all 4 engines in 10minutes.

In the absence of any data somebody will pick a number out of the air and in a few years this will become the standard for safe ash density, in the same way that someone decided that a 3.9oz bottle of shampoo is safe but a 4.1oz one is a threat to the aircraft.

[ViewsofMars]

Apparently the eruption has virtually stopped.

Best news I've heard today. Thanks Ivan. Where did you find that info?

[Ivan Seeking]

Best news I've heard today. Thanks Ivan. Where did you find that info?

CNN has been reporting it all morning.

[ViewsofMars]

CNN has been reporting it all morning.

Thanks. I normally don't listen to the news. I'll check it out online or look at the newspaper then confirm it with a website that I consider to be a source for the lastest scientific data.


One brief comment, I did read several days ago in my local paper that the damage to a airplane's engine flying through ash is possible and it could take up to three years before the engine dies. Personally, as a frequent flyer I want to feel secure by knowing I'm safe in the air and on the ground too.

[Frame Dragger]

A sulphur lining... http://www.cnn.com/2010/TRAVEL/04/18/volcano.ash.test.flights/index.html?hpt=T1

[Count Iblis]

http://www.wired.com/autopia/2010/04/airlines-push-to-reopen-airspace-nasa-study-urges-caution/

In 2000, NASA conducted a study where it intentionally flew a DC-8 through volcanic ash that was not visible to the flight crew. Despite the relatively small amount of ash encountered, there was damage to the engines, though it was only seen in a detailed examination after the flight. A detailed report on the test includes pictures of damaged engine parts and explains pilots may not have any clues they are flying through ash.

[Frame Dragger]

http://www.wired.com/autopia/2010/04/airlines-push-to-reopen-airspace-nasa-study-urges-caution/

Funny how the people who are urging caution are:

1.) The people with the most experience and qualifications to make such a judgement.
2.) People without a personal financial and political stake in air-travel resuming.

Good to know that eruptions don't change human nature... death before loss of profit or inconvenience. :rolleyes:

[Andre]

....So why aren't they considering at least some flights (high priority, perhaps) at lower, safe, altitudes? Is it just an admin (ATC) problem?

That may very well be the case, apart from the safety issue of range/endurance and reserve fuel for diversion to alternate airport (legal issue) which of course suffer proportionally but the airspace structure and the rules and regulations limits the capacity for safety. But given these restrictions I concur that some contingency plans could have existed to deal with that and allow for limited high priority air traffic.

[joelupchurch]

There are some things being said by authorities which are pretty silly:
A spokesperson from from Nats told BBC News that there was "no threshold" for concentrations at which volcanic ash was acceptable.

http://news.bbc.co.uk/2/hi/science/nature/8629609.stm

In another place I read:
The problem with such ash is that it is extremely fine – less than 2mm in diameter, and in the case of fine ash only 6 microns in diameter – which means that it is easily carried by the wind; and because it is ejected by enormously hot air from a volcano it will often be thrown high into the jetstream at exactly the height that aircraft like to fly. The ash particles' light weight means that they will then remain there, dispersing so slowly it can take two to three years for them to vanish.

http://www.guardian.co.uk/science/2010/apr/15/volcanic-ash-bad-for-planes

[Frame Dragger]

There are some things being said by authorities which are pretty silly:


http://news.bbc.co.uk/2/hi/science/nature/8629609.stm

In another place I read:


http://www.guardian.co.uk/science/2010/apr/15/volcanic-ash-bad-for-planes

Well, it does take 2-3 years for the gasses and ash from an eruption such as this (look at Pinatubo) to return to earth, but it doesn't mean they are a threat to air-safety for that long. There is ALWAYS particulate matter in the air, but it has to be enough to form glass on the turbines in the case of volcanic ash.

As for "no safe threshold", who knows at this point? I don't take that to mean that as long as a particle is aloft that planes won't be.

[mgb_phys]

A spokesperson from from Nats told BBC News that there was "no threshold" for concentrations at which volcanic ash was acceptable
That's what happens when you have a country where nobody with a science background is in charge of anything.

[Frame Dragger]

That's what happens when you have a country where nobody with a science background is in charge of anything.

I'm ready to embrace the notion of "Philosopher-Kings" at this point! :wink:

[tomkeus]

Funny how the people who are urging caution are:

1.) The people with the most experience and qualifications to make such a judgement.
2.) People without a personal financial and political stake in air-travel resuming.

Good to know that eruptions don't change human nature... death before loss of profit or inconvenience. :rolleyes:

Exactly. They might as well say, "Hey let's shut down air traffic for the entire year". If you really want to play it safe and the only thing you care about is human life, you will certainly say that. But if safety is the only thing you are concerned, you might as well say, hey planes tend to drop from the sky here and there and cost hundreds of lives each year, so let's ban air traffic altogether.

Point is that things have to function and you have to take risks. All the time. Nothing is absolutely safe and certain. It really begins to tick me off how our Western societies can easily get paralyzed by fear and grind to a halt at the slightest sign of uncertainty.

Look at the safety precautions at the airports now. Getting more draconian all the time. We had planes bombed out of the skies in 50s, 60s, 70s, 80s, but authorities didn't institute for passenger to get stripped down or cavity searches. The way things are going now I wouldn't be too surprised if within next 10 years the only way to travel by air is to strip naked, get tranquilized and then tied down to your seat.

