Volcanic Eruption: The Unforeseen Phenomenon


Volcanoes are not a big problem for aviation, but the material spewed during its eruption is a real issue. Magma is the result of volcanic eruptions, through the conduct from inside the earth. This consists of melted stone, gasses and crystals, and the aggressivity of the eruption will vary depending on its chemical composition.


Volcanic ash originates in eruptions, with three basic forms of formation: magmatic, phreatomagmatic/hydrovolcanic, and phreatic. In the same eruption, there can be different formations of these ashes, a consideration for pilots during a flight.

In 2010 European Aviation was affected. From April 14th to 20th, due to the ash cloud from the eruption of a the Eyjafjallajökull volcano in Iceland, Ireland and the United Kingdom gradually closed their airspaces and similar measures were taken in Finland, Norway, Sweden, Denmark, Belgium, Holland, Poland, and northern France.


The ash cloud, located at an altitude of between 5,500 and 11,000 meters, does not represent a health problem for the population at this time because the ash will reach the ground in a very scattered and staggered manner. But it poses a major threat to aviation because the floating particles can damage the fuselage of aircraft and, above all, block the engines. This was the case on June 24, 1982, when a British Airways Boeing 747 flying over the Mount Galunggung volcano in Indonesia, unaware that it was erupting, suffered a blockage of its four jet engines for several minutes, although the pilots were finally able to restart them and land safely in Jakarta.


Eruption of Eyjafjallajökull in 2010


Mid-flight engine failure accidents due to the presence of ash in the atmosphere are rare, but they do occur. In the last 56 years, they have happened on eight more occasions, according to aeronautical records.

  • In 1989, the 245 passengers and crew of KLM Flight 867 intercepted an ash cloud ejected 90 minutes earlier by the Rebout volcano in Alaska, and all four engines shut down. After a free fall of (13,000 feet) about 3,962 meters, the pilots managed to start the engines and make an emergency landing in Alaska, without any deaths or injuries.


  • In 2011, the eruption of the Chilean volcano Puyehue forced the closure of airports in Chile, Argentina, Uruguay, and Brazil. This plane was in Bariloche in Argentina, 100 kilometers from the volcano.


Between 1953 and 2009, 79 aircraft were damaged by volcanic ash, 26 of them severely damaged.

Planning to Prevent After the incident occurred by BA's B747 in 1982, the International Civil Aviation Organization (ICAO) implemented a service with a series of volcanic ash observation centres (VAAC). These 9 centres, distributed by various geographical areas, have the task of reporting on the location, flight level of the cloud, and its estimated movement through SIGMET and volcanic ash warning messages called ASHTAM.


Photo by: NASA NASA Satellite Data Improving Volcanic Ash Forecasts for Aviation Safety


Volcanic ash clouds must be globally monitored, as well as their evolution. Considering the existing probabilities in the variation of its movement and occupied levels.

Due to their composition, they are highly dangerous for the safe operation of aviation, therefore, flight planning and dispatch units must choose to be highly conservative when choosing the most appropriate routes and using the most correct and accurate reports, both those issued by the VAAC centres and by the pilots.


Training and proper application of procedures are the last barriers that crewmembers must face in the event of an emergency such as flying in a volcanic ash cloud. Despite all this, the number of incidents or accidents (without injuries or deaths) is almost non-existent since the implementation of the VAACs. Still another argument to claim the plane as the safest means of transport.

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