L-188 From United States of America, joined Jul 1999, 29622 posts, RR: 59
Reply 11, posted (10 years 11 months 2 weeks 1 day 17 hours ago) and read 2155 times:
You can get up pretty close to a volcano as long as you are upwind of it.
Downwind you can get into trouble pretty fast.
We conducted Flight operations 37 miles away from Pavloff Volcano with Electras and 727's throughout the eruption of 1995 and 96. Pretty much constant ash. Never had to cancel a flight since the prevailing wind was mostly west to east.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
Dustweek From Japan, joined Aug 1999, 77 posts, RR: 0
Reply 13, posted (10 years 11 months 2 weeks 1 day 11 hours ago) and read 2099 times:
I did it in 1989....
In December, 1989, Redoubt Volcano in Alaska erupted. That was when a KLM 747-400 lost all 4 engines at 7500 meters as they entered a cloud that had ash in it, and got them started again at only 1500m above the mountains.
Anyway, I was stuck in Fairbanks, Alaska trying to get to Florida.
Understandably, none of the airlines were going to risk flying -- EXCEPT Alaska Airlines. They correctly reasoned that if there was daylight and the skies were clear (except for the volcanic ash plume), they could simply fly to the upwind side of the volcano.
So that's what we did....a direct flight from Fairbanks to Seattle, taking a long detour to the west of Redoubt. What a sight! A huge, beautiful gray plume in the sky. Pretty much everyone in the full plane took turns looking out the left side (I think it was an MD80, but not sure).
I still have great respect for Alaska Airline's ability to fly safely in Alaska in conditions that make others give up.
Spacepope From Vatican City, joined Dec 1999, 2856 posts, RR: 1
Reply 14, posted (10 years 11 months 2 weeks 1 day 8 hours ago) and read 2051 times:
The ash doesn't actually become a gel at high temperatures. Keep in mind that these explosive eruptions form ash clouds composed of fragments of one kind of rock, Rhyolite. This rock has a very high Quartz content. Quartz melts at a very low temperature, one that is readily attained in jet engines. What you end up with is a slurry of melted quartz, along with feldspar and mica chunks coming through the engine, abrading the delicate parts in a way much unlike water, being that it is 3 times the density. The other bad part of low temperature silicates is that once they cool enough, they will resolidify and can gum up the moving parts in an instant.
But upwind of these volcanoes, there is no problem whatsoever.