You might remember the infamous Eyjafjallajökull eruption of 2010, bain to newscasters and boon to the Icelandic tourist industry, and the sweeping air travel ban across much of Europe that followed. Plenty of people were annoyed, not least of all for how far-reaching the air ban was. Can’t pilots just fly around the volcano? Turns out, it’s more complicated than that, as volcanic ash can be damaging to airplanes in numerous ways, as Sara Barsotti, Coordinator for Volcanic Hazards at the Icelandic Meteorological Office, explains:
“Let‘s start by saying that during an explosive eruption, volcanic material is ejected into the atmosphere as the result of a fragmentation process that the magma experiences while it is moving toward the surface. The fine fraction of this material (everything smaller than 2mm in diameter) is called volcanic ash. So, volcanic ash – due to its shape, small size and weight – can persist into the atmosphere for quite la ong time and travel long distances. Actually, within the volcanological community we say volcanic ash is a trans-boundary volcanic hazard.
“Depending on several factors (ash cloud altitude, its location, scheduled air route) aircrafts might encounter it. If this event happens, the aircraft might suffer from several types of damage, such as the abrasion of the external structure and surfaces, the ingestion of volcanic material into the jet engines, and the contamination of internal air system. The severity of these damages depends also on the duration of the exposure to volcanic ash. Jet engines are designed to work at high-temperatures and the presence of volcanic ash in the engines themselves would cause the volcanic material to melt and to become sticky.
“Eventually the increase in the air pressure in the turbine would cause an increase of the engine internal temperature that could cause the complete failure and breakage of the engines themselves. This is of course the worst case scenario, but this has happened in the past, and the scientific community and the engine manufacturers are working together to avoid this happening again in the future.”