With the volcanic ash situation being mentioned so frequently in the news, you might be wondering why is volcanic ash dangerous for aircraft? When a Volcano erupts, it injects a huge plume of ash into the stratosphere. Apart from visibility problems, volcanic ash can cause aircraft jet engines to stop working completely.
Volcanic ash is made up of tiny glass shards and rock, which can re-melt inside an aircrafts engines, causing them to stop. If the ash is fine enough it can suffocate the jet engines which also cause engine failure. Fine ash particles also cause problems with the air conditioning systems which provide fresh air to passengers.
Any forward-facing surfaces on the outside of the aircraft can become pitted as a result of the tiny particles, this causes significant damage and can be expensive to repair. In some cases this can prevent the pilots from seeing out of windows of the flight deck which can impede a safe landing. The particles also cause problems with radio equipment.
In 1982 a British Airways flight flew into a cloud of volcanic ash, resulting in the failure of 4 engines. The plane had to glide through the remainder of the cloud, where they managed to restart 3 of the engines and finally made a safe landing.
In the past 20 years, more than 80 commercial aircraft have unexpectedly encountered volcanic ash clouds in flight, which have reached nearly 100 million USD in damages.
Every year around 15 major explosive eruptions occur which are powerful enough to inject ash into the stratosphere.
