The first notable encounter was the British Airways 747 near Galunggung, Indonesia, in 1982. It showed that, in such encounters, we might expect a loss of engine power, problems with airspeed indications, and extensive abrasion damage, including a loss of windshield transparency. During the eruption of Redoubt Volcano in Alaska on 15 December 1989, a new B747-400 on a flight from Amsterdam to Anchorage flew into the plume and lost power from all four engines. The crew were able to restart the engines and land the aircraft safely. To ensure aviation safety, it is necessary that reports of eruptions are processed without delay into warnings to Pilots, Air Traffic Control Centers, and Air Carrier Operations Centers.
Volcanoes are a threat to air safety from the moment that they erupt.
A warning system should be capable of a 5-minute response time once an eruption has been detected. A modern jet aircraft is traveling over 500 mph and advancing 6-8 miles per minute. Winds play the dominant role in the distribution of volcanic ash. The agency for subsequent ash-location advisories should be the meteorological office. In order to meet their goal they decided the world should be divided into different regions, differentiated by their volcanic activity and volcano observatories.