The concern over volcanic ash and airplanes stems from two incidents in the 1980s.
British Airways Flight 9 on June 24, 1982, where all four engines failed after the aircraft flew into a cloud of volcanic ashthrown up by the eruption of Mount Galunggung south-east of Jakarta, Indonesia. The captain made made what is widely considered a masterpiece of understatement. “Ladies and gentlemen, this is your captain speaking. We have a small problem. All four engines have stopped. We are doing our damnedest to get them under control. I trust you are not in too much distress.”
KLM Flight 867 on December 19, 1989, was descending into Anchorage, Alaska, when it flew into the plume of the erupting Mount Redoubt, and had all four engines fail. As it descended, it was able to restart the engines and land safely. As of 2010, the aircraft is still in service with KLM under the KLM Asia livery.
