Scientific advice and evidence in emergencies


House of COMMONS




Scientific advice and evidence in emergencies: Volcanic ash  

Wednesday 3 November 2010

Ray Elgy, Dr Guy Gratton, Dr Sue Loughlin and CaptaIN Tim Steeds

Professor Brian Collins, Dr Miles Parker and Professor Julia Slingo

Evidence heard in  Public Questions  60 - 154



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Oral Evidence

Taken before the  Science and Technology Committee

on  Wednesday 3 November 2010

Members present:


Andrew Miller (Chair)

Gavin Barwell

Gregg McClymont

Stephen Metcalfe

David Morris

Stephen Mosley

Pamela Nash

Graham Stringer



 Examination of Witnesses

Witnesses: Ray Elgy, Head of Licensing and Training Standards, Safety Regulation Group, Civil Aviation Authority, Dr Guy Gratton, Royal Aeronautical Society, Dr Sue Loughlin, Head of Volcanology, British Geological Survey, and Captain Tim Steeds, Director of Safety and Security, British Airways, gave evidence.

Chair: Can I welcome you here this morning and thank you for your attendance. We understand that Dr Guy Gratton will be joining us shortly. He is delayed, compliments of the Tube strike, but hopefully he will be with us shortly. At that point I will, possibly, re-run some of the questions that we start with for him. Could I ask the three witnesses, first of all, to introduce yourselves?

Captain Steeds: Good morning. I am Tim Steeds. I am the Director of Safety and Security at British Airways.

Dr Loughlin: Hello. I am Dr Sue Loughlin. I am the Head of Volcanology at the British Geological Survey.

Ray Elgy: Good morning. I am Ray Elgy, Head of Licensing and Training Standards at the Civil Aviation Authority.

Q60 Chair: Welcome everyone. First of all, a general question for you. How prepared was the Government for the volcanic ash incident?

Ray Elgy: Perhaps I could start, if I may. I think the scale of the eruption and the prevailing weather conditions at the time caught everybody by surprise. We were prepared as an industry for the volcanic eruptions in the sense that these had been anticipated and exercises are conducted on a regular basis every six months to cater for volcanic eruptions, but the scale of that particular eruption, combined with the very unique set of weather conditions that prevailed at the time, quickly demonstrated to us all that the plans that we had were not adequate for that particular eruption.

Dr Loughlin: Unfortunately, I don’t think the Government was well prepared. It wasn’t particularly a surprise to the volcanology community that something like this would happen, but somehow that message hadn’t got through to Government. Fortunately, the volcano community is quite well prepared based on our experience of Montserrat. So the British Geological Survey was managing between 1997 and 2008 the Volcano Observatory in Montserrat. There is a very explosive volcano there, very dangerous, so there is a community in the UK of BGS academics and many students who have got experience through that eruption. That network is in the UK. It is very experienced and, fortunately, was ready to go when this began.

Also the British Geological Survey had been in communication with the Cabinet Office about geological and geophysical hazards in general, so when this happened the Cabinet Office did know who to call. At least we were into the loop very, very quickly and able to provide advice very sharply. So that was good.

Captain Steeds: From our point of view, the Government, which is a very broad term, obviously, was unprepared. They may have run exercises, but we’d never experienced before the mass closure of airspace, which was the reaction of the Government in this case. It is hard to believe that anybody had thought of the consequences of closing the airspace in the way that it happened. We operate worldwide. We operate where there are volcanoes going off somewhere in the world every day. We have procedures in place and crew are trained what to do if they encounter volcanic ash. We have never, ever experienced a mass closure of airspace of the proportion that we got in April.

Q61 Chair: But you have experienced closures of airspace?

Captain Steeds: When a volcano goes off, the ICAO recommendation is to close airspace in the immediate vicinity of the volcano, and that is regular, but it is a small amount of airspace. Then the normal procedure is for the relevant VAAC to publish what they forecast as the volcanic output and then for the operators to decide where it is safe to operate.

If you take Montserrat as an example, earlier this year, or was it last year, we did not operate into Antigua because Montserrat was going off. There was nothing from the UK CAA to tell us not to operate. So we have a case of double standards, if you like, because we operate under an Air Operator’s Certificate issued by the UK CAA. They oversee our safety worldwide, not just in the UK. They oversee safety worldwide. When volcanoes go off in other parts of the world they have never expected us to do what they required us to do with this particular volcano.

Q62 Chair: Could I just push you a little further? Is the worldwide advice broad advice covering volcanoes full-stop or does it differentiate between volcanoes that produce clouds with different particulate size or the quirks that occurred because of the explosions coming through the ice in the Icelandic case?

Captain Steeds: The basic ICAO guidance and the guidance from the airframe and engine manufacturers is to avoid flying in visible volcanic ash. That is ash that you can see.

Q63 Chair: Full-stop?

Captain Steeds: Full-stop.

Q64 Chair: Dr Loughlin:, you are clearly saying that the Government could have engaged better with the scientific community. They knew who to ask because of the advice you had already offered the Cabinet Office on broad geological issues. How would you expect them to have done that?

Dr Loughlin: There was an inquiry following deaths that occurred in Montserrat. One of the recommendations following that was that a single Department could be responsible for Montserrat. It’s a joint effort between DFID in the early days and then FCO. If a Department had responsibility for volcanic hazards and risks then that might have been one way the message could have got through, and lessons learned from Montserrat could have been passed on to our experience in Europe. The problem in Europe, of course, is that Iceland is not the only place that has volcanoes. So, although we are now getting to grips with potential impacts from Iceland, there are also other volcanoes to consider.

There are a number of issues which we can, we should and we will take forward from this point to make sure that we are better prepared for future activity. We have been rather fortunate worldwide in the fact that there haven’t been large explosive eruptions in recent decades. This is particularly the case with Iceland. There’s been a bit of a lull over the last 50 years in terms of activity, but levels of activity are picking up now and they have been increasing since about the 1980s. Iceland scientists have published pretty solid data suggesting that there is a 140-year periodicity to the volcanic activity and that we are heading now towards a peak. It is absolutely imperative that we work now to ensure that we are better prepared for next time and that we consider not just Iceland but also the other volcanoes in Europe.

Q65 Chair: Was that advice about the Iceland data made available to the Cabinet Office before the events?

Dr Loughlin: No, not by us, but I do know that there were other scientists who had made reference to volcanoes. So, yes, it should have been more explicit, I think. The situation should have been made more explicit, but we were working in BGS, in particular, to get a range of geological and geophysical hazards considered, not just volcanoes.

Q66 Chair: Do you have anything to add, Mr Elgy?

Ray Elgy: Yes, if I may, Chairman, just to respond to the point that Tim was making. The advice that’s contained in the Contingency Plan for Europe is entirely consistent with the advice that is provided worldwide. So what we saw in Montserrat, for example, is entirely consistent but on a completely different scale. Airspace in the local area for Montserrat would have been closed and airlines would have had to route round that airspace closure. It is just the scale of the event here and the weather conditions meant that that particular area of closure where the flow rate was closed down to zero was much bigger and in a very complicated and complex piece of airspace.

Q67 Stephen Metcalfe: Good morning. Casting your mind back to earlier this year, at what point do you think it became an emergency, and by the use of the word "emergency" I mean in terms of the fact it had such an impact on the running of the country and the operation of the airlines? Was it clear straightaway who was actually in charge within Government, who was going to take responsibility for this? I know you touched on that. Did it take a little time to work out who was actually going to lead on this?

