Volcanoes have a long reach
On Dec. 15, 1989, KLM flight 867 from Amsterdam was approaching its destination in Anchorage, Alaska, when the plane flew into what appeared to be a thin layer of normal clouds. Suddenly, according to flight-crew reports, it got very dark outside and the air in the cockpit filled with a brownish dust and the unmistakable smell of sulfur. One minute after beginning a high-power climb to escape the cloud, all four of the Boeing 747's jet engines died when the combustion within them was extinguished. When the engines spun to a stop, the generators ceased making electrical power, leaving only battery-powered instruments functional. Airspeed sensors began to give false readings and then ceased to provide data. A cockpit warning light erroneously suggested there was a fire in one of the forward cargo bays.