This article sumps up nicely everything that bothers me about this culture of excessive caution that seems to be emerging more and more lately

http://www.spiked-online.com/index.php/site/article/8607/

[Ivan Seeking]

The way things are going now I wouldn't be too surprised if within next 10 years the only way to travel by air is to strip naked, get tranquilized and then tied down to your seat.

Wow, that would be something. I haven't dated in years.

[Hurkyl]

But if safety is the only thing you are concerned, you might as well say, hey planes tend to drop from the sky here and there and cost hundreds of lives each year, so let's ban air traffic altogether.
Only if you're doing it wrong.

If safety was the only thing you are concerned about, then you would have to balance the dangers of air travel against the dangers of people traveling other ways.

[Frame Dragger]

Exactly. They might as well say, "Hey let's shut down air traffic for the entire year". If you really want to play it safe and the only thing you care about is human life, you will certainly say that. But if safety is the only thing you are concerned, you might as well say, hey planes tend to drop from the sky here and there and cost hundreds of lives each year, so let's ban air traffic altogether.

Point is that things have to function and you have to take risks. All the time. Nothing is absolutely safe and certain. It really begins to tick me off how our Western societies can easily get paralyzed by fear and ground to a halt at the slightest sign of uncertainty.

Look at the safety precautions at the airports now. Getting more draconian all the time. We had planes bombed out of the skies in 50s, 60s, 70s, 80s, but authorities didn't institute for passenger to get stripped down or cavity searches. The way things are going now I wouldn't be too surprised if within next 10 years the only way to travel by air is to strip naked, get tranquilized and then tied down to your seat.

This article sumps up nicely everything that bothers me about this culture of excessive caution that seems to be emerging more and more lately

http://www.spiked-online.com/index.php/site/article/8607/

I see a clear difference between security screening that routinely FAILS, and is therefore an illusion of comfort (re: your point about western views), and taking a risk when intelligent people are telling you to do different things.

There is this as well... the airlines and airport associations are complaining that they are losing $200 million USD per day. They are already asking governments for recompense. Passengers meanwhile (or strandees more properly) have no such recourse, unless their traveler's insurance covers Force Majeure up to volcanic eruptions.

So, there is a desire for money on one hand, which is nearly devoid of conscience because responsiblity is spread across an industry. On the other you have people who care ONLY about keeping planes from falling out of the sky. Clearly as with all things in life, it's a matter of risk/benefit, but how does a politician make that judgement based on conflicting advice?

Answer: They don't always make the right one. That doesn't mean that the western world is hysterical... it means that gambling with a plane full of people (who may be desperate to get somewhere,and thereofore not making their own clear judgements) is not acceptable. If a plane DID crash due to the ash, can you imagine the outrage?... it would be NOTHING compared to this.

Finally... there is "uncertain", and there is "needless risk". How is erring on the side of caution hysterical? I suspect that based on this, contingency plans for future eruptions will be put in place. THAT is what should have been done already, along with more research to understand just WHAT contitutes a safe concentration of ash. That said, you can't make up for prior negligence by gambling with lives and the confidence of people who fly.

You're also being a bit narrow here... people are TERRIFIED of spending the last minute or two of their lives helpless, in a metal tube, knowing they are about to die. That terror skews judgement, because although we all know we're going to eventually die, and maybe sooner rather than later, an air-crash is a nightmare for most. You mention security in, say, US airports, but you neglect to mention that we have almost NO security for rail travel, and other clear risks. People need to get through life without being paralyzed by terror, and for most, that means a certain level of denial.

Bottom line: People are terrified of falling to their deaths, being eaten alive, burning, and having their eyes, hands and genitals mutilated. Their fear is rooted in reason, but it's amplified by basic human nature, the same that makes Anatomy students faint when they actually SEE a cadaver... especially the face and hands. That isn't reasonable either, but it's enough to force some people out of medicine. We're human, we make human mistakes, and we know that death is final (afterlife or no, it's an end to THIS) so we try not to make mistakes which we SEE as risky.

Governments almost always bow to fear, and realize that they would be out of a job and probably a conscience if something DID go wrong. So, you accept some risks, and when an obvious and unusual (to people) event occurs which contains a great deal of fear and uncertainty... this is what you get.

This, is putting aside the notion that in fact, traveling through an ash cloud IS dangerous, I'm speaking only to the human element here.

[sophiecentaur]

That may very well be the case, apart from the safety issue of range/endurance and reserve fuel for diversion to alternate airport (legal issue) which of course suffer proportionally but the airspace structure and the rules and regulations limits the capacity for safety. But given these restrictions I concur that some contingency plans could have existed to deal with that and allow for limited high priority air traffic.

