The ongoing eruption of an Icelandic volcano and prevailing winds pushing east to the European mainland forced every British airport to close on Thursday afternoon, the tightest restriction on air travel the country has experienced since the hours following the Sept. 11, 2001, attacks on the US using hijacked airplanes.
Nothing like a cloud of ash is visible in Britain, whose shores are 800 miles or more from Iceland, though meteorologists say Thursday's sunset could be more vivid than usual because of the filtering effect the ash has on sunlight.
Instead, safety officials are worried that fine ash ejected into the sky – as far as 5 miles high – will remain suspended there and possible foul the engines of high-flying commercial jets.
Though the US Geological Survey says there have been no commercial air crashes caused by volcanic ash, there have been a number of close calls over the years, particularly in June 1982, when an eruption of Indonesia's Mt. Galunggung almost brought down a British Airways and a Singapore Air flight.
British Airways Flight 9 was the first to run into trouble that June, when it was flying south of Indonesia en route to Australia. Though it's often reported that the pilots "flew into a cloud of ash," the pilots had no visual cues they were flying into danger. They only realized they were in trouble when passengers began to report a sulfurous smell and what appeared to be fires in the engines.
Moments later, all four engines on a plane with 247 passengers had failed. Disaster was only averted by the pilots, who managed to glide the plane without power and eventually restart some of the engines. A month later, a Singapore Air 747 ran into the same problem. The incidents prompted worldwide reviews for how to identify and help planes avoid volcanic ash.