Can eruptions really threaten helicopters, as in the movie, and other aircraft?
Yes. Encounters between aircraft and clouds of volcanic ash are a serious concern. Jet engines and other aircraft components are vulnerable to damage by fine, abrasive volcanic ash, which can drift in dangerous concentrations hundreds of miles downwind from an erupting volcano. During the past 15 years, at least 80 aircraft have accidentally encountered volcanic ash clouds, and in 6 cases jet engines temporarily lost power. An international consortium of government agencies, including the U.S. Geological Survey, Federal Aviation Administration, and National Weather Service, is now monitoring ash-producing volcanoes and tracking volcanic ash clouds to reduce the likelihood of future encounters.