I'm glad you see my point. It is obviously possible to arrange some sort of service which could be optimised for any particular flight ceiling. Even a 25% service at 200% of the running cost would be well worth while.
I should hope that someone in a backroom somewhere has already been told to prepare for a similar eventuality. The present situation has been handled particularly badly and you can see why. The slightest hint of an accident or even 'incident' would have someone's arse severely kicked; air travel is that sort of business and no one admits to placing a value on human life in that particular context. I have always been impressed by the way NICE manage to do that, so explicitly, with regard to medicine without being pilloried.
There should have been a proportionate response. Once 'the dust has settled' there are bound to be huge recriminations about the cost to everyone, including the lives lost when organ transplants and drugs haven't got through. Questions will be asked!:grumpy:

[dorlomin]

Finnish F-16s were damaged by the ash on Friday. (http://www.flightglobal.com/articles/2010/04/16/340727/pictures-finnish-f-18-engine-check-reveals-effects-of-volcanic.html)

They also have flown sampling missions in BAe Hawks.

Should lay aside one or two of the myths about this lock down.

[Frame Dragger]

Finnish F-16s were damaged by the ash on Friday. (http://www.flightglobal.com/articles/2010/04/16/340727/pictures-finnish-f-18-engine-check-reveals-effects-of-volcanic.html)

They also have flown sampling missions in BAe Hawks.

Should lay aside one or two of the myths about this lock down.

Now THAT, is good stuff.

[mgb_phys]

then you would have to balance the dangers of air travel against the dangers of people traveling other ways.
US highway deaths are something like 50,000/year = a full 737 crashing everyday!

[Frame Dragger]

US highway deaths are something like 50,000/year = a full 737 crashing everyday!

True, but is that per capita, or a result of how much time people spend in cars vs. airplanes?

This keeps making me think of 'Freakonomics'... granted hardly a scientific trove, but still...

http://books.google.com/books?id=LkQPOSXMUscC&pg=PA150&lpg=PA150&dq=freakonomics+airplane+car+death&source=bl&ots=4oSgG1juHT&sig=hfw8oQFyZYzheNOKCH-DU9EcPpY&hl=en&ei=YcjMS7KuBIL98AbxmZCzBA&sa=X&oi=book_result&ct=result&resnum=4&ved=0CBQQ6AEwAw#v=onepage&q&f=false[

I really appreciate the equation: Risk = Hazard + Outrage.

[mgb_phys]

True, but is that per capita, or a result of how much time people spend in cars vs. airplanes?
Mostly a result of confusion about the correlation between wearing a seatbelt and not flying through the windscreen.

The US+Canada have about twice the highway fatality rate of most western european countries, in spite of being in theory safer as more miles are driven on freeways. And the US+Canada have much lower levels of wearing a seatbelt.

[Frame Dragger]

Mostly a result of confusion about the correlation between wearing a seatbelt and not flying through the windscreen.

Oh, that's part of it, but remember that most accidents DON'T end with ejection from the vehicle, but those who do tend to die.

http://askville.amazon.com/Statistics-survival-rates-seat-belt-open-convertible-%5BHusband-questions-intuition/AnswerViewer.do?requestId=4828631

In a way, everyone in an airplane (believes) they are essentially an unrestrained passenger, lacking ANY control, and in the event of a crash, they are unlikely to survive (they believe). This is clearly not rational when seatbelt usage figures would seem to indicate that many people are tired of living. I think we need to accept that without major education initiatives, these views will remain and people who would otherwise survive car wrecks will die.

Of course, this is still very much a "the elevator is the safest place for you to be"... until you start spending quality time in it. IF something goes wrong in a car, and you've taken precautions, you're likely to live. In a plane, you're more liley to die, and experience prolonged terror.

[lisab]

New ash cloud is reported by BBC: (http://news.bbc.co.uk/2/hi/uk_news/8631144.stm)

A new ash cloud spreading towards the UK is causing uncertainty over plans to reopen some airspace on Tuesday, air traffic control body Nats has said.

Earlier, it said the flight ban would be lifted over Scotland, Northern Ireland and the north of England.

But Nats said there was now a worsening situation in some areas. The outlook for Northern Ireland is most uncertain.

Dang, just as the airspace restrictions were beginning to ease.

Is there any way to see ash at night?

[BobG]

Nobody wants to have to tell anyone's relatives that their loved one died because of from Eyjafjallajökull.

9jq-sMZtSww
http://www.youtube.com/watch?v=9jq-sMZtSww

It's even worse than notifying the deaf about a death.

_zheeF5yPak
http://www.youtube.com/watch?v=_zheeF5yPak

[Frame Dragger]

New ash cloud is reported by BBC: (http://news.bbc.co.uk/2/hi/uk_news/8631144.stm)



Dang, just as the airspace restrictions were beginning to ease.

Is there any way to see ash at night?

There should always be ways to at least bounce a laser and see how the light scatters... but really, it's tough to see period. On radar, it's just invisble at this point... glass and dust don't make an impression, and modern radars screen "noise".

[tomkeus]

New ash cloud is reported by BBC: (http://news.bbc.co.uk/2/hi/uk_news/8631144.stm)

Yes but the ash plume is much lower than last time. It is reaching only 4km or so opposed to 10km last week so it shouldn't present as big problem in affected areas.

[joelupchurch]

The US+Canada have about twice the highway fatality rate of most western european countries, in spite of being in theory safer as more miles are driven on freeways. And the US+Canada have much lower levels of wearing a seatbelt.

That is incorrect. The current seat belt usage in the United States is 84% (2009). The latest number I could find for Europe is 76% for front seat occupants and 46% for rear seat occupants. The only countries that do consistently better the United States are Scandinavia, Germany and the UK.

