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MITIGATING THE IMPACT OF

VOLCANIC ASH CLOUDS ON AVIATION:

WHAT DO WE NEED TO KNOW?

HEARING

BEFORE THE

SUBCOMMITTEE ON SPACE AND AERONAUTICS 

COMMITTEE ON SCIENCE AND 

TECHNOLOGY 

HOUSE OF REPRESENTATIVES

ONE HUNDRED ELEVENTH CONGRESS

SECOND SESSION

MAY 5, 2010

Serial No. 111–93

Printed for the use of the Committee on Science and Technology

(

Available via the World Wide Web: http://www.science.house.gov 
(II)

COMMITTEE ON SCIENCE AND TECHNOLOGY 

HON. BART GORDON, Tennessee, Chair 

JERRY F. COSTELLO, Illinois 

EDDIE BERNICE JOHNSON, Texas 

LYNN C. WOOLSEY, California 

DAVID WU, Oregon 

BRIAN BAIRD, Washington 

BRAD MILLER, North Carolina 

DANIEL LIPINSKI, Illinois 

GABRIELLE GIFFORDS, Arizona 

DONNA F. EDWARDS, Maryland 

MARCIA L. FUDGE, Ohio 

BEN R. LUJA ́ N, New Mexico 

PAUL D. TONKO, New York 

STEVEN R. ROTHMAN, New Jersey 

JIM MATHESON, Utah 

LINCOLN DAVIS, Tennessee 

BEN CHANDLER, Kentucky 

RUSS CARNAHAN, Missouri 

BARON P. HILL, Indiana 

HARRY E. MITCHELL, Arizona 

CHARLES A. WILSON, Ohio 

KATHLEEN DAHLKEMPER, Pennsylvania 

ALAN GRAYSON, Florida 

SUZANNE M. KOSMAS, Florida 

GARY C. PETERS, Michigan 

JOHN GARAMENDI, California 

VACANCY 

RALPH M. HALL, Texas 

F. JAMES SENSENBRENNER JR., 

Wisconsin 

LAMAR S. SMITH, Texas 

DANA ROHRABACHER, California 

ROSCOE G. BARTLETT, Maryland 

VERNON J. EHLERS, Michigan 

FRANK D. LUCAS, Oklahoma 

JUDY BIGGERT, Illinois 

W. TODD AKIN, Missouri 

RANDY NEUGEBAUER, Texas 

BOB INGLIS, South Carolina 

MICHAEL T. MCCAUL, Texas 

MARIO DIAZ-BALART, Florida 

BRIAN P. BILBRAY, California 

ADRIAN SMITH, Nebraska 

PAUL C. BROUN, Georgia 

PETE OLSON, Texas 

SUBCOMMITTEE ON SPACE AND AERONAUTICS

HON. GABRIELLE GIFFORDS, Arizona, Chair 

DAVID WU, Oregon 

DONNA F. EDWARDS, Maryland 

MARCIA L. FUDGE, Ohio 

PARKER GRIFFITH, Alabama 

STEVEN R. ROTHMAN, New Jersey 

BARON P. HILL, Indiana 

CHARLES A. WILSON, Ohio 

ALAN GRAYSON, Florida 

SUZANNE M. KOSMAS, Florida 

BART GORDON, Tennessee 

PETE OLSON, Texas 

F. JAMES SENSENBRENNER JR., 

Wisconsin 

DANA ROHRABACHER, California 

FRANK D. LUCAS, Oklahoma 

MICHAEL T. MCCAUL, Texas 

RALPH M. HALL, Texas 

RICHARD OBERMANN Subcommittee Staff Director 

PAM WHITNEY Democratic Professional Staff Member 

ALLEN LI Democratic Professional Staff Member 

KEN MONROE Republican Professional Staff Member 

ED FEDDEMAN Republican Professional Staff Member 

DEVIN BRYANT Research Assistant 
(III)

C O N T E N T S 

May 5, 2010

Page 

Witness List ............................................................................................................. 2

Hearing Charter ...................................................................................................... 3

Opening Statements

Statement by Representative Gabrielle Giffords, Chairwoman, Subcommittee 

on Space and Aeronautics, Committee on Science and Technology, U.S. 

House of Representatives .................................................................................... 10

Written Statement ............................................................................................ 11

Statement by Representative Pete Olson, Ranking Minority Member, Subcommittee on Space and Aeronautics, Committee on Science and Technology, U.S. House of Representatives ............................................................... 12

Written Statement ............................................................................................ 12

Witnesses:

Dr. Tony Strazisar, Senior Technical Advisor, Aeronautics Research Mission 

Directorate, National Aeronautics and Space Administration 

Oral Statement ................................................................................................. 13

Written Statement ............................................................................................ 15

Dr. Jack A. Kaye, Earth Science Division, National Aeronautics and Space 

Administration 

Oral Statement ................................................................................................. 19

Written Statement ............................................................................................ 21

Ms. Victoria Cox, Senior Vice President, Nextgen and Operations Planning, 

Air Traffic Organization, Federal Aviation Administration 

Oral Statement ................................................................................................. 26

Written Statement ............................................................................................ 27

Captain Linda M. Orlady, Executive Air Safety Vice Chair, Air Line Pilots 

Association, International 

Oral Statement ................................................................................................. 30

Written Statement ............................................................................................ 31

Mr. Roger Dinius, Flight Safety Director, GE Aviation 

Oral Statement ................................................................................................. 35

Written Statement ............................................................................................ 36

Discussion 

Characterizing the Risk ....................................................................................... 39

The European Response ...................................................................................... 40

Coordinating Research Among Agencies ............................................................ 41

The Use of Simulations for Training .................................................................. 42

Engine Design ...................................................................................................... 43

European Consultations ...................................................................................... 45

Detecting Contaminants ...................................................................................... 45

Human Factor ...................................................................................................... 46

NASA DC–8 Experience ...................................................................................... 46

Detection Systems ................................................................................................ 48

Future Remote Sensing ....................................................................................... 49

Priorities ............................................................................................................... 50
Page

IV

Appendix: Answers to Post-Hearing Questions

Dr. Tony Strazisar, Senior Technical Advisor, Aeronautics Research Mission 

Directorate, National Aeronautics and Space Administration ......................... 54

Dr. Jack A. Kaye, Earth Science Division, National Aeronautics and Space 

Administration ..................................................................................................... 57

Ms. Victoria Cox, Senior Vice President, Nextgen and Operations Planning, 

Air Traffic Organization, Federal Aviation Administration ............................. 59

Captain Linda M. Orlady, Executive Air Safety Vice Chair, Air Line Pilots 

Association, International ................................................................................... 61

Mr. Roger Dinius, Flight Safety Director, GE Aviation ....................................... 63
(1)

MITIGATING THE IMPACT OF VOLCANIC ASH 

CLOUDS ON AVIATION: WHAT DO WE NEED 

TO KNOW? 

WEDNESDAY, MAY 5, 2010

HOUSE OF REPRESENTATIVES, 

SUBCOMMITTEE ON SPACE AND AERONAUTICS, 

COMMITTEE ON SCIENCE AND TECHNOLOGY, 

Washington, DC.

The Subcommittee met, pursuant to call, at 10:10 a.m., in Room 

2318 of the Rayburn House Office Building, Hon. Gabrielle Giffords 

[Chairwoman of the Subcommittee] presiding.
2
3

HEARING CHARTER

U.S. HOUSE OF REPRESENTATIVES

COMMITTEE ON SCIENCE AND TECHNOLOGY

SUBCOMMITTEE ON SPACE AND AERONAUTICS 

Mitigating the Impact of Volcanic

Ash Clouds on Aviation–

What Do We Need to Know? 

MAY 5, 2010

10 A.M.–12 P.M. 2318 RAYBURN HOUSE OFFICE BUILDING

I. Purpose 

On May 5, 2010 the Subcommittee on Space and Aeronautics will hold a hearing 

on the research needed to improve our understanding of the impact of volcanic ash 

clouds on aircraft and aircraft operations and what can be done to mitigate that impact. Last year, when the Mount Redoubt volcano erupted southwest of Anchorage, 

one of the operating airlines grounded its fleet, diverted flights and wrapped the engines of its parked planes in plastic sealant. Most recently, the eruption of Iceland’s 

Eyjafjallajo ̈kull volcano paralyzed air travel in Europe for six days, is reported to 

have inconvenienced hundreds of thousands of passengers around the world, and is 

projected to cause airline revenue losses of at least $1.7 billion. At this hearing, the 

Subcommittee will examine the role Federal research can play in:

• Characterizing the damage volcanic ash causes to aircraft and aircraft engines;

• Devising ways to minimize the negative effects of volcanic ash on aircraft and 

aircraft systems such as engines;

• Improving the modeling, detection, and prediction of how volcanic ash clouds 

propagate and dissipate, particularly through the integrated use of civil 

space-based assets;

• Informing guidelines and regulations that establish what aircraft should do 

when encountering volcanic ash clouds and when it is safe to fly in airspace 

contaminated with volcanic ash; and

• Improving air traffic management procedures, capabilities and features, including those planned for the new NextGen air traffic control system, to efficiently circumvent contaminated airspace.

II. Planned Witnesses: 

Dr. Tony Strazisar

Senior Technical Advisor 

Aeronautics Research Mission Directorate 

National Aeronautics and Space Administration 

[Substituting for Associate Administrator Jaiwon Shin]

Dr. Jack A. Kaye

Earth Science Division 

National Aeronautics and Space Administration

Ms. Victoria Cox

Senior VP, NextGen and Operations Planning 

Air Traffic Organization 

Federal Aviation Administration

Captain Linda M. Orlady

Executive Air Safety Vice Chair 

Air Line Pilots Association, International

Mr. Roger Dinius

Flight Safety Director 

GE Aviation
4

III. Overview 

Following the biggest disruption in air travel since September 11, 2001, there is 

much discussion in Europe about the response to the volcanic ash cloud emergency 

created by the Eyjafjallajo ̈kull volcano. Some of the discussion focuses on whether 

the closure of European airspace and its duration were necessary in the first place. 

The controversy in Europe over the United Kingdom’s Civil Aviation Authority’s 

(CAA) decision to close British airspace and the authority’s subsequent permission 

to allow resumption of flights in specified areas highlights the challenge aviation 

regulators face in light of insufficient scientific data to establish (1) the volcanic ash 

contaminant level below which air travel is safe and permissible; (2) the atmospheric location and concentrations of ash such that safe flying corridors can be determined on a real-time basis; and (3) the damage, both immediate and long-term, 

that volcanic ash inflicts on aircraft, particularly their engines. 

Although the disruption caused by the Icelandic volcano is not the first time air 

travel has been impacted by volcanic ash, the magnitude of the disruption is the 

greatest experienced to date. Anecdotal evidence from several incidents where aircraft have previously encountered volcanic ash alerted aviation regulatory bodies on 

the dangers of flying through such conditions. Several near-catastrophic incidents 

involving volcanic ash have occurred:

• In 1982, after flying through an ash cloud, a British Airways Boeing 747 near 

Jakarta, Indonesia lost all four of its engines as they choked on the ash and 

flamed out. Ash was reported to have filled the cabin through air vents and 

the cockpit window was severely scratched. Subsequently, the pilots were able 

to restart three of the four engines and land safely in Jakarta.

• In 1982, one month after the British Airways incident, a Singapore Airlines 

Boeing 747 lost two of its four engines and was forced to land in Jakarta because of an ash encounter.

• In 1989, a KLM Royal Dutch Airlines Boeing 747 encountered an ash cloud 

caused by Mount Redoubt while descending into Anchorage International Airport. The aircraft lost all four engines and about half of its instruments failed. 

Pilots were able to restart all four engines and landed safely.

In response to these incidents, and because there were no agreed upon values of 

ash concentration that constitute a hazard to aircraft engines, the International 

Civil Aviation Organization (ICAO), a U.N. agency, recommended avoidance of volcanic ash clouds as the preferred course of action. ICAO also created a worldwide 

monitoring system composed of 9 Volcanic Ash Advisory Centers (VAAC). The 

Washington VAAC and Anchorage VAAC are operated by the National Oceanic and 

Atmospheric Administration (NOAA). [Attachment I shows the VAACs and their 

areas of responsibility]. According to the Federal Aviation Administration (FAA), the 

problem of ash clouds in the United States generally occurs in Alaska, Hawaii or 

the Pacific Northwest. In addition, in part to address the hazard posed by airborne 

volcanic ash in the North Pacific, the U.S. Geological Survey (USGS), in cooperation 

with the University of Alaska Fairbanks Geophysical Institute and the Alaska Division of Geological and Geophysical Surveys, established the Alaska Volcano Observatory (AVO) with offices in Anchorage and Fairbanks. The AVO provides hazard assessments, updates and warnings of volcanic activity in Alaska. 

NASA has first-hand knowledge of the effects of flying through volcanic ash clouds 

and the delayed effect on jet engine performance. When its scientists were flying 

in a DC–8 research aircraft en route to Sweden in February 2000, they flew for 

about 8 minutes through an ash cloud, a fact unknown to the pilots until they were 

alerted by on-board scientists who had noticed the event using special instrumentation; conventional radar equipment is incapable of discerning volcanic ash clouds. 

Although the pilots saw no change in performance in the aircraft, either immediately after being told of the encounter or even after 60 hours of flying in Sweden, 

a borescopic inspection was performed on all four engines following the aircraft’s return to the U.S. Results of the analysis caused NASA to send one of the engines 

for an overhaul. The agency found that ash clogged holes that provide bleed air cooling to turbine blades, and also left deposits on the turbine blades after ash entered 

the combustion chamber and melted. [See pictures of damage to one of the engines 

in Attachment II] The maintenance factory told NASA that they had substantially 

decreased the life of the engines and that they would have noticed a degradation 

in performance in as little as a hundred flight hours because of overheating of the 

engine fan blades. All four engines were subsequently overhauled. Dr. Jaiwon Shin, 

a witness at the hearing, can provide details on NASA’s related aeronautics research activities. He will be accompanied by Mr. Thomas Grindle who is familiar 

with the events associated with the February 2000 flight. 
5

NASA does not have operational responsibility for observation and analysis of volcanic gas and aerosol emissions. However, its fleet of research spacecraft provides 

data that are directly applicable to understanding the hazards presented by these 

phenomena. According to NASA, in response to the recent European situation, it is 

providing near-real-time information on volcanic sulfur dioxide and ash aerosols 

from the Ozone Monitoring Instrument aboard the Aura satellite for the VAACs in 

London and Toulouse, in collaboration with NOAA. NASA states that the information provided to the London and Toulouse VAACs had been previously available for 

sectors covering the Americas and the Pacific (in collaboration with the Anchorage 

and Washington VAACs). Numerous other NASA spacecraft instruments provide 

important data relevant to the problem of volcanic ash clouds. One example is data 

recently acquired by the Multiangle Imaging SpectroRadiometer instrument on the 

Terra spacecraft that provide not only the horizontal extent of the plume over Iceland but detailed information about its vertical extent as well. In addition to providing measurements and information to aid decision-makers in responding to the 

volcanic event and its aftermath, these data from NASA’s research satellites are 

being utilized in several ongoing NASA-sponsored scientific studies of solid Earth 

processes, atmospheric composition and air quality, Earth’s radiation balance and 

aviation forecasting improvement methodologies within NASA’s Earth Science Division’s Research and Analysis (R&A) and Applied Sciences programs. Dr. Jack Kaye, 

a witness at the hearing, can provide additional details on the capabilities of 

NASA’s Earth observation satellites. 

The Airline Pilots Association (ALPA), the largest airline pilot union in the world, 

representing nearly 53,000 pilots at 38 U.S. and Canadian airlines, has devoted several years to expanding the database of operationally relevant information on the 

potential hazard caused by volcanic ash and improving the warning system necessary to reduce unplanned encounters with hazardous ash clouds. ALPA believes 

its information may be useful towards understanding the hazard; understanding 

recommended practices for avoidance, if possible; achieving survival in the event of 

an unexpected encounter; and finally, reporting the experience. Regarding the recent situation in Europe, it warned members to identify alternate routes to avoid 

ash clouds. Captain Linda Orlady, a witness at the hearing, can provide additional 

details on ALPA’s relevant activities. 

When the ban over air travel was lifted in Europe, officials broke the affected 

areas of airspace into three tiers: normal flight zones where ash no longer poses a 

risk, no-fly zones where ash remains in high concentrations, and intermediate, potentially hazardous zones where flights can proceed with caution, subject to route 

restrictions and other limitations. The UK Civil Aviation Authority (UK’s equivalent 

of the FAA) lifted flight restrictions after consulting with many parties, including 

the FAA and aircraft and engine manufacturers. In a statement, the FAA indicated 

its support for the decision by the European Commission to resume air traffic in 

parts of continental Europe. The FAA said, in its press release, that ‘‘This gradual, 

cautious return of operations is reliant on the track of the volcanic ash cloud which 

is being monitored closely. The FAA is continuing to work with the European Union 

and is sharing technical information and guidance based on previous experience 

managing weather and volcanic events that have affected portions of U.S. airspace. 

The FAA remains ready to assist both the air carriers and our colleagues in Europe 

to do whatever is necessary to help stranded passengers and to safely return air service between our continents.’’ In addition, the FAA released on April 22, 2010 a Special Airworthiness Information Bulletin (SAIB) advising ‘‘owners and operators of 

aircraft equipped with turbine engines that operate in airspace where volcanic ash 

may be present, of recently issued communications from engine manufacturers.’’ 

SAIB Number NE–10–28 recommends that:

‘‘Before flying from the United States to Europe or within Europe, aircraft owners and operators should review the following recommendations:

• Although the FAA does not recommend engine operation or flight into a visible 

volcanic ash cloud, we do recommend that you obtain definitive information 

on operational limitations around ash clouds, if any, from each of the European National Authority of the State(s), of which you plan flight operations.

• Follow all aircraft and engine manufacturer’s operating and maintenance instructions pertaining to operations in airspace where volcanic ash may be near 

or present.

• Report any inadvertent encounter with volcanic ash or relevant findings, including abnormal engine behavior, to the respective type certificate holders of 

the aircraft and engines.’’
6

Ms. Victoria Cox, a witness at the hearing, can provide additional details on 

FAA’s collaborative efforts to assist other aviation regulators as well as how similar 

situations may be managed under the NextGen air traffic control system. In addition, Mr. Roger Dinius, also a witness at the hearing, can provide details on GE 

Aviation’s role in helping European aviation regulators establish conditions for 

flight resumption. 

There is widespread agreement on the need for a better understanding of the effects of volcanic ash on aircraft and how particulates propagate in the atmosphere. 

Of particular concern is the small amount of research so far on the cumulative impact of flying for extended amounts of time through even low levels of volcanic ash. 

What knowledge we still lack and how we go about gaining that better understanding—possibly through additional research, data collection and computer modeling—will be discussed during this hearing.

IV. Issues

Aeronautics Research and Information Needs

• What is known about the impact of aircraft flying through volcanic ash 

clouds? What are the areas of greatest uncertainty in our knowledge and what 

research is needed to reduce that uncertainty?

• What research is needed to better understand when and under what conditions 

(e.g., size of particulates, ash concentration, and height of the cloud) it is safe 

to fly through airspace that has been contaminated with volcanic ash particulates? Is there a way to characterize the risk of flying under different conditions?

• What research is needed to develop sensors and instrumentation to warn aircraft operators of volcanic ash conditions?

• Can human factors research enhance the training of pilots who might deal 

with volcanic ash conditions?

• What is known about how much damage volcanic ash can inflict on aircraft 

engines? What research can help engine designers determine the extent to 

which the safety of aircraft engines could be enhanced on future aircraft that 

inadvertently fly through volcanic ash conditions?

• What is the extent of research on the effects of aircraft flying through volcanic 

ash clouds by the National Aeronautics and Space Administration (NASA) 

and the Federal Aviation Administration (FAA)? What has been learned?

• What additional research is needed to help establish limits and conditions 

under which it is safe to fly in contaminated airspace? What level of resources 

would such research entail?

• To what extent are Federal research programs on aircraft flying through volcanic ash coordinated and how easy or difficult is it to share the research results with relevant stakeholders? To what extent are U.S. and international research programs coordinated?

• Are there other sources of research (e.g. by the commercial, or private, non-government sectors) on the effects of aircraft flying in volcanic ash conditions?

Detection, Monitoring and Modeling Activities and Assets

• What civil Federal capabilities, such as Earth-observation satellites, are used 

to assist in detecting and monitoring volcanic ash cloud propagation and dispersion? How effective are they?

• To what extent will planned Earth observing satellites contribute to the detection, monitoring and understanding of volcanic ash clouds and their composition?

• What enhancements to space-based or airborne sensors, technologies, or techniques are needed to further our understanding of volcanic ash clouds and 

particulate dispersion?

• How effective are current modeling techniques in forecasting the propagation 

of volcanic ash clouds?

• How are the scientific results of research and monitoring of volcanic ash 

clouds coordinated, analyzed, filtered and disseminated to decision makers 

who are responsible for determining when it is safe to fly, and what, if any, 

improvements need to be made to ensure the effectiveness of coordinating and 

disseminating the information?
7

• What is the extent of collaboration, both nationally and internationally, in the 

detection and monitoring of atmospheric volcanic ash conditions and dissemination of warnings?

Air Traffic Management/NextGen and Voluntary Reporting Mechanisms

• What air traffic regulations are currently in effect to manage aircraft operations in the event of a volcanic ash cloud event, such as those experienced in 

Alaska? Are there contingency plans for dealing with such events? What information is needed to establish ‘‘safe’’ flight corridors?

• What was FAA’s role in collaborating with international aviation regulatory 

bodies to establish safe conditions for resumption of air travel following the 

eruption of the Eyjafjallajokull volcano?

• Can research help inform the establishment of airspace management and air 

traffic control procedures in the event of a volcanic ash cloud situation? If so, 

in what areas is research needed and who should conduct such research in the 

U.S.?

• Will the management of aircraft flying in volcanic ash situations be handled 

differently under NextGen? What information does NextGen need to automatically assign safer air traffic routes? Is that information available today?

• Have any of the voluntary safety reporting mechanisms, such as the Aviation 

Safety Information and Sharing (ASIAS) System, identified issues associated 

with aircraft flying through volcanic ash clouds?
8
9
10

Chairwoman GIFFORDS. This hearing will now come to order. 

Good morning, everyone. It is with real pleasure that we invite 

you today to the Subcommittee’s hearing. We have an impressive 

panel of experts, and I am really fortunate to have had a chance 

to speak, before we started, with some of them. We look forward 

to having a very good and timely discussion. 