Ray Elgy: If I may start, it was clear to us probably in the early hours of Friday and probably even late Thursday , on the Thursday evening . O n the Friday morning the CAA realised that the potential for this period of closure was that it could be prolonged and that it was cove ring a great deal of airspace. Therefore, we took the lead. We felt we were best positioned and were very well placed to take the lead in corralling experts from around the w orld. The CAA, as the independent regulator, has experts in economic regulation, the Met authority, airspace policy, consumer pro tection and safety regulation. We have a broad network around the world and we felt that we were very well placed, given that network, to take a leading role to draw those experts together, which we did from that Friday onwards. So very early on would be the answer to that question about at what point did we realise it was going to be something different to what we would normally have seen in other volcanic eruptions.

Q68 Stephen Metcalfe: And the role with Government? You, obviously, did take the lead?

Ray Elgy: Yes.

Q69 Stephen Metcalfe: Who were you then dealing with within Government and how did they formalise the fact that you were taking the lead ?

Ray Elgy: That was with the Department for Transport.

Q70 Stephen Metcalfe: So it was Transport, right, o kay?

Ray Elgy: Yes.

Q71 Stephen Metcalfe: Were there difficulties? Was there some conflict between who was taki ng the lead within Government? Was it c lear that it was going to be a T ransport issue straightaway or did the Cabinet Office get involved?

Ray Elgy: From the point of view of the CAA, we were looking after the safety of the passengers, looking at trying to re-open as much airspace as we could and we are well placed as the regulator to do that. From our point of view, from the aviation sector, it was clear to us that we were very well placed to take that role.

Q72 Stephen Metcalfe: Did it work? Do you think that you taking the lead and then working wi th the Department for Transport was the right relationship or could, in hindsight, it have been different?

Ray Elgy: No. I think the relationship between the CAA and the Department for Transport worked very well. We kept them closely in touch with what we were doing with developments and the rate of progress that we were making.

Q73 Stephen Metcalfe: Do you have any views on it?

Dr Loughlin: I think it was clear to us very early on that this was going to be a cross-disciplinary problem and that it would include several Departments, including DEFRA, the Department for Transport and so on. It was also clear, therefore, that the Cabinet Office would need to take a co-ordinating role. So although the Department for Transport was the main Department affected, yes, it was clear that the Cabinet Office would need to co-ordinate it across several Departments.

Q74 Stephen Metcalfe: In your view, did they get involved quickly enough?

Dr Loughlin: Yes. Given that there wasn’t planning, it happened extremely quickly and they had a great deal of information and advice very quickly on that first day from a whole range of people. It got into gear extremely quickly, yes.

Captain Steeds: From our point of view, the main Government agency that we dealt with, clearly, was the CAA and with the Department for Transport. There was disagreement within the CAA, within the different departments at the CAA, as to how airlines should operate. The Safety Regulation Department, basically, viewed the worldwide previous experience as the operator making the safety case and operating or not operating as the right way to go.

The Directorate of Airspace Policy is the department which issues the NOTAMs from the information provided by the Met Office, which closed the airspace. There was clearly disagreement between the two because you may recall that on the Sunday we did a test flight. On the Friday we tried to do a test flight because if you looked out of the window you would see clear blue skies and yet we were being told that it was dangerous to fly.

Q75 Chair: Just a second. Mr Elgy, you are disagreeing with that. Can we be clear where your line of disagreement is coming from?

Ray Elgy: Yes. There was absolutely no disagreement within the CAA whatsoever. We were very closely aligned in all the sectors.

Captain Steeds: On the Friday we asked permission to do a test flight. The Safety Regulation Department was happy for us to do a test flight. The Directorate of Airspace Policy was not happy for us to do a test flight and it took until Sunday to resolve that issue. NATS were unable to offer us a service. You cannot fly into controlled airspace without an air traffic service. Clearly, over the Atlantic and above 24,000 feet you are in controlled airspace. So we had to have the Directorate of Airspace Policy tell NATS that they were to provide us a service. So there was a NOTAM out issued by one part of the CAA closing the airspace. NATS were, therefore, unable to offer us a service. Therefore, we were not able to get airborne to conduct a flight test. It took a direction from the Secretary of State to the DAP to tell NATS to give us a service so that we could do our test flight on the Sunday when we encountered absolutely no ash at all. So to me that is confusion within the CAA. I apologise if the CAA disagree.

Ray Elgy: If I may, perhaps I could set that in context. There were two issues. One is the airspace issue itself and the way in which that was being managed, but it became very quickly apparent that the solution to this would be an airworthiness one. That was about how the aircraft systems and the engines themselves could tolerate ash. As we said before, the international advice at that time was for all aircraft to avoid ash.

From an airworthiness point of view, we were looking for a scientific-based-an evidence-based-solution to this. We were making sure that any evidence and any flights that were taking place provided some test points that we could use to build up that evidence base. So the British Airways flight was absolutely key in that respect. It took place on the Sunday, as Tim has said. It was planned very carefully and co-ordinated with the test aircraft that flew a very similar route beforehand so that we could align the test results from an instrumented aircraft with the results, effects and any adverse effects that might have been observed on the British Airways one. There had been a number of flight tests carried out over the preceding days but they were on instrumented aircraft.

Clearly, there are a number of other issues that are quite important such as the characteristics of the particular aircraft and the engine systems. So the British Airways aircraft, the 747, was quite different in terms of those characteristics from any other aircraft that had been flying, and that provided us with a very useful test point and data point in the evidence that helped us to re-establish or to establish a new limit of tolerance with the aircraft and engine manufacturers.

Chair: Gavin, you have a query.

Q76 Gavin Barwell: Can I get some clarity on these issues? Are you saying that it is true that BA wanted to do this test flight on the F riday and they were turned down but that was because you wanted to do these instrumented flights first?

Ray Elgy: We felt that it was very important that any test flights-any flights-that took place were useful from the point of view of providing evidence. It was a question of making sure that we could get a test flight, an instrumented aircraft flying a route, that the British Airways flight could then almost mirror. The British Airways test flight did take place on the Sunday and was providing real-time data down links to Rolls-Royce who were monitoring the performance of the engines throughout the duration of that flight.

Q77 Stephen Metcalfe: Captain Steeds, you seemed to have wanted to come in a minute ago.

Captain Steeds: It’s a complicated subject but I have to disagree with my colleague from the CAA. The fact is that even now there has been no change whatsoever in the engine or airframe manufacturers’ view on the tolerance. The engine manufacturers all define "visible ash" as "2x10-3g/m3". Whether or not it is 2x10-3g or 3 or 4x10-3g is, frankly, irrelevant. They define it as what you can see. There has been no change in that.

The CAA have been pushing the engine manufacturers to come up with some other figure, 4, 5 or 6x10-3g, but it is irrelevant because the position of the OEMs-the original equipment manufacturers-is avoid visible ash. As you can’t measure on the day exactly what it is that you are going to be flying through, having a different limit is, frankly, irrelevant. What we need to do is to have a policy where we can define and the Met Office can tell us where they expect visible ash to be and then we will avoid it.

Q78 Stephen Metcalfe: I have just one minor question. Obviously, this was taking place in the run-up to the General Election. Did that have any impact or any effect on the way the system operated, or was that just a side-show that we were all involved with but actually it did not affect the scientific advice that the Government was receiving? It is to all three of you, I suppose.

Captain Steeds: It didn’t affect us at all.

Stephen Metcalfe: No.

Ray Elgy: Nor the CAA.

Dr Loughlin: It didn’t affect the advice that Government was receiving but I think it did-

Q79 Stephen Metcalfe: How it used it, then?