The 2009 fatality rate for the United States is 7.2 per billion vehicle kilometers which is a respectable number compared to Europe.

http://www.usatoday.com/news/nation/2010-04-12-traffic-deaths_N.htm

Of course Americans have an advantage over other countries since we tend to stay inside our cars.
Risk comparisons for the EU show that the fatality risk for motorised two-wheelers is the highest of all modes, being on average 20 times higher than for car occupants. Also cycling and walking have on average a 7 to 9 times higher fatality risk per distance travelled than car travel.

http://www.etsc.eu/oldsite/rep_all6.htm

[Count Iblis]

Yes but the ash plume is much lower than last time. It is reaching only 4km or so opposed to 10km last week so it shouldn't present as big problem in affected areas.

It has just been announced that the airports in Southern Britain will remain closed.

[ViewsofMars]

Sorry for the delay Ivan in fully responding yesterday regarding correspondence (your *replies* my responses) please, reference msgs. 118, 120, 121, 122. (My delay was due to the unexpected happening and I had to deal with it! :biggrin: Car problems yesterday. I have no desire in fixing my turbo.)

As a female aka WOMAN science researcher, I naturally did some research today that might be helpful.

NASA:

4.19.10
NASA Observes Ash Plume of Icelandic Volcano
by Rob Gutro, NASA's Goddard Space Flight Center

The continuing eruption of Iceland'sEyjafjallajökull volcano was observed Mon., April 19, 2010, by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument onboard NASA's Terra spacecraft. The new image shows a white eruption column being carried toward the south by prevailing winds. The image is dominated by the gray, ash-laden eruption cloud dispersed south and east by the winds, blowing from the southern Iceland coast toward Europe. The bright red areas mark the hot lava at the current vent (upper left), and the still-hot lava flows from the earlier phases of the eruption (upper center). The high-temperature material is revealed by ASTER's thermal infrared bands.

This image covers an area of 58.6 by 46.8 kilometers (36.3 by 29 miles). The resolution is 15 meters (49 feet) per pixel.

4.19.10
Two NASA Satellites Capture Last Three Days of Eyjafjallajökull's Ash Plume
by Rob Gutro, NASA's Goddard Space Flight Center

NASA's Aqua and Terra satellites fly around the world every day capturing images of weather, ice and land changes. Over the last three days these satellites have provided visible and infrared imagery of the ash plume from the Eyjafjallajökull volcano in Iceland.

Eyjafjallajökull is pronounced similar to "EYE-a-fyat-la-yu-goot," and it is still spewing ash into the atmosphere. Volcanic eruptions are important sources of gases, such as sulphur dioxide (SO2) and volcanic ash (aerosols) in the atmosphere.

The Moderate Resolution Imaging Spectroradiometer, also known as MODIS, is an instrument that flies aboard both NASA's Aqua and Terra satellites. MODIS captures daily visible and infrared earth imagery and has provided daily images of the volcanic plume. NASA’s MODIS instrument and the Atmospheric Infrared Sounder (AIRS) instrument, both of which fly on Aqua, contain sulfur dioxide (SO2) absorption channels to enhance volcanic ash detection. These applications have significantly improved upon existing satellite-based multi-spectral techniques in identifying and tracking ash clouds and estimating their height.

On Saturday, April 17 at 13:20 UTC (9:20 a.m. EDT), Aqua captured a visible image of the ash plume so clearly that in the satellite image a viewer could see the billowing cloud spewing from the volcano and blowing almost due south before turning east over the Atlantic Ocean.

On Sunday, April 18 at 12:05 UTC (8:05 a.m. EDT), NASA's Terra satellite flew over the volcano and captured an image of the brown ash cloud mostly obscured by higher clouds. The brown plume was partly visible underneath the high clouds.

By Monday morning, April 19 at 12:50 UTC (8:50 a.m. EDT) the high clouds had cleared, and the brown line of spewed volcanic ash was visible once again blowing south, then turning east toward the United Kingdom.

The ash cloud basically consists of fine particles of pulverized rock. Volcanic ash is a rare but potentially catastrophic hazard to aviation. Encounters with volcanic ash while in flight can result in engine failure from particulate ingestion and viewing obstruction of the cockpit widescreen from etching by the acidic aerosols. Volcanic Ash Advisory Centers were established to monitor the air space in areas prone to eruptions and to issue volcanic ash warnings.

NASA works with other agencies on using satellite observations to aid in the detection and monitoring of aviation hazards caused by volcanic ash. For more on this NASA program, visit: http://science.larc.nasa.gov/asap/research-ash.html.

Eyjafjallajökull is one of Iceland's smaller glaciers, located north of Skógar. Skógar is a small Icelandic village with a population of roughly 25 located at the south of the glacier. Eyjafjallajökull lies west of another glacier called Mýrdalsjökull.