As you know, the eruption of the volcano in Iceland forced the 

closure of European airspace, paralyzing air traffic travel for 6 

days. Hundreds of thousands of passengers around the world, including many Americans, in fact, friends and family members I 

think of all of us, were stranded and airline revenue losses may 

end up reaching at least $1.7 billion. 

While the ink has yet to dry on that episode, one thing is certainly clear: Aviation regulators have insufficient scientific data to 

establish, one, at what level of volcanic ash contamination air travel is safe; two, where ash clouds are and how concentrated they are 

on a real-time basis; and three, the extent of damage, both immediate and long-term, that volcanic ash inflicts on aircraft and particularly on their engines. 

Moreover, the dangers to aircraft and passengers are not hypothetical, as our witnesses will testify. For example, in 1982, after 

flying through an ash cloud, a British Airways Boeing 747 near Jakarta, Indonesia, lost all four of its engines as they choked on the 

ash and flamed out. Ash was reported to have filled the cabin 

through air vents and the cockpit window was severely scratched. 

Also in 1982, one month after the British Airways incident, a 

Singapore Airlines Boeing 747 lost two of its four engines and was 

forced to land in Jakarta because of an ash encounter. In 1989, a 

KLM Royal Dutch Airlines Boeing 747 encountered an ash cloud 

caused by Mount Redoubt while descending into Anchorage International Airport in Alaska. The aircraft lost all four engines and 

half of its instruments failed as well. 

I strongly believe that this Subcommittee should, as one of its 

primary responsibilities, identify space and aeronautics issues of 

concern to the Nation and encourage the development of practical 

solutions if possible. Oftentimes, focused research can help. 

While we have been fortunate not to have experienced this type 

of widespread volcano-induced airspace closure that Europe just experienced, we should view this as a wake-up call for all of us. The 

reality is that we do have some relevant experience and technologies that can be brought to bear on this problem. As you will 

hear later, the inadvertent encounter of a volcanic ash cloud by a 

NASA research aircraft in 2000 showed how much damage volcanic 

ash can inflict to aircraft engines and the hidden nature of that 

damage. And NASA was recently called on by our European friends 

to monitor, using its unique satellite-based instruments, the ash 

plume as it made its way towards continental Europe. 

As our country’s aviation regulator, FAA collaborates with other 

Federal agencies to ensure that our Nation’s air traffic safely circumvents any problematic conditions, including volcanic ash situations. 

Avoiding volcanic ash clouds certainly is not as easy as it sounds. 

Conventional radar cannot discern ash particulates. Pilots are 
11

keenly aware of this and have been trained on what to do when 

advised of potential problems. 

Finally, as you will hear today, engine manufacturers provided 

assistance during the decision-making period leading up to the reopening of Europe’s skies. 

I called today’s hearing so that this Subcommittee can help determine what we know and where our knowledge is still lacking. 

Most importantly, I would like to find out if any additional research can enhance our understanding of the impact of volcanic ash 

on aviation so that we can ensure that our reaction to future situations is based on sound data and information. 

With that, I want to again welcome our witnesses. 

[The prepared statement of Ms. Giffords follows:]

PREPARED STATEMENT OF CHAIRWOMAN GABRIELLE GIFFORDS

Good morning, it’s a pleasure to welcome you to today’s Subcommittee hearing. 

We have an impressive panel of experts appearing before us this morning, and I 

look forward to a good discussion. 

Today’s hearing is timely. As you know, the eruption of the volcano in Iceland 

forced the closure of European airspace, paralyzing air travel for six days. Hundreds 

of thousands of passengers around the world—including many Americans—were 

stranded and airline revenue losses may reach at least $1.7 billion. 

While the ink has yet to dry on that episode, one thing is clear: 

Aviation regulators have insufficient scientific data to establish (1) at what level 

of volcanic ash contamination air travel is safe; (2) where ash clouds are and how 

concentrated they are on a real-time basis; and (3) the extent of damage, both immediate and long-term, that volcanic ash inflicts on aircraft and particularly on their 

engines. 

Moreover, the dangers to aircraft and passengers are not hypothetical—as our 

witnesses will testify. 

For example, in 1982, after flying through an ash cloud, a British Airways Boeing 

747 near Jakarta, Indonesia lost all four of its engines as they choked on the ash 

and flamed out. Ash was reported to have filled the cabin through air vents and 

the cockpit window was severely scratched. 

Also in 1982—one month after the British Airways incident—a Singapore Airlines 

Boeing 747 lost two of its four engines and was forced to land in Jakarta because 

of an ash encounter. 

In 1989, a KLM Royal Dutch Airlines Boeing 747 encountered an ash cloud 

caused by Mount Redoubt while descending into Anchorage International Airport in 

Alaska. The aircraft lost all four engines and half of its instruments failed. 

I strongly believe that this Subcommittee should, as one of its primary responsibilities, identify space and aeronautics issues of concern to the Nation and encourage the development of practical solutions if possible. Oftentimes, focused research 

can help. 

While we have been fortunate not to have experienced the type of widespread volcano-induced airspace closure Europe just experienced, we should view this as a 

wake-up call. 

The reality is that we do have some relevant experience and technologies that can 

be brought to bear on the problem. 

As you will hear later, the inadvertent encounter of a volcanic ash cloud by a 

NASA research aircraft in 2000 showed how much damage volcanic ash can inflict 

to aircraft engines and the hidden nature of that damage. 

And NASA was recently called on by our European friends to monitor, using its 

unique satellite-based instruments, the ash plume as it made its way towards continental Europe. 

As our country’s aviation regulator, FAA corroborates with other Federal agencies 

to ensure that our Nation’s air traffic safely circumvents any problematic conditions, 

including volcanic ash situations. 

Avoiding volcanic ash clouds is not as easy as it sounds. Conventional radar cannot discern ash particulates. Pilots are keenly aware of this and have been trained 

on what to do when advised of potential conditions. 

Finally, as you will hear today, engine manufacturers provided assistance during 

the decision-making period leading up to the reopening of Europe’s skies. 
12

I called today’s hearing so that the Subcommittee can help determine what we 

know—and where our knowledge is still lacking. 

Most importantly, I would like to find out if additional research can enhance our 

understanding of the impact of volcanic ash on aviation so that we can ensure that 

our reaction to future situations is based on sound data and information. 

With that, I again want to welcome our witnesses, and I now will yield to Mr. 

Olson for any opening remarks he would care to make.

Chairwoman GIFFORDS. And now I yield to Mr. Olson for any 

opening remarks that he would like to make. 

Mr. OLSON. Madam Chairwoman, thank you for calling this 

morning’s hearing. I greatly appreciate that. 

I would like to thank our witnesses for your appearance today. 

I appreciate your expertise and your willingness to share your perspective with us on this very important issue of how our air traffic 

management system can best respond to volcanic eruptions and 

whether any additional research is needed to improve safety and 

system performance. 

The recent volcanic eruption in Iceland was a powerful example 

of the interconnected world we live in today. Travelers brace for almost anything but delays due to the eruption of an Iceland volcano 

is not something many would have predicted when they drove to 

the airport that day. 

As a pilot myself, I am very interested to learn what we know 

of the impact volcanic ash has on aircraft. I am also eager to learn 

how our air traffic system weighs the known and unknown risks 

associated with volcanic ash, how our system responds when confronted with such a circumstance, and coupling that knowledge 

with the desire of thousands of travelers wanting to get to their 

destinations and airlines eager to get them there. 

Post 9/11, the world has been vigilant to prevent the disruption 

of air travel as we saw on that day, but who could have imagined 

the second biggest disruption since that day would have been 

caused by a volcano in Iceland? 

That leads to another topic that we need to discuss today: What 

is the appropriate level of funding we should invest in research and 

development on events or circumstances that would be classified as 

rare or highly unlikely? It is easy to imagine that prior to the Iceland volcano erupting, many experts would have likely argued that 

funding additional research on issues related to the impact of volcanic ash on airplanes, it would be a low priority. Some might even 

say a waste of money. But events of the previous month may now 

cause many to reconsider. 

Are there other calamities like this that are rare but highly disruptive that we should be researching? These questions are difficult and frankly might be impossible to answer but learning from 

this situation will help us going forward, and for that I am pleased 

we are having today’s hearing. 

Thank you much for coming. I yield back my time, Madam 

Chairwoman. 

[The prepared statement of Mr. Olson follows:]

PREPARED STATEMENT OF REPRESENTATIVE PETE OLSON

Madam Chairwoman, thank you for calling this morning’s hearing. I’d like to 

thank our witnesses for their appearance today. I appreciate your expertise and 

willingness to share your perspective with us on the very important issue of how 

our air traffic management system can best respond to volcanic eruptions and 
13

whether any additional research is needed to improve safety and system performance. The recent volcanic eruption in Iceland was a powerful example of the interconnected world we live in today. Travelers brace for almost anything, but delays 

due to the eruption of an Icelandic volcano is not something many would have predicted when they drove to the airport that day. As a pilot myself, I’m very interested 

to learn about what we know of the impact volcanic ash has on aircraft. I’m also 

eager to learn how our air traffic system weighs known and unknown risks associated with volcanic ash, how our system responds when confronted with such a circumstance, and coupling that knowledge with the desire of thousands of travelers 

wanting to get to their destinations and airlines eager to get them there. 

Post 9–11, the world has been vigilant to prevent the disruption of air travel as 

we saw on that day. But who could have imagined the second biggest disruption 

since that day would have been caused by a volcano in Iceland. 

That leads to another topic we need to discuss here today. What is the appropriate level of funding we should invest in research and development on events or 

circumstances that would be classified as rare or unlikely? It is easy to imagine that 

prior to the Iceland volcano erupting, many experts would likely have argued that 

funding additional research on issues related to the impact of volcanic ash on airplanes would be a low priority. Events of the previous month may now cause many 

to reconsider. Are there other calamities like this that are rare but highly disruptive 

that we should be researching? These questions are difficult, and frankly might be 

impossible to answer, but learning from this situation will help us going forward 

and for that I am pleased we are having today’s hearing. 

I thank you and yield back the balance of my time.

Chairwoman GIFFORDS. Thank you, Mr. Olson. 

If there are members who wish to submit additional opening 

statements, your statements will be submitted for the record. 

At this time I would like to introduce our witnesses. First up, we 

have Dr. Tony Strazisar, who will be representing Dr. Jaiwon Shin 

of NASA’s Aeronautics Research Mission Directorate. Dr. Shin unfortunately can’t be here with us today but we wish him the best. 

We understand that he is under the weather, but Dr. Strazisar is 

a senior technical advisor for the Aeronautics Research Mission Directorate at NASA. Welcome. We also have Dr. Jack Kaye, who is 

a member of the Earth Science Division at NASA. Good morning. 

Ms. Victoria Cox, who is a Senior Vice President of NextGen and 

Operations Planning in Air Traffic Organization at FAA. Good 

morning. Also, Captain Linda Orlady, who is the Executive Air 

Safety Vice Chair of the Air Line Pilots Association. We are very 

glad that you are with us this morning, Captain. And finally we 

have Mr. Roger Dinius, who is the Flight Safety Director at GE 

Aviation. Again, welcome. 

Our witnesses should know that you will each have five minutes 

for your spoken testimony. Your written testimony will be included 

in the record for the hearing. When you have completed all of your 

spoken testimony, we will begin with our first round of questions, 

and each member will have five minutes to ask questions. So we 

are going to begin this morning with Dr. Tony Strazisar. 

STATEMENT OF DR. TONY STRAZISAR, SENIOR TECHNICAL 

ADVISOR, AERONAUTICS RESEARCH MISSION DIRECTORATE, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 

Mr. STRAZISAR. Madam Chair Giffords, Ranking Member Olson 

and members of the Subcommittee, thank you for the opportunity 

to appear before you today. I am here to discuss NASA’s past experiences related to the impact of volcanic ash on aircraft systems 

and operations and some past and current research activities con-
14

ducted by NASA and the aviation community that could be relevant to the issue. 

The International Air Transport Association reported that the recent eruption of Iceland’s volcano cost the world’s airlines at least 

$1.7 billion and affected as many as 1.2 million passengers a day. 

Many Americans were directly or indirectly impacted by this stoppage. Certainly there will be a significant assessment of this issue 

by the global aviation community in the coming months and years. 

Detecting, monitoring and understanding volcanic ash clouds and 

their composition are critical first steps in addressing this issue, 

and my colleague, Jack Kaye from NASA’s Science Mission Directorate, is discussing this issue with the subcommittee today. 

Encounters with volcanic ash are known to have detrimental effects on modern turbine engines. Particulate erosion testing is not 

a part of commercial engine certification testing. Therefore, today’s 

engines are not certified for volcanic ash ingestion. Engine manufacturers are currently the best source of information regarding the 

impact of volcanic ash on their engines and various conditions. To 

be safe, the current established practice is to avoid flight operations in the vicinity of known volcanic debris. As a result, volcanic 

ash ingestion is not a leading cause of aircraft safety accidents or 

issues. In fact, they are quite rare. There have been no known or 

reported aircraft fatalities as a result of flying through volcanic 

ash. Nonetheless, there are several documented cases of aircraft experiencing engine shutdowns and/or costly damage as a result of 

unintended encounters. 

NASA’s understanding of the effects of aircraft flying through 

volcanic ash clouds comes from its evaluation of an unplanned inflight encounter. Early on the morning of February 28, 2000, a 

NASA DC–8 airplane, a highly instrumented research platform for 

conducting atmospheric science research, inadvertently flew 

through the fringe of a diffuse volcanic ash cloud produced by the 

Mount Hekla volcano in Iceland. This encounter lasted approximately 7 minutes and occurred in total darkness during a ferry 

flight from Edwards, California, to Kiruna, Sweden. During this 

flight, scientists on board the DC–8 monitoring sensitive research 

instruments reported a sudden increase in sulfur dioxide measurements that indicated the presence of a volcanic ash cloud. Except 

for the reports from the onboard science team, the DC–8 crew had 

no indication they were flying through the plume from Mount 

Hekla. After the airplane returned to Edwards Air Force Base, all 

four engines were sent to the General Electric Strouther overhaul 

facility, where they were disassembled and refurbished. Detailed 

engine inspection revealed that even though this was a brief flight 

through a diffuse ash cloud, the exposure was long enough and engine temperatures were high enough that engine hot section blades 

and vanes were coated and cooling air passages were partially or 

completely blocked. 

NASA does not have any ongoing research efforts that are focused on the understanding of the impact of volcanic ash on aircraft engines, mainly because the volcanic ash encounters are very 

rare events and have been consistently placed at a very low priority for research needs by the aviation community. While NASA 

aeronautics research has not directly addressed impacts of volcanic 
15

ash on aviation, it is possible that some past and current research 

activities conducted by NASA and the aviation community could be 

of value to industry and airspace regulators as they seek to better 

understand the impact of volcanic ash and devise strategies for addressing similar situations in the future. 

Making the best possible use of available airports and airspace 

is critical to sustaining limited service during and recovering from 

a major disruption such as occurred last month. NASA-developed 

analysis tools can simulate air traffic scenario, evaluate outcomes 

and support decisions made by air traffic managers and airline operators. 

Past research in dealing with severe weather has shown that 

even the most daunting scenarios provide limited yet workable 

operational solutions. Better plume measurements and propagation 

forecasts and operational procedures together could contribute to 

air traffic management solutions to the problem of volcanic ash. 

Since there are so many factors that contribute to the severity 

of damage from volcanic ash, it is likely that even a robust research effort will lead to engines that are tolerant of significant 

amounts of ash ingestion. However, NASA research on integrated 

propulsion and control systems and robust engine control could 

have potential applicability in mitigating hazards associated with 

volcanic ash. 

Current research regarding effective interaction or monitoring 

methods for the crew under degraded engine operating conditions 

could be applied in instances where those circumstances are due to 

volcanic ash. NASA aeronautics will continue to make available our 

expertise and knowledge in these areas to other Federal agencies 

and the broader aviation community as they assess plans for national and global flight operations in these conditions. 

Thank you for your attention. 

[The prepared statement of Dr. Strazisar follows:]

PREPARED STATEMENT OF TONY STRAZISAR

Madam Chair Giffords, Ranking member Olson, and Members of the Subcommittee, thank you for the opportunity to appear before you today. I am here to 

discuss NASA’s past experiences related to the impact of volcanic ash on aircraft 

systems and operations, and some past and current research activities conducted by 

NASA and the aviation community which could be relevant to this issue. 

Airlines thrive on reliability and predictability, as witnessed by their published 

‘‘on-time departure’’ metrics. As we have recently learned, volcanic eruptions, and 

specifically, the dispersal ash clouds are beyond today’s predictive capabilities, thus 

upsetting the reliability of airplane operations. In light of the great uncertainty of 

the location of volcanic ash, and the extreme hazard it presents to jet aircraft, airlines and air traffic managers take extraordinary precautions to avoid flying into 

these danger zones. In the case of the recent eruption of Iceland’s Eyjafjallajokull 

volcano, the risk was deemed so great that the only prudent response was to ground 

all aircraft within the danger zone, which encompassed the United Kingdom and 

most of northern Europe. The problems associated with the eruption in Iceland were 

compounded by the fact that many of the impacted flights were the trans-Atlantic 

oceanic routes, where there is no continuous surveillance (such as radar) and the 

requirement for proximity to contingency landing sites presents a significant constraint to alternate routes. 

The International Air Transport Association reported that the volcanic eruption 

cost the world’s airlines at least $1.7 billion and affected as many as 1.2 million passengers a day. Many Americans were directly or indirectly impacted by this stoppage. Certainly there will be a significant assessment of this issue by the global 

aviation community in the coming months and years. 
16

Detecting, monitoring and understanding volcanic ash clouds and their composition are critical first steps in addressing this issue. My colleague, Jack Kaye, from 

the NASA’s Science Mission Directorate is discussing this issue with the Subcommittee at this hearing today.

Volcanic Ash and Aircraft 

Encounters with volcanic ash are known to have detrimental effects on modern 

turbine engines. Particulate erosion testing is a part of some engine testing, but 

these tests are generally focused on abrasive materials such as sand, which have 

some material properties that have a different impact compared to volcanic ash. 

Therefore, today’s engines are not certified for volcanic ash ingestion. 

There has been some notable research on the impact on gas turbine engines of 

ingesting dust-laden air that was conducted by the Calspan Advanced Technology 

Center in the late 1980s and early 1990s under sponsorship of the Defense Nuclear 

Agency. The Calspan team tested several military gas turbine engines using volcanic ash to better understand the impacts of dust-laden air on engine operation. 

An important research result is that there are a number of factors that significantly 

impact the effect of a volcanic ash encounter, including engine type, operating conditions, constituents of the ash cloud, and ash concentrations. This research also identified several ways that ash can damage an engine including: melting of ash on components in the engine hot sections, erosion of components, blockage of cooling passages in turbines, and contamination of the oil or bleed air systems. This research 

also developed and validated various potential recovery strategies for addressing inflight operational problems, depending upon the engine and conditions encountered. 

The signs that an aircraft is in a volcanic ash condition are not always clear. Previous ground tests of engines by Calspan indicate that the warning signs of ash 

damage vary with engine type and that an ash encounter is often very difficult to 

discern from existing instrumentation until a serious problem like an engine surge 

or flame-out occurs. 

Engine manufacturers currently are the best source of information regarding the 

impact of volcanic ash on their engines in various conditions. The Subcommittee will 

be hearing directly from industry sources about this subject at this hearing, including their experiences recently in facilitating the resumption of commercial operations in European airspace. 

To be safe, the current established practice is to avoid flight operations in the vicinity of known volcanic airborne debris. As a result, volcanic ash ingestion is not 

a leading cause of aircraft safety accidents or issues—in fact they are quite rare. 

There have been no known or reported aircraft fatalities a result of flying through 

a volcanic ash cloud. Nonetheless, there are several documented cases of aircraft experiencing engine shutdowns and/or costly damage as a result of an unintended encounter.

NASA DC–8 Volcanic Ash Incident 

NASA’s understanding of the effects of aircraft flying through volcanic ash clouds 

comes from its evaluation of one unplanned in-flight encounter. This evaluation was 

enabled by the presence of an onboard science team and specialized instrumentation 

for unrelated airborne chemistry research. These findings and lessons were developed from volcanic ash plume and satellite trajectory analysis, analysis of ash particles collected in cabin air heat exchanger filters and removed from engines, and 

data from onboard instruments and engine conditions. 

Early on the morning of February 28, 2000, the NASA DC–8 airplane, a highly 

instrumented research platform for conducting atmospheric science research, inadvertently flew through the fringe of a diffuse volcanic ash cloud produced by the Mt. 

Hekla volcano in Iceland. This encounter, which lasted approximately seven minutes, occurred in total darkness (no moonlight) during a ferry flight from Edwards, 

California to Kiruna, Sweden. 

This particular encounter demonstrated the difficulty of predicting the location of 

the ash plume produced by a volcanic eruption. Thirty five hours after the eruption, 

the London Volcanic Ash Advisory Center (VAAC), using observatory inputs, satellite pictures, radar imagery and pilot reports, predicted the ash plume would be 

south of the proposed DC–8 track. However, to provide an additional margin of safety, the DC–8 flight path was adjusted an additional 200 miles north, with the expectation of totally avoiding any possibility of encountering the ash plume. 

From this research mission, we have learned that a damaging encounter with volcanic ash can be undetectable, even to an alerted flight crew. During this flight, scientists onboard the DC–8 monitoring sensitive research instruments reported a sudden increase in sulfur dioxide (SO2) measurements that indicated the presence of 
17

a volcanic ash cloud. Except for the reports from the on-board science team, the DC–

8 crew had no indication they were flying through the plume from Mt. Hekla. In 

previous ash plume encounters by aircraft, the events were frequently accompanied 

by an odor in the cabin air, by changes in engine readings, by the frosting of windows, and at night, by the presence of St. Elmo’s fire on forward-facing parts of the 

aircraft. NASA’s DC–8 flight crew noted no change in cockpit readings, no St. 

Elmo’s fire, no odor or smoke, and no change in engine instruments. They did notice 

that no stars were visible, but this is typical of flight through high cirrus clouds. 

Since in-flight performance checks and detailed visual inspections after landing in 

Sweden revealed no damage to the airplane or engine first-stage fan blades, the research campaign was completed, and the airplane was ferried back to Edwards Air 

Force Base in California. More complex engine borescope inspections revealed 

clogged cooling passages and some heat distress in the high temperature section of 

the engines. One engine appeared to be more heavily damaged. 

