Raking over the ashes

Sydney Morning Herald: Raking over the ashes
Volcanic plumes have been a danger to air traffic for decades. It's just taken us a while to catch on.

WHEN flights along the eastern and south-eastern seaboard were cancelled yet again on June21, social commentator and Fairfax columnist Mia Freedman took to Twitter with thoughts that reflected the views of many.

"I don’t remember volcanic ash clouds from when I was a kid. Are they, like, a new thing?’’ she wrote.

A professor of geology at the Australian National University, Richard Arculus, says no. He says that in the past century, there have been at least 10incidents when vast plumes of volcanic ash traversed the globe. It’s just that airlines have become responsive to them, which is why we now know when they hit.

Advertisement: Story continues below Arculus puts that down to an incident in 1982 when a British Airways 747 almost crashed due to volcanic ash from Mount Galunggung, south-east of Jakarta.

A 1989 engine failure (that’s all four engines) on a KLM flight, which was landing in Anchorage, Alaska, after flying through ash, sealed the deal for airline sensitivity to such events.

Not only did the 1982 incident cause near-death for hundreds of people; in the 1989 case the ash, which is essentially tiny particles of glass, caused tens of millions of dollars worth of damage to the six-month old KLM aircraft, sandblasting windshields, seizing engine components and creating one hell of a vacuum job later.

‘‘Airlines started to realise just how dangerous these incidents were for aircraft,’’ Arculus says.

He also adds this discomforting fact: it’s not just Puyehue-Cordon Caulle lurking as a possible cause of disruption to Australian aviation; plenty of other volcanoes at our latitude are active.

‘‘Rest assured, the volcano in Chile has erupted many times before. There have been huge eruptions,’’ says Arculus, who visited the Puyehue-Cordon Caulle volcano in 2007.

‘‘But no one took any notice of it. Basically, this volcano is 40 degrees south. There are 30 to 40 in Chile atour latitude and three or four in New Zealand. Of course there is alsoa stack to the north of us whichcould threaten airspace at higher latitude.’’