from Der Spiegel:
Since the eruption of an Icelandic volcano caused havoc with Europe's air transport system just over a year ago, doubts have persisted over how dangerous the ash clouds really were. A new study has concluded that the ash released in the first part of the eruption did, in fact, represent a risk for planes.It appears aviation authorities may have been correct to ground planes across Europe following last year's volcanic eruption in Iceland, a new scientific study has concluded. The continent's airspace was shut down for seven days over fears the ash thrown into the air by the Eyjafjallajökull eruption could damage jet engines and cause planes to crash.
At the time, however, criticism was widespread over the drastic measures taken in closing large parts of European air space, which affected millions of passengers and cost close to €5 billion ($7.3 billion) in damages and lost revenues. Critics said the moves were unnecessary and that aircraft were not in any serious danger.
"The closing of airspace was a total overreaction to a relatively small volcanic outbreak, but unfortunately methods for measuring the ash concentration are still insufficient," volcanologist Haraldur Sigurðsson told SPIEGEL last year. ............(more)
The complete piece is at:
http://www.spiegel.de/international/europe/0,1518,758987,00.html