http://news.bbcnewsd73hkzno2ini43t4gblxvycyac5aw4gnv7t2rccijh7745uqd.onion/2/hi/uk_news/8621407.stm
"This is a sensible precaution." In 1982 a British Airways jumbo had all four of its engines shut down as it flew through a plume of volcanic ash. There was also an incident on 15 December 1989 when KLM Flight 867, a B747-400 from Amsterdam to Anchorage, Alaska, flew into the plume of the erupting Mount Redoubt, causing all four engines to fail.