Dr Loughlin: Yes. I think it did potentially affect, perhaps, response and times. I believe there was some delay and some uncertainty about funding and such issues which would not have occurred if there hadn’t been an election.

Q80 Stephen Metcalfe: Because Government Ministers were pre-occupied in other areas?

Dr Loughlin: Yes, and I think there was just uncertainty about who will be dealing with the issue and so on, and what policy will be in future. Yes, I think there were some delays over that period.

Q81 Stephen Metcalfe: Finally, how do you think the situation could have been improved? Could it have been improved-the co-operation between the Departments and the Agencies involved? What would your advice to us be to improve that into the future?

Ray Elgy: There are two points there. If I may come back before I answer your question to the point about moving the engine manufacturers, the reason that the airspace restrictions were able to be changed was because we did get the aircraft and airframe manufacturers and engine manufacturers to change the limits from 2x10-4g/m3 by an order of magnitude up to the 2x10-3 that exists now.

To come back to your question, I think for next time the important bit will be to co-ordinate better across Europe from a European dimension. There is work in place to improve co-ordination across Europe. There is a new emergency crisis co-ordination cell that is being set up. So within the UK, I am not sure that there is much that we could say would need to be improved. I think the big issue for us would be for Europe.

Dr Loughlin: There are a number of things. Obviously, you will discuss, perhaps, in more detail the modelling in the next panel, but a key to the modelling is the source term at the volcano. There needs to be a great deal more scientific research into volcanic processes, into how magma is fragmented, what particle size distributions are produced by different volcanoes and different eruption types. There is a huge variety, even just in Iceland. There needs to be much more work on finding default values. Some work has been started on this in the USGS, but default values for source parameters that can be fed into models, particularly in the early days of an eruption, when observations can be limited, when there is a great deal of uncertainty, will enable the modelling to get off to a good rapid start. There is a great deal of work that needs to be done in volcano science in that respect.

It would be good, of course, if this was mirrored by advances in research in aviation on a risk basis and dealing with engine tolerances and so on, and also in the meteorology community. I mean dealing with the transport of material and deposition of material.

We are working very closely with the Met Office and we are working very closely across Europe now, so there are a number of initiatives and worldwide. There was a meeting, for example, in Geneva just a couple of weeks ago where we had representatives from six of the VAACs across the world comparing models, looking at what the next steps should be in improving model performance and getting good observations to back up and validate those models. All this work is going on and it will, of course, feed into the next crisis.

I think all of this is a great step forward but the momentum needs to be kept up. More importantly, the funding needs to be supplied. That is a key issue because this was not available to us on the shelf when this happened. That is partly because of limited funding in the past for this sort of science.

Captain Steeds: Could I ask you to repeat what the question was?

Q82 Stephen Metcalfe: Yes. It was really how the strategic co-ordination between departments and the agencies involved could be improved. What have we learnt, which I think is covered, and how will that be used next time to improve the situation, especially for perhaps people like yourselves?

Captain Steeds: Firstly, just clarifying what visible ash is, the engine manufacturers did not change their limit. They just defined what they considered visible ash was. So originally all the airspace where there was any possibility of any ash at all was closed. Then when the engine manufacturers said that visible ash is 2x10-3 that area was published. Subsequently, a time limited zone with no time limit was published as well, which was 4x10-3.

In regard to what would happen next time, our fear is that next time we will be in exactly the same position as we were last time because, currently, as far as we can understand it, the CAA would take exactly the same line that they took last time and they would close airspace, whereas in the rest of the world the VAACs publish the information. There is one area of radius 120 miles over the volcano that is closed for a period of six hours until the VAAC broadcasts start coming out. It is not true to say that the area over Montserrat was closed. It was closed when the volcano goes off for six hours, and then it is down to the operators. Worldwide it is down to the operators to decide. Uniquely, in Europe, when the CAA closes the airspace Europe follows suit, but it is only in Europe. It hasn’t happened anywhere else in the world. Our belief is that if the volcano goes off again tomorrow we will be in exactly the same position again.

Q83 Gregg McClymont: Can I relay to you a quote from British Airways and then ask Captain Steeds and then the other witnesses to comment on it. "Blue skies prevailed over much of the predicted area of contamination for the majority of the time that the volcano was erupting but this evidence was not taken into account by government agencies. They contradicted ICAO guidance and imposed unreasonable restrictions upon operators against established protocols." Can I ask Captain Steeds to comment on that?

Captain Steeds: That is exactly our view. If you looked out of a window on these days, these were some of the best summer days that I can remember. Yet, somehow, the Government managed to persuade the public that flying in clear blue skies was going to be dangerous. Actually, nothing at all changed and, all of a sudden, the Government changed their view and flying in those clear blue skies was safe. From our point of view it was safe all along. If there had been visible ash we would have avoided it.

Dr Loughlin: I think everybody is aware of the two major incidents that took place in the 80s, basically where aircraft had serious impacts from ash and engine failure. There were opportunities following that to develop thresholds for aviation. As far as I am aware those thresholds were not still in place when this crisis began. So there was an ad hoc requirement to come up with these thresholds very quickly, which is what the CAA facilitated. As far as I am aware, those lower thresholds were not in peer reviewed literature when this began. So it was a situation that had to be rapidly put into place.

In terms of the blue skies, there were test flights. It is unfortunate that Dr Gratton is not here, but the Natural Environment Research Council and FAAM, which Dr Gratton represents-he will speak for himself later, I am sure-did test flights through UK airspace. As far as I understand, and I am not the expert, usually, that did detect ash where the models suggested the ash would be. Yes, it was at very low concentrations but there was ash up there. There have also been incidents where there has been damage to planes-okay, not total engine failure-in areas where there has been no visible ash. So this is quite a complex problem and it is not as simple as looking to see whether there is ash there or not. There are also issues of gas as well.

I am not an expert on aviation but, as I understand it, visible and visual ash is another complex area. It depends also on conditions of course. It depends on clouds and it depends on visibility. If you are considering satellite remote sensing visibility of ash, that also depends on cloud cover conditions. It depends on the altitude of ash, whether the ash is water-laden, whether there is ice cover. So this is not a straightforward issue either-what is visible and what is visual ash. There was ash up there, it was low concentration but it wasn’t a simple issue of coming up with a threshold. That threshold was a complex issue.

Ray Elgy: I agree entirely with Sue. The test aircraft did fly during those days when it was a bright blue sky. They did detect ash. There is work on-going now in the ICAO Volcanic Ash Task Force, which has set up a number of different work streams, one of which is on the science in particular. We have asked them and the people in that particular team whether or not it is possible for ash to exist in a clear blue sky and they have said they can’t tell. They need to do a lot of work to establish that. So the fact that it is clear blue sky does not necessarily mean that there isn’t ash up there at a level that could have caused some kind of adverse airworthiness effect.

Captain Steeds: Can I come back? Thank you. The ICAO guidance is to avoid visible ash. ICAO also has guidance on other issues. I would like to emphasise that the two well-known incidents where there have been engine failures have been where aircraft flew through the plume of the volcano, very close to the source of the volcano. ICAO guidance is to avoid wind shear. ICAO guidance is also to avoid thunderstorms and lightning strikes. You don’t have authorities around the world closing airspace on the whole because there is wind shear-the USA does from time to time-or lightning strikes. It is left down to the operators.

No one is doubting there is ash because there are volcanoes going off, so there is ash in the atmosphere and aircraft fly through it. What is important for the travelling public is, is it safe to do so? There will be an economic impact on engine overhaul, but is it safe to fly or is it not safe to fly?