The DC–8 is powered by four General Electric CFM56–2 high bypass turbofan engines. All four engines were sent to the manufacturer’s General Electric Strouther 

overhaul facility near Arkansas City, Kansas, where they were disassembled and refurbished. Their detailed engine inspection revealed that even though this was a 

brief flight through a diffuse ash cloud, the exposure was long enough and engine 

temperatures were high enough that engine hot section blades and vanes were coated and cooling air passages were partially or completely blocked. All engines exhibited a fine white powder coating throughout, leading edge erosion on high-pressure 

turbine vanes and blades, blocked cooling air holes, blistered coatings, and a buildup 

of fine ash inside passages. A blade with blocked cooling operates at a sufficiently 

higher temperature, significantly impacting blade life. Although engine trending did 

not reveal a problem, hot section parts may have begun to fail (through blade erosion) if flown another 100 hours, in contrast to the normal service life of thousands 

of hours. The engines were overhauled, at a total cost of $3.2 million.

Research That Could Benefit Future Situations 

NASA does not have any ongoing research efforts that are focused on understanding the impact of volcanic ash on aircraft engines, mainly because the volcanic 

ash encounters are very rare events and have been consistently placed at a very low 

priority for research needs by the aviation community. 

While NASA aeronautics research has not directly addressed impacts of volcanic 

ash on aviation, it is possible that some past and current research activities conducted by NASA and the aviation community could be of value to industry and airspace regulators as they seek to better understand the impact of volcanic ash and 

devise strategies for addressing similar situations in the future.

Operational procedures 

Making the best possible use of available airports and airspace is critical to sustaining limited service during, and recovering from, a major disruption such as 

Eyjafjallajokull. NASA-developed analysis tools can simulate air traffic scenarios, 

evaluate outcomes, and support decisions made by air traffic managers and airline 

operators. There could be some applicability of these analysis tools to decision support tools for the oceanic flight realm, benefiting routine daily operations as well as 

recovering from system disruptions such as ash plumes. 

Parallels exist between the problems presented by an ash plume and by severe 

convective weather: both form in an unpredictable manner, present a dynamically 

changing hazard to aviation, and require coordinated modification of flight routes. 

The aviation community has made a large, sustained investment in technology development to address convective weather, resulting in sensors, models, and tools 

that have significantly improved the ability to keep people and aircraft safely moving when subjected to adverse weather conditions. Past research in dealing with severe weather has shown that even the most daunting scenarios provide limited yet 

workable operational solutions. 

Better plume measurements and propagation forecasts and operational procedures 

together could contribute to air traffic management solutions to the problem of volcanic ash. Tracts of useable airspace could be identified to build routes that can be 

used to maximize traffic throughput in constrained airspace. Fleet management options could be assessed to quantify the advantages and impacts of different strategies. For example, corridors-in-the-sky that use the available airspace could be developed and dynamically updated based on the prevailing wind and plume conditions. Based on the traffic demands, additional reroutes could be developed as appropriate.
18

Sharing information about hazards 

NASA is developing new display concepts to intuitively convey new information 

sets available to pilots. One such concept could improve the current Notices to Airmen (NOTAM) system. Current NOTAMs of changes to flight conditions are not instantaneous. Expeditious datalink of NOTAMs with an appropriate display and notification could shorten this to seconds to minutes of when such events occur. 

NOTAMs related to volcanic ash activity are called ASHTAMs by the International 

Civil Aviation Organization (ICAO), and are regularly released when such events 

occur across the globe. However, such information today is very coarse and delayed, 

and is therefore open to misinterpretation. Improvements in display concepts, while 

not developed to specifically address the issue of hazardous ash conditions, could enable the provision much more detailed ash information along with real-time updates 

as they become available through air traffic service providers. 

NASA also has available data mining tools that might be of use to industry and 

regulators to make sense of data resulting from recent operational experiences or 

future tests.

Engine technologies 

Since there are so many factors that contribute to the severity of damage from 

volcanic ash, it is unlikely that even a robust research effort will lead to engines 

that are tolerant of significant amounts of ash ingestion. However, some NASA research in novel materials may have an effect of mitigating some of the negative effects from ash ingestion. For example, ceramic matrix composite turbine blades may 

need fewer cooling channels which would make them less susceptible to degraded 

cooling performance due to clogging. These materials may also have better damage 

tolerance qualities. Similarly, research in engine monitoring and instrumentation 

might also have applicability in this circumstance. 

In the 1990s, NASA conducted flight research to examine deteriorated engine operation and performance (the Dryden Performance Seeking Control research 

project). Extrapolating from that experience, NASA research on integrated propulsion and control systems and robust engine control (i.e. controller design and possible modification of actuators to extend engine operating life) could have some potential applicability in mitigating the hazards associated with volcanic ash. Current 

research regarding effective interaction or monitoring methods for the crew under 

degraded engine operating conditions could be applied in instances where those circumstances are due to volcanic ash.

Conclusion 

NASA Aeronautics will continue to make available our expertise and knowledge 

in these areas to other Federal agencies and the broader aviation community as 

they assess plans for national and global flight operations in these conditions.
19

BIOGRAPHY FOR TONY STRAZISAR

Chairwoman GIFFORDS. Thank you, Dr. Strazisar. 

Dr. Kaye, please. 

STATEMENT OF DR. JACK A. KAYE, EARTH SCIENCE DIVISION, 

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 

Mr. KAYE. Good morning, Chairwoman Giffords, Ranking Member Olson and members of the Subcommittee. I appreciate having 

the opportunity to appear before you today to discuss NASA’s earth 

science-related activities to observe and carry out scientific research of volcanic ash clouds. 

The recent eruption of Eyjafjallajo ̈kull highlights the different 

types of contributions that NASA’s Earth Science program makes 

to the study of and response to such events. Through its fleet of 

13 major earth-observing missions, NASA is able to rapidly generate and broadly disseminate imagery and data products on the 

locations, heights and densities of ash plumes and related hazards. 

These data products fuel a range of research investigations which 

enhance our knowledge of solid earth processes, atmospheric transporting composition and the impacts that volcanic eruption have on 

the earth system. NASA is also able to, and did, provide critical 

data streams from these research satellites to the National Oceanic 
20

and Atmospheric Administration to support that agency’s operational prediction of ash plumes. 

Although NASA does not have operational responsibility for observation and analysis of volcanic gas and aerosol emissions, its 

fleet of research spacecraft provides data that are directly applicable to the societal hazards presented by these phenomena. NASA 

has been using its research satellites to study volcanic eruptions, 

especially their atmospheric impact, for more than 3 decades. 

Several of the research satellite missions that NASA is currently 

developing will be able to provide new and advanced insights into 

volcanic ash cloud properties. Missions that will be able to study 

the presence of aerosols in the atmosphere include Glory, scheduled 

for launch later this year, NPP, scheduled for launch in 2011, and 

tier 2 missions from the decadal survey, GEO–CAPE and ACE. 

NPP will help to track volcanic ash clouds using sulfur dioxide observations. Two other decadal survey missions will also support 

this effort. The DESDynI mission will improve the determination 

of the likelihood of volcanic eruptions and document posteruption 

changes while the HyspIRI mission will be able to detect volcanic 

eruptions and determine the ash content of volcanic plumes. 

In addition to providing measurements and information to aid 

decision makers in responding to the volcanic events and its aftermath, these data from NASA’s research satellites are being utilized 

in several ongoing NASA-sponsored scientific studies of solid earth 

processes, atmospheric composition and air quality, earth’s radiation balance and aviation forecasting improvement methodologies 

within both NASA’s Earth Science Division’s Research and Analysis program and its Applied Sciences program. For example, over 

the past several years the project competitively funded through the 

Applied Sciences program demonstrated reliable and accurate detection of volcanic ash clouds using observations of sulfur dioxide 

from the ozone monitoring instrument on board NASA’s Aura satellite. 

Since volcanic eruptions are essentially the only variable sources 

of SO2 large enough to be observed by satellites, false alarms are 

nonexistent. Satellite observations of sulfur dioxide thus assist 

operational agencies in identifying and locating volcanic ash clouds, 

in particular during the first few days after an eruption. 

NASA, in collaboration with NOAA, provides near real-time information on volcanic sulfur dioxide and ash aerosols from the OMI 

instrument. NOAA provides this information to its U.S.-based volcanic ash advisory centers. The international network of these centers is charged with gathering information on the presence and motion of volcanic clouds and assessing any hazards to aviation. In 

April, NASA products were provided for the first time to the European volcanic ash advisory centers to assist in their decision making. 

From a research perspective, NASA-developed global models can 

be used to simulate the emission of volcanic ash and sulfur dioxide 

into the atmosphere and to track its subsequent transport and dispersion on regional and global scales. NASA also routinely uses air 

particle trajectory modeling to estimate the source regions of features seen in satellite data that are suspected to have a volcanic 

origin. However, such model runs are generally undertaken after 
21

an eruption has taken place in order to advance scientific understanding, leading to improvements in the accuracy of the models. 

At present, our understanding of solid earth processes and our 

ability to obtain adequate global measurements to initiate the models are both insufficient for generating routine, accurate predictions 

of volcanic ash plume range and composition. However, NASA efforts to improve observations will yield new and more refined data 

on various aspects of the plume including area, height, aerosol 

properties and associated sulfur dioxide which can be used to help 

critically evaluate current models and drive the improvement of 

such models in the future. 

Thank you again for the opportunity to testify before you today. 

I look forward to answering your questions. 

[The prepared statement of Mr. Kaye follows:]

PREPARED STATEMENT OF JACK KAYE

Good morning Chairwoman Giffords, Ranking Member Olson and Members of the 

Subcommittee. I appreciate the opportunity to appear before you today to discuss 

the National Aeronautics and Space Administration’s (NASA’s) Earth Science-related activities to monitor and study volcanic ash clouds. The recent eruption of 

Eyjafjallajo ̈kull highlights the different types of contributions that NASA Earth 

Science makes to the study of, and response to, such events. Through its fleet of 

satellite assets, NASA is able to rapidly generate and broadly disseminate imagery 

and data products on the location, heights, and densities of ash plumes and related 

hazards. These data products fuel a range of research investigations which enhance 

our knowledge of solid Earth processes, atmospheric transport and composition, and 

the impacts that volcanic eruptions have on the Earth system. NASA is also able 

to—and did—provide critical data streams from these research satellites to the National Oceanic and Atmospheric Administration (NOAA) to support that agency’s 

operational prediction of dust plumes. In response to the intense public interest in 

this event, NASA has conducted focused public outreach activities regarding our research capabilities and science activities in the areas of volcano research and hazard 

prediction. Although NASA does not have operational responsibility for observation 

and analysis of volcanic gas and aerosol emissions, its fleet of research spacecraft 

provides data that are directly applicable to the societal hazards presented by these 

phenomena. 

NASA has been using research satellites to study volcanic eruptions, especially 

their atmospheric impact, for more than three decades. NASA pioneered such activities using the Total Ozone Mapping Spectrometer (TOMS) instrument flying aboard 

the Nimbus 7 satellite launched in 1978. The record for the Nimbus 7 TOMS and 

the flight of successor TOMS instruments on other missions covers the years 1978–

2003 and includes observations of a total of 274 eruptive events from 70 different 

volcanoes (see http://toms.umbc.edu/). Starting in 2004 and extending to the 

present, key successor measurements are provided by the Ozone Monitoring Instrument (OMI) flying aboard NASA’s Aura spacecraft. 

Information on atmospheric composition in the TOMS/OMI data is based on measurements of ultraviolet radiation; however, this is only one of the ways in which 

NASA uses its satellites to study the atmospheric impact of volcanic eruptions. 

NASA’s currently operating fleet of 13 satellite missions is being used to generate 

several data products which provide complementary information on volcanic effects 

on the atmosphere through measurements obtained from different wavelength regions, viewing geometries, and employing a variety of remote sensing technologies. 

These products provide information not only on the location of ash clouds and sulfur 

dioxide (SO2) injected into the atmosphere, but on the height, size, and composition 

of the particles. Such data are critically important for the initialization and evaluation of the models that are used to predict the evolution of the gas and ash plumes 

associated with volcanic eruptions, as well as for direct guidance as to the location 

and severity of ash plumes.

Monitoring Eyjafjallajo ̈kull Using NASA Assets 

NASA’s satellites have observed the ash plume since the eruption of 

Eyjafjallajo ̈kull, providing essential data on the size and composition of the plume 

as it expanded and moved over Europe. For example, data acquired by the Multi-
22

angle Imaging SpectroRadiometer (MISR), one of the instruments on NASA’s 

TERRA spacecraft (launched in 1999) provided information on both the horizontal 

and vertical extents of the plume. The Moderate Resolution Imaging 

Spectroradiometer (MODIS) instruments on the Terra and Aqua (launched in 2002) 

satellites captured images of the eruption; the multiple wavelength measurements 

provided by the MODIS instruments aid researchers in separating ash plumes from 

clouds in the imagery. Information on the height of the ash plume was also provided 

by MODIS. NASA was able to validate the Terra and Aqua ash plume height observations using data from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite 

Observations (CALIPSO) satellite, launched in 2006. CALIPSO’s active remote sensing (lidar) approach not only detects aerosols (small particles such as dust, smoke 

and pollution) and thin clouds that are often invisible to radar, but determines their 

heights and vertical concentration profiles. The Advanced Spaceborne Thermal 

Emission and Reflection Radiometer (ASTER) instrument, also onboard Terra, is 

able to detect and track lava flows, as well as ash and gas plumes, with high spatial 

resolution. For the Eyjafjallajo ̈kull eruption, additional thermal and visible images 

of the plume were captured using the Atmospheric Infrared Sounder (AIRS) instrument on Aqua and the Hyperion instrument on Earth Observing-1 (EO–I), launched 

in 2000. The data and images are archived and available from the NASA Earth Observing System Distributed Active Archive Center. Select imagery can be accessed 

at: http://earthobservatory.nasa.gov/NaturalHazards/event.php?id=43253. 

In addition to providing measurements and information to aid decision-makers in 

responding to the volcanic event and its aftermath, these data from NASA’s research satellites are being utilized in several ongoing NASA-sponsored scientific 

studies of solid Earth processes, atmospheric composition and air quality, Earth’s 

radiation balance, and aviation forecasting improvement methodologies within 

NASA’s Earth Science Division’s Research and Analysis (R&A) and Applied Sciences 

programs. 

For example, over the past several years a project competitively funded through 

NASA’s Applied Sciences Program demonstrated reliable and accurate detection of 

volcanic ash clouds using observations of sulfur dioxide (SO2) from the Ozone Monitoring Instrument (OMI) onboard the NASA Aura satellite. SO2 is a reliable marker 

for fresh ash clouds from explosive magmatic eruptions as it provides a clear discrimination between volcanic plume and ordinary clouds. Since volcanic eruptions 

are essentially the only large sources of stratospheric SO2, false alarms are non-existent. Satellite observations of SO2 thus assist operational agencies to identify and 

locate volcanic ash clouds, in particular during the first few days after an eruption. 

In general the ash in a volcanic plume will drop due to gravity effects faster than 

the SO2, so that some distance away from the volcano the ash and SO2 clouds may 

be separated. Details of how this Applied Sciences work is now being used in an 

operational regime are presented in the next section.

Collaboration with U.S. and International Organization to Monitor Volcanic Ash Plumes 

NASA works with other agencies to ensure that data from NASA’s research satellites can be used to meet operational needs. For example, NASA, in collaboration 

with NOAA, provides information on volcanic sulfur dioxide (SO2) and ash aerosols 

from OMI aboard the Aura satellite every three hours after the data is acquired. 

This information is used to supplement data from NOAA’s Geostationary Operational Environmental Satellites (GOES) and Polar Operational Environmental Satellite (POES) fleets. NOAA distributes these data on-line to its Volcanic Ash Advisory Centers (VAACs) at: http://satepsanone.nesdis.noaa.gov/pub/OMI/OMISO2/

index.html. Nine VAACs were founded in 1995 as a part of an international system 

set up by the International Civil Aviation Organization (ICAO) called the International Airways Volcano Watch (IAVW). The VAACs are charged with gathering 

information on the presence and motion of volcanic clouds and assessing any hazards to aviation. They issue advisories and alerts to airline and air traffic control 

organizations on the possible danger of volcanic clouds. VAACs assist the aviation 

community to utilize satellite data, pilot reports, and other sources of information 

to detect and track ash clouds, and to use trajectory and dispersion models to forecast the motion of ash plumes. 

At the time of the latest eruption, SO2 information was being made routinely 

available for sectors covering the Americas and the Pacific, through the Anchorage 

and Washington Volcanic Ash Advisory Centers (VAACs). However, beginning on 

April 19, 2010, NASA began to provide this information for sectors covering Iceland 

and Northwest Europe to the VAAC in London. This information is now being utilized in the formulation and validation of Volcanic Ash Advisories over Europe. 
23

As an additional response to the eruption, the Support to Aviation Control Service 

(SACS), a support center for the European VAACs, is now directly linking to the 

Aura/OMI near-real time products (http://sacs.aeronomie.be/). The SACS SO2 data 

and alert service delivers near-real time data derived from satellite measurements 

regarding SO2 emissions possibly related to volcanic eruptions, and in case of exceptional SO2 concentrations (‘‘SO2 events’’) can use the data to send out alerts by 

email to interested parties. When volcanic activity poses a hazard to aviation, the 

VAACs issue alerts to air traffic control and airline organizations to help them decide whether to reroute planes away from volcanic clouds. In the case of the 

Eyjafjallajo ̈kull eruption, the satellite measurements and products were also directly 

shared with Schiphol Airport (Amsterdam) and the Netherlands Ministry of Traffic 

Affairs through the OMI Principal Investigator at the Royal Netherlands Meteorological Institute.

Future NASA Assets With Volcanic Ash Monitoring Applications 

Several of the research satellite missions that NASA is currently developing will 

be able to provide new and advanced insights into volcanic ash cloud properties. 

Later this year, NASA will launch the Glory mission to study the Earth’s energy 

budget and the presence of aerosols in the atmosphere. Glory will be able to distinguish various species of aerosols, information which will advance the study of volcanic effluent composition. 

In 2011, NASA is scheduled to launch the NPOESS Preparatory Project (NPP). 

The Visible/Infrared Imager Radiometer Suite (VIIRS) instrument on NPP is designed as an operational follow-on to the research-grade MODIS instrument on 

Terra and Aqua. The Ozone Mapping and Profiler Suite (OMPS) on NPP will provide data that to continue support for the detection of volcanic ash clouds using SO2

observations, currently performed by Aura/OMI. Operational availability of VIIRS 

data will continue on the Joint Polar Satellite System, scheduled for launch in 2015. 

The 2007 National Research Council (NRC) Decadal Survey recommended several 

missions that promise to advance future volcano research. The Deformation, Ecosystem Structure and Dynamics of Ice (DESDynI) mission, a Tier 1 mission, 

has as a key mission objective to improve the determination of the likelihood of 

earthquakes, volcanic eruptions, and landslides. This will enhance our ability to anticipate future eruptions, whereas the response to the Eyjafjallajo ̈kull eruption was 

reactive. Likewise, the Tier 2 Hyperspectral Infrared Imager (HyspIRl) mission 

would include measurements over a range of optical and infrared wavelengths useful for detecting volcanic eruptions, determining the ash content of volcanic plumes, 

and identifying the occurrence and effects of associated landslides. The Geostationary Coastal and Air Pollution Events (GEO–CAPE) mission, also a Tier 

2 mission, would measure aerosols and allow the tracking of pollutants being transported in the atmosphere. Similarly, data from the Tier 2 Aerosol-Cloud-Ecosystems (ACE) mission would be able to distinguish volcanic aerosols from other 

aerosol types and clouds, and will track the dispersion of volcanic plumes in three 

dimensions on a global basis.

Improvements to Volcanic Ash Plume Modeling 

NASA-developed global models can be used to simulate the emission of volcanic 

ash and SO2 into the atmosphere, and to track its subsequent transport and dispersion on regional and global scales. NASA also routinely uses air parcel trajectory 

modeling to estimate the source regions of features seen in satellite data that are 

suspected to have a volcanic origin. However, such model runs are generally undertaken after an eruption has taken place in order to advance scientific understanding, leading to improvements in the accuracy of the models. At present, our 

understanding of solid Earth processes and our ability to obtain adequate global 

measurements to initiate the models are both insufficient for generating routine, accurate predictions. 

The mandate of NASA’s Earth Science program is to increase scientific understanding of Earth processes as an integrated system. NASA thus does not produce 

routine, operational predictions of volcanic ash and SO2 cloud transports and evolution. Because there is a lack of immediately available information on the quantity 

and characteristics of emissions from any particular volcano, any forecasts of ash 

and SO2 emission and propagation are relatively crude. With the present ‘‘state of 

the art,’’ estimates of SO2 cloud transport and characteristics are based heavily on 

estimates of emitted SO2, and while model results usually match well with observed 

cloud dispersion and distribution, they do not produce reliable estimates of SO2 concentrations. At this time, air parcel trajectory models, in which columns of air parcels are initialized over erupting volcanoes at the time of the eruption and then 
24

tracked as the parcels are transported away from the volcano location by forecast 

wind fields, estimate the evolution of the ash cloud but do not consider important 

loss processes such as fallout, rainout, and washout, precluding a reliable forecast 

of ash cloud mass loading. 

The Global Modeling and Assimilation Office at NASA Goddard Space Flight Center generates weather forecasts for the NASA research community, using the Goddard Earth Observing System—Version 5 (GEOS–5) Data Assimilation System. This 

system includes an aerosol model, Goddard Chemistry Aerosol Radiation and Transport (GOCART), as part of its routine twice-daily weather forecast. GOCART must 

be forced with appropriate emissions and produces 3-dimensional distributions of 

aerosols during the forecast period. At present, the GEOS–5 system includes an inventory of continuously outgassing volcanoes, but episodic volcanic eruptions are not 

included. 

Routine forecasts of the propagation of volcanic ash and SO2 clouds following an 

eruption using the GEOS–5 system would be possible given some modifications. 

More detailed observations of the constituents of the ejecta and their vertical distribution are required. Observations need to include information about the timing 

and duration of the eruptions, the injection altitudes as a function of time, and the 

particular characteristics of the emissions (amount, size, type). The information 

would need to be made available or converted to machine-readable data files with 

time of eruption, location, plume height and strength of the emission in terms of 

SO2 and ash. The GOCART aerosol model would need to be modified explicitly to 

include a volcanic ash constituent. A third area of improvement is the development 

of statistical models of uncertainty useful to decision makers. For this, an ensemble 

forecasting technique would be necessary, spanning likely scenarios of ejecta and 

their vertical distribution as well as weather forecast uncertainty. 

