Operation of Gas Turbine Engines in an Environment Contaminated With Volcanic Ash

Abstract

Airborne volcanic ash poses a significant threat to the safe operation of gas turbine powered aircraft. Recent volcanic activity in Iceland and other parts of the world have resulted in interruption of air traffic and in the case of the April 2010 eruption of the Eyjafjallajökull volcano in Iceland, the interruption resulted in a significant loss of revenue. Over the past 30 years there have been several events involving commercial aircraft that have suffered significant damage to the propulsion system as a result of ingesting volcanic ash during a flight event, but a relevant engine focused database to provide guidance for dealing with the problem has not been generally available until recently. In Sept. 2010 after the Iceland volcano activity, a body of data that had not been in the public domain was released and those measurements that are described in some detail herein can be helpful to the airlines, the aircraft manufacturers, the engine manufacturers, those responsible for flight operations, and hopefully to the flight crews. The intent of this paper is to describe some of the more notable aircraft/ash cloud events, the available data associated with those encounters and how those data can be used to effectively deal with this problem while maintaining safe flight operations. The paper specifically (a) illustrates the engine damage mechanisms, (b) estimates the potential operational life of a particular class of engines if the ash concentration is at a very low level, and (c) illustrates how this database is helpful in dealing with future interruptions of flight routes caused by volcanic eruptions. A section at the end of this paper provides the comments and concerns of the industry and government stakeholders regarding this general problem area.