The MODIS Rapid Response System was developed to provide daily satellite images of the Earth's landmasses in near real time. True-color, photo-like imagery and false-color imagery are available within a few hours of being collected, making the system a valuable resource. The MODIS Rapid Response Team that generates the images is located at NASA's Goddard Space Flight Center in Greenbelt, Md.
[Please view images and further text from the link below. Thank you.]
http://www.nasa.gov/topics/earth/features/iceland-volcano-plume.html

Science Magazine :

Iceland’s Volcano Proving Tough to Predict
by Richard A. Kerr on April 19, 2010

Volcano prediction can be tough going, but volcanologists really have their hands full with the ongoing eruption at Iceland’s Eyjafjallajökull. When will it end? Will there be even more ash? And will Eyjafjallajökull's bigger and badder neighbor Katla join in? It seems that the very character of Icelandic volcanoes is working against reliable forecasting. If anything, the long-term outlook is bad.

Eyjafjallajökull’s orneriness became obvious 17 April, when scientists at the University of Iceland and the Icelandic Meteorological Office announced that the volcano’s chemistry had changed. At the extremes, volcanoes behave one of two ways: quietly like Hawaii’s Mauna Loa, which almost always just oozes lava for years on end; or boisterously like Mount St. Helens, which quickly rose to an explosive climax and then retired.

The latest chemical analyses of ash explain how Eyjafjallajökull switched without warning from quiet lava to plane-grounding ash plume. The key was a boost in the silica content of the magma arriving at the surface. Silica-rich magma makes for more viscous—and thus more explosive—lavas and can be produced as some minerals crystallize out of subterranean magma. The mountain, which was regularly monitored, gave no chemical warning that the switch was on the way.

Eyjafjallajökull is not divulging its longer-term intentions either. According to geophysicist Páll Einarsson of the University of Iceland, the magma feeding the current eruption seems to be coming from down deep rather than a shallow chamber. So it is impossible to gauge just how much magma could emerge during this episode of activity.[Please read on . . .]
http://news.sciencemag.org/sciencenow/2010/04/icelands-volcano-proving-tough-t.html#disqus_thread

I think my previous message #69 might be helpful.

[pivot]

does anyone know what causes volcanic lightning? seems like it could be various things (change in pressure, particles in the air, moisture, magnetic materials, etc)

[Count Iblis]

Actually this is nothing new. Eyjafjallajökull shuts down air traffic in the 21st century, and in the 18th century Laki (http://en.wikipedia.org/wiki/Laki) shut down shipping traffic:

The summer of 1783 was the hottest on record[citation needed] and a rare high pressure zone over Iceland caused the winds to blow to the south-east. The poisonous cloud drifted to Bergen in Norway, then spread to Prague in the Province of Bohemia by 17 June, Berlin by 18 June, Paris by 20 June, Le Havre by 22 June, and to Great Britain by 23 June. The fog was so thick that boats stayed in port, unable to navigate, and the sun was described as "blood coloured".[6]

[Frame Dragger]

does anyone know what causes volcanic lightning? seems like it could be various things (change in pressure, particles in the air, moisture, magnetic materials, etc)

Friction between particulate matter. Think of an ash cloud as a BIG carpet, with it's own slippers. :smile:

[pivot]

I feel like, then, all volcanoes would have lightning, but that isn't the case.

[Frame Dragger]

I feel like, then, all volcanoes would have lightning, but that isn't the case.

All volcanoes don't produce large, energetic explosions, or ash plumes. If we're just talking about a pyroclastic flow (which not all volcanoes have), with little or no plume, then:

1.) There may be a lot of moisture which would inhibit the process, but mostly
2.) The cloud is mostly grounded already.

[DaveC426913]

I feel like, then, all volcanoes would have lightning, but that isn't the case.

By that logic all rain clouds should have lightning too. As it is though, only the really big ones do.
:smile:

[mgb_phys]

I think this event shows it's time to think of a tunnel again.

http://homepage.ntlworld.com/forgottenfutures/express/express.htm

[Frame Dragger]

Holy ****...

http://www.businessandfinance.ie/cat_news_detail.jsp?itemID=1479

BA should be shot in the knees for taking passengers for such a "ride". The bloody fools should have taken their fleet home a few hours later and avoided this. 6K passengers are going to be deeply pissed.

[cristo]

Holy ****...

http://www.businessandfinance.ie/cat_news_detail.jsp?itemID=1479

BA should be shot in the knees for taking passengers for such a "ride". The bloody fools should have taken their fleet home a few hours later and avoided this. 6K passengers are going to be deeply pissed.

BA decided to play hardball with NATS by launching some of their long haul flights towards heathrow, an airport that, when the flights will have taken off, BA would have been told is closed until at least 0100 on Weds. This resulted in some planes being diverted to Ireland, some being held in holding patterns for hours.

It seems that BA has won, since NATS has just announced that airspace will be opening in phases from 2200.

[Count Iblis]

A plane from Toronto was diverted to Newcastle. So, you'll have a lot of passengers finding themselves in the Middle of Nowhere

[cristo]

A plane from Toronto was diverted to Newcastle. So, you'll have a lot of passengers finding themselves in the Middle of Nowhere

Newcastle isn't such a bad place to divert to (and isn't too bad a city.. watch it, Kurdt will get you :tongue2:) as there's a direct rail link. Shannon, on the other hand, is on a different island!

[Frame Dragger]

Newcastle isn't such a bad place to divert to (and isn't too bad a city.. watch it, Kurdt will get you :tongue2:) as there's a direct rail link. Shannon, on the other hand, is on a different island!