Since 2003, British Airways has recorded 5.71 million aircraft flying hours, 1.93 million aircraft cycles, 15.25 million engine hours and 4.3 million engine cycles. During that time our long-haul fleet has been subject to 726 engine shop visits and 635 APU shop visits. We have not found any mention of volcanic ash in any of the 1,224 main engine or 635 APU strip reports.

So no one is doubting that there is ash. We don’t disagree at all that there is ash up there. The issue is, does it affect flight safety? And it doesn’t. When it does we avoid the ash. We have a proven track record of being able to do that. Uniquely, in this case, the UK CAA closed the airspace and that caused mass disruption to everybody.

Q84 Chair: Just before we go on, can I welcome Dr Gratton. I want to enable you to catch up slightly. If you would be kind enough when the written transcript emerges if there are any other additional comments you would like to make following the evidence of the other three panellists this morning, I would be grateful if you would drop us a note.

Before we go on, I just want to catch up on my first question to the other panellists about the preparedness of Government for a volcanic ash incident. I want to probe you on that specifically in the context of your expertis e as an aeronautical engineer. What are your thoughts, generally?

Dr Gratton: I think, in essence, we were not prepared. There were not plans in place for dealing with the contamination of British and northern European airspace by volcanic ash. The VAAC-the Volcanic Ash Advisory Centre-was certainly in place and able to predict the presence of it, but essentially all they were able to do was say, "It’s there", and give an estimate of how much. There had been no prior preparation with regard to acceptable limits, how to promulgate that information. We really were making everything up as we went along for those first few days of the airspace closure.

Q85 Chair: Was it clear to you who the lead Government Department, Agency or Minister was?

Dr Gratton: The lead organisation-that with responsibility for aviation safety- was the Civil Aviation Authority. That certainly should have been the case. Early on in the process they took a very effective lead. There was some subsequent confusion as other Departments started to get involved rather than allow the CAA to maintain the lead that they had already taken. Essentially, in terms of technical decisions, airspace closure, where aircraft could and could not fly, that was with the CAA.

Q86 Chair: But given the multi-disciplinary nature of this challenge, shouldn’t the Cabinet Office have taken the lead from the outset?

Dr Gratton: It is a very difficult question to answer because, as you say, it was very multi-disciplinary. The CAA, probably, still were the best placed organisation because they are a multi-disciplinary organisation. They handle engineering; they have scientists on their staff; they do handle the aircraft operational issues. So, within the industry, whilst there are some disagreements about specific actions, I think generally it is accepted that the CAA were the right people to take the main lead.

Q87 Chair: How would you have improved the co-ordination between Departments and Agencies if you had had the power so to do?

Dr Gratton: Probably by giving the CAA in the short term more power and more resources, actually handing over to them and saying, "Right, the Cabinet Office", or whoever is the relevant organisation within central Government, "should essentially back up the CAA, but tell them to get on with it", as the specialist regulator and the people with the expertise.

Chair: Back to you, Gregg.

Q88 Gregg McClymont: I guess this is a question for Captain Steeds, in particular but the other witnesses, too. I wanted to ask, finally, whether those two previous incidents were, maybe, misinterpreted by certain agencies? You mentioned that they flew over the plume of the volcano.

Captain Steeds: Yes. The two previous-the British Airways one down in Indonesia and the KLM one up over Alaska-flew right through the central plume. We are talking ash concentrations many thousands of times what we were talking in the clear blue skies over the UK. It is worth emphasising again that no one has ever died as a result of flying through volcanic ash, whereas people have been killed due to wind shear, people have been killed due to lightning strikes and all these are, in theory, within the remit of the CAA, but they pass the safety of those operations to the operators, which is exactly what they should do and it is exactly what they should have done in this case.

Q89 Gavin Barwell: I have two follow-up questions on this issue of whether it was safe or not and the points you have been making, Captain Steeds. We have got, in our evidence bundle, a quote from Research Councils UK, which is about this issue of payments to the NERC for the use of their research aircraft, which I may come back to later. In that quote, it says: "anticipated cost of repairs to the Dornier engines". Are these repairs completely unrelated to flying through ash or are those repairs because there was some damage to the engines of the aircraft? That is my first question.

My second one is in relation to the ICAO regulations that you have been talking about. What is the scientific evidence behind the assertion that it is visibility of the ash that determines safety or otherwise as opposed to particle size, mass, any other effect? What scientific evidence is that test of visibility based on?

Captain Steeds: I can’t answer the first question because I don’t know the answer. In regard to the ICAO regulation, as you call it, it is not a regulation. It is not even an ICAO standard. It is an ICAO recommended practice. So there is confusion when people say that ICAO required the airspace to be closed. ICAO standards did not require the airspace to be closed.

What is the scientific basis behind that? Per se, I can’t answer that question, but ICAO is the originator of all basic operational regulation. The ICAO working panels on this will have reviewed the information thoroughly before they publish it. The engine manufacturers and the airframe manufacturers endorse that as a recommendation to avoid visible ash, because there is currently no method of accurately, in real time, measuring what is up there.

The Met Office use a model, the model is a good model, but it relies on accurate information as to what the volcano is putting out for the model to be good. In this case, the information from what the model was putting out came from a single source radar, which was not a bi-polar radar, in Iceland operating on the extreme of its range. So the output of the volcano was inaccurate. That was fed into the Met Office model. If you put rubbish into a computer you tend to get rubbish out of it. That was the case here. We got inaccurate data.

I have forgotten which day it was, but there was one day when the airspace was closed over the south of the UK and we had to stop operating again. We complained to the Met Office and they went back and re-looked at what the output from the volcano was. They went back and put it into the model and, lo and behold, the airspace opened. You can blame the Met Office. They’re doing what they have been asked to do. It must be difficult because you haven’t got accurate information about what’s coming out of the volcano.

What we need is real time. If we are going to go down the path that is being suggested, we need to have a lot better information on what is coming out of the volcano. ICAO has purchased some radars which are being put up in Iceland-I don’t know whether they have arrived yet but they are on the way if they haven’t arrived-so that the Met Office model will get better information. Then on top of that we need to be able to update the model in real time. We are not there yet.

Ray Elgy: If I could come back to the point you were making about the two aircraft incidents that you referred to, they are not the only aircraft incidents that have happened in the past. There are at least eight others that I am aware of where engines have been adversely affected by volcanic ash. It is on that basis of global experience that ICAO has come up with the recommended standard. Clearly, volcanic ash and "avoid visible ash" as a criterion is not in and of itself sufficient, and the worldwide experience has demonstrated that. Captain Steeds is quite right. There have been no fatal accidents but there have been some very near misses.

The situation we are in at the moment is that we have got this new three-zone approach and that, again, has its limitations, and we recognise that. But that approach, combined with the visible ash criterion, is something that we are pursuing with the ICAO Volcanic Ash Task Force to put together a risk-based assessment that would enable us to be better placed in managing ash.

Again, to come back to the point I made earlier on, there were established criteria, internationally agreed, and to move from those we wanted evidence, and science-based evidence, in order to move from the established threshold up to something new. At the heart of what we were doing is passenger safety. We are looking after the interests of the passenger.

Dr Gratton: If I could come in there on the issue of aircraft damage and the issue of visible ash, there was an incident we have all studied a great deal in 2000. NASA own a DC8. It is a four-engined airliner they use for research. They inadvertently flew it through the efflux from an Icelandic volcano in 2000. I have actually spoken to the captain of that aircraft at some length. They did not see anything visibly. They knew they flew through those conditions because they had 40 scientists up the back and a lot of instruments telling them.

