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Data Series 545

Encounters of Aircraft with Volcanic Ash Clouds: A Compilation of Known Incidents, 1953–2009

By Marianne Guffanti, Thomas J. Casadevall, and Karin Budding

ABSTRACT

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Information about reported encounters of aircraft with volcanic ash clouds from 1953 through 2009 has been compiled to document the nature and scope of risks to aviation from volcanic activity. The information, gleaned from a variety of published and other sources, is presented in database and spreadsheet formats; the compilation will be updated as additional encounters occur and as new data and corrections come to light. The effects observed by flight crews and extent of aircraft damage vary greatly among incidents, and each incident in the compilation is rated according to a severity index. Of the 129 reported incidents, 94 incidents are confirmed ash encounters, with 79 of those having various degrees of airframe or engine damage; 20 are low-severity events that involve suspected ash or gas clouds; and 15 have data that are insufficient to assess severity. Twenty-six of the damaging encounters involved significant to very severe damage to engines and (or) airframes, including nine encounters with engine shutdown during flight. The average annual rate of damaging encounters since 1976, when reporting picked up, has been approximately 2 per year. Most of the damaging encounters occurred within 24 hours of the onset of ash production or at distances less than 1,000 kilometers from the source volcanoes. The compilation covers only events of relatively short duration for which aircraft were checked for damage soon thereafter; documenting instances of long-term repeated exposure to ash (or sulfate aerosols) will require further investigation.

Of 38 source volcanoes, 8 have caused 5 or more encounters, of which the majority were damaging: Augustine (United States), Chaiten (Chile), Mount St. Helens (United States), Pacaya (Guatemala), Pinatubo (Philippines), Redoubt (United States), Sakura-jima (Japan), and Soufriere Hills (Montserrat, Lesser Antilles, United Kingdom). Aircraft have been damaged by eruptions ranging from small, recurring episodes to very large, infrequent events. Moderate-size (Volcanic Explosivity Index 3) eruptions are responsible for nearly half of the damaging encounters. Vigilance is required during the early phases of eruptive activity when data about ash emission may be the most limited and warning capabilities the most strained, yet the risk the greatest. The risk-mitigation strategy for minimizing damaging encounters continues to rely on the combination of real-time volcano monitoring and rapid eruption reporting, detection and tracking of ash clouds in the atmosphere using satellite-based sensors, dispersion modeling to forecast expected ash-cloud movement, and global dissemination of specialized warning messages.

To obtain the entire Data Series 545 report, download the text file and appendixes 1-4, which are available as separate files. Click on the links at right.

Please Send Updates
We hope that publication of this compilation will encourage more reporting of encounters by the aviation industry and civil aviation authorities. We actively seek corrections and additions to the information presented here. Persons who have corrections or additional data pertaining to incidents already in the database or who have data about previously unreported incidents are urged to contact the authors.

Version 1.0, First posted December 7, 2010

For additional information contact:
Marianne Guffanti
U.S. Geological Survey
926A National Center
12201 Sunrise Valley Drive
Reston, Virginia 20192-0002
703-648-6708
URL: Volcano Hazards Program

Part of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.


Suggested citation:

Guffanti, Marianne, Casadevall, T.J., and Budding, Karin, 2010, Encounters of aircraft with volcanic ash clouds; A compilation of known incidents, 1953–2009: U.S. Geological Survey Data Series 545, ver. 1.0, 12 p., plus 4 appendixes including the compilation database [http://pubs.usgs.gov/ds/545/].



Contents

Abstract

Introduction

Characteristics of Encounters

Severity of Encounters

Frequency of Encounters

Times and Distances of Encounters from Source Volcanoes

Duration of Encounters

Altitude

Volcanic Sources

Discussion

Acknowledgments

References Cited

Appendix 1A. Compilation of Encounters of Aircraft with Volcanic Ash Clouds, 1953–2009, as a Microsoft Access Database File (.mdb)

Appendix 1B. Compilation of Encounters of Aircraft with Volcanic Ash Clouds, 1953–2009, as a Microsoft Excel 93-2007 Spreadsheet File (.xls)

Appendix 2. Explanation of Database Fields and Disclaimer

Appendix 3. Sources of Data in the Database

Appendix 4. Severity Factors for Each Incident in Appendix 1, Documenting How Severity Class was Assigned


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