The London VAAC runs a version of the Numerical Atmospheric-dispersion Modeling Environment (NAME) model (http://www.metoffice.gov.uk/aviation/vaac/

eruption¥detection.html). The London VAAC has used the OMI aerosol index (AI) 

to validate their dispersion model output, although their main source of satellite 

data has been the Spinning Enhanced Visible and Infra-Red Imager (SEVIRI) infrared instrument on the European geostationary Meteosat Second Generation (MSG) 

satellite, which has better temporal resolution than the polar-orbiting OMI. However, their automatic system based on SEVIRI detects only about 2/3 of the eruptions. Using near real time ultraviolet data, such as OMI Aerosol Index and SO2

(as an ash proxy) in addition to thermal infrared data could improve early (thick) 

volcanic plume detection, not visible in the infrared. 

NASA recently began providing OMI near real time SO2 and AI data to Operations Department of the European Centre for Medium Range Weather Forecasts 

(ECMWF) for evaluation in assimilation tests. The goal is to create an advanced 

operational data assimilation system that will: (1) reasonably model a volcanic 

plume (given the uncertainties in injection height, and composition of the plume); 

(2) assimilate available satellite near-real-time data to constrain the model forecast; 

and (3) provide forecasts for the VAACs. 

It is important to note that the North American-Asia air traffic routes overfly the 

volcanic arcs of the North Pacific from Tokyo, Japan to Anchorage, Alaska. These 

are among the most violent and active volcanoes on Earth. The Washington and Anchorage VAACs, operated by NOAA, have a stellar record of tracking, monitoring 

and warning of volcanic ash dispersion. These VAACs run NOAA’s HYbrid SingleParticle Lagrangian Integrated Trajectory (HYSPLIT) model. They utilize operational NOAA GOES and POES satellite data, NASA research observations, as well 

as data leveraged from European, Japanese, Indian, and other environmental satellites. The Washington and Anchorage VAACs’ areas of responsibility extend from 

South America through the Caribbean and cover the continental United States, 

Alaska, and most of the Pacific.

Airborne Assets With Volcano-Monitoring Capabilities 

Volcano remote sensing researchers have a strong need for in situ sampling of 

eruption plumes and drifting ash clouds to improve, calibrate and validate ash dispersal models. Airborne assets are uniquely qualified to measure the gas and ash 

content of volcanic plumes at altitude. However, sampling a volcanic plume is also 

a hazardous procedure given the dangers that volcanic-ash contamination poses to 

aircraft engines. 

The United States maintains both research and operational airborne assets that 

could be used to monitor future eruptions. However, NASA’s research aircraft and 

unmanned aerial vehicles are typically engaged in coordinated field campaigns investigating other science research questions, but could be diverted to a hotspot on 

an emergency basis. Such a decision would constitute an interruption to the baseline 
25

mission profile and would require at least a one week lead time in order to position 

the aircraft, instruments, and crew. 

One such asset is NASA’s ER–2 aircraft, which could be instrumented with the 

Cloud Physics Lidar (CPL) and Airborne Visible/Infrared Imaging Spectrometer 

(AVIRIS) in order to study atmospheric particles. In the future, NASA’s new highaltitude, long-endurance, heavy-lift Global Hawk unmanned aerial system might 

also be utilized for volcanic plume monitoring. The Global Hawk is still in its development phase, so rapid response use will be limited for the next few years as NASA 

gains operational experience with the Global Hawk and integrates new instruments 

onto the platform.

Conclusion 

As the Eyjafjallajo ̈kull eruption has shown, volcanic eruptions have a significant 

impact on the Earth’s atmosphere and the planes that travel through that airspace. 

Although NASA does not have an operational requirement to monitor and predict 

volcanic ash plumes, existing and planned NASA assets provide essential data on 

volcanic emissions that can be used by operational agencies around the world to determine if there are hazards to aircraft. NASA’s satellites and associated research 

programs have added significantly to our ability to observe not just the position of 

volcanic ash plumes, but to understand their composition, height, and properties. 

Through the NASA Applied Sciences Program, we can facilitate the use of the data 

collected by NASA’s research satellites in operational regimes. NASA researchers 

are developing and improving models that can be used to predict how volcanic ash 

plumes will propagate. While there are still areas for improvement, NASA’s Earth 

Science Division supports this work through new instruments and satellites and 

continued work in its Applied Sciences and Research Programs.

BIOGRAPHY FOR JACK KAYE

Jack Kaye currently serves as Associate Director for Research of the Earth 

Science Division (ESD) within NASA’s Science Mission Directorate (SMD). He has 

been a member of the Senior Executive Service since August, 1999, managing 

NASA’s Earth Science Research Program. Earlier positions in his more than 26 year 

career at NASA include being a Space Scientist at the Goddard Space Flight Center 

and Manager of the Atmospheric Chemistry Modeling and Analysis Program at 

NASA HQ. In addition, he has held temporary acting positions as Deputy Director 

of ESD and Deputy Chief Scientist for Earth Science within SMD. His academic 

training is in chemistry (B.S. Adelphi University, 1976; Ph.D., California Institute 

of Technology, 1982). He also held a post-doctoral research associateship at the U.S. 

Naval Research Laboratory. As Associate Director for Research, Dr. Kaye is responsible for the research and data analysis programs for Earth System Science, covering the broad spectrum of scientific disciplines that constitute it. 

He represents NASA in many interagency and international activities and has 

been an active participant in the U.S. Global Change Research Program (USGCRP) 

in which he has served for several years as NASA principal and Vice Chair of the 

Subcommittee on Global Change Research (since Jan. 20, 2009 he has served as the 

Acting Chair for these activities). He also serves as NASA’s representative to the 

Senior Users’ Advisory Group for the National Polar Orbiting Operational Environmental Satellite System and to the Joint Subcommittee on Ocean Science and Technology. He is a member of the Steering Committee for the Global Climate Observing 

System and is an ex officio member of the National Research Council’s Roundtable 

on Science and Technology for Sustainability. He has received numerous NASA 

awards (most recently, the Outstanding Leadership Medal in 2009), as well as been 

recognized as a Meritorious Executive in the Senior Executive Service in 2004. He 

was elected to serve as co-secretary of the Atmospheric Sciences Section of the 

American Geophysical Union (AGU) for 1998–2000 and earlier served on the AGU 

Publications Committee. The AGU has recognized him on two occasions with a Citation for Excellence in Refereeing. He has published more than 50 refereed papers, 

contributed to numerous reports, books, and encyclopedias, and edited the book Isotope Effects in Gas-Phase Chemistry for the American Chemical Society. In addition, 

he has attended the Leadership for Democratic Society program at the Federal Executive Institute and the Harvard Senior Managers in Government Program a the 

John F. Kennedy School of Government at Harvard University.

Chairwoman GIFFORDS. Thank you, Dr. Kaye. We appreciate 

your testimony. The volcano who normally goes unnamed, I appre-
26

ciate your courage in attempting to pronounce the name correctly. 

I appreciate that. Welcome. 

Ms. Cox, please. 

STATEMENT OF VICTORIA COX, SENIOR VICE PRESIDENT, 

NEXTGEN AND OPERATIONS PLANNING, AIR TRAFFIC ORGANIZATION, FEDERAL AVIATION ADMINISTRATION 

Ms. COX. Thank you, Chairwoman Giffords, Ranking Member 

Olson, members of the Subcommittee. Thank you for inviting me 

to testify today on mitigating the impact of volcanic ash clouds on 

aviation. 

The FAA has dealt with the issue of volcanic ash clouds before, 

both from a research and an operational perspective, and we are 

happy to share this information with the Subcommittee. 

Volcanic eruptions are not unusual. In fact, there is almost always an eruption somewhere in the world that may pose a hazard 

to international air navigation. What is rare are accidents and incidents resulting from encounters with volcanic ash. FAA’s voluntary 

reporting databases show only five encounters and 20 complications due to volcanic ash since 2007. When compared to the thousands of aviation operations taking place in the national airspace 

system every day, this is indeed a small number. 

The FAA’s primary method of dealing with volcanic ash events 

is operator avoidance. Since the geographical location of areas that 

may be affected by volcanic ash is weather dependent, our model 

of managing air traffic when confronted with volcanic ash is to 

treat it much like a major weather event. That is, we gather the 

information from the reporting agencies and disseminate that information to the operators of aircraft. In turn, the operator makes the 

decision of go or no go. If the operator chooses to fly, then our air 

traffic controllers will direct the operator around volcanic ash to 

the best of our abilities. 

Our past participation in volcanic ash research reflects this. Because the FAA is essentially a consumer of weather services that 

can help tell us where the volcanic ash will disperse, we have 

worked with the weather reporting agencies to develop weather 

products specifically for aviation use. 

The European response to last month’s volcanic eruption in Iceland was generally to close the airspace where volcanic ash could 

pose a threat to aviation safety. This may have been due to the 

constrained airspace over Europe that limited the possibility of reroutes as well as the need to coordinate the actions of the multiple 

civil aviation authorities in the various countries of the European 

Commission. 

After the shutdown of airspace, European regulators were faced 

with the challenge of reopening their airspace, and the FAA was 

able to lend its expertise to our counterparts in Europe. FAA air 

traffic personnel also participated in daily telephone conferences 

with the United Kingdom’s Civil Aviation Authority and the interdisciplinary group that they assembled. While we primarily offered 

information on our operator avoidance practices, we also helped to 

brainstorm operational solutions for reopening European airspace 

such as developing a collaborative volcanic ash forecasting process 
27

and developing pathfinder test flight traffic patterns between cities 

with low ash impact. 

I know that this Committee is interested in how the Next Generation Air Transportation System, NextGen, may affect our current model of operator avoidance when confronted with volcanic 

ash. Because the issue is really based upon receiving the best information, NextGen will enable an improved information-sharing 

process. NextGen focuses on how to best put information in a format that can be used by pilots, controllers and dispatchers, and integrated into decision support tools. 

Volcanic ash information is treated like significant weather information. Under NextGen, the NextGen Network Enabled Weather 

product enables the publication of the same weather information to 

all airspace users. The role of NOAA, the National Oceanic and Atmospheric Administration, is to provide quality data to all its users 

including data that meets the FAA’s air traffic control requirements. The FAA integrates the information provided by NOAA into 

tools expressly for air traffic management. NextGen will help improve the quality and delivery of information to the FAA and aviation users, enabling all of us to make better informed operational 

decisions when confronted with adverse conditions such as volcanic 

ash. 

Madam Chairwoman, Ranking Member Olson, members of the 

Subcommittee, this concludes my prepared remarks. Thank you 

again for inviting me here today to discuss the impact of volcanic 

ash on aviation operations. I would be happy to answer any questions you may have. 

[The prepared statement of Ms. Cox follows:]

PREPARED STATEMENT OF VICTORIA COX

Chairwoman Giffords, Ranking Member Olson, Members of the Subcommittee: 

Thank you for inviting me to testify before you today on mitigating the impact of 

volcanic ash clouds on aviation. The Federal Aviation Administration (FAA) has 

dealt with the issue of volcanic ash clouds before, both from a research and an operational perspective, and we are happy to share this information with this Subcommittee.

Effects of Volcanic Ash on Aircraft 

Volcanic ash is extremely damaging to aircraft. Should an aircraft encounter volcanic ash during flight, it could ingest the ash into the engines. If the volcanic ash 

passes through the turbine engines of an aircraft, the burner section can melt the 

ash, which then can deposit on the turbine’s nozzles as a hard glaze. This can negatively affect the engine’s operation and can result in a loss of power or total shutdown of the engine. When an engine loses power or shuts down due to turbine nozzle glazing, it will cool down rapidly. This can result in the fracturing of the volcanic 

ash glaze. Once the glazing breaks up and falls away, the engine may be able to 

resume normal operation. 

There are additional negative effects of volcanic ash on an aircraft turbine engine. 

These may include erosion of compressor blades and rotor-path components as well 

as turbine cooling passages, contamination of the oil system and bleed air system, 

and plugging of the engine’s inlet pitot static probes. These effects can cause severe 

and costly damage to an aircraft and its components.

FAA Volcanic Ash Response 

While the severe impact of a major volcanic event such as we saw in Europe last 

month is extremely unusual, volcanic eruptions are not unusual. There is almost always an eruption somewhere in the world that may pose a concern to international 

air navigation. In certain parts of the United States, such as Alaska, volcanic eruptions are enough of a possibility that the FAA has developed an operational response. 
28

FAA Orders 7900.5B and 7110.65T and JO 7930.2M Notice to Airmen (NOTAM) 

provide operational information regarding volcanic ash. The FAA’s primary method 

of dealing with volcanic ash events is operator avoidance. Since the geographical location of areas that may be affected by volcanic ash is weather-dependent, our 

model of managing air traffic when confronted with volcanic ash is to treat it much 

like a major weather event. That is, we gather the information from the reporting 

agencies and disseminate that information to the operators of aircraft. In turn, the 

operator makes the decision to fly or not. If the operator chooses to fly, then our 

air traffic controllers will direct the operator around the volcanic ash to the best of 

our abilities. 

As an additional safety precaution, on April 22, 2010, the FAA issued a Special 

Airworthiness Information Bulletin, NE–10–28, regarding turbine engine operation 

in volcanic ash airspace. The FAA noted that before flying from the United States 

to Europe or within Europe, aircraft owners and operators should review the following recommendations:

• Although the FAA does not recommend engine operation or flight into a visible volcanic ash cloud, we do recommend that aircraft owners and operators 

obtain definitive information on operational limitations around ash clouds, if 

any, from each of the European National Authority of the State(s), over which 

they plan flight operations.

• Follow all aircraft and engine manufacturer’s operating and maintenance instructions pertaining to operations in airspace where volcanic ash may be 

near or present.

• Report any inadvertent encounter with volcanic ash or relevant findings, including abnormal engine behavior, to the respective type certificate holders 

of the aircraft and engines.

FAA Past Volcanic Ash Research Efforts 

In the 1990s, the International Civil Aviation Organization (ICAO) established 

Volcanic Ash Advisory Centers (VAAC) that disseminate information worldwide on 

atmospheric volcanic ash clouds that may endanger aviation. There are nine VAACs 

located around the world run by local weather forecasting organizations. In the 

United States, the National Oceanic and Atmospheric Administration (NOAA) runs 

VAACs in Anchorage, Alaska and Washington, D.C. 

In the past, the FAA has participated with other Federal agencies on developing 

a national plan for dealing with volcanic ash with regard to aviation operations. 

Under the auspices of the Office of the Federal Coordinator for Meteorological Services and Supporting Research (OFCM), led by NOAA, the FAA helped develop the 

National Volcanic Ash Operations Plan for Aviation. 

Because the FAA is essentially a consumer of weather services, we work with the 

weather-reporting agencies to develop weather products specifically for aviation use. 

Our role in that partnership is to set the requirements of what the weather products 

must provide in order to be useful for aviation users, whether they are air traffic 

controllers or pilots. Accordingly, our participation in the OFCM project was primarily to set the requirements for the development of volcanic ash information products for the FAA and aviation operators to use. 

Aviation operations in volcanic ash situations rely on information based on detection and monitoring, alerting, modeling, and post event assessments. The U.S. Geological Survey (USGS) provides seismic monitoring for early detection and passes 

the information directly to the FAA to provide early warnings when an eruption is 

imminent or has occurred, which is especially important for en route aircraft. NOAA 

uses satellite monitoring as a core element in detection, tracking, and monitoring 

eruptions, and the resultant ash plume. Pilots also make observations, and the FAA 

disseminates pilot reports or PIREPS along with NOTAMs and Significant Meteorological Information (SIGMETs). SIGMETS originate from NOAA’s National Weather 

Service. 

Much of the capability to predict dispersion of volcanic ash clouds is based on 

mathematical modeling. The HY–SPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) model is the current model in use by NOAA and Australia’s Bureau of Meteorology and its Darwin VAAC. Other, similar, models are used by other 

VAACs. Post assessment is carried out by the USGS, NOAA and the Smithsonian 

to determine how we can improve the services provided to industry and the FAA’s 

air traffic management.
29

FAA Assistance in Response to Eyjafjallajokull Eruption 

The European response to last month’s volcanic eruption in Iceland was generally 

to close the airspace where volcanic ash could pose a threat to aviation safety. This 

was due in part to the constrained airspace over Europe and the need to coordinate 

the actions of the multiple civil aviation authorities of the various countries of the 

European Commission. 

After the shutdown of airspace, European regulators were faced with the challenge of reopening their airspace, and the FAA was able to lend its expertise to our 

counterparts in Europe. FAA air traffic personnel also participated in a daily telephone conference with the United Kingdom’s Civil Aviation Authority and the interdisciplinary group they assembled. While we primarily offered information on our 

operator avoidance practices, we also helped to brainstorm operational solutions for 

reopening European airspace such as developing a collaborative volcanic ash forecasting process and developing ‘‘pathfinder’’ test flight traffic patterns between cities 

with a low ash impact.

NextGen and Volcanic Ash 

I know that this Committee is interested in how the Next Generation Air Transportation System (NextGen) may affect our current model of operator avoidance 

when confronted with volcanic ash. Because the issue is really based upon receiving 

the best information, NextGen will enable an improved information sharing process. 

NextGen focuses on how to best put information in a format that can be used by 

pilots, controllers, and dispatchers and integrated into decision support tools. 

Volcanic ash information is treated like significant weather information. Under 

NextGen, the NextGen Network Enabled Weather (NNEW) product will enable the 

publication of the same weather information to all airspace users. NOAA’s role will 

be to provide quality data to all its users including data that meets the FAA’s air 

traffic control requirements. The FAA will integrate the information provided by 

NOAA into tools expressly for air traffic management. NextGen will help improve 

the quality and delivery of information to the FAA and aviation users, enabling all 

of us to make better informed operational decisions when confronted with adverse 

conditions such as volcanic ash. 

Madame Chairwoman, Ranking Member Olson, Members of the Subcommittee, 

this concludes my prepared remarks. Thank you again for inviting me here today 

to discuss the impact of volcanic ash on aviation operations. I would be happy to 

answer any questions that you may have.

BIOGRAPHY FOR VICTORIA COX

As the Air Traffic Organization’s Senior Vice President for NextGen and Operations Planning, Vicki Cox provides increased focus on the transformation of the nation’s air traffic control system by providing systems engineering, research and technology development, and test and evaluation expertise. She is also responsible for 

the NextGen portfolio and its integration and implementation. 

Within the FAA, Cox has served as the Director of the ATO’s Operations Planning 

International Office, the Director of Flight Services Finance and Planning and the 

Program Director of the Aviation Research Division. 
30

Prior to joining the FAA, Cox was Director of International Technology Programs 

in the Office of the Director of Defense Research and Engineering in the Office of 

the Secretary of Defense. She has an extensive research and development and program management background, having supported the Deputy Undersecretary of Defense for Science and Technology as the DOD Laboratory Liaison. She also worked 

as a Program Manager for a number of ballistic missile defense technology programs 

for the U.S. Air Force. A physicist, Cox served as Chief of Physics and Scientific 

Director of the European Office of Aerospace Research and Development in London. 

She also worked as a scientist responsible for thermal vacuum conditioning and 

testing of the Hubble Telescope for NASA. 

Cox graduated from Converse College and received a Master’s degree from East 

Carolina University. She has a certificate in U.S. National Security Policy from 

Georgetown University and is a DOD Level III Certified Acquisition Professional in 

Systems Planning, Research, Development and Engineering. She also earned her 

private pilot’s license in 1985.

Chairwoman GIFFORDS. Thank you, Ms. Cox. We are glad you 

are here with us. 

Captain Orlady. 

STATEMENT OF CAPTAIN LINDA M. ORLADY, EXECUTIVE AIR 

SAFETY VICE CHAIR, AIR LINE PILOTS ASSOCIATION, INTERNATIONAL 

Ms. ORLADY. Madam Chair, Ranking Member Olson, members of 

the Subcommittee, I am Captain Linda Orlady, Executive Air Safety Vice Chair of the Air Line Pilots Association International representing the safety interests of more than 53,000 professional pilots in the United States and Canada. On behalf of our members, 

I thank you for this opportunity to testify on volcanic ash and the 

risks it poses to aviation. 

Fifty-five to 60 volcanic eruptions annually worldwide and resulting ash and gases reach altitudes routinely traveled by the airlines. 

As vividly demonstrated during the recent Icelandic eruption, ash 

cloud can drift for days, weeks, contaminate large areas of airspace. 

Flying in volcanic ash and gases poses a significant but little understood threat to the integrity of aircraft, its engines and to the 

health of its occupants. 

Although no fatal airline accidents have been attributed to volcanic ash, damage to aircraft, potential damage to passengers and 

crew have been well documented. Two notable involved a British 

Airways 747 flight over Indonesia in 1982 and a KLM 747 flying 

over Alaska in 1989. Both of these aircraft lost power to all four 

engines during an inadvertent volcanic ash encounter. In each case, 

the pilots struggled to restart engines, handle other malfunctions 

and managed to safely land badly damaged aircraft. The encounters caused extensive damage to the engines, windshields and other 

aircraft systems. Documented volcanic ash encounters have revealed these vulnerabilities. Further study is required to fully understand our susceptibilities to volcanic ash and gas cloud contamination. 

Additionally, volcanic gases pose serious health hazards to aircraft crew and passengers including breathing difficulties, headaches, itchy eyes. Volcanic gases can produce an acrid odor which 

may mislead a flight crew into thinking they have an electrical 

problem or might mask the presence of an actual electrical problem. Volcanic ash cloud gases are not displayed on cockpit radar 

nor on radar at air traffic control. They are extremely difficult to 

detect at night. Pilots must rely on information from dispatchers, 
31

other pilots to determine the location of these hazards. Coordinating and standardizing this information is further complicated by 

the number of different entities who supply it. 

The recent Icelandic eruption demonstrated a lack of standardization between the various forecasts available to flight crews and 

dispatchers. As operations resumed in Europe, we received reports 

from pilots at different airlines who were given conflicting information in their dispatch release documents. In some cases, pilots had 

one depiction showing extensive air coverage while others showed 

nothing at all. While we have made progress in predicting where 

and when an eruption may occur, work must be done to improve 

forecasting and standardizing information about where and how an 

ash cloud will spread. 

The recent air travel disruption demonstrated the benefit of having data to reliably and objectively define a specific hazard area, 

potentially allowing flights into some regions. However, we did not 

have scientifically reliable data to make that determination. Arrays 

of potential hazards cannot currently be defined in terms that 

flight crews can use for dispatching while airborne. 

