"The effects of encountering volcanic ash during flight." Encountering volcanic ash in-flight has been known to have damaging effects on aircraft such as surface abrasion, and loss of pilot visibility. When ash is sucked into jet engines, it can melt and then re-solidify in cooler parts of the engine reducing the performance, and even causing engine stress. It has been known also that volcanic ash can cause avionics and electrical equipment to fail. " Encounters of Aircraft with Volcanic Ash Clouds: A Compilation of Known Incidents, 1953-2009 documents 79 damaging ash /aircraft encounters. Twenty-six of those involved significant to very severe aircraft damage, including nine encounters where engine failure occurred during the flight." (Volcano Hazards Program, 2015) Luckily, according to the NTSB , there have been no known plane crashes or fatalities recorded ...