Hmmm, they designated these flight numbers as landing in Heathrow and Gatwick... I maintain there are going to be some seriously ticked passengers. Granted, it's cheaper than leaving planes grounded, but if they were not honest about the destination... damn.

Then there are the people stuck in Amsterdam... and they're complaining! The Dutch are sending lovely women in traditional dress to entertain people in a city with legal marijuana. As Force Majeure goes... not too bad an outcome.

This is all the same BS as per usual... getting people on the plane, instead of warning them of certain delays.... etc...
I'll just say this... I'm ever stuck on the tarmac for 4+ hours, I'm getting up to take a little walk down the aisle, and blow the first emergency hatch or door I find.

[mheslep]

Occurs to me that that this ash problem is another reason for aviation to pursue electric ducted fan powered aviation, along with an appropriate energy source. (Discussed in this thread (http://www.physicsforums.com/showpost.php?p=2292842&postcount=14)). The high temperatures inside current turbine jet engines that melt ash silicas are absent in ducted fans. In addition to fans, find a material tough enough for a windscreen and the Friendly Skies will be unlikely, or at least much less likely, to be interrupted by the next mons flammas eructans.

[turbo]

Occurs to me that that this ash problem is another reason for aviation to pursue electric ducted fan powered aviation, along with an appropriate energy source. (Discussed in this thread (http://www.physicsforums.com/showpost.php?p=2292842&postcount=14)). The high temperatures inside current turbine jet engines that melt ash silicas are absent in ducted fans. In addition to fans, find a material tough enough for a windscreen and the Friendly Skies will be unlikely, or at least much less likely, to be interrupted by the next mons flammas eructans.How do you power it, though and allow efficient operation? Right now, fossil-fuel-driven turbines are the big game in town and every step in conversion, transmission, storage, etc, steals from the efficiencies.

[Frame Dragger]

I'm guessing we'll be riding RAMjets before we find safe energy storage of the density needed for that kind of ducted fan as propulsion.

This is really a big problem for the military... as civilians we have rail technology we COULD implement if we chose, that would be fairly effecient.

[mheslep]

How do you power it, though and allow efficient operation? Right now, fossil-fuel-driven turbines are the big game in town and every step in conversion, transmission, storage, etc, steals from the efficiencies.The fan itself would be ~98% efficient. The energy source is another hard problem*, but some possibilities include fuel cells run from hydrogen or natural gas, etc, or a normal jet fuel powered turbine electric generator + batteries which are used at cruise.

*Edit: If a fuel cell or electric turbine generator is used they will suffer the usual efficiencies and losses.

[mheslep]

I'm guessing we'll be riding RAMjets before we find safe energy storage of the density needed for that kind of ducted fan as propulsion. How do you take off and land with a RAMjet? Also, I doubt RAMjets solve the ash problem. Though the moving parts are gone, the high temperatures melting the ash remain, eventually corroding the engine structure.

[Frame Dragger]

How do you take off and land with a RAMjet? Also, I doubt RAMjets solve the ash problem. Though the moving parts are gone, the high temperatures melting the ash remain, eventually corroding the engine structure.

You misunderstand... I'm not saying we SHOUlD, I'm saying that I believe that technology is going to be ahead of the kind of energy storage you describe.

As for taking off and landing... um... how about ducted fans or props for ascent and descent? (yes, I get the irony) You'd already be carrying hydrogen, which makes the fuel-cell quite feasible. You also can fly ABOVE the ash cloud at high efficiency, and with no delicate moving parts, removing the glass becomes a much smaller issue. I'm also unclear as to whether glass would actually VITRIFY in a RAMjet... it seems to me that it would remain molten and blow out the um... backside.

[mheslep]

You misunderstand... I'm not saying we SHOUlD, I'm saying that I believe that technology is going to be ahead of the kind of energy storage you describe.Understood. My point is I don't see a path forward for RAMjets given the physics of RAMjets. I do see a way forward for the physics of ducted fans; on balance fans + an energy source appear to be an engineering problem.

As for taking off and landing... um... how about ducted fans or props for ascent and descent? (yes, I get the irony)Not clear what you mean. Do you mean use RAMjets plus another set of engines to handle the total flight envelope? That's a big aircraft performance hit to payload.

You'd already be carrying hydrogen, which makes the fuel-cell quite feasible. You also can fly ABOVE the ash cloud at high efficiency, That's a good point - RAMjets make the high altitude possible unlike the turbine.

and with no delicate moving parts, removing the glass becomes a much smaller issue. I'm also unclear as to whether glass would actually VITRIFY in a RAMjet... it seems to me that it would remain molten and blow out the um... backside.Can't prevent interaction with the containing walls, though I have no idea of the gross effect.

[Frame Dragger]

Understood. My point is I don't see a path forward for RAMjets given the physics of RAMjets. I do see a way forward for the physics of ducted fans; on balance fans + an energy source appear to be an engineering problem.

Not clear what you mean. Do you mean use RAMjets plus another set of engines to handle the total flight envelope? That's a big aircraft performance hit to payload.

That's a good point - RAMjets make the high altitude possible unlike the turbine.

Can't prevent interaction with the containing walls, though I have no idea of the gross effect.

Yeah, I have no idea what the end effect would be either. We're talking about MUCH higher sustained temps in a RAMjet than a jet-turbine. That said, FA-18s were being glassed on their engines... and they aren't slouches in the heat department.