ALPA is encouraged the Senate version of the FAA reauthorization bill supports research on volcanic ash hazards. We urge Congress to enact this legislation. Without such research to improve 

the understanding of the hazards and ways to mitigate them, 

ALPA continues to advocate that the only safe course of action for 

flight crews is to avoid any encounter with volcanic ash. We need 

to determine if scientifically validated threshold levels developed 

with stakeholder participation can define an acceptable ash encounter. This determination must be based on rigorous, structured 

testing and produce reliable, scientifically quantifiable results. It 

will never be acceptable to hope for the best as we see how close 

we can fly to an ash cloud. 

To continue operating in areas where there is a risk of flight into 

volcanic ash, ALPA believes we need several improvements. First, 

onboard systems to detect ash clouds concentrated volcanic gases 

which allow pilots enough time to identify potential hazards and 

sufficient time to provide for safe navigation around them. Secondly, more vigorous aircraft certification standards. Thirdly, new 

procedures and training programs for flight crews, dispatchers, mechanics and air traffic controllers. 

As a rare but positive example, Alaska Airlines has developed 

volcanic ash training scenarios. They provide tools, techniques for 

both avoidance and recovery from inadvertent entry into volcanic 

ash and gas cloud conditions. Unfortunately, this type of comprehensive training is not universal for airlines operating in the vicinity of potential volcanic activity. 

Thank you for the opportunity to testify on this important topic. 

[The prepared statement of Captain Orlady follows:]

PREPARED STATEMENT OF LINDA ORLADY

Ms. Chairwoman and members of the Subcommittee, I am Captain Linda Orlady, 

Executive Air Safety Vice-Chair of the Air Line Pilots Association, International 

(‘‘ALPA’’) which represents the safety interest of over 53,000 professional pilots at 

38 airlines in the United States and Canada. On behalf of our members, I thank 

you for this opportunity to testify before you on the issue of volcanic ash and the 

risk it poses to aviation. 
32

There are 1,500 known volcanoes around the world, and 600 (40%) of them are 

currently listed as active. Collectively, there are 55 to 60 volcanic eruptions annually, and the ash and gases propelled from these eruptions reach altitudes that are 

routinely traveled by the airlines. Flying in the presence of volcanic ash and gases 

poses a significant, but unfortunately little understood threat to the integrity of an 

aircraft, its engines, and to the health of all occupants onboard. Adding to these 

threats is the disturbing fact that volcanic ash clouds and gases are not displayed 

on either radar installed in the aircraft or on radar used by air traffic controllers. 

Furthermore, volcanic ash and gas conditions are extremely difficult to identify at 

night. When trying to avoid drifting ash clouds or gases, pilots must rely on forecasts from dispatchers, reports from air traffic controllers, or feedback from other 

pilots flying in the area to determine the location of these potential hazards. The 

coordination and standardization of this information is further complicated by the 

number of different entities who supply information to airlines and their crews. 

The recent Icelandic eruption demonstrated quite clearly that there is a lack of 

standardization between the various forecasts available to flight crews and dispatchers. As operations resumed in Europe last week, we received several reports 

from crews at different airlines who were given conflicting information in their dispatch release documents. In some cases, crews had one depiction showing extensive 

ash coverage and yet another which showed nothing at all. 

Although there have been no fatal commercial airline accidents attributed to volcanic ash, the occurrence of damage to aircraft and potential dangers to the passengers and crew have been well documented. The two most notable incidents involved a British Airways 747–200 flight over Indonesia in 1982 and a KLM 747–

400 flying over Alaska in 1989. Both of these aircraft lost power to all four engines 

during an inadvertent volcanic ash encounter. In the case of the British Airways incident, all four engines lost power when the flight, operating in darkness, encountered a volcanic ash cloud invisible to them or the aircraft’s weather radar. The crew 

declared an emergency as the airplane descended to about 12,000 ft where they 

were beneath the ash cloud but near mountainous terrain. They were able to restart 

three of the four engines but lost power to one of the three remaining engines when 

they again encountered ash while attempting to remain clear of the mountains! The 

crew was finally able to safely land the crippled airplane with only two of the four 

engines operating and with badly scratched windshields that impaired their visibility. Similarly, in the case of the KLM incident, the crew was able to restart the 

engines and safely land a crippled airplane, averting the loss of human life and a 

catastrophic aviation event. In both cases, there was extensive damage to the airplane engines, windshields, and environmental control systems. Documented volcanic ash encounters such as these have revealed the known vulnerabilities in current aircraft systems; however, as aircraft are constructed and equipped with newer 

technologies such as sophisticated electronic systems, we will need to study and understand those susceptibilities to volcanic ash contamination. 

The flight safety risk associated with operations in the vicinity of volcanic ash 

clouds is not limited to just the vulnerability of the aircraft, engines, and the onboard systems. There is also a potential health hazard from the volcanic gases such 

as Sulfur Dioxide (SO2) or Hydrogen Sulfide (H2S). For example, SO2 can cause 

breathing difficulties if inhaled at significantly high concentration levels. H2S may 

cause headaches and itchy eyes. Indications that volcanic gases are present include 

an acrid odor similar to electrical smoke, which may mislead the crew into thinking 

they have an electrical problem and cause further distractions or, worse yet, mask 

the presence of an actual serious electrical problem. Prolonged exposure to H2S may 

dull the sense of smell causing the flight crew to believe erroneously that they are 

clear of the gaseous environment. 

Since the occurrence of the two near catastrophic events cited above, there has 

been an increased awareness in the airline community of the potential hazards of 

ash encounters. The improved availability of satellites coupled with technologies to 

transform satellite data into useful information along with improved coordination 

among international volcano monitoring facilities has helped to reduce the number 

of volcanic ash encounters worldwide. To date, ALPA along with the aviation industry has advocated for continued improvements in forecasting capabilities and dissemination of information to enable crews to safely avoid areas where there is a potential for a volcanic ash encounter. One outcome of this advocacy has been the creation of the Volcanic Ash Advisory Centers (VAAC), which is a network of nine facilities located worldwide. Each VAAC monitors the status of the active volcanoes 

within their assigned areas and disseminates information as needed to enable aircraft to safely avoid flying in hazardous volcanic ash conditions. ALPA continues to 

advocate for improved monitoring and forecasting capabilities but currently main-
33

tains the position, as is stated in the FAA Aeronautical Information Manual, to 

avoid any encounter with volcanic ash. 

As vividly demonstrated during the recent eruption of the Eyjafjallajo ̈kull Volcano 

in Iceland, an ash cloud can drift for several days, travel thousands of miles, and 

envelop large areas of airspace. And while we have made progress in predicting 

where and when an eruption may occur, as previously stated, there is still work 

needed in forecasting and standardizing the information on where and how the resulting ash cloud will spread. The seismic activities and events leading up to the 

Eyjafjallajo ̈kull eruption were well monitored by the London-based VAAC, and as 

a consequence, flight crews had ample awareness of the imminent hazard and the 

possible need to re-route their flights accordingly. Unfortunately, the resulting ash 

cloud was so widespread that re-routing flights around European airspace to avoid 

potentially hazardous areas was not a viable option. European regulators, to their 

credit, recognized that in the absence of data demonstrating that safe flight was 

possible, the prudent course of action was to cease operations in the interest of safety. The disruption in air travel service cost billions of dollars to the industry and 

extreme inconvenience to the traveling public. The conservative approach taken by 

authorities—to put safety ahead of economic considerations—ensured that no lives 

were lost. However, the extent of the impact on worldwide operations demonstrated 

clearly that the strategy of circumventing an area of ash and gas is not necessarily 

a practical solution. Just as clearly, the situation demonstrated the benefit of having 

data to make it possible to reliably and objectively define a specific hazard area, potentially making it possible for flights to operate in some regions. The dilemma is 

that currently we do not have scientifically reliable and valid data which tells us 

how that might be accomplished. The areas of potential hazard cannot currently be 

defined in terms that are useable to flight crews both for dispatch and for use while 

airborne. Furthermore, the nature of potential damage to airframes and engines is 

not well understood. ALPA agrees that action is warranted to address future disruptions in service, however, as the economic impacts are assessed and mitigation strategies considered, the safety risk of flight operations in the vicinity of volcanic ash 

clouds cannot be compromised. ALPA is encouraged that the Senate version of the 

current FAA reauthorization bill contains language supporting the importance of research into volcanic ash hazards as well as other weather phenomena, and we urge 

the Congress to continue efforts to enact this legislation. Without such research to 

improve understanding of the hazards and ways to mitigate them, ALPA continues 

to advocate that the only safe course of action is for flight crews to avoid any encounter with volcanic ash. 

If in the future, flight crews are allowed to fly in areas where there is a potential 

to encounter volcanic ash or gas concentrations, then any acceptable threshold established for safe operations within this environment must be based upon credible 

scientific data, analysis, and sound verification processes. New technologies will be 

needed to ensure all associated hazards within the allowable pre-established threshold are anticipated for and can be detected, measured, and safely mitigated by the 

flight crew prior to any encounter.

Anticipate the hazard: Better forecasting methods and information dissemination 

will be needed to enable crews to plan for and to implement, if necessary, safe exit 

strategies in the event of a volcanic ash encounter that exceeds the pre-determined 

limits of the airplane. As noted earlier, the current products available to flight crews 

vary widely in their interpretation of available data. These products must be standardized so that flight crews operating in an area, dispatchers on the ground, and 

air traffic controllers have a common understanding of where the threats areas may 

be and what mitigations may be possible. In addition, flight crew training programs 

must accommodate scenarios designed to help crews understand when volcanic effects are a potential hazard, how to recognize and cope with those effects, and how 

to develop effective exit strategies. This challenge is particularly true for carriers 

whose typical route structure involves flight in areas of known volcanic activity. 

Alaska Airlines, for example, has developed extensive classroom and scenario-based 

simulator training that provides crews with effective tools and techniques that can 

be used in the event of inadvertent airborne ash cloud exposure. In this training, 

pilots face a full range of hazards, both to the aircraft and to its occupants, and develop strategies for successfully recovering from such an emergency. More importantly, awareness of and simulated exposure to ash and gas clouds underscores the 

need for avoidance of these hazards. This type of comprehensive training, however, 

is not universal for airlines that may operate in the vicinity of volcanic activity. Detailed study of the effects of ash and gas on aircrews and airplanes must be undertaken and this information must be incorporated in training programs for crews operating in potential threat areas.
34

Detect & Measure the hazard: Currently, ATC and aircraft radars do not distinguish 

ash clouds from other weather related clouds. Crews may not realize they have entered a hazardous volcanic ash situation until they are already in it. By that time 

damage may have already occurred to the airplane engines and/or other flight systems. Forward looking systems are needed to detect an ash cloud and gases ahead 

of the airplane at sufficient distances to allow adequate time for the crew to safely 

divert around an unacceptable hazard. The forward looking system will also need 

to measure vital characteristics of the volcanic cloud, such as density and hazardous 

gas levels, to enable the crews to evaluate the hazard relative to pre-determined 

threshold levels and decide if it safe to proceed through an area of concern or to 

divert. Aircraft certification requirements will need to be updated to provide for 

more ruggedized aircraft health monitoring systems and management processes. 

Both flight and maintenance crews will need to know and act accordingly if an aircraft engine or other vital component has been damaged or has deteriorated at an 

accelerated rate that would compromise the continued safety of flight. Finally, we 

need to understand if any encounter with ash might be considered acceptable. This 

understanding must be based on rigorous, structured testing and produce reliable 

and scientifically quantifiable results. It will never be acceptable to simply see how 

close to an ash cloud we can fly and hope for the best.

Mitigate the hazard: Regarding the establishment of an acceptable threshold for 

flight near or into known volcanic ash or gaseous conditions, there are important 

and applicable lessons learned from the regulatory and operational experiences that 

have enabled allowable flight into known icing conditions. Extensive wind tunnel research, studies, and flight testing has been done over many years to assess and certify the safety of flight into icing. Though flight into known icing conditions is allowed and can be safely conducted under certain conditions and with specific aircraft anti-icing and de-icing equipment and appropriately trained crews, icing-related accidents and incidents still remain an important flight safety issue in the airline community. As we have learned with icing, mitigating the risk of flight into acceptable volcanic cloud conditions will not be a quick process but evolutionary as 

we learn more about the nature of the hazards. As testing, research, and development mature enough to establish initial acceptable threshold levels and to identify 

the required equipment changes, new procedures will also be needed.

Government and industry must work together to develop consistent regulatory 

and operational guidance and training plans to ensure the new technologies and information is properly transitioned to the primary users such as airline dispatchers, 

air traffic controllers, mechanics, and pilots. 

In conclusion, we have made good progress over the past several years in monitoring worldwide volcanic activity and alerting the affected aviation community of 

an imminent eruption. However once an eruption has occurred, there is still work 

needed to better forecast and standardize information so that hazards associated 

with drifting volcanic ash clouds and gases can be safely avoided in flight. ALPA 

currently maintains that flights into volcanic ash environments are to be completely 

avoided. There is a significant amount of research and coordination needed to fully 

understand the hazards, vulnerabilities, and mitigation strategies to ensure safety 

is not compromised before we would support the dispatch and operation of aircraft 

into areas of known volcanic ash, even with a pre-determined threshold level considered to be safe. 

Thank you again, for the opportunity to testify on this important subject.

BIOGRAPHY FOR LINDA ORLADY

Captain Linda Orlady presently holds two positions for the Air Line Pilots Association, International (ALPA). She was appointed as the Executive Air Safety ViceChair in January, 2009 and serves as the Safety Management System (SMS) Project 

Director. Captain Orlady is a member of the FAA SMS Focus Group and the Joint 

Planning and Development Office (JPDO) Safety Working Group. She was appointed 

by the FAA to serve as one of the tri-chairs for the FAA’s SMS ARC (aviation rulemaking committee). 

Captain Orlady has been involved in aviation and human factors for thirty years 

as author, researcher, instructor and lecturer. She helped organize the first International Symposium on Aviation Psychology in 1981 and later served as Technical 

Chair. She has been a NASA-sponsored researcher for Yale and Harvard University 

on a research project investigating crew complement, procedures and automation. 

With her late father, Harry Orlady, Linda co-authored a 600-page book, Human 

Factors in Multi-Crew Flight Operations, published by Ashgate Publications in 

1999. 
35

Captain Orlady is a third-generation pilot. She received her initial flight training 

at the Ohio State University while completing a Masters in Business Administration 

with concentration in organizational behavior and human factors. She flew for several corporations and for Henson and Comair Airlines in the early ’80s. She was 

hired by United Airlines as a line pilot in 1985 and has flown the Airbus A–319, 

A320, Boeing B–737, and B–747–400. Captain Orlady also worked in United’s Crew 

Resource Management Department and was the program manager. She presently 

flies domestic and international routes on the Boeing B–757 and B–767 out of Washington, DC. She also holds a commercial rotorcraft rating. 

Captain Orlady is the Chair of the Flight Safety Foundation Icarus Committee 

and serves on the Board of Governors for the Foundation. She also serves as a 

Trustee for the Vaughn College of Aeronautics and Technology in New York. 

Captain Orlady resides in Lothian, Maryland with her husband, John Cirino, and 

four dogs.

Chairwoman GIFFORDS. Thank you, Captain. 

Mr. Dinius. 

STATEMENT OF ROGER DINIUS, FLIGHT SAFETY DIRECTOR, 

GE AVIATION 

Mr. DINIUS. Madam Chair, members of the Subcommittee, I am 

Roger Dinius, Flight Safety Director for GE Aviation. Thank you 

for providing the opportunity to share these observations of the impact of volcanic ash on engines. 

In 1989, we supported the NTSB investigation of a KLM 747 

which experienced multi-engine power loss as a result of a severe 

volcanic ash encounter over Alaska. In this event, approximately 

one minute after the aircraft entered the dense volcanic ash cloud, 

power loss occurred. After exiting the volcanic ash cloud, the engines started and the aircraft landed safely. 

Volcanic ash impacts the engine in three significant ways. One 

is corrosion of the compressor blades plugging cooling holes. It also 

accumulates on hot parts, deposits on hot parts. This last failure 

mode is the least understood and the most impactful on engine operation. Ash melts as it passes through the combustor and deposits 

on turbine nozzles, which can lead to stalls and subsequent power 

losses. This is the KLM event. In the KLM event, ash accumulation 

on high-pressure turbines’ nozzles led to the engine stall and power 

loss. The rate of accumulation from a specific threat is unknown 

but likely a function of local volcanic ash concentrations, ash chemistry, engine design and engine power setting. Compressor erosion 

and plugged cooling nozzles or cooling holes are longer-term deterioration, leading to failure. 

In the days following the volcanic eruption in Iceland, GE issued 

communications to airlines, the procedures to inspect and maintain 

engines post-exposure to volcanic ash. GE participated in a series 

of international phone calls dealing with the volcanic ash crisis. We 

researched records, relevant data of the past. We freely shared this 

information on the safety matter with agencies, airframers and 

other engine companies. The three large engine manufacturers 

reached consensus with the FAA and CAA that a no-fly zone would 

be established based on a model that predicted volcanic ash concentration and visible volcanic ash. In addition, a volcanic ash advisory area with a lower predicted concentration was established. Operations in this advisory area outside the no-fly zone would be 

monitored to determine the impact to engine operation. We reached 
36

this consensus based on industry experience and engineering judgment. 

One quick example. A core engine on a 737-sized aircraft on hold 

at 20,000-feet altitude will ingest approximately one pack of Sweet 

and Low per minute. This seems like a low amount but this 

amount can accumulate as debris and cause engine failure, leading 

to premature engine failure. Industry practices have been to avoid 

volcanic ash. Such avoidance is made possible by worldwide weather services, air traffic control and proper flight planning. 

Volcanic ash is a flight safety hazard and can impact multiple 

engines on a given flight. Ash has caused failures within minutes 

after encounter. GE recommends avoiding flight into visible ash. If 

industry is not satisfied with avoidance as a solution, additional research into two areas is recommended to reduce risk. The first is 

volcanic ash prediction, validation of the models, and the second is 

to quantify the impact ash damage has on commercial engines 

through controlled experimentation. 

Thank you for the opportunity to discuss this with you. 

[The prepared statement of Mr. Dinius follows:]

PREPARED STATEMENT OF ROGER DINIUS

Madame Chair, Members of the Committee, I am Roger Dinius, Director, Aviation 

Safety for GE Aviation. Thank you for providing us this opportunity to present our 

views and observations to the Subcommittee today. 

GE aircraft engines and CFM International engines fly approximately 50 million 

flight hours per year worldwide. Every two seconds, a GE or CFM-powered airplane 

is taking off somewhere in the world. At any given moment, more than 2,200 of 

these aircraft are in flight, carrying between 50 and 300 passengers. That’s more 

than 300,000 people, right now, who are depending on our engines. 

In order to appreciate the potential hazard posed by volcanic ash on commercial 

aviation, and in particular on aviation gas turbine engines powering these aircraft, 

one has to have a basic understanding of how these engines operate. The modern 

turbofan engines that power today’s commercial airliners are complex machines that 

contain more than 10,000 individual parts. In today’s commercial aviation operations, the engine is expected to remain on the wing for 20,000 hours, or about five 

years. Therefore, the engines have to be very reliable while being capable of operating in all kinds of environments. 

Each commercial engine is certified to 14 CFR part 33. This regulation requires 

specific design characteristic, design analysis, and testing be completed and approved by the FAA prior to being certified for installation on a commercial aircraft. 

There are currently ingestion requirements for birds, ice, rain and hail, but no requirement for volcanic ash ingestion. Sand ingestion is no longer a certification requirement, since effects of sand ingestion are more of a longer-term maintenance 

issue and not a flight safety issue typically. Volcanic ash ingestion is not a certification requirement for commercial engines. Historically, engines have not been required to meet a specific volcanic ash threat as a result of the relatively infrequent 

encounters. 

Before I discuss GE Aviation’s experience with volcanic ash ingestion, a short lesson on engine technology is needed. A gas turbine engine is comprised of five basic 

sections: the fan, compressor, combustor, high-pressure turbine and low-pressure 

turbines. 

The fan brings in a large amount of air from the outside and pressurizes it. This 

is either exhausted directly to product thrust, the force that pushes an airplane 

through the air, or passes it to the compressor. The fan is typically made up of a 

single row of blades (airfoils—wings) to pressurize the air. 

The compressor takes the air from the fan and pressurizes it further. This compressed air is passed to the combustor. The compressor is typically made up of 9 

to 14 rows of blades (airfoils) to pressurize the air. Each one of these blade rows 

contains between 30–76 blades (airfoils). These compressor blades are aerodynamically shaped for efficient air pressurization. Additionally the compressor provides air for cooling hot metal parts in the turbine stages of the engine, enabling 

long reliable life. 
37

The combustor takes the air, mixes a portion of it with fuel and then burns it 

to increase the temperature of the air stream. Since the fire in the combustor is so 

hot, the remainder of the compressors supplied air is typically used to cool the metal 

liner of the combustor and first stage turbine nozzle and blades. Without this cooling the combustor liner would crack and subsequently lead to a rupture failure, and 

engine shutdown. 

The high-pressure turbine takes the hot high-pressure air from the combustor and 

takes work out of the air stream to drive the compressor. The high-pressure turbine 

is comprised of two main components: the turbine nozzles and turbine blades. The 

turbine nozzles set the area behind the combustor to maintain the pressure and 

turn the air to efficiently interact with the rotating turbine blades. The turbine nozzle section is a row of stationary vanes (airfoils). The turbine blades are typically 

one or two rows of airfoils that receive the discharged hot high-pressure air from 

the turbine nozzles and convert it to rotational force to turn the compressor. The 

turbine is like a waterwheel in operating concept, or a windmill. The high-pressure 

turbine operates at very high temperatures, in excess of 2500 degrees Fahrenheit. 

At these temperatures the base materials lose their strength properties, so in order 

to survive under these conditions and provide long reliable life, the blades and nozzles are cooled with un-burned compressor discharge air. 

The low-pressure turbine receives the air exhausted from the high-pressure turbine and takes work out of the air stream to drive the fan. The low-pressure turbine 

is comprised of both nozzles and blades similar to the high-pressure turbine, except 

the low-pressure turbine is typically not cooled or cooling is limited to structural 

frames and nozzles. 

For a jet engine to operate properly and produce continuous thrust, it is imperative that the air continuously flows from the fan section and proceed to exit the lowpressure turbine. When this continuous flow of air is disrupted in the compressor, 

the engine is said to ‘‘stall’’. To maintain the continuous flow of air it is important 

that the airfoils, both stationary and rotating, maintain their shape. 

