Volcanic eruption

Flying through a volcanic ash cloud is dangerous for airliners as it could lead to a complete engine failure.According to an aviation specialist, this occurs when an erupting volcano spews ash and particles into the sky, the majority of which are silicates.Malaysian Pilots Association president Captain Abdul Manan Mansor said the very high temperature inside a jet engine would melt these particles but in cooler parts of the engine, they would solidify again forming a glassy coating."This disrupts the airflow which can lead to the engine stalling or failing completely."He said, if the engines were to fail during take-off or landing, there would not be enough time for that and a crash would be highly likely.He cited an earlier case, the 1982 British Airways flight from Kuala Lumpur to Perth."The Boeing 747 with 247 passengers on board flew – without realising it – through an ash cloud over Indonesia."The pilots noticed fire on the windscreen and within minutes all four Rolls Royce engines failed."The plane glided from 11,300m (37,000ft) to 3,650m (12,000ft) before the engines started working again and the plane was able to make a safe landing in Jakarta," he said.Aside from shutting down the engines, he added the ash clouds might influence several of the plane's sensors, resulting in, for example, incorrect speed readings."It also affects visibility for the pilots and can affect air quality in the cabin – making oxygen masks a necessity."The sharp particles in the ash also cause abrasions and damage to the exterior of the plane though this is not an immediate danger to the flight."Abdul Manan also said that the ash clouds could be hard to spot for pilots and its small particles were not visible on a weather radar."At high altitudes, volcanic ash does not look like the dense cloud currently seen above Mount Ruang.""As such, the first action recommended at that point is to simply turn the plane around hoping to escape the area quickly."The pilot can also reduce the thrust of the engines which will lower engine temperatures making a failure less likely."Ideally, though, pilots shouldn't even find themselves in that situation. There are nine Volcanic Ash Advisory Centres around the world, each responsible for a specific region."Earlier, multiple flights to and from Kuala Lumpur International Airport to Sabah and Sarawak today have been cancelled due to the Mount Ruang volcanic eruption in Indonesia.Mount Ruang, a stratovolcano in North Sulawesi Province, erupted several times on Tuesday and Wednesday.Authorities had raised the alert level to its highest point after the dome spewed a column of smoke more than 1.6 kilometres into the sky, and forced hundreds to evacuate.The alert level for the volcano, which has a peak of 725 metres above sea level, was then raised on Wednesday evening from three to four, the highest possible level in the four-tiered system.