On April 15, 2010, flights in the United Kingdom, Ireland, and Sweden were grounded due to the volcanic eruption of Eyjafjajokull in Iceland. This isn’t the first time volcanic eruptions have caused issues with air flight. In April of 1982, there was an almost fatal accident when an aircraft flew into a cloud of volcanic ash caused by the eruption of Mount Galunggung, located on an Indonesia island named Java. It caused all four engines to stall out. The British Airways flight 009 was able to glide out of the cloud and restart three of the four engines for a safe landing.
Another example of the devastating effects of flying into a volcanic ash cloud is when KLM flight 887 flew into one in December of 1989. Once the pilots realized they were in a volcanic ash cloud, they tried to climb above the cloud. Unfortunately, the engines stalled. The pilots were able to get two engines restarted and land the plane.
Ninety commercial aircrafts in the last thirty years have experienced the dangers of flying into a volcanic ash cloud. But why does volcanic ash cause such havoc on an aircraft?
Volcanic eruption cause solid rock and magma to be crushed into millions of particles the size of sand to be shot up 3,200 miles (2,000 km) into the air. This can not only cause health problems for humans and animals, but it severely affects aircraft. The particles in a volcanic ash cloud are like millions of razor blades hammering into the aircraft with a force of several hundred miles per hour. This can cause damage to the hull, windshield, fan blades, and fuselage surfaces.
According to the US Geological Survey (USGS), the temperature of these volcanic particles are lower than the heat emitted from the engine of an airplane, therefore the particles can melt, cool down rapidly in the turbine causing the particles to re-solidify; thus leaving deposits in the engine. The ash can block nozzles to the fuel as well as blocking the cooling passages. It has been known to contaminate the oil supply and erode surfaces. All of this can lead to engine failure.
Volcanic ash particles can penetrate into the navigation and operating instruments. This can cause the instruments to not work properly and possibly fail to work at all. This may make it difficult for pilot to determine the speed and altitude of the aircraft.
Unfortunately, it is hard to visually distinguish a volcanic ash cloud from an ordinary cloud. Weather radars even have difficulty distinguishing between the two. Advancements are being made to satellite radars to help diminish the risk to flying into a volcanic ash cloud. Regardless, all aircraft should avoid volcanic ash clouds all together. The risk to the aircraft and the lives on board can be devastating.