With this understanding of the engine, we can now look at how and why volcanic 

ash poses a hazard to aviation. Volcanic ash can hazard an aircraft if the encounter 

is of high enough concentration and long enough duration. There have been a number of engine temporary power losses due to volcanic ash cloud encounters. GE’s 

first experience with volcanic ash came in 1989 when we supported the investigation 

after a KLM 747–400 experienced a multi-engine power loss while encountering severe volcanic ash. In this event, approximately a minute after the aircraft entered 

a dense volcanic ash cloud, a multi-engine power loss occurred. After exiting the volcanic ash cloud, the engines restarted and the aircraft landed safely. The volcanic 

ash damaged the engines, causing power loss as well as a permanent performance 

loss from the engines. It should be noted that while this is an extreme case, there 

are many cases of minor volcanic ash encounters that go unnoticed by the crew, but 

contribute to reduced engine on-wing life. 

Industry wide experience with the volcanic ash threat has been acceptable because when aircraft avoid volcanic ash clouds, the airborne hazards are mitigated. 

This is a result of worldwide weather services, Air Traffic Control, and proper flight 

planning. Volcanic ash advisories occur across the globe on a weekly basis. Operators respond to these advisories by avoiding the troublesome area. 

Volcanic ash damages engines and can lead to engine failure. The volcanic ash 

impacts the engine in at least three significant ways: erosion of compressor blades, 

plugging of cooling circuits, and accumulation on turbine nozzles. 

Of these three failure modes, the volcanic ash deposits on turbine nozzles is the 

least understood and most impactful on engine operation as a result of high concentrations of volcanic ash. Volcanic ash can melt as it passes though the combustor 

and is then deposited on turbine nozzles, leading to a reduction in flow area, making 

the compressor work harder and resulting in subsequent engine stall (loss of airflow 

and thrust). This failure mode was likely the most operationally disruptive on the 

KLM 747/CF6 event for which GE has detailed data. In this event, the ash accumulated on the high-pressure turbine nozzles in approximately one minute, which led 

to the engine stall. The rate of ash accumulation on turbine nozzles in a specified 

volcanic ash environment (estimated to be 2 grams per cubic meter in this event) 

is unknown and likely a function of volcanic ash density in the atmosphere, volcanic 

ash chemical make-up, engine design, and engine power setting. 

The next most impactful failure mode is airfoils erosion. Volcanic ash, like sand, 

erodes compressor blades, changing their shape. This change in shape reduces the 

efficiency of the airfoil and reduces its aerodynamic capability to maintain the airflow. Taken to the engines limit, erosion will lead to an engine stall (loss of airflow 

and thrust). Depending on the volcanic ash density in the environment and particle 
38

size of the volcanic ash encountered this can be more severe, from an erosion stand 

point, than a sand storm. 

The last of the most impactful failure modes is the disruption in airflow in the 

hot section cooling circuits. Long life of the turbine hardware is predicated on maintaining the temperatures within design limits. As volcanic ash passes through an 

engine it will find its way into the cooling circuits and deposit, which results in limiting, or loss of, cooling flow. This loss of cooling will lead to premature combustor, 

turbine blade and/or turbine nozzle failure. 

Additionally, volcanic ash contaminates oil systems, air conditioning systems, 

erodes flowpath hardware and piping, and deposits ash in the combustor. While 

these failure modes are real, and impact engine operation, they’re not typically the 

most significant failure modes from a time to failure standpoint when exposed to 

significant volcanic ash density. These are expected to be longer-term failure modes 

resulting from light to moderate levels of volcanic ash exposure. 

The week following the eruption of the Eyjafjallajokull volcano, GE provided support to our customers to minimize disruptions in service, and supported U.S. agencies and European agencies to establish safe guidelines for the resumption of operations in European airspace while volcanic ash may be present. 

On April 14, following the eruption of Eyjafjallajokull volcano, GE initiated efforts 

to ensure airlines had information to continue operations with a volcanic ash threat. 

The following day, we issued an update to all operators to inform airlines of procedures to inspect and maintain engines post-exposure to volcanic ash. Also on that 

day, the UK Civil Aviation Authority (CAA) suspended flight operation, due to volcanic ash in the environment. 

On April 16, we received an invitation from the FAA New England Regional Office to participate in an international teleconference to deal with the European volcanic ash issue. GE initiated efforts to understand past volcanic ash events with engines. On April 17 and 18, we supported additional international phone calls hosted 

by the UK CAA. 

Actual ash concentration predicted based on the UK National Weather Service 

(MET) office model for volcanic ash concentration was discussed and the group 

worked to establish an appropriate level to prevent a hazardous environment for 

civil flights. GE freely shared our knowledge, observations and experience on this 

potential safety matter with agencies, airframers and other engine companies (Pratt 

& Whitney, & Rolls-Royce). We researched records to gather relevant data on past 

volcanic ash encounters with engines. The UK CAA was acting on guidance within 

the International Civil Aviation Organization (ICAO) ‘‘Manual on Volcanic Ash, Radioactive Material, and Toxic Chemical Clouds’’ DOC 9691, which states in paragraph 3.4.8: ‘‘. . . the recommended procedure in the case of volcanic ash is . . . 

. regardless of ash concentration—AVOID AVOID AVOID’’. 

The group worked to understand the UK MET office model and its validation. The 

UK MET office initiated flights to support model validation. On April 19th, there 

were further phone calls to establish consensus on the concentration level of volcanic ash an engine could tolerate without causing a safety hazard. 

On April 20th, engine manufacturers (RR, P&W, & GE) reached consensus with 

FAA NE office that flights in volcanic ash would be acceptable up to volcanic ash 

concentration levels of up to 2milligrams per cubic meter and in absence of visible 

volcanic ash. Additionally the London Volcano Area Advisory Center IVAAC) would 

issue volcanic ash advisories for predicted concentration in excess of 0.2 milligrams 

per cubic meter. Operation in volcanic ash concentrations between 0.2 and 2 milligrams per cubic meter and clear of visible volcanic ash would be monitored to determine the long-term impact on engine operation. This consensus was based on industry experience and engineering judgment. 

GE continues to support regulating agencies and airlines with volcanic ash inquires, and mature sampling plans. In addition, GE issued All Operator Wires and 

Service Bulletins to socialize the agreement above and to provide guidance for operators on sampling plans to access longer-term engine impact. In summary, government and industry working together determined that the Volcanic Ash threat can 

be mitigated as long as aircraft avoid visible volcanic ash. 

Volcanic ash can pose a threat to safe aviation flights. It has caused engine failure 

within minutes of the encounter in severe volcanic ash cloud environments. Much 

work still needs to be done to understand the effects on aircraft gas turbine engines. 

The quantitative flight safety risk due to volcanic ash is dependent on a number 

of factors, some known and some unknown. These unknowns make establishing a 

quantitative limit on volcanic ash a challenge. GE provided and continues to provide 

support to our customers and regulatory agencies to maintain safe operation in light 

of the recent volcanic ash threat. The current best practice for abating the volcanic 

ash hazard is to avoid visible volcanic ash. GE supports further research to better 
39

define the volcanic ash threat and to establish working limits, that maintain safe 

environment for flight and provide meteorologists a metric to establish a forecast 

volcanic ash area to allow ATC and flight crews a known area to avoid. 

Thank you again for the opportunity to discuss this issue with you.

Chairwoman GIFFORDS. Thank you, Mr. Dinius, and thank you 

to all of our witnesses today. I honestly don’t think we could have 

assembled a more senior expertise and really diverse group of witnesses to an issue that is very important. And of course, what 

strikes me is, as Mr. Olson said in his opening comments, that 

really not since 9/11 have we had such a large disruption in air 

traffic. We have yet to have any fatalities or catastrophic incidents 

associated with volcanic ash but the possibility is great and our job 

here on the Subcommittee is to make sure that we are doing everything we can so that we have the research and the information to 

keep air travelers safe, to keep airlines running and to make sure 

that we can have the information also to explain it to passengers 

and to the general public as well. 

CHARACTERIZING THE RISK

We are going to begin our first round of questions, and the Chair 

will recognize herself for five minutes. 

I would like to begin with Captain Orlady. Speaking of expertise, 

she is a third-generation pilot, which is tremendous, and as I said 

when we had a chance to meet before the hearing, those of us who 

commute here to Washington every week feel like we have a very 

close relationship with all the pilots and we have a lot of trust in 

the FAA and other organizations that of course keep us safe as well 

as obviously the general public. But Captain, you indicated in your 

written statement that the dilemma is that currently we do not 

have scientifically reliable and valid data which tells us how we 

might—how that might be accomplished in terms of the need for 

research and development. So I was hoping that you could and 

then the other members as well, if you could talk about the research that you feel is needed to better understand when it is safe 

to fly through airspace that has been contaminated with volcanic 

ash and is there a way to characterize the risk of flying under such 

conditions? 

Ms. ORLADY. Thank you very much, Madam Chair, and I appreciate your business and the confidence you have in the air transportation system because we work hard and it is a process to keep 

working with that. 

There is not an acceptable level of contamination right now. Part 

of the dilemma I think is twofold. One, we don’t get—we do not receive, rather, good real-time data. There is data that is collected, 

and these folks, my fellow panel members can talk much more precisely about it than I can, but there are models that are interpreted. There are different models that are used. Even if they are 

using the same model, there are different interpretations that are 

used, and in fact, my husband made, I think, a good analogy last 

night when we were talking about this as I was driving through 

some DC. traffic and looking at a display. He said well, that is not 

real-time data so just go ahead and plow through even though it 

is red. We can’t do that up in the air. You know, if you don’t like 

it on the beltway, you pull over and park or something else perhaps 
40

but you can’t do that airborne. We cannot afford to take that risk 

so we don’t get good real-time data as well we don’t have a high 

level of confidence. It has gotten much better but in terms of the 

forecasting methods, in terms of are we all talking on the same 

terms, with agreement on the same terms and understanding as to 

what they mean. 

So I don’t mean to seem a little bit skeptical with that but at this 

point there is no acceptable level of contamination that we think 

we know enough about to accept. I wish we did, given how the economic problems that we had with, as my partner here suggested 

with the big E volcano because it was quite disastrous. 

Chairwoman GIFFORDS. And in terms of characterizing the risk 

of this, can you put it in layperson’s terms of—I mean, we have 

heard a lot of information, but as a pilot, with all of us in the 

cabin, I mean, how do you quantify that? 

Ms. ORLADY. This would not be that difficult. So you have your 

power plants, your engines. They potentially stop working. You become a glider. Your windshield can be very quickly eroded. In fact, 

one of the procedures I have seen from one of our member airlines 

mentions specifically if the windshields are eroded, consider diverting to an airport where an auto land can be made. This does not 

exactly make your day. Then you have what sort of things are you 

breathing, you know, in terms of this and how much do we really 

know about it in terms of the itchy eyes, in terms of breathing difficulties. There is nothing about this that sounds appealing. If it 

was just one item, one factor, maybe we would do that. Maybe we 

will have engines that will be able to withstand some of this. That 

would power plants, that would be good, but we have so many 

other issues and aircraft systems that are affected that we really 

do not understand. I think of all of the ramifications. We have a 

learning to do. But mostly for passengers and certainly for pilots, 

no interest in kind of going there. There are just too many things 

that kind of go wrong, and heaven forbid not being able to see out 

the windshield to land. 

Chairwoman GIFFORDS. Thank you. 

Would others care to comment? 

Mr. KAYE. I will just comment briefly then. In terms of one of 

the real challenges is both having the observations and the models. 

For NASA as a research organization, the satellites can overfly a 

particular volcano at a regular time based on durable mechanics. 

There are other satellites that NOAA as an operational agency and 

particularly has used geostationary satellites that do get enhanced 

temporal coverage, but you can only—for most of the satellites that 

we have, we can only overfly them in a certain time period but we 

can use models to help. We can initialize models and the data can 

help evaluate them and improve them for the future. 

Chairwoman GIFFORDS. Thank you. 

Mr. Olson. 

THE EUROPEAN RESPONSE

Mr. OLSON. Thank you, Madam Chairwoman. I don’t know if you 

all had an opportunity this morning to see there was an article in 

the Wall Street Journal this morning, and let me read the headline: ‘‘E.U. ministers to speed up talks on aviation rules,’’ and there 
41

was just one little paragraph here that I thought was pretty appropriate for what we are taking about today. ‘‘The 27 ministers also 

agreed that there is a need to urgently come up with limits as to 

how much ash is dangerous for the airplane engines,’’ and so sort 

of taking up on that and following up on some of the comments you 

made, Mrs. Cox, in your opening statement, how would you characterize—this is a question for all of you but how would you characterize the European Civil Aviation Authority’s response to the Icelandic volcano? I mean, was the breadth and duration of the shutdown a sensible approach based on sound science? Was it kind of 

a play-it-safe reaction because of a lack of scientific knowledge? 

And also, just sort of want comments on what was the impact of 

a balkanized air traffic control system here? 

Ms. COX. So I don’t want to second-guess the Europeans’ decision 

to close the airspace not having been there with the actual data 

that they were looking at. I will say that certainly the geographic 

layout of Europe probably contributed to their decision. In the 

United States, we largely handle volcanic ash by routing around it. 

Their particular situation probably prohibited their ability to do 

that. So that was a contribution. But certainly there is no known 

level of volcanic ash that is known to be safe to fly through. 

And as I mentioned in my testimony, the fact that there were 27 

civil aviation authorities who had to contribute to the decision 

probably contributed to the difficulty in once the decision was made 

in deciding what to do about resuming flight. 

Mr. OLSON. Captain Orlady, any comments? 

Ms. ORLADY. I agree with Ms. Cox. I am not sure—Europe has 

some different challenges that I think they handled very, very well 

most of the time but we handle things a little bit differently. We 

have a little bit more airspace here so it is difficult, you know, 

when one is going to the other and you want to be safe, but basically I agree with everything Ms. Cox has just said. 

Mr. OLSON. Any other panel members want to comment on that 

issue? Okay. We will take that as a big no. 

COORDINATING RESEARCH AMONG AGENCIES

All right. Dr. Kaye, the next question is for you then. This is 

about coordinating research among the Federal agencies. It appears that other operational agencies are heavily reliant on NASAprovided data to enable their own capabilities to characterize, 

measure and forecast volcanic ash cloud movements. To what degree are research efforts being coordinated among Federal agencies 

to develop future sensor and modeling products? 

Mr. KAYE. Well, there is an interagency coordinating effort carried out under the auspices of the Office of the Federal Coordinator 

for Meteorological Services and Supporting Research, so I think 

that deals with some of these kinds of things on a regular basis. 

In the longer term, there is any of a number of ways in which we 

will work together to help develop plans. Some of the things that 

we are trying to do at NASA, especially as we look towards the future and some of the future missions, those that have been identified by NRC and the decadal survey is to bring the users into the 

mix as early as possible so, for instance, one thing that we did this 

past February was hosted, we call it essentially an applications 
42

workshop between our Applied Science program and our Flight program so that we could have a way for those who would be potential 

users of the data that we would be able to provide with the next 

generation of satellites talking with us so we better understand 

what their needs are and the relationship between what we can 

provide and what they do need. So those kinds of conversations, especially for NASA, bringing people, potential users in at an early 

stage helps us understand and potentially tailor things where it 

makes sense. For instance, one of the—the HyspIRI mission, which 

is a SO2 decadal survey mission, some of the wavelength bands are 

specifically chosen to provide information on volcanic SO2. 

Mr. OLSON. Thank you very much. Just in closing, I would like 

to make a statement. I mean, it is pretty clear to me that we need 

to develop onboard equipment and a thorough communication network, so as Captain Orlady said, the pilots on board the traffic can 

get real-time information about any volcanic ash activity. I mean, 

the only thing that is going to be 100 percent safe is avoidance, and 

I was in the Navy, a P–3 pilot. As a young patrol plane commander, I made a mistake and we are coming home after an 8-hour 

mission about 4:00 in the morning, had some get-home-itis and we 

had a radar on board that wasn’t weather certified but guys kind 

of made guesses and they said we have got a thunderstorm here 

in front of us, Mr. Olson, it is about 10 miles wide. I am big and 

bad, I am a new patrol plane commander, all-weather aircraft, we 

will just punch it through, guys, rather than spend another 45 minutes going around it. We punched it through. We got through fine. 

The lightning bounced off the aircraft. That is very uncomfortable. 

You know you have gotten yourself in a position you shouldn’t be 

in, and, you know, I threw the people around on the aircraft for 

a good three, four minutes and that was completely unnecessary. 

And of course, when I got back to the ground and had to deal with 

11 crew members walking around, ‘‘Oh, Mr. Olson, my back, it’s so 

sore.’’

The point of it is, is we got to get them the information. If I had 

had the information and seen how dense that cloud was when we 

punched through it, I would have never done it. I would have gone 

around it and we would have been 100 percent safe. Same thing 

with volcanic ash. If we avoid it, if we get the air crews the information they need to that aircraft, they will make the right decision 

every time. 

Thank you, Madam Chairwoman. 

Chairwoman GIFFORDS. Thank you, Mr. Olson. 

We are going to hear now from Ms. Kosmas. 

THE USE OF SIMULATIONS FOR TRAINING

Ms. KOSMAS. Thank you, and thank you all for being here today. 

I happen to represent the central Florida area which has the National Center For Modeling and Simulation, which is in Orlando, 

and that develops the simulator tools that are used to increase 

skills, mostly in my area for the military at this current time but 

of course all of that information leads to simulation that helps us 

in nearly every scientific endeavor that we are working on these 

days. 
43

Captain Orlady, you had discussed the use of simulators by 

American Airlines in training their crews to provide them with advanced training in the event of ash cloud exposure, and so I was 

curious whether you or any of the other members could discuss the 

use of simulators for advanced training for crews in this type of situation and whether it can or should be incorporated into crew 

training universally? 

Ms. ORLADY. Thank you very much, and just for the record, it is 

Alaska Airlines rather than American that——

Ms. KOSMAS. Oh, I am sorry. 

Ms. ORLADY. —that had that, and as you might imagine, because 

they have the chance to—their exposure rate is quite a bit higher. 

I have talked to in fact a captain 2 days ago who had just been 

through some recurrent training, and recurrent training at the airlines, as you may know, will have different things every year. 

Wouldn’t you know this year they have some scenario for volcanic 

ash and inadvertent entry? Obviously this was planned well before 

Iceland decided to kind of get active so the timing is quite curious. 

It can be very effective in terms of putting you through the scenario and the checklists that we have and seeing how it works, and 

I am reminded from talking with him and your question, one of the 

symptoms also that I did not mention or potential consequences, all 

the avionics we have in today’s aircraft, the radios, navigation radios and particularly with the newer generation aircraft, they needed to be cooled just like our computers at home. They don’t get the 

cooling of the airports if you will, our cooling ports are blocked. 

They do not-desirable things. They blank and they just kind of disappear. So that isn’t very helpful. 

So it is very good with training scenarios. The high-fidelity simulators that we have do allow a high degree of realism. It is helpful 

to do it and it is good to go through it and I think it certainly sends 

home the message quite loudly that you do not want to be in this 

air and don’t try be a P–3 trying to get home kind of quickly so 

you can be done with it. It is just, you know, not worth it. So the 

simulations can be very good although the message at least for us 

right now is, you don’t want to get in this, it reinforces. Thank you. 

Ms. KOSMAS. Thank you. I appreciate that. 

Does anyone wish to comment on that particular question? Obviously the desire is not to be there but should the occasion come up 

where someone is, the ability to be prepared and to make the right 

kinds of decisions is helped, I think, by early training and simulation training. 

Thank you very much. 

Chairwoman GIFFORDS. Thank you, Ms. Kosmas. 

Mr. Rohrabacher. 

ENGINE DESIGN

Mr. ROHRABACHER. Thank you very much, and thank you, 

Madam Chairman, for calling this hearing. It is obviously of great 

interest to the overall public and to those of who travel every week 

on jet airplanes. I flew in last night. I would like to identify myself 

with the statement by Ranking Member Olson, who put this in perspective in terms of threats. What we have here is a threat that 

rarely is confronted, but when we do confront it, it becomes some-
44

thing of utmost importance because it could result in a tragic loss 

of life, and we hear this argument a lot on Near-Earth Objects. I 

mean, the chance of a meteorite hitting the earth, what is that. But 

of course if it does, it could kill hundreds of thousands if not millions of people, so these are the threats that we need to pay attention to. Unfortunately, and how that relates to our committee, is 

that research is skewed or at least directed towards threats that 

are a little bit more frequent than these threats that don’t happen 

very often, but when they do happen, they pose a great danger. 

Let me ask, is there any—first of all, Mr. Dinius, your Sweet and 

Low package, you are saying that that much debris in a jet engine 

could actually bring down a plane? 

Mr. DINIUS. Okay, so to clarify. No, sir, it will not. 

Mr. ROHRABACHER. Okay. 

Mr. DINIUS. That was just a particular example for a one-minute 

time. If that same kind of concentration were to be taken, for instance, from London to Paris and back on five trips a day, you are 

talking multiple pounds of contaminant that can get in the engine 

to either deposit on turbine blades, plug cooling holes and potentially lead to failure. 

Mr. ROHRABACHER. And right now is there any research efforts 

going on that would—with your company or that you know of in 

the Federal Government that is taking this threat into consideration in terms of jet engine design or is this something that is just 

not being addressed now? 

Mr. DINIUS. Sir, from a very obvious standpoint, contaminants in 

the engine and the small cooling holes in these parts, the reality 

is, we have to keep those clean for long life. We expect these engines to stay on wing for 20,000 hours, five years. Flying through 

this type of debris shortens the life of the engine, could lead to failure. It is a cumulative thing. You know, you fly through it——

Mr. ROHRABACHER. Do you know of any efforts or is there anyone 

looking at this and saying here would be an engine design that 

would be less susceptible to that? 

Mr. DINIUS. Not that I know of, sir. 

Mr. ROHRABACHER. Anybody else know of any research like that? 

Again, this might be one of those instances where because the 

threat is not frequent, that we are paying attention to other 

threats rather than this and it may be worthy of us looking into 

that. 

Mr. Olson’s experience in terms of cloud density, let me just ask, 

when we are talking about cloud density, Mr. Olson, that turbulence that you experienced, did that affect the engines of the plane 

or is it just the other dynamics of the plane? 

Mr. OLSON. It did not affect the engines on the aircraft. I mean, 

the big problem that I encountered that I didn’t appreciate was the 

fact that the equipment on board my aircraft wasn’t weather radar 

and it was an operator who could make guesses, and I took that 

as something, okay, we can punch through this and decided to 

punch it through, but it was not anything that damaged the aircraft. 

Mr. ROHRABACHER. So the research that we are talking about 

might—if there is a research and a scientific solution or something 

that would help might take in, for example, research into radar 
45

and that would then—or methodology of determining density of 

what people are flying into, the density of the air, the clouds, et 

cetera. What about materials research? Mr. Dinius or anyone else 

who would have this, is there something that we could do in terms 

of the materials that engines are made out of or is this simply the 

design of those engines? 