The first thing that tells you is that volcanic ash is not always visible at levels that are significant. That is fairly intuitive because aeroplanes fly at night and they fly in cloud, in neither of which are you going to see ash. That aircraft continued to fly. It returned to base but then three of the four engines on the aeroplane required rebuild. They quoted a rebuild cost of $3.2 million just on that one aeroplane. So it is indicative of several things. Firstly, the fact that you can see or can’t see the ash is not a reliable indicator; secondly, the level of damage that can be done; but, third, which does support the approach which has been taken of these multiple levels, that actually you can fly through a significant level of ash, do damage, pick up a substantial maintenance overhead but without immediately endangering the flight. It is important to realise this graduation.

In Jakarta, frankly, they were very lucky to live. They had a very good crew and a fair bit of luck on their side. That could have turned into a fatal accident very easily but that was an extremely high level of ash. The NASA DC8 saw a much lower level of ash which did significant damage but did not immediately endanger the flight.

One of the big scientific problems that has not really yet been solved is exactly where the line sits between the NASA DC8 and Jakarta. Clearly, where a lot of the engineering work is going is understanding what your trade-off is. If I fly there, I get this operational advantage but it’s going to cost me this many millions of pounds in subsequent repair bills on the aeroplane.

Captain Steeds: I don’t disagree with what has been said except that it is proven from our figures, which I won’t read out again, that we successfully operate worldwide and we avoid volcanoes and volcanic ash, and we have methodology of doing so. If we had ever encountered a strip examination where the engine manufacturers told us that they had found volcanic ash in our engines, we would have gone back, reviewed our procedures and made the necessary changes.

What happened in this case is interesting. There is, clearly, a scientific answer but we haven’t got the answer. Yet we closed the airspace, we cost the airlines hundreds of millions of pounds and we cost the economy billions of pounds all because we haven’t got a scientific answer. Yet we could safely operate, not without additional maintenance costs, perhaps, but we could safely operate without endangering passengers if we had used the procedures and the processes that we use everywhere else in the world.

Q90 Chair: I understood you to say earlier on that the industry is providing the new radar in Iceland.

Captain Steeds: No, ICAO.

Q91 Chair: Is there an argument for the industry to put some investment in there?

Captain Steeds: The industry is putting investment in. British Airways is working with Rolls-Royce and Boeing to put probes on a number of our aircraft-we are also speaking to the Met Office-so that we can research ash concentrations. Actually, if you are talking about air safety, ash is not the most significant issue at the moment. The most significant issue is frozen water at high altitude, which the scientific community, the engine manufacturers and the airframe manufacturers don’t fully understand. It is more dangerous, in my view, than volcanic ash because you can’t see it and we don’t understand it.

Dr Gratton: If I could just compare those. Historically, iced water conditions are causing somewhere between one and 10 power losses per year across the world airline fleet. Volcanic ash is causing a significant problem across the world fleet round about three times a year. It is true to say that the iced water content issue is perhaps a higher priority for global aviation safety. It is probably also true to say that we’ve been extremely lucky that neither has yet caused a fatal accident. Both certainly have that potential.

Q92 Pamela Nash: I would like to ask each of you how effective you feel SAGE was in advising the Government and how well the Government used that information?

Captain Steeds: I am sorry, but I didn’t hear the first part. Whose advice?

Q93 Pamela Nash: SAGE-the scientific advice that was given to the Government.

Ray Elgy: From our point of view, SAGE was very helpful in validating the work that we had been doing. The first meeting of SAGE that the CAA attended was after the airspace had been re-opened and the restrictions had been lifted. Certainly it seemed to us to have the right sort of composition in terms of the expertise that it had drawn upon. It was very helpful from our point of view to validate the work that had been done and to help set the path for future research and work.

Dr Loughlin: Yes, I agree. Unfortunately, because of the lack of preparedness, SAGE didn’t meet earlier than that, but when it did meet, I agree, it had a very good representation of expertise. The key issues were addressed, pointed out very quickly, discussed and debated. I would have liked to see even more people involved, but through time all additional people whose expertise was required were brought in.

SAGE is an excellent opportunity for getting experts, particularly on a complex problem like this, to speak directly to Government Departments. That is very, very important. It is also important that SAGE is open so that those experts can act as a kind of peer review within SAGE, so the discussion and debate is open and people are free to discuss, to criticise, if necessary, the issues openly. SAGE was a very good thing, particularly for that reason. In this case it really facilitated the inter-disciplinary aspect of this problem. It brought together people who had not worked together before, across the CAA, the Met Office and volcanology. Immediately, that bringing together of all this expertise triggered a lot of interesting science and research which was absolutely critical to the future handling of these sorts of situations.

On a slightly less positive point of view, as time went on, SAGE became slightly less focused but, again, I think that was partly because of the lack of planning in the first case, but the first few meetings certainly were very, very good. It would be good if, for future situations, there is a SAGE plan in advance so that it is already made up before the next situation happens.

Q94 Pamela Nash: Can I just push on that view? You mentioned that you felt it would have been better if there was further expertise as part of that group at an earlier stage. Do you feel that you did eventually strike the right balance and what expertise would you have needed?

Dr Loughlin: In terms of the scientific issues at the beginning we had the people we needed. Certainly we had the CAA there, we had the Met Office, we had the Departments and we had experts who we knew, across volcanology, covered the key things, so remote sensing and the modelling, from a volcanic point of view, from a resource point of view. We also had experts on aggregation, which is a key way of removing ash from the plume, which is a key scientific issue. So all of those things were tackled. But we could have gone further in managing the risk aspects of this situation.

Dr Gratton: I would like to add a point to that. It is clear that SAGE formed a vital function in informing Government and allowing the most senior scientists engaged in this to cross ideas and discuss where each other was engaged with the problem. What was very hard to understand, particularly from outside SAGE, is why the organisation was treated with such secrecy. The composition of SAGE was never published and the minutes from the meetings were never available. So for anybody who sat outside of SAGE, and there were a great many people very intimately involved with the problem, it became extremely hard to feed into SAGE and to use it to contact other organisations affected by the volcanic ash problem purely because of the level of secrecy with regard to its construction.

It is very hard to see the justification for that secrecy given that, really, it didn’t matter what you told the public. It wasn’t going to change what the volcano did. It’s not like a terrorist problem where you could see that case. The volcano is going to do its own thing and any amount of secrecy or openness does not change that, but openness certainly throughout the whole event was absolutely paramount. We really did find that the more everybody engaged shared their knowledge with everybody else, the better we were able to solve it. The moment anybody started behaving with any secrecy or saying, "This is my bit to solve. You’re not involved", things did start to go wrong. I think the secrecy of SAGE did contribute to some problems in that regard.

Q95 Pamela Nash: Can I just put that to those of you who were part of SAGE? Do you feel that the secrecy was necessary and, if so, why?

Ray Elgy: From my point of view, the secrecy wasn’t really apparent. We were invited to attend and we felt there was the right representation there. From an external perspective, I am afraid I don’t have a view.

Dr Loughlin: From my perspective, no, I would have liked to see less confidentiality. I think the default should be that everything is open and made apparent. I think that is particularly important where uncertainty and risk is involved. One of the impacts that I personally had from the confidentiality is that there was some confusion amongst SAGE members about what they could discuss and what they couldn’t. It’s like Guy said. There was a lot of information discussed in SAGE which was not, for any reason, secret. It was about the way volcanoes work, the way meteorology works. All of this information should have been shared as widely as possible, as quickly as possible. So there was a little bit of repetition that I felt had come about because Government Departments or others had felt unable to pass information on.

