SINGAPORE: If the Mount Agung volcano really blows its top, flight disruptions in and out of Bali could extend for some time.
“The airport (in Bali) will re-open when no volcanic ash is detected around the area,” Mr Abbas Ismail, course manager of Temasek Polytechnic’s Diploma in Aviation Management and Services, told Channel NewsAsia.
“However, flight disruptions could continue for about a week due to the uncertainty surrounding when the next eruptions for Mount Agung could occur.”
This comes as volcano experts warn that Mount Agung could still produce larger eruptions.
Already, eruptions have shut down Bali’s airport after ash was detected 30,000 feet in the air, the altitude at which planes fly.
So, why is it so dangerous for planes to fly through volcanic ash?
“This ash can enter the aircraft’s engines, where it can become a glassy substance and stall jet engines,” said Mr Greg Waldron, Asia managing editor at Flightglobal.
In addition, Mr Abbas said, the ash can cause the plane’s auxiliary power unit – which powers up the jet engines – to stop working.
“The end result could be catastrophic,” he added.
Even if an engine takes in small amounts of ash, Mr Abbas noted, it might still “suffer from irreparable damage due to the disruption of airflow and cooling air”.
“This is costly and involves the aircraft or engine being out of operation,” he said.
INVISIBLE ASH
The damage does not stop there. Because the ash is abrasive, the experts said, it can damage a plane’s wings, sensors and windscreen. What’s more, pilots cannot see fine ash from the cockpit.
“Regular primary radar cannot detect the ash and the airborne weather radar cannot identify it,” Mr Abbas said.
“Generally, accurate particulate information takes a long time to be available and the science of measuring airborne volcanic ash is new at best.”
Mount Agung is throwing out smoke, hot gases and fragments of molten rock as an eruption looms AFP/SONNY TUMBELAKA
While Mr Abbas noted that pilots have the final say on whether they can fly in such conditions, Mr Waldron said authorities will typically suspend flights in the area when they see “clouds of ash billowing skywards”.
“It’s not so much an issue of visibility, because no commercial aircraft would venture close to a major ash cloud,” Mr Waldron added. “Rather, the issue is about small amounts of ash rising high into the atmosphere.”
THE PRECEDENT
In 2010, the eruption of Iceland’s Eyjafjallajokull sent plumes of ash into the upper atmosphere, shutting down European air space for almost two weeks in what would be the biggest disruption to air travel in recent history.
File photo of a volcano in Iceland. (Photo: AFP/BERNARD MERIC)
“Agung is an issue, but the Iceland eruptions were more problematic because of prevailing winds potentially driving ash to one of the most important aviation markets in the world,” Mr Waldron said.
“While Bali Denpasar is a major airport regionally, the traffic in that region is nowhere near as heavy as on continental Europe. So, this is a more of a localised issue.”
Still, Mr Abbas estimates industry losses from the Mount Agung disruptions could stretch into the millions, depending on the number of flights cancelled and how long airports are closed.
“In the case of Bali, the authorities have stepped in and clearly deemed it necessary to close the airspace,” he said.
