Flying over a volcano was never on my list, until now. Sometimes, just finding out that we can prevent something makes me aware of the danger:
On December 15, 1989, the 231 passengers aboard KLM Flight 867 were cruising at 28,000 feet over Alaska when a strange sulfur smell filled the cabin. Suddenly all four engines quit, and the Boeing 747 started to plummet. The pilots had skirted the edge of an ash plume billowing from Redoubt volcano, about 150 miles away. The ash, mostly made of tiny particles of rocks and glass, was almost invisible. “It melted and resolidified inside the engines, and they stalled,” says Peter Webley, a researcher at the University of Alaska’s Volcano Observatory. Flight 867 and its horrified passengers fell more than two miles—13,300 feet—before the pilots managed to restart the engines and land in Anchorage.
From Popular Science, talking about Google Earth Environment.