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Iceland Volcano's Ash Grounds European Air Travel
Ch_Omega writes "From the article at CBSNews: 'An ash-spewing volcano in Iceland emptied the skies of aircraft across much of northern Europe on Thursday, grounding planes on a scale unseen since the 9/11 terror attacks. British air space shut down, silencing the trans-Atlantic hub of Heathrow and stranding tens of thousands of passengers around the world. Aviation officials said it was not clear when it would be safe enough to fly again and said it was the first time in living memory that an ash cloud had brought one of the world's most congested airspaces to a standstill.'"
The BBC says "Safety group Eurocontrol said the problem could persist for 48 hours," and the Deccan Herald describes some of the effects on the ground in the volcano's home turf: "In Iceland, hundreds of people are fleeing rising floodwaters as the volcano under the glacier Eyjafjallajokull erupted yesterday again, for a second time in less than a month."
As watching endless episodes of Discovery channel would tell you ash has been responsible for plane crashes in the past. http://en.wikipedia.org/wiki/British_Airways_Flight_9
They closed the airports because the ash eats up jet engines, and can't easily be detected on radar. It's mostly silica and doesn't have a dielectric constant different enough from air to show up on most aircraft radar. So even if the cloud is thin enough on the ground to take off safely, you are relying on visual indications of the clouds thickening, and your visibility is poor so it's hard to see.
Any pissed off European travelers stuck in the airport reading /. may want to read KLM vs. Mt. Reboubt before hitting the friendly skies.
http://www.thenakedscientists.com/HTML/content/questions/question/2008/
The volcano is roughly 100 times as green if we're talking about CO2 emissions, and 10 times as green if we're talking about SO2. Of course, that's assuming that given
Pv = the pollution output from this volcano over two years
Pvt = total pollution output by volcanoes.
Pe = European airplane pollution
Pht = total human-sourced pollution
Pe / Pht == Pv / Pvt
And there are some gaping flaws in that logic, but the point is volcanoes are fairly inconsequential as drivers of pollution.
Well, I just had a beer with my little brother, a BA Pilot grounded here at our home in switzerland.
BA Flight 009 was special because it is the first such incident documented in a modern jet airliner. The pilots were pretty clouless when they suddenly saw funny flares through their front windows (cause by ash particles). "Somke" was reported from the cabin and after some time they piloted a very expensive glider plane (all 4 engines failed). The 747 has a glide angle of something about 1:15 which is very good for a heavy airliner. But with failing speed indicators it is quiet a challange to restart engines midair (windmill effect is used, they need to hold a certain speed before they can inject fuel and ignite it again).
I think these pilots back then did a tremendously good job if one takes into account that they had no fucking clue what was going on (today they have procedures for such situations, my brother showed me his checklist for such cases). And they had a lot of luck. The pilots lost height due to engine failure, decided to do a 180 turn and once the engines restarted (pretty low) they got into the ash cloud again and lost some engines again before they landed with reduced sight (sandpaper effect on the front window) and reduced IFR instrumentation at night.
Cheers,
-S