Mr. DINIUS. I am not aware of any material work that could be 

done to avoid this at this point. 

Mr. ROHRABACHER. Any other thought on that? This is a materials issue then, it is an actual design issue. Well, thank you very 

much for your testimony. 

Madam Chairman, again, thank you for putting together an expert panel for us to enlighten us on this issue, and I have gotten 

a lot out of this. Thank you. 

Chairwoman GIFFORDS. Thank you, Mr. Rohrabacher. 

Now we are going to hear from Ms. Edwards. 

EUROPEAN CONSULTATIONS

Ms. EDWARDS. Thank you, Madam Chairwoman, and I will tell 

you, for weeks I have been dying to say, what is it, Eyjafjallajo ̈kull 

or something. 

My question actually, Mr. Dinius, goes to you. Was GE Aviation 

consulted by the Europeans before resuming flights, and was 

NASA’s DC–8 experience taken into consideration in that consultation? 

Mr. DINIUS. So yes, we were invited to participate in a series of 

teleconferences with the FAA and the CAA over the weekend that 

followed the eruption in Iceland. We took into consideration the 

data we knew of, the DC–8 NASA, we knew of that one. There are 

other events that we have data from. It should be pointed out that 

the DC–8 event NASA had was not an engine failure, it was an 

economic impact but not an engine failure. 

DETECTING CONTAMINANTS

Ms. EDWARDS. And I guess I am curious, on the ground like in 

testing engines, because you have to do some kind of cost-benefit 

analysis, I mean, it is not as though aircraft are flying through volcanic ash all the time, although it is significant. How do you actually—how would you design and test an engine for whatever level 

of volcanic ash would be acceptable? 

Mr. DINIUS. Ma’am, there is no certification requirements today 

for sand and dust or volcanic ash. However, you could run engineering tests or you can control the level of contaminants that are 

put in the engine and then see how the engine responds as well 

as look at the engine afterwards to see its condition, its health. 

Ms. EDWARDS. And over time, you could have a number of given 

contaminants that might impact an engine or other aircraft parts 

so you might know on a first run, for example, on one flight it 

might be sand, depending on where that flight is going. On another 

flight it might be volcanic ash. I think what the discussion hasn’t 

come to is, what combination of those things, even if it is not one 

or the other, is there a combination of those kind of environmental 

materials that really could contribute to engine failure and meas-
46

uring one and not the combination might not tell you very much 

about whether the aircraft could travel safely? 

Mr. DINIUS. So the chemical constituents inside the volcanic ash 

make a difference on the failure modes. The melting point of the 

contaminant, the volcanic ash, make a difference. If it doesn’t melt, 

it is not going to stick to the turbine blades. It may erode them but 

it won’t stick to them. So that is a different failure mode than your 

classic sand and dust. We have good history with sand and dust. 

We understand how blades erode. With volcanic ash, the data is 

fairly sparse. 

HUMAN FACTOR

Ms. EDWARDS. And Captain Orlady, one of the things that you 

pointed to was the fact that, you know, so for example, with volcanic ash, for one pilot it might result in itchy eyes, for another it 

might result in not being able to see out of a windshield where 

some other pilot actually might be able to see out of that windshield but wouldn’t have itchy eyes, so there are a whole number 

of human factors that one couldn’t possibly account for. I guess 

what I am getting to is that when the question becomes do you 

shut down an entire system or not, I think it is very hard to measure the point of your testimony that you get to which is do you 

really want to take that chance. I mean, it is a huge economic cost 

but it may be better to shut down the system because you could 

never really account for the factor or other human or mechanical 

that could contribute to a failed flight. 

Ms. ORLADY. I think that is an accurate perception. It really is 

a multi-pronged problem. The questions that were asked of Mr. 

Dinius about the engine, perhaps——

Chairwoman GIFFORDS. Captain, your microphone. 

Ms. ORLADY. I pushed it. We will put it closer. But it is a multiprolonged problem because let us say we determine something with 

the engines and maybe we do—but that just doesn’t solve the avionics that still need to be cooled. It still doesn’t solve the windshield that if I can’t see out of, even if I don’t have breathing difficulties and itchy eyes, if I can’t see out of it, then it doesn’t make 

much difference. So I wish I was more optimistic but I think your 

description is correct in terms of looking at the severity, potential 

severity and consequences. We don’t have much choice until we get 

better data at this point. 

Ms. EDWARDS. Thank you, Madam Chairwoman. 

Chairwoman GIFFORDS. Thank you, Ms. Edwards. 

We are going to have a second round. We have got a couple of 

follow-up questions that would like the panel to answer. Following 

up on Mrs. Edwards’ point about the DC–8, with us in the audience 

we have Mr. Thomas Grindle, who is a propulsion engineer, and I 

was hoping that he could come up to answer a couple of questions. 

Thank you, Mr. Grindle. 

NASA DC–8 EXPERIENCE

A report that you wrote indicates the pilots did not notice anything out of the ordinary after flying through volcanic ash clouds. 

After landing, could you talk about what parts of the aircraft that 
47

you did look at and did any other aircraft besides yours go through 

the same areas and did they also reach similar no-problem conclusions? 

Mr. GRINDLE. Thank you, Madam Chairwoman. Yes, once we—

the scientists on board were the ones that alerted the flight crew 

that we were currently flying a diffuse ash cloud from the Hekla 

volcano. The pilots noticed no onboard indications whatsoever. Engine parameters were normal. No smells in the cockpit. Because it 

was night, we looked for the St. Elmo’s fire. No indications whatsoever. The scientists were the only ones because of their instrumentation on board to notice that we were flying through the cloud. 

The incident lasted for about seven minutes, and the aircraft continued on to Sweden. 

Once there, they contacted us back at NASA Dryden and asked 

about, you know, what they should and we recommended to do a 

complete visual inspection on all the leading surfaces of the airplane, the windshield, the leading edges, to look at the engine fan 

blades, engine cowls, anything that could have had any abrasive 

damage or anything. They performed those inspections, found no 

damage whatsoever. Our recommendation from Edwards was to 

then replace the air conditioning filters and the engine oil on all 

four engines and hold samples for us for once they returned back 

to NASA Dryden. They flew for about 68 hours in Sweden doing 

other atmospheric research missions and returned back to Dryden 

where we were able to do a complete engine borescope on all four 

engines and there we noticed some clogged cooling holes and abraded leading edges on the turbine section. We removed one of the 

engines, which was getting close to an overhaul maintenance requirement, and sent it to the engine manufacturer in Strother, 

Kansas. They tore it down and found more damage inside. We then 

removed the other three engines and sent them to the same manufacturer as well, and upon those teardowns they found more of the 

same contaminations inside and the same damage listed in all four 

engines. 

Chairwoman GIFFORDS. Mr. Grindle, can you talk about the lessons learned from this experience? What are the key take-aways 

for us that we should be focusing on, and in your view, from all 

the knowledge and information that you have gathered, are these 

lessons actually being applied today? 

Mr. GRINDLE. I can only speak about the DC–8 incident which 

we had, and prior to us leaving Edwards we knew about the eruption and so we purposely made our course as far north as possible, 

and in fact on the way over we added another 200 miles, so I think 

our total distance from the volcano was almost 800 miles, and at 

the altitude and the latest information we had gotten from the 

London Volcanic Ash Advisory Center, we were well north of any 

kind of ash cloud whatsoever, and upon the engine teardown and 

the scientific data evaluation, some of the particles we flew through 

were less than one micron in diameter, and even at those limits, 

we didn’t experience any engine parameter failures or any indications whatsoever but the engine manufacturer who did the work 

specified that we probably would have started seeing performance 

degradation in some of the engines in as little as 100 flight-hours 

because of the loss of cooling and other things. 
48

And as far as I know, we were the only aircraft to fly in that 

area through the ash cloud, and once we did realize we were in it, 

we updated the London center and told them that we had experienced it in that area and they were able to update their predictions 

in those areas as well. 

Chairwoman GIFFORDS. Thank you. 

Mr. GRINDLE. Thank you. 

DETECTION SYSTEMS

Chairwoman GIFFORDS. I have a follow-up question for either Dr. 

Strazisar or Dr. Kaye, and this builds on Mr. Olson’s comments 

about having an onboard display. How far away are we technologically speaking or even from an implementation standpoint from 

a cost perspective for an onboard volcanic ash-type detection system that ALPA was talking about in terms of really giving the pilots the information that they need? I am curious, I mean, do we 

know how to build them and do we know when we will have them? 

Mr. STRAZISAR. We are in our aviation safety program working 

constantly on instrumentation that is forward looking, primarily to 

provide better indications of weather because convective weather is 

actually on a probability basis a much greater problem than volcanic eruptions. Some of those forward-looking systems have the 

potential to detect ash but that is not their primary purpose. So we 

are continuing to do research on constantly improved instrumentation. We will keep our eyes open in the future for any technologies 

that would have a side benefit of being able to also detect ash, but 

we are not working currently on any system specifically to detect 

ash. 

Chairwoman GIFFORDS. Ms. Cox or Mr. Dinius or Dr. Kaye, any 

additional—because Captain Orlady is looking a little nervous, so 

maybe wants some reassurance that we are working on this technology. 

Ms. COX. I can comment on some of the work the FAA is investing in with our NextGen research and our NextGen programs. 

While we are not focusing on onboard sensors on aircraft, we are 

focusing on delivering better information to the pilot, to the controllers, to the airline dispatchers so that they would all have the same 

information in real time that they could use to make better decisions collaboratively about how to proceed in these conditions. Reports—there was a very good report done by NOAA after the 

Mount Redoubt eruption in 2009. It was just published this January, actually. And they published best practices and findings and 

recommendations. Overall, one of the best practices was web-based 

communications that they had during the Mount Redoubt eruption. 

Findings and recommendations focused in large part around better 

communication and better collaboration, so this is where our focus 

is. 

Chairwoman GIFFORDS. Anyone else? 

Mr. KAYE. I think what I will have to do is to take an action to 

try to get additional information and report back, especially as to 

what precisely the sensors were that were aboard the DC–8. I don’t 

know if we know exactly what they were doing that provided us 

some information, whether they were in situ measurements that 

actually made air sampling in the vicinity of the aircraft or remote 
49

sensing kinds of things. It is an answerable question. I just don’t 

have that. If it is in situ, of course, then that becomes an issue because then you essential have to have a detector which if that involves cutting a hole in the plane, that is a whole separate set of 

issues for that, and if it is a remote sensing thing, then you have 

to find out, you know, radar is—for very small aerosol particles, radars typically don’t work. That is the way we do a lot of optical 

wavelengths and LIDARs, but I will have to get back to our people 

and find out specifically what the instrumentation was that detected that and then see whether that is something that potentially 

would be applicable or not. 

Chairwoman GIFFORDS. We would appreciate that, Dr. Kaye, if 

you could report back to the Subcommittee. Obviously we are interested. This is a timely hearing, and you know, the general public 

is also very interested. You know, we hadn’t focused on this for 

many years but with this eruption certainly it was all on our radar 

screens. 

Mr. Olson, do you have any follow-up questions? 

Mr. OLSON. Two more questions. Home stretch. 

FUTURE REMOTE SENSING

The first one is for you, Dr. Kaye. You outlined a number of instruments found on orbital NASA research satellites that have 

been key towards helping understand the composition physics of 

volcanic plumes. What is the future of doing these kinds of capabilities from space related to what is the likelihood that NOAA or 

the USGS will be able to absorb these capabilities into their own 

operational systems? 

Mr. KAYE. A number of the sensors that we have and the satellites that we have are past their—what we call their prime life 

period. They are in extended operations. But thanks to good engineering, we can nurture these things for quite a while, the satellites, for a very long period of time. There is some evolution that 

is planned, future satellites that we have planned, the Glory satellite, which is specifically designed to measure aerosols using 

polar metric technique, so that will add significantly to our body 

of knowledge because those observations will help provide information not just about aerosol presence, where something is, but what 

something is, which is very important as well, especially for 

initializing models. 

For including a lot of the optical infrared observations that are 

done through our modus instrument, the NPP mission, we will do 

the launch in 2011, we will continue those, and that is a precursor 

to the Joint Polar Satellite System, which will provide enhanced 

operational capability into the future. 

There are some other things that we do that there is no sort of 

near-term plans but people look at in the long term. We use multiangle viewing with the MISR instrument that looks in nine different directions and helps provide information about altitude, composition. One of our decadal survey missions, the ACE mission 

would use multiple-angle techniques but that one is further out 

into the future, and one of the neat things that we have right now 

is the Calypso. It is a LIDAR-based measurement which can get 

very accurate and very precise information about thin layers. It 
50

looks straight down but it is an optical equivalent of radar so you 

can see very thin layers and know precisely what altitude they are 

at. That has been flying since 2006, and we don’t have—the next 

LIDAR I think that we will be looking at for aerosol purposes 

would be also the ACE mission, which is one of the DOD decadal 

survey missions. 

One thing I can say is that for a lot of these things we don’t have 

to go it alone. There is a good record of data sharing with our international partners to the extent that the Europeans will do things 

or the Japanese will do something, the Europeans in particular I 

think are looking at LIDAR missions. So we will have some opportunities there. 

You mentioned U.S. Geological Survey. I haven’t talked about 

them. They have the primary responsibility for surface-based measurements, especially about what is going on and at the surface of 

volcanoes, so that is a different kind of thing than what we normally do. We work with them on land cover observations as well 

and that is a good relationship. 

PRIORITIES

Mr. OLSON. Thank you very much. One last question, and I don’t 

mean to put words in your mouth but given the constrained spending environment we are dealing with up here, if we had to 

prioritize our efforts going forward, what do you believe makes the 

most sense? And I think the group, if I could summarize, and if you 

disagree with this, please hit the button and chime in. But I think 

the first priority should be developing technology both on board 

and within the aircraft tracking system, get real-time information 

to the pilots as these volcanic plumes developed. The second priority should be develop a better understanding of engine performance and degradation, and the third priority should be trying to 

harden the engines and make them where they can fly through 

things that they probably can’t fly through now. And again, to me 

that seems to be the consensus here of our priorities going forward 

with our limited dollars. If anybody has a disagreement with that, 

I would certainly like to hear it. All right. Amen. Thank you very 

much. 

Chairwoman GIFFORDS. Thank you, Mr. Olson. Before we bring 

this hearing to a close, I want to thank all of our witnesses for 

being here. We have just scratched the surface today. The Subcommittee hearing is timely. Obviously your expertise is an asset 

and a real value to the Congress, to the American people and to 

the international community as well. So we look forward to any additional information that you would have for us, updates of course 

we would welcome, and thank you for taking time out of your busy 

schedules to be here, and Mr. Grindle as well, thank you for coming in from California. We very much appreciate all that you do to 

keep our skies safe. We sincerely appreciate it. And again, as mentioned many times, this is an unusual incident but the potential of 

catastrophic loss of life and risk to the airline industry is great, so 

we appreciate particularly Captain Orlady. Again, I think because 

all of us commute so much, we really feel like we have a personal 

relationship with all of our pilots, so appreciate everything you do 

on behalf of all of our airline pilots and of course all the flight at-
51

tendants and everyone who we, you know, spend a lot of our time 

with as well. 

The record will remain open for two weeks, so if there are any 

additional statements from members and any answers to any of the 

questions that we would like our witnesses to follow up on, please 

submit that for the record. 

The witnesses are excused and the hearing is now adjourned. 

Thank you again. 

[Whereupon, at 11:23 a.m., the Subcommittee was adjourned.] 

(53)

Appendix: 

ANSWERS TO POST-HEARING QUESTIONS
54

ANSWERS TO POST-HEARING QUESTIONS

Responses by Dr. Tony Strazisar, Senior Technical Advisor, Aeronautics Research 

Mission Directorate, National Aeronautics and Space Administration

Questions submitted by Chairwoman Gabrielle Giffords

Q1. It is clear that from the difficulties European aviation regulators experienced 

while deciding when to reopen airspace, some fundamental data was missing. 

Yet, the negative impact of flying into volcanic ash clouds has been demonstrated. And, thanks to NASA, we have been warned that engines may not 

show signs of damage until after 100 flying hours. So why do you think there 

hasn’t been greater focus on this area by the world’s aeronautics research community? What research needs to be performed?

A1. We believe there has not been greater focus on the issue of commercial aircraft 

operations in and around volcanic ash clouds because an event such as the recent 

eruption in Iceland is rare. Hazardous weather conditions such as convective weather (thunderstorms) and icing pose daily disruptions to commercial air traffic around 

the world. As a result, the aviation community has focused research and development efforts on the development of capabilities such as airborne and ground weather radar, air traffic re-routing procedures, and aircraft icing protection systems. Satellite assets are capable of detecting volcanic ash clouds, but the dispersion of the 

cloud and the concentration of ash are difficult to accurately predict with current 

weather modeling capability. Research leading to improved prediction of ash cloud 

extent and ash concentration within the cloud would enable more accurate air traffic 

re-routing to avoid flying into airspace in which ash concentrations are unacceptable.

Q2. What technology is needed such that aircraft can have onboard warning of volcanic ash conditions? What research is needed to develop and demonstrate that 

technology? Who should perform such research?

A2. Technologies capable of detecting small-diameter particles suspended in the atmosphere are required if onboard indication of volcanic ash conditions is desired. Although techniques such as Cloud Physics Lidar and Visible Infrared Imaging Spectrometry are available for NASA research aircraft, it would be prohibitively expensive to equip the commercial aircraft fleet with such capability. NASA continues to 

develop capability for airborne forward-looking sensing of atmospheric hazards. This 

research is looking across a suite of state-of-the-art sensing technologies that have 

potential to detect various hazards types, which could include volcanic ash. Improvements in technologies such as LiDAR (Light Detection and Ranging), FLI (ForwardLooking Interferometry), and X-band radar hold potential for detecting volcanic ash 

and aiding pilots to determine the safety of flight through volcanic ash areas. Current NASA aviation safety research on LiDAR seeks, encourages, and emphasizes 

the ability to detect multiple hazards (which to date have primarily included icing, 

wake turbulence, and limited visibility). Some current research, such as the forward-looking interferometer research, has looked at volcanic ash detection capability. NASA will continue to support the development of sensing technology capable 

of detecting multiple hazards, including volcanic ash. This month EasyJet airlines 

announced plans to test a system consisting of two infrared sensors carried in a 

plane’s tail fin http://www.guardian.co.uk/world/2010/jun/04/easvjet-volcanicash-radar. The system, developed by the Norwegian Institute for Air Research, has 

the potential to detect volcanic ash particles up to 62 miles ahead of a plane’s flight 

path. 

As an alternative to onboard ash detection, research leading to improved forecasting of plume location and ash concentration would be beneficial. Improved 

plume prediction models would enable the Volcanic Ash Advisory Centers (VAAC) 

to pass more accurate information through the aviation advisory capability of the 

aeronautical fixed services operated by the Federal Aviation Administration so that 

plume location information could be used for flight planning for plume avoidance. 

The NASA Science Mission Directorate testimony outlined several improved modeling activities.

Q3. It is probably impractical and uneconomical to design a jet engine that can 

withstand all volcanic ash conditions. From what we know about aircraft engines, aviation safety, and the economics of the airline industry, what is the best 

that we can expect from future engine technology improvements?
55

A3. The most immediate effect on a modern aircraft engine of ingesting volcanic ash 

is the melting of the ash in the hot section of the engine. The ash then forms glassy 

deposits that alter the airflow through the turbine blades downstream of the combustor. Continued buildup of these deposits can restrict airflow through the engine 

and cause the engine to stall. In several well-publicized incidents, engine stall has 

occurred in a matter of minutes after passing through severe concentrations of ash. 

In addition, volcanic ash can clog the cooling holes and damage the thermal barrier 

coatings which are used to protect the turbine blades from combustor exhaust temperatures that exceed the melting point of an unprotected blade. This reduced thermal protection can over a longer period of time reduce the remaining safe life of the 

turbine components. To increase cycle efficiency and reduce fuel bum, future engine 

technology is pushing toward ever-increasing combustor exit temperatures, which 

will only exacerbate the problems caused by melting ash and reduced cooling system 

performance. There is current research on adaptive engine technology being performed under the DOD Versatile Affordable Advanced Turbine Engine (VAATE) initiative. This research is developing technology to enable gas turbine engines to alter 

their operating mode to adapt to varying mission requirements. Once these technologies are demonstrated for military applications they may find their way into 

commercial applications and could enable an engine to re-configure its operating 

conditions in response to the accumulation of ash deposits and a reduction of cooling 

flows to turbine components. This technology is several years away from reaching 

a maturity level at which it could be included in new commercial aircraft engine 

designs.

Q4. Captain Orlady indicated in her statement that Alaskan Airlines has developed 

extensive classroom and scenario-based simulator training that provides crews 

with effective tools and techniques that can be used in the event of inadvertent 

airborne ash cloud exposure. Considering NASA’s unique expertise in human 

factors in aviation, is there value in more focused research on developing technologies that can simulate volcanic ash conditions to pilots and crew?

A4. There is value in educating pilots and crew in proper procedures to follow in 

the event that an unintended encounter with a volcanic ash cloud impacts engine 

performance. However, it is not clear that any additional research on simulating ash 

conditions is required. In the late 1980s and early 1990s, research on the effects of 

dust ingestion on gas turbine engine performance was led by Dr. Michael Dunn at 

the Caispan Corporation in Buffalo, N.Y. Dr. Dunn is currently at Ohio State University. Dr. Dunn used volcanic ash as a source of dust during those investigations. 

In the course of that research, Dr. Dunn discovered that glassy deposits of volcanic 

ash that accumulated on the surface of turbine blades could be cleared by reducing 

engine power to idle and then returning to a cruise throttle setting. During the brief 

return to idle the turbine blades cooled and shrank slightly, causing the glassy ash 

deposits to break off. This finding was incorporated in a flight crew briefing video 

created by the Boeing Company in 1992, Volcanic ash avoidance—flight crew briefing: Boeing Commercial Airplane Group, Customer Training and Flight Operations 

Support, which is available as Video 4V703 from the International Civil Aviation 

Organization (ICAO). The video discusses what pilots and airline dispatchers can do 

to avoid volcanic eruption clouds, and the recommended steps a pilot should take 

in the event of an unexpected encounter. This training video also shows how volcanic ash can affect jet aircraft and provides a pilot’s first-hand account of an incident in which a Boeing 747 encountered an eruption cloud and temporarily lost 

power in all four engines. ICAO provides translations of the video into French, Russian, and Spanish. Presently, neither that video nor other volcanic-ash information 

developed by airframe and engine manufacturers is mandated for inclusion in training material for pilots. http://volcanoes.usgs.gov/ash/trans/aviation¥threat.html

Q5. To what extent are Federal research programs on aircraft flying though volcanic 

ash coordinated, and how easy or difficult is it to share the research results with 

relevant stakeholders? What about coordination with non-U.S. research programs?