Ray Elgy: It is important perhaps to support that view in the sense that every decision that we took and all the rationale behind each decision we did publish to make sure it was open and transparent to everybody. So all of the decisions we took were recorded and published on our website.

Dr Gratton: Could I mention that a very major leadership was taken by a series of, inevitably, teleconferences-for instance, we couldn’t fly to see each other-led by the Civil Aviation Authority. I was certainly a part of that process, as were several hundred other people right across the world. The way in which the CAA published absolutely everything, every bit of discord, every bit of disagreement on the data, all of the discussions, I think is absolutely exemplary and is a very large part of why we tackled the problem as effectively as we did.

Q96 Chair: Dr Gratton, do you think, with hindsight, it would have improved the degree of understanding between Government, SAGE and the airline industry had there been an engine manufacturer present?

Ray Elgy: Engine manufacturers were present at every stage.

Q97 Chair: They were present?

Ray Elgy: Yes.

Q98 Chair: They concurred with the general advice coming from SAGE?

Dr Gratton: I struggle to answer that because I wasn’t part of SAGE, but certainly there were SAGE people who were part of the CAA conference and certainly all of the major engine manufacturers were part. The discussion was extremely robust and extremely constructive.

Q99 Chair: So how is it that there is a gap between what Captain Steeds is saying and the outcomes from SAGE if the engine manufacturers were present?

Captain Steeds: I was grateful to Dr Gratton for saying that this meeting was held in secret and the minutes were kept secret because I have been silent up to now because I have never heard of this and we were not involved. You would have thought that the scientific community would have wanted to interface with the operators because we were the ones who were affected by the volcanoes. We were the ones who were going to have to fly in this airspace if it was dangerous or not dangerous. Yet we appear to have been totally excluded from this group that was discussing it, which seems quite bizarre.

Q100 Stephen Metcalfe: Can I just pick up on that briefly? That seems to be the hub of the problem. Our investigation is into the use of scientific evidence and advice in emergencies which, presumably, is to enable the operator of the industry, whoever is affected, to carry on and to minimise the impact that emergency has on that operation, but that doesn’t seem to have happened in this case. What we seem to have had is some very good science going on about potential impact-there is no doubt there was some ash up there-but it wasn’t actually translated properly to the industry so that they understood, because they had a different view, which was that they could continue to operate using what they had already established as their code of practice. What we are trying to get to, I suppose, is, how does the Government decide who best to listen to when the industry is saying that the scientific advice that we were receiving wasn’t necessarily how they might have liked to have seen it presented?

Ray Elgy: Can I answer that? In terms of the overall timescale, SAGE, as I said, didn’t start to meet until after the airspace restrictions had been lifted. In terms of all the teleconferences that the CAA led and that Guy Gratton has referred to-certainly there were operators-industry was fully informed in all stages of those discussions and were contributing and participating in that debate. SAGE, as I said before, was helpful to us from the point of view of validating the work that had been done, but by that time all of the work to change the limits and increase the threshold had been completed and agreed. So SAGE wasn’t instrumental at the outset in helping us to overcome the initial problem.

Dr Gratton: Just to discuss a little bit of the time line, the initial airspace closure occurred on the morning of Thursday, 14 or 15 April. On the Thursday and the Friday we were all desperately trying to get on top of the problem. There was also an expectation, because this is the way Europe is supposed to work, that EASA, the European authority, was supposed to take the lead in this. They didn’t. They were, really, very inactive indeed.

By Saturday morning, the CAA had clearly come to the conclusion that somebody needed to take the lead and they were probably best placed to do so. So it was on the third day, the Saturday afternoon, that there was the first of the CAA’s teleconferences. There were about 150 people on that from I think I counted seven countries. Certainly British Airways was there; Rolls-Royce was there; General Electric was there. So you have got the largest operator in UK airspace and you’ve got the two largest engine manufacturers. The Met Office was on board. The Natural Environment Research Council was on board, and certainly the CAA and the FAA, who have clearly got a lot of volcanic expertise, particularly with regard to Alaska. So that worked extremely well. SAGE came along a little bit later and was a much smaller group of very senior scientists. It was much less of the all players event that the CAA conference was.

Q101 Graham Stringer: Captain Steeds, you have been commendably clear in your answers and disagreements with the CAA. Can I just ask you, is your view that we don’t need all these models? We don’t need the CAA interfering. Actually the industry itself is best placed to look after its aeroplanes and passengers in the way that it has done since it started flying?

Captain Steeds: Yes and no.

Graham Stringer: That’s a difficult answer.

Captain Steeds: We need regulation, and the CAA is a very good regulator in safety regulation. Can I just correct or disagree with what Dr Gratton said about EASA? At the moment the airlines operate under EU-OPS, which is European law published by the Commission and directly controlled by the Commission. EASA don’t take competence for aircraft operations until April 2012. They do have competence for airworthiness. One might have expected them to be more interested in the airworthiness aspects, but traditionally volcanic ash has been an operational issue. So to blame EASA for not being involved in the operational issue is, I think, misunderstanding how the regulation is currently drafted.

Airlines operate under an Air Operator’s Certificate. The Air Operator’s Certificate is issued by the CAA currently on behalf of the European Commission. From 2012 it will be on behalf of EASA. The CAA is responsible currently to the Commission and, shortly, to EASA, for ensuring that operators operate within the regulation.

The regulation requires operators to have safety management systems and other bits and pieces but, basically, what we are talking about here is a safety management system to ensure safe flight in different conditions. The CAA doesn’t have the expertise in all the individual bits that flow from that. What they are interested in, what they oversee and they audit is that you have a safety management system and it is effective. But if you get right down into the nitty-gritty about flying in volcanic ash, the CAA don’t operate aircraft and they don’t have the expertise in that area. Operators do. If you look at the worldwide statistics, we are talking about two serious incidents, maybe eight serious incidents, over the last 20 years.

If you talk about ice in the upper atmosphere, British Airways has 16 to 20 ice incidents a week. Now, we operate safely, overseen by the CAA, in these events. To think that the CAA is going to come in and tell you when the volcano has gone off exactly what you should be doing, I think is asking too much of the CAA. My personal view is that the senior management in the CAA expected too much of the Safety Regulation Group. They should have asked the Safety Regulation Group to ensure that operators had considered the problem and were reacting correctly to it rather than just closing the airspace and inconveniencing everybody.

Q102 Graham Stringer: So that was the "yes" part of the answer, was it? You are, basically, saying that you should have talked to the CAA and told them that you considered all the facts about the volcano and the decision should have been yours, and in these circumstances you would have carried on flying?

Captain Steeds: Yes.

Q103 Graham Stringer: So you are not interested in the big computer that the Meteorology Office has got. You are not interested in all the information coming in?

Captain Steeds: No, no.

Q104 Graham Stringer: It’s irrelevant, is it?

Captain Steeds: No, it’s not irrelevant at all. For example, when we didn’t fly into Antigua earlier on in the year, that was not because of anything that had been output by the CAA. It wasn’t because the airspace was closed over Montserrat. It was because we looked at the output from the North American VAAC and other agencies-WSI is one that we use-and we came to the decision that it was not safe to operate so we cancelled our flights. Actually, some other UK operators continued flying, but we decided it was not safe to fly. Indeed, in this particular event, some Scottish airports were open. Our information was that actually there was visible ash there and we wouldn’t fly to them. We take the output of the UK Met Office, but the UK Met Office model at the time was outputting inaccurate data, not because the Met Office aren’t good, but because the input into their model was inaccurate.

