Hugh Pickens writes: "The NY Times reports that British civil aviation authorities ordered the closure of the country’s airspace as of noon on Thursday to shield aircraft from a high-altitude cloud of ash drifting south and east from an erupting volcano in Iceland. The perils of volcanic ash are well known to pilots and airline operators. After the 1982 eruption of Galunggung volcano in Indonesia, for example, a Boeing 747 flying from Kuala Lumpur to Perth, Australia, lost power in all four engines and descended from 36,000 feet to 12,500 feet before pilots could restart them and make an emergency landing in Jakarta. It was impossible to predict how long the disruptions might last or the extent of the flight cancellations, since the volcano was still erupting, says Deborah Seymour, a spokeswoman for Britain’s National Air Traffic Service. “We are completely and utterly hostage to weather conditions.""