Examples of an airplane encounter with a volcanic eruption:
(1) small plane with scientists observing the volcano
(2) jet aircraft encountering an ash cloud many miles from the eruption
Hazards posed by volcanoes:
(1) blast wave
(2) flying stones (which can be very large)
(3) superheated gases
(4) toxic gases, including sulfur dioxide
(5) acidic compounds, which can result in corrosion
(6) reduced atmospheric oxygen
(7) engine malfunction associated with volcanic ash and low oxygen
(8) abrasion of plane's exterior surfaces
(9) ash contaminating the interior of the plane
(10) lightning in the eruption cloud over the volcano
Most of these risk are posed if the plane is near an erupting volcano, but volcanic ash and toxic gases can be hazardous at great distances.
Silica in volcanic ash melts at the temperatures seen within jet engines, which creates a glass-like coating as it cools.