Q105 Graham Stringer: When you did your test flight on the Saturday or whenever it was, when you got permission to go, what were your objectives? What standards of measurements were you making? Were those standards of measurements in line with the ICAO standards?

Captain Steeds: To go back to the ICAO standards, there aren’t ICAO standards. When somebody said "an ICAO standard recommendation", it is confusing the terms. The standards are the requirements and the recommended practice is what it is. It is recommendations. So it is the standards you have to comply with. The recommended practice is to avoid visible ash.

What we did on the Sunday was we inspected the airframe and we borescoped the engines before we flew. When you borescope, you have a look inside the engine and see what’s there. Then we flew along where the VAAC forecast was telling us that there was significant ash. When we landed again, we carried out another examination and we found absolutely no evidence of any ash whatsoever.

Q106 Graham Stringer: The CAA at different times recommended closing airspace for six or eight-hour chunks of time. What was the evidence on which you did that? Why was it six or eight hours, because it is particularly inconvenient for airport operators and airlines to have such short periods? Were you completely relying on these models that the Meteorological Office was using?

Ray Elgy: In terms of the periodicity, the outputs of the model that is being used are generated every six hours. That explains the periodicity of it. There is a huge amount of data.

Q107 Graham Stringer: I am just trying to get that clear. So the time you were recommending closure for was based on how often the computer could turn out results?

Ray Elgy: The model is run and the output of that is generated four times a day every six hours. So, yes, we were relying upon that. There is a huge amount of data that is fed into the model and it has to be analysed and the output of that model is then validated against other information, for example, from satellite data, from ground-based LIDARs, to help validate the output.

Captain Steeds is quite right. Some of the input data for that model was very difficult to quantify accurately, in particular the amount of ash that was being generated at source from the volcano. So the reason is that updates were given every six hours and the information promulgated-the information provided in the industry to the airmen-was on a six-hourly basis.

Can I also clarify that it’s not the CAA that closed the airspace? Technically, what happened is that the air traffic service provider, NATS, zero-rated the airspace, so it wasn’t actually closed. In fact there were general aviation flights operating in certain parts of the airspace, but they were zero-rating it for instrument flight rules.

Q108 Graham Stringer: On your advice?

Ray Elgy: No, on the basis of their own safety case. If I can go back to the point I made very early on, it is an extremely congested piece of airspace. It is one of the busiest and most complex pieces of airspace in the whole world. The ICAO recommended practice was adopted. It formed the heart of the contingency plan that was in place, and it was unthinkable, in our view, to move away from that recommended practice without some scientific basis.

Q109 Graham Stringer: So you were talking to NATS. In the NATS evidence here they clearly were not very confident in the information that was being fed into the Met Office computer. It says: "It is clear that data of sufficient granularity was lacking although we understand that accurately establishing the density and composition of the ash is the most difficult scientific challenge." So they had no idea what they were doing.

Ray Elgy: No, I don’t think that is fair. There were limitations with the model. The model itself has been validated-

Q110 Graham Stringer: Let me finish. They had no idea what they were doing. They themselves didn’t have the information and they were closing airports down for six hours at a time because that just happened to be how the computer turned out its results from the rubbish information that had been put in. That’s extraordinary. That is just simply extraordinary.

Ray Elgy: No. That’s not a fair reflection of the actual events.

Q111 Graham Stringer: But it is the description that you have just given to us?

Ray Elgy: No. What I am saying is that there is a model that was being used by the Met Office. That model has been used on many other occasions and is constantly validated, updated and corrected. It’s been compared with other VAAC charts-

Q112 Graham Stringer: But it’s not the model I’m questioning just at the moment. It’s the rubbish that’s going into the model. The NATS evidence given to this Committee says that they have no confidence in the information going in.

Ray Elgy: The input to the model was questionable. The major issue was the source data, the source input, i.e. the amount of ash that was being generated at the volcano itself. That was recognised and that is why other inputs were put into the model, such as validating the output against satellite imagery and against ground-based LIDARs.

Q113 Graham Stringer: How were the satellite readings standardised? What were they standardised against?

Ray Elgy: Again, there are limitations with the way in which satellite imagery can be used. So all of those-

Q114 Graham Stringer: So more rubbish information going in?

Ray Elgy: No.

Q115 Graham Stringer: We have just been to the National Standards Laboratory and they told us that there were no measurements made of the ash until the NERC plane went up. They also told us, when talking about something else, that when you put satellites into orbit they get bashed about a bit, so it is very difficult standardising anything from them.

Ray Elgy: Yes. The point I am making is that the model itself is valid and has been validated. The input information was questionable and we used all means available-satellite imagery and LIDAR-recognising that those themselves were not perfect, but the model itself has been compared to all the other models used around the world by other VAAC centres. Also the test aircraft that were being flown were used to validate the model and the output. It was looking to see whether the ash existed and in what composition.

Q116 Graham Stringer: So how accurate was it? We’ve heard previously that when BA flew their aeroplane the engines were fine when they were flying through space where the model from the Met Office had told them there was ash. You say it is validated. Plus or minus, how accurate was it?

Ray Elgy: The point that was made earlier with regard to the level of ash that caused engines to flame out within a few minutes is 2g/m3. The model generates a chart which delineates an area where the concentration is below 2x10-4. So we are four orders of magnitude away from the point at which we know that engines will flame out in a very short period of time, in a matter of minutes. So it was on that basis that we were saying, right from the outset, if we could move at least one order of magnitude closer to that point-

Q117 Graham Stringer: That’s not quite the question I am asking. I’m asking how accurate was the information being churned out by the computer. How accurate was it?

Dr Gratton: I would just like to comment. We, here, at the table at the moment have all had significant sight of this and we could all discuss aspects of it, but I understand that in the next session you have the Met Office Chief Scientist. I suspect she is probably far better equipped to answer those questions than any of us.

Q118 Graham Stringer: That’s as may be, but NATS actually took the decision. The CAA were involved in the process. I want to know how you assess the accuracy of what was coming out of this because this had a tremendous impact on the economy. It seems to me that you were working with rubbish going into a computer and, therefore, rubbish coming out.

Q119 Stephen Mosley More specifically, when you actually sent the flight up there to do the test, so the plane was actually there, testing these areas and the model was saying there was an ash concentration, what did the aeroplane actually pick up? What were the results of the actual flight when compared with the model?

Dr Gratton: I am in a slightly difficult position here because I was on that flight. However, what I was not involved in was the direct analysis of the data. Again, I am going to slope shoulders in the direction of the Met Office because Professor Slingo has had full sight of that data and will be able to give you a much better description of that and the data that was obtained. What I can certainly say is that, in general terms, we were definitely seeing ash and we were definitely seeing sulphate chemicals where the Met Office model outputs had told us we were going to find something.

I would just make one other observation, which I think is particularly relevant to the British Airways and Virgin test flights. None of the British Airways and Virgin flights, and also a few days later there was an Airbus test aircraft out of Toulouse that came up over the north of Scotland, had instrumentation that was capable of detecting volcanic ash. With the aircraft that we did fly, what we saw was thin layers. So you might have a layer of ash a couple of hundred feet deep and then a couple of thousand feet of clear air and then another thin layer of ash. Without any instrumentation, you could fly from one end of the UK to the other and not know if you’d flown right through the most dense part of the ash or been in clear air all the way. You just couldn’t tell, other than if you inspected the engines and they were damaged then you were probably in the concentrated part of the ash. It was a very difficult problem from that perspective.