As for takeoff and landing, yes, I mean having another set of engines. I can't imagine anything short of a "capture craft" which would be insane, as an alternative. Remember, RAMjets don't NEED to be be carrying huge payloads... that's not realistic anyway. That said, for medical evacuations, organ transplants, and high priority rapid travel it would be VERY useful. In that scenario, reduced payload is offset by the EXTREMELY low price of the fuel, and how rapidly you can turn over a flight.

That... I don't think anyone can reliably predict. That said, energy storage that isn't essentially a bomb is tough to come by. Batteries are not racing ahead, but hindering virtually everything. Maybe super-capacitors could be useful, but not in their current incarnations. As for a hydrogen fuel-cell... you can use them on a sub, but one to power ducted fans for a plane? That's a tough one, and without radical technological breathroughs I see 2 problems:

1.) Hindenberg^2. Jet fuel is flammable, but hydrogen under pressre?! Damn. Same with LNG. This would also be a storage NIGHTMARE on the tarmac in terms of refueling. We would be flying bombs, in a way that current aircraft don't even BEGIN to approach.

2.) If we're talking about liberating hydrogen, there are limited way to do this. Is burning coal for electrolysis really better than jet-fuel? Hydrogen has a long way to go, and at least a RAMjet doesn't need anywhere near the amount a fuel-cell does.

Plus... RAMjets are VERY simple, and I pity the bird who is sucked into one. Roast goose anyone... at mach 3? SCRAMjets are probably bound to be missile/drone only... but RAMjets have a great deal of potential.

Batteries... it always comes down to stupid batteries in some form or another. A breakthrough in energy storage would be magnificent. Look what modern Lithium-Ion-Polymer batteries have done! If we could store energy reliably and safely on a large scale (short of vanadium batteries the size of an elementary school), it would change the world overnight. So much technology is just waiting for more juice... so frusterating.

*shouts at materials engineers at PF* Come on... GET ON IT! We need dilithium crystals post-haste. :biggrin:

[Evo]

does anyone know what causes volcanic lightning? seems like it could be various things (change in pressure, particles in the air, moisture, magnetic materials, etc)Great picture of the lightning.

http://www.swisseduc.ch/stromboli/perm/iceland/eyafallajokull_20100416-en.html?id=3

[Frame Dragger]

Great picture of the lightning.

http://www.swisseduc.ch/stromboli/perm/iceland/eyafallajokull_20100416-en.html?id=3

Wow. If I saw that in real life, I would be running with a pantload of poop and shame... my dignity would be absent.

My mother once encountered a Puma in Tikal (truly, the middle of a jungle in Guatamala), and while the experience has been memorable... it also scared the crap out of her. I love lightning, but that, plus volcanic plume + magma = I get why people looked at that and decided to worship the damned things.

[mheslep]

1.) Hindenberg^2. Jet fuel is flammable, but hydrogen under pressre?! Damn. Same with LNG. This would also be a storage NIGHTMARE on the tarmac in terms of refueling. We would be flying bombs, in a way that current aircraft don't even BEGIN to approach.
Myths. Hindenberg fire and explosion was due to the coating on the skin, not the H2. H2 has safety pros and cons (http://www.physicsforums.com/showpost.php?p=2592657&postcount=44) compared to hydrocarbon fuels. It's not clear that it is more dangerous than jet fuel.

Back to the mountain of fire.
http://news.bbc.co.uk/nol/shared/bsp/hi/dhtml_slides/10/volcano_overview/img/slide_1.gif

[NeoDevin]

http://www.swisseduc.ch/stromboli/perm/iceland/icons-eya-20100416/ejafjalla18apr2010-mfulle4290j.jpg

Looks like something out of a sci-fi movie.

[mheslep]

Looks like something out of a sci-fi movie.Yes it does. If this was from Hollywood I would have thought, nah, not believable, they overdid the special effects again.

[Frame Dragger]

Myths. Hindenberg fire and explosion was due to the coating on the skin, not the H2. H2 has safety pros and cons (http://www.physicsforums.com/showpost.php?p=2592657&postcount=44) compared to hydrocarbon fuels. It's not clear that it is more dangerous than jet fuel.

Back to the mountain of fire.
http://news.bbc.co.uk/nol/shared/bsp/hi/dhtml_slides/10/volcano_overview/img/slide_1.gif

Are you talking about the "thermite" proposal for the doping agent? Hell man, even MYTHBUSTERS took that one on. Sure, it may well have contributed to the disaster, but that doesn't make hydroge SAFE. Keep in mind as well, that the hydrogen in a zeppelin isn't under high pressure... if it had been the doping wouldn't have mattered, it would have been confetti.

Jet fuel really isn't that dangerous... it requires the proper mixture with oxygen to "go boom". LNG is pretty well studied, and a blast from a propane tank vs. a similar vessel filled with jet-fuel isn't even a contest. There is also the issue of leaks... a fuel leak is dangerous... an H2 or LNG leak is disastrous. Hell, the most dangerous things on a plane right now are O2 tanks, for much the same reason. Yes, part of this is the need for high pressures in the case of LNG and H2, versus jet fuel (which if you stuffed in high pressure would be a Fuel-Air bomb), but that's inescapable without some material liberating H2 within a fuel cell.