A5. Federal agencies including the Federal Aviation Administration (FAA), NASA, 

the National Oceanic and Atmospheric Administration, the National Weather Service, and the National Satellite, Data, and Information Service are working to improve the state-of-the-art of the global transport models needed to accurately predict 

volcanic ash plume location and dispersion. 

Information has been shared through two international forums to date—one in Seattle, Washington in 1991 and a second in Alexandria, Virginia in 2004. 

The International Civil Aviation Organization (ICAO) continues to advocate increased scientific understanding of ash cloud dynamics. In May 2010 ICAO called 
56

for establishment of the International Volcanic Ash Task Force (IVATF) to develop 

during the next year a global safety risk management framework that will make 

it possible to determine the safe levels of operation in airspace contaminated by volcanic ash. The IVATF will closely coordinate with ICAO’s International Airways 

Volcanic Watch Operational Procedures Study Group and ICAO’s European and 

North Atlantic Volcanic Ash Task Force. Mr. Steve Albersheim of the FAA has been 

nominated to represent the United States on the IAVTF and will coordinate U.S. 

participation in the task force activities.
57

ANSWERS TO POST-HEARING QUESTIONS

Responses by Dr. Jack A. Kaye, Earth Science Division, National Aeronautics and 

Space Administration

Questions submitted by Chairwoman Gabrielle Giffords

Q1. I understand that NASA’s MODIS instrument that is flying aboard the Terra 

satellite has collected data that provided information on the horizontal as well 

as the vertical extent of the volcanic ash plume over Iceland. To what extent will 

future planned instruments be capable of maintaining these types of observations?

A1. The Terra platform, launched in 1999, has two instruments that provide information about atmospheric particulates: the Moderate Resolution Imaging 

Spectroradiometer (MODIS) (http://modis.gsfc.nasa.gov/) and the Multi-Angle Imaging SpectroRadiometer (MISR) instrument (http://www-misr.ipl.nasa.gov/). The 

MODIS instrument on Terra and its twin on the Aqua satellite provide information 

about the horizontal and temporal variability of aerosols, but do not provide information about their vertical location. However, the MISR instrument, which is 

unique to Terra, has demonstrated global stereoscopic measurement of the heights 

of many volcanic plumes, including Eyjafjallajo ̈kull. MISR makes height estimates 

by taking measurements at nine different viewing angles, ranging from 70.5 degrees 

in front of the spacecraft to 70.5 degrees behind it. The multi-angle and multispectral capability of MISR also allows additional information to be acquired such as 

wind speed in the plumes and particle properties such as size and shape. 

The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument will continue 

the MODIS observations of the horizontal extent of volcanic ash clouds. The Ozone 

Mapping and Profiling Suite (OMPS) will continue the Ozone Monitoring Instrument’s (OMI) measurements of volcanic ash and volcanic sulfur dioxide. Both instruments, VIIRS & OMPS will fly first on NASA’s NPOESS Preparatory Project (NPP) 

mission in late 2011 and then on subsequent Joint Polar Satellite System (JPSS) 

missions. 

The next NASA mission that might produce a data set using both multispectral 

(like MODIS) and multi-angle (like MISR) approaches is the Aerosol/Cloud/Ecosystems (ACE) Mission (http://dsm.gsfc.nasa.gov/ace/index.html), described by the 

National Research Council in its 2007 Decadal Survey (Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond). The ACE 

mission is one of the Survey’s ‘‘Tier 2’’ missions, and no launch date is currently 

scheduled. NASA is currently investing in technology through its Earth Science 

Technology Office in order to advance the techniques and instrumentation that will 

ultimately be part of the ACE mission (see ACE-related links in http://

esto.nasa.gov/about¥esto¥documents.html). Infrared observations from current (e.g. 

the AIRS instrument on NASA’s AQUA satellite) and future research (e.g. the CRIS 

instrument aboard NPP) as well as operational (e.g. the IASI instrument aboard 

MetOp) instruments also contribute to our knowledge of volcanic gases and ash.

Q2. How challenging is it to fuse data from weather satellites, volcano observatories 

on the ground and science instruments in orbit? Is it mostly a technical issue 

or are there organizational considerations?

A2. The fusion of data from different types of instruments and platforms for scientific and/or operational uses certainly constitutes a technical challenge and can 

constitute an organizational one as well. Scientifically, the fusion of very different 

data types is best done within the context of a data assimilation system. The more 

different the data type, the greater the challenge in the assimilation process simply 

because they measure different aspects of the environment. These challenges include addressing differences in data formats, spatial resolution, measurement uncertainties, and temporal coverage among the data sources, along with subtle differences in the actual quantities being measured. Scientists at NASA and other Federal agencies, most notably the National Oceanic and Atmospheric Administration 

(NOAA), have significant capability in data assimilation. At NASA, most data assimilation expertise resides within the Global Modeling and Assimilation Office at 

the Goddard Space Flight Center—see http://gmao.gsfc.nasa.gov/. Most of NASA’s 

efforts in data assimilation have emphasized atmospheric (meteorology, i.e., temperature, moisture, winds, and non-volcanic aerosols) and also oceanic and land surface data; assimilation of atmospheric aerosols is currently under development. 

While satellite measurements are important for constraining the aerosol composition of the atmosphere on a global scale, much information about the timing and 
58

intensity of the volcanic emissions (most notably ash and sulphur dioxide) can be 

obtained from ground-based volcanic observatory data. The improved information of 

a volcanic event afforded by accurate surface emissions greatly enhances our ability 

to utilize the satellite-based measurements. Although volcanic emissions have been 

incorporated in retrospective data assimilation of the climate record, global multiagency coordination is still necessary for this information to be utilized in near real 

time applications. In order for NASA’s observation and model results to be most useful for operational purposes, continuing and enhanced cooperation between NASA 

personnel and the those of the Volcanic Ash Advisory Centers (VAACs), building on 

current successes, will be necessary. 

Substantial organizational challenges do not exist, in part owing to long-time investments in comprehensive data systems, format standards, and multi-agency 

science centers such as the Joint Center for Satellite Data Assimilation and Shortterm Prediction Research and Transition Center (SPoRT).

Q3. It has been reported that Europe needs better models to predict the path of volcanic ash and that this had been done in other parts of the world. I understand 

that more accurate models would allow us to be surgical in what airspace to 

close down and what to keep open. So how does one make a model ‘‘better’’? Is 

more empirical data what is needed to verify the model’s accuracy? What is the 

most effective way to collect such empirical data?

A3. There are several approaches which can be used to improve forecast models. 

The first step is to improve the initial conditions for such models so that they start 

off from conditions as close to reality as possible. For the volcanic ash case, that 

means knowledge about the spatial distribution of particulates and gas phase molecules ejected by the volcano, as well as the underlying meteorology (temperature, 

moisture, clouds) in near-real time. For particulates, it is important to know not 

only where they occur, but also their properties (size, chemical composition, radiative properties). The discrimination of ash from condensate clouds both horizontally, and especially vertically, is also important. Other improvements in models 

can come from sustained use of observations and advances in theory and modeling 

approaches in order to improve the representation of atmospheric processes and 

quantitative evaluation of models. Frequently, it is through detailed comparison of 

observations with models that modelers best understand the shortcomings of the 

models and can focus their energies on their improvement. The availability of such 

data is particularly important when there are only a limited number of case studies 

for comparison, which is the case when dealing with major volcanic clouds. These 

data are obtained from diverse sources: geosynchronous satellite imagers, multispectral techniques, polar-orbiting satellite instruments, and high-altitude airborne 

lidar, creating data fusion challenges. Model improvement can also come from the 

ability to resolve more fully the processes represented in them and the spatial scales 

at which they operate. Achieving enhanced resolution in these areas is dependent 

on the availability of adequate computational resources, without which approximations that may degrade model quality are required. The development, improvement, 

and utilization of forecast models is a labor-intensive effort that requires sustained 

effort by a multi-disciplinary team able to harness the power of observations, theory, 

and computation to provide results for real-time use.
59

ANSWERS TO POST-HEARING QUESTIONS

Responses by Ms. Victoria Cox, Senior Vice President, Nextgen and Operations Planning, Air Traffic Organization, Federal Aviation Administration

Questions submitted by Chairwoman Gabrielle Giffords

Q1. The FAA Administrator was reported to have suggested that Europe take the 

lead in establishing a standard for future volcano situations but offered FAA’s 

technical assistance. What type of technical assistance was he referring to and 

why does he believe Europe should be taking the lead in establishing a standard?

A1. The FAA will provide assistance to the European community in establishing a 

standard for situations related to volcanic eruptions. This assistance involves many 

different levels of expertise. The FAA has already established a team of experts who 

will be supporting the FAA on the International Civil Aviation Organization (ICAO) 

Volcanic Ash Task Force. The FAA will work in a collaborative decision making 

process through the ICAO on the establishment of any global standards for volcanic 

ash in support of aviation. Specifically, the FAA in consultation with the NOAA/

NWS/NESDIS will examine the current state-of the-art of global transport models 

and define the operational performance requirements for these models for decision 

support tools for operators. In addition, the FAA will work collaboratively with the 

United States Geological Survey on the development of good scientific practices for 

any proposed international standards that support modeling.

Q2. What was the extent of FAA’s consultation with international aviation regulatory 

agencies and aircraft manufacturers in developing the Special Airworthiness Information Bulletin on volcanic ash operations FAA released on April 22, 2010?

A2. The FAA participated in a series of international volcanic ash teleconferences 

that started on April 17, 2010. On April 22, the FAA issued Special Airworthiness 

Information Bulletin (SAIB) NE–10–28 after close consultation with European and 

Canadian regulatory agencies and aviation industry. The FAA worked closely with 

the European Aviation Safety Agency as each authority shared their draft safety 

bulletins with each other. The regulatory agencies and industry reached consensus 

prior to final issuance of our respective bulletins. In addition, the FAA held separate 

teleconferences with engine manufacturers to assure a coordinated industry/regulator response. The FAA also requested each of the manufacturers to issue immediate guidance to the airlines on inspections after an ash encounter.

Q3. To what extent are Federal research programs on aircraft flying through volcanic ash coordinated, and how easy or difficult is it to share the research results with relevant stakeholders? What about coordination with non-U.S. research programs?

A3. The FAA does not sponsor any specific Federal research program that addresses 

aircraft flying through volcanic ash. There is research supported by other Federal 

agencies that examines the state-of-the-art in modeling, forecasting, and using remote sensing to provide greater accuracy on the location of ash clouds. These combined programs result in a body of knowledge that supports the issuance of warning 

messages to avoid or mitigate ash encounters. Similar to our work in forecasting 

convective weather, this research is focused on ash avoidance—not on engine tolerance. The International Civil Aviation Organization, the World Meteorological Organization, and the International Union Geodesy and Geophysics work collaboratively 

to promote scientific understanding of volcanic eruptions and subsequent ash clouds 

that affect aviation. The information is shared at international fora and through 

peer review of published papers. All information garnered from these fora are 

shared with all interested stakeholders.

Q4. As you know, the National Weather Service’s (NWS) Volcanic Ash Advisory Centers (VAAC) and Meteorological Watch Offices (MWO) provide warnings and 

advisories to the aviation industry regarding volcanic ash hazards. Such weather products area a vital component of FAA’s air traffic control system.

a. During recent volcanic ash incidents, how would you characterize the role of 

the NWS and the working relationship between FAA and NWS?

A4a. The FAA and NWS work collaboratively in a positive manner on detecting and 

reporting volcanic ash that can pose a hazard to aviation. As you have noted, the 

NWS provides advisories and warning messages from VAAC and the MWO respectively. The FAA’s responsibility is to disseminate the information to flight crews and 
60

airline operation centers. The FAA operates and maintains the aeronautical fixed 

services (AFS) that disseminate all ICAO-compliant messages to stakeholders. 

These messages receive high priority distribution over the AFS and are immediately 

integrated into support decision tools for flight planning purposes. 

With regard to the eruption of Mount Eyjafjallajokull, the NWS had no direct involvement because the ash cloud did not affect a U.S. Flight Information Region 

under the responsibility of a NWS VAAC. The role of the Washington VAAC was 

to advise users to check the London VAAC for information on the ash cloud. The 

FAA also worked collaboratively with National Air Traffic Services on contingency 

plans for the overseas tracks that were available to avoid the ash cloud.

b. How did the NWS work products mitigate the impact these incidents had on 

aviation?

A4b. Although the ash cloud that resulted from the eruption of Mount 

Eyjafjallajokull did not affect a U.S. Flight Information Region, the Washington 

VAAC, if requested by the FAA, would provide any pertinent information in support 

of traffic flow management as to how the ash cloud might affect operations.
61

ANSWERS TO POST-HEARING QUESTIONS

Responses by Captain Linda M. Orlady, Executive Air Safety Vice Chair, Air Line 

Pilots Association, International

Questions submitted by Chairwoman Gabrielle Giffords

Q1. A Wall Street Journal article reported the following:

Meanwhile, commercial pilot groups remain concerned about the safety implications of the current situation. For instance, the Air Line Pilots Association, the largest pilot union in North America, on Friday warned members 

to identify alternate or escape routes to avoid ash clouds. Descending and 

turning around is recommended by the union, rather than climbing through 

such clouds. Upon encountering volcanic debris, ALPA recommends that pilots reduce engine thrust to idle and don oxygen masks. And the union’s update stressed that if an engine shuts down, it may take longer and be harder 

to restart than normal.

Is such a warning from ALPA unusual? What has been the feedback from your 

members?

A1. Safety guidance provided by ALPA to its member pilots is not unusual. When 

ALPA becomes aware of a safety concern such as a potential volcanic eruption which 

could have an immediate impact to a broad spectrum of our members, the applicable 

information is then distributed to our members via ALPA Safety Alerts and/or Operational Bulletins. For example, since 2005 ALPA has issued 64 Safety Alerts and 

Operational Bulletins, four of which have been related to volcanic activity. In the 

case of potential volcanic ash encounters, the guidance provided by ALPA is considered by its members as useful backup information which is complementary and consistent with guidance from operators, aircraft manufactures and the FAA. The feedback received from our membership is that these Safety Alerts and Operational Bulletins are quite helpful and are often shared with the management of their airline 

for further dissemination.

Q2. In your statement, you raised an issue that has been seldom mentioned by the 

media following the Icelandic volcano eruption, namely that volcanic gases such 

as Sulfur Dioxide (SO2) or Hydrogen Sulfide (H2S) could pose potential health 

hazards to passengers and crews. Who do you believe should be conducting research in the health effects of volcanic ash on aircraft passengers and crews?

A2. ALPA believes the FAA should take the lead in sponsoring and conducting research on the effects of volcanic gases on aircraft occupants, and in particular the 

FAA Civil Aerospace Medical Institute (CAMI) located in Oklahoma City. CAMI is 

the medical certification, research, education, and occupational health wing of the 

FAA’s Office of Aerospace Medicine. The goal of CAMI is to enhance aviation safety.

Q3. At the hearing, we discussed the need for onboard warning of volcanic ash conditions. How high a priority is it for pilots that we have such an airborne capability?

A3. Currently aircraft weather radar systems cannot detect volcanic ash clouds. 

Consequently, at night or in low visibility conditions, pilots have no way of knowing 

where the potential danger areas are other than by weather forecast or reports from 

other pilots who have encountered the ash cloud. Forecast information is by its nature an estimation rather than a direct observation of actual conditions. Even reports from other pilots do not necessarily reflect what may be occurring immediately 

around another aircraft. If in the future, pilots are expected to consider operations 

in some scientifically pre-determined acceptable levels of volcanic ash concentration, 

then there must be some onboard sensing and warning capability to enable the pilot 

to remain clear of the danger areas. Until such capabilities are available to the pilots, flight into known volcanic ash areas of any concentration level is to be avoided.

Questions submitted by Representative Pete Olson

Q1. Your statement emphasized the importance of developing standardized data 

products for use by flight crews, dispatchers and air traffic controllers to track 

volcanic clouds. Presumably, your peers at other carriers here and abroad would 

similarly benefit from a common set of standards and definitions. What organization, in your view, should lead this effort, and why hasn’t this type of standardized data format already been implemented?
62

A1. In our view, the FAA would be the lead organization within the U.S. for coordinating the development of standardized data products to track and detect volcanic 

ash clouds. And to effectively achieve a global standardization of definitions and 

products, the International Civil Aviation Organization (ICAO) would lead with the 

FAA participating. The FAA can better answer the status of any such activity and 

why products, if available, have not already been implemented.

Q2. Following resumption of air operations in Europe, including flights into or near 

airspace containing volcanic ash, what has been the anecdotal experience of operators and flight crews? Are they seeing any surprises with respect to engine 

damage, abrasion, or degradation of other aircraft systems? Have air service authorities become more adept at coordinating traffic? Have the volcanic could 

models proved reliable?

A2. Since the resumption of air operations in Europe we have seen a heightened 

awareness by the aircrews concerning the potential dangers of volcanic ash encounters. There has also been significant activity among the European aviation regulators and industry to determine if an acceptable concentration level of volcanic ash 

can be established for safe flight. But until any new policy or technology is provided, 

we have advised our membership to stay fully cognizant of and to abide by their 

particular airline’s policy for flight in the vicinity of volcanic ash. To the best of our 

knowledge the U.S. air carriers and the FAA, although looking into the matter, have 

not changed their previous policies that flight into known volcanic ash conditions 

is to be avoided. Consequently, we have not seen a rise in the amount of damage 

to aircraft due to inadvertent volcanic ash encounters. We are not aware if there 

has been any change in the difficulty of coordination of air traffic with respect to 

volcanic activity or if the forecast models have been updated. However, we are concerned that flight safety would be compromised if new policies are implemented 

where pilots are expected to enter into known areas of volcanic ash concentration, 

yet are not equipped with the means to measure if the concentration levels are within pre-determined acceptable thresholds.
63

ANSWERS TO POST-HEARING QUESTIONS

Responses by Mr. Roger Dinius, Flight Safety Director, GE Aviation

Questions submitted by Chairwoman Gabrielle Giffords

Q1. It is probably impractical and uneconomical to design a jet engine that can 

withstand all volcanic ash conditions. From what we know about aircraft engines, aviation safety, and the economics of the airline industry, what is the best 

that we can expect from future engine technology improvements?

A1. Today GE & our partners have approximately 25,000 engines operating world 

wide in commercial service. It is expected to be economically impractical for all engines in the fleet to be retrofitted if a ‘‘volcanic ash kit’’ were identified. 

It is not anticipated that significant technology advances will be made to ‘‘harden’’ 

modern commercial turbojet engines to volcanic ash exposure. There is not an anticipated commercial market for an engine robust to volcanic ash, if it costs any 

more than today’s engines. Technologies would be required to: 1) eliminate the need 

for hot section cooling, 2) an ‘‘ash-phobic’’ coating would be required on all hot section components, and 3) advances would be required in anti-erosion materials. Additionally, oil system components would need to be designed to be robust to ash contamination.

Q2. Captain Orlady indicated in her statement that aircraft certification requirements will need to be updated to provide for more ruggedized aircraft health 

monitoring systems and management processes. Recognizing that GE aircraft 

engines are part of the aircraft’s overall system, what are your views on Captain 

Orlady’s suggestion?

A2. If the industry elects intentionally fly into volcanic ash, a ‘‘history record’’ will 

likely be required to keep track of the volcanic ash exposure. This ‘‘history record’’ 

will likely involve a volcanic ash exposure record that will likely be a function of 

power setting of engine, engine operability margin available, local ash concentration 

and exposure time. Today, technology does not support a sensor that can determine 

the local ash concentration on-board commercial aircraft. This is not expected to be 

operationally economical, and it will likely degrade overall aviation safety. GE does 

not recommend flight into visible volcanic ash.

Q3. I understand that engine manufacturers and international aviation regulators 

had been in discussion for a few years on trying to establish the concentration 

level of volcanic ash an engine could tolerate without causing a safety hazard. 

Six days after the closure of European airspace, consensus was reached. Why 

was consensus so difficult to achieve and what finally precipitated an agreement?

A3. GE was not involved in establishing an engine tolerance level for volcanic ash 

over the past few years, until April 16, 2010. The difficulty in establishing a tolerable level of volcanic ash centers on the assumption that a concentration level is 

all that is important to understand engine damage. Actually it is only one of several 

factors critical to assess the impact. It is anticipated to understand engine tolerance 

requires knowledge of exposure time, engine condition prior to encounter, particle 

size distribution, and ash chemistry. The airspace closure over Europe brought engine manufacturers and government agencies together to assess available data to 

establish the current interim ash concentration limits. Long-term engine impacts of 

operations in these levels of volcanic are unknown. GE continues to recommend 

against flight in visual volcanic ash.

Questions submitted by Representative Pete Olson

Q1. Your written statement noted that it is ‘acceptable’ for jets to fly through volcanic 

clouds having ash equal to or less than 2 milligrams per cubic meter. What do 

you mean by using the term ‘acceptable’? Are modem turbojet engines capable 

of operating in such an environment without enduring any lasting, long-term 

damage? Would operators be at risk of having to overhaul their engines on a 

shorter cycle because of this level of exposure?

A1. ‘‘Acceptable’’ here referred to a qualitative engine impact assessment where engines impacts are limited to economic impacts and not operational safety impacts. 

If engines are operated in volcanic ash environments, up to 2 milligrams per cubic 

meter, cumulative engine damage is anticipated which will drive engines off wing 
64

early and require a shop level overhaul to restore engine performance. GE does not 

recommend flight into visible volcanic ash.

Q2. Following resumption of air operations in Europe, including flights into or near 

airspace containing volcanic ash, what has been the anecdotal experience of operators and flight crews? Are they seeing any surprises with respect to engine 

damage, abrasion, or degradation of other aircraft systems? Have air service authorities become more adept at coordinating traffic?

A2. No unserviceable conditions have been observed to date from volcanic ash exposure following the April 2010 Icelandic volcanic activity, to my knowledge. No flight 

crew reports of volcanic ash encounters impacting engine operation have been reported, to my knowledge. Based on inspection results to date engines accumulated 

ash, but not to a point of being unserviceable. I don’t have an expertise in air traffic 

or the air service authorities capabilities, so can’t comment on their past or current 

capabilities.

Æ