Volcanic clouds: It came to light with ‘Jakarta Incident’

Volcanoes are a much-feared peril in civil aviation, disgorging fine ash that can damage jet engines, choke the hi-tech probes used in modern avionics and scour a plane’s windscreen to the point of invisibility. In the past 20 years, there have been 80 recorded encounters between aircraft and volcanic clouds, causing the near-loss of two Boeing 747s with almost 500 people on board and damage to 20 other planes, with repair costs totaling hundreds of millions of dollars. “Volcanic ash in the upper troposphere, where jet aircraft fly, can cause jet engine failure, damage to turbine blades and pitot static tubes with the possibility of the loss of the aircraft and lives,’’ the journal Natural Hazards warned last year. The threat first made the headlines in a 1982 episode now known as the “Jakarta Incident’’. At 35,750 ft, a British Airways jumbo en route from London to Auckland entered a cloud of ash disgorged by an Indonesian volcano, Mount Galunggang. All four engines flamed out, leaving the plane and its terrified passengers on a glide towards doom before the crew were able to restart the engines at 13,325 ft. The plane made an emergency landing at Jakarta, with the crew flying on manual, following a roughly calculated glide slope. 


It was impossible to see out because the windscreen had been sandblasted to opacity. In 1989, a KLM 747 bound for Anchorage, Alaska, endured a five minute powerless descent with 231 passengers on board when it inadvertently entered a cloud of ash blown from Redoubt Volcano, 177 km away, which had erupted 10 hours earlier. After the engines were restarted, the plane landed safely at Anchorage. Repairs cost $80 million, for all four engines needed replacing. “The threat to aviation is very obvious,’’ Kjetil Toerseth, director of regional and global pollution at the Norwegian Institute for Air Research, said. One of the most problematic areas is in the Pacific, home of the ‘Ring of Fire’ where volcanoes are most active, said Toerseth. In the biggest eruption of recent decades, Mount Pinatubo in the Philippines spewed out an ash cloud on June 15, 1991 that in less than three days traveled more than 8,000 km to the east coast of Africa, the US Geological Survey says. The KLM incident led to a global effort to track volcanic clouds and notify aviation of the hazard.

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The above article was extracted from Skyline updates of Skyline College. Skyline College is amongst the top MBA and BBA institutes in Delhi, Gurgaon (NCR).