KLM had a 4 engine flameout in Alaska, ash scoured the windscreen so bad crew had little forward visibilty, the aircraft almost set down on a 2 lane highway before relighting engines. Major repairs (I seem to recall over a month) had to be done in Anchorage before it could ferry out and the entire interior had to be replaced as well. Total repair bill was over USD $80 million. Here's a great page on KLM and the volcanic problem: http://geology.wr.usgs.gov/fact-sheet/fs030-97/ This one is an overview of the problem of volcanic ash, including the BA 747 flameout and others: http://www.nw.faa.gov/releases/volash.html I worked for an airline at the ANC airport during the eruptions of 3 different volcanos, and have flown over many steaming ones in the Aleutians, so this remains a real threat to us. Mike