Anyway, as for "Ejyfidgetwaddawaddahakala", I agree... reality is no substitute for SFX. Of course, if you SEE this in real life, and not a picture, it's a bit more impressive I imagine. The word "surreal" springs to mind.

[mheslep]

Jet fuel really isn't that dangerous... it requires the proper mixture with oxygen to "go boom". LNG is pretty well studied, and a blast from a propane tank vs. a similar vessel filled with jet-fuel isn't even a contest. There is also the issue of leaks... a fuel leak is dangerous... an H2 or LNG leak is disastrous. ...FrameD, I provided sources for the various relevant combustion facts on H2 vs hydrocarbons, use them.

[Frame Dragger]

FrameD, I provided sources for the various relevant combustion facts on H2 vs hydrocarbons, use them.

Those aren't "sources", that's a post by you. You don't address the issue of pressurization, and I believe you're ignoring some basic engineering issues here. By the way, define "jet fuel". Kerosene? A? A-1? B? If you're going to get pissy, at least do it for the right reasons. You're just going to have to explain a LOOOT about how highly pressurized H2, or LNG is NOT a bomb, compared to low-pressure, high-flash point (concentration aside) Jet Fuels!

You also should probably address the "leak" issue. You also have failed to cite a source for your assertion about the Hindenburg, and your "source" in this case, is you. If you want to be combative about this, at least come armed.

[mheslep]

Those aren't "sources", that's a post by you.
As linked in that post by me:
http://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html
o Kerosene lower concentration flammable limit is 0.7%, Hydrogen 4% (4-5X).
o HHV hydrogen is 286 kJ/mole (http://en.wikipedia.org/wiki/Heat_of_combustion), for heavy hydrocarbons like kerosene vapor HHV is ~42 MJ/kg (http://en.wikipedia.org/wiki/Energy_density) x ~170 gm/mole = ~7000kJ/mole, i.e. more than 20X more energy release per STP volume.
o Low energy of ignition (http://web.archive.org/web/20060905074536/http://www.hydrogen.org/Knowledge/w-i-energiew-eng2.html), hydrogen's main danger: The minimum required ignition energy required for a stoichiometric fuel/oxygen mixture is for hydrogen 0.02 mJ, for methane 0.29 mJ and for propane 0.26 mJ.

Also see:
Airbus's work with liquid H2 planes, especially slides 21-24 on safety here (http://www.fzt.haw-hamburg.de/pers/Scholz/dglr/hh/text_2001_12_06_Cryoplane.pdf).
http://web.archive.org/web/20080607080532/http://www.hydrogen.org/Knowledge/w-i-energiew-eng2.html

References for H2 horrors and 'bombs', about how jet fuel is 'not dangerous'?

[Frame Dragger]

As linked in that post by me:
http://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html
o Kerosene lower concentration flammable limit is 0.7%, Hydrogen 4% (4-5X).
o HHV hydrogen is 286 kJ/mole (http://en.wikipedia.org/wiki/Heat_of_combustion), for heavy hydrocarbons like kerosene vapor HHV is ~42 MJ/kg (http://en.wikipedia.org/wiki/Energy_density) x ~170 gm/mole = ~7000kJ/mole, i.e. more than 20X more energy release per STP volume.
o Low energy of ignition (http://web.archive.org/web/20060905074536/http://www.hydrogen.org/Knowledge/w-i-energiew-eng2.html), hydrogen's main danger:

Also see:
Airbus's work with liquid H2 planes, especially slides 21-24 on safety here (http://www.fzt.haw-hamburg.de/pers/Scholz/dglr/hh/text_2001_12_06_Cryoplane.pdf).
http://web.archive.org/web/20080607080532/http://www.hydrogen.org/Knowledge/w-i-energiew-eng2.html

References for H2 horrors and 'bombs', about how jet fuel is 'not dangerous'?

I didn't say that jet fuel wasn't at all dangerous, I said, Jet fuel really isn't that dangerous... it requires the proper mixture with oxygen to "go boom". LNG is pretty well studied, and a blast from a propane tank vs. a similar vessel filled with jet-fuel isn't even a contest. There is also the issue of leaks... a fuel leak is dangerous... an H2 or LNG leak is disastrous. ...

You're also not addressing the issue of PRESSURE! H2 under pressure in a tank = BOMB. Jet Fuel in the same circumstances = BOMB! (specifically a Fuel-Air Bomb). You can't drag a zeppelin filled with hydrogen behind you as a fuel source... this is an issue. One you continue to ignore, by focusing only on fuel-air mixtures and relative combustibility!

As for you second link, this is what I get:



Not in Archive.



No archived versions of the page you requested are available. If the page is still available on the Internet, we will begin archiving it during our next crawl.

This is not helpful as a source to me, and while I'd like to read it, I'd also like to know why it's no longer there.

[Ouabache]

http://news.bbc.co.uk/1/hi/uk/8623364.stm
From the BBC.
Were you able to save some ash in a vial?

A geology friend gave me a vial of ash from Mt Saint Helen's (http://s-tiger.photovillage.org/photosDir/2369/thumb/800-JLM-NatGeo-Mount_St_Helens-1980-May_18.jpg) blow.. (located in Pacific Northwest US)..