Ray Elgy: If I could just come back to Mr Stringer on the model itself, what we were using is a model that was internationally agreed. It is comparable with other models around the world. There are inaccuracies in it and they were recognised. The best information that we had was used to feed into that model to get the best output that we could. There is work that’s going on now to improve the model in terms of vertical granularity, for example. So the limitations of it are recognised, but we were working with internationally agreed standards and with a model that is comparable with any around the rest of the world.

Captain Steeds: Can I just clarify a couple of points? On day one it is true that NATS reduced the flow rate to zero. On day two going forward, or it might be day three going forward, it was the UK NOTAM Office, which is, as I understand it, part of the Directorate of Airspace Policy Office, which issued NOTAMs which closed parts of airspace. So it moved from being a zero flow rate, which you could understand NATS imposing because they didn’t know what was going on on day one, to airspace closure imposed by a part of the CAA, just to clarify that.

In the comments about the test flights, it’s true that we weren’t certified. I beg your pardon-we were certified. We didn’t have test equipment on board, but we measured the engines before and we measured them afterwards and we found nothing at all.

The Airbus A340 was instrumented. It was following a NERC 146. The NERC 146 refused to fly into the black area-the closed airspace-and turned round and came back. Therefore, the Airbus did the same. Airbus themselves were furious about it.

Q120 Stephen Mosley: At the time in April when all of this was going on, I was a lay person, a member of the public, and to me there did seem to be a great deal of confusion or lack of information coming out. I think we have seen that today as well. We’ve got the airlines. We’ve got Captain Steeds here, who is learning things today. He is learning things about SAGE etcetera which he wasn’t aware of. How well do you think the information was disseminated by Government, by organisations like yourselves, to the public, to the airlines? How well do you think the level of risk and the reasons for the airspace closure were made available to the public?

Dr Loughlin: From the British Geological Survey point of view, we were putting out information daily, specifically about the volcano and the type of activity, particularly drawing attention to some aspects that relate to what we have just talked about, which is the great diversity of volcanoes, volcano types, eruption types, and why this particular eruption was responsible for some of the difficulties.

Just to go back to Montserrat again and also to discuss places like Alaska and Pinatubo, some of these other well-known volcanoes, these are short-lived explosions that last a few minutes to hours. They produce discrete ash clouds which then can be tracked as they move through the atmosphere. Also these kind of vertical single explosions have well-known empirical relationships that relate the height of the plume to the eruption flux. These are the parameters that go into the modelling. It worked quite well for these types of explosions at these types of volcanoes.

The point about the Eyjafjallajökull volcano is that it was an eruption through ice-it was quite weak-that did not generate a vertical transient eruption cloud. The cloud carried on for weeks generating more and more ash. Also, it wasn’t a vertical column so this empirical relationship between height and eruption rate didn’t really stand as well. So the fact was that for this particular eruption it was very difficult to get these source terms right for what was, basically, a very weak plume. It was not this discrete body of ash that you could easily track around, which you get in places like Montserrat and also in Alaska and the like. So it was a very different type of eruption and it caused particular problems for the source terms of the modelling. So we were putting out information describing this type of eruption on our website.

But I would have liked to have seen more interaction between the volcanology community and airlines, I think. The CAA and SAGE did facilitate a conference very early on. It’s true that SAGE didn’t meet until all these major decisions had been made, but once it did meet the CAA and SAGE facilitated a conference where the scientists and the airlines were able to get together and we presented some of the key science to airline executives.

Ray Elgy: The information that we provided as well was on the website. All the decisions we took and all of the evidence that was taken into account in coming to those decisions was published. On our website as well, we did publish information that explained what was going on and the reasons for it. We were also in contact on a very regular basis with all sectors of industry to explain to them what was going on so that they could then pass on the messages to their customers.

Dr Gratton: With regard to putting information out to the whole community, however you define "community", one thing was very evident. This was a huge problem. It involved an awful lot of people and virtually all of those people were working 18 or 20-hour days trying to solve it. That left very little capacity for anybody to then go out and start explaining to the media, to politicians like yourselves, to everybody else, what we were doing.

The position scientifically was changing very rapidly. The understanding was constantly being refined, and it was being refined by people who simply had very limited time to do additional communication. To be honest, I think, yes, there were failings in the scientific, engineering and aerospace communities’ ability to communicate with the outside world and, to an extent, with each other. I really don’t think you could have avoided that because, if people were taking time out to explain what was going on, then they would have been taking that time away from solving the problem.

For example, the Science Media Centre, which is based at the Royal Institution, which has an active role in pairing up scientists with the media in the event of a science-related news story, and I think does a really fantastic job, I think managed to find four people who weren’t directly involved in trying to solve the problem and therefore had enough time. Those four people ended up working every hour available just trying to explain what was going on and keep their own knowledge up to date. Realistically, if you have another problem like this again, you’re going to get the same difficulty simply because those who understand the problem are just too busy to talk about it for those few days, few weeks, until the emergency is subsiding.

Q121 Chair: I have just one very quick question and not more than a short sentence response, please. Given the fact that NERC is still owed money, do you think that has damaged the trust between the research community and Government, and will that impact upon future events like this?

Dr Gratton: Yes.

Chair: Thank you.

Q122 Gavin Barwell: This is really a wrap-up question. It seems to me from what we have heard from you this morning that the existing ICAO recommended practice doesn’t seem to me to be based on clear scientific evidence. There is difficulty in getting accurate data about what’s coming out of these volcanoes, there are different kinds of eruptions, and you were making the point, Dr Gratton, that we don’t know exactly what level, what mass, what concentration of ash poses a risk in terms of long-term maintenance or actually to the safety of passengers and crew on aircraft. You’ve just been talking about some of the difficulties in relation to media handling. Given all of that, do you feel that the UK would be any better prepared if the same thing happened against next year?

Ray Elgy: Yes, I do. I think we are better prepared. We do have a new system in place. You made the point about existing guidance not being scientifically based and that’s true to a certain extent in the sense that the advice is to avoid ash. There is a huge amount of work being led now by the ICAO Volcanic Ash Task Force to refine the model, to get better systems in place. Until that is in place and that work has been completed, then we will be left with managing any future situation with the system that we currently have in place, which is the three zones.

Dr Gratton: I agree with that, absolutely. The engineering work is continuing. There is a phenomenal effort that continues to be put in now that the world community has realised how big a problem this is. Clearly, it’s going to go in two directions. One is better modelling and presentation of the model. The other is about the safety factors and the maintenance overheads. Inevitably, we played safe because, for all of the hundreds of millions of pounds that have been lost, that’s not worth loss of human life. So we had to play safe. But that work is now heading towards reducing the safety factors, expanding the contaminated airspace that can be flown in for no maintenance costs, and it will continue to go in that direction. So, scientifically, we are going to be in a much better position.

I would just like to mention something that hasn’t really been discussed. From an aeronautical engineering viewpoint the big issue is the aircraft engines. The numbers that we were using and that have defined the limits that still stand were, essentially, those agreed by the major aircraft engine manufacturers. I have never seen anything like this. Rolls-Royce and General Electric, two massive multi-national companies, both spend their entire lives fighting tooth and nail against each other in the market. They just pooled their engineering departments. They just put everybody together and said, "Work together. Share all the data. Solve this problem." It was really impressive to watch. I don’t suppose we’ll ever see it again, but it was great. That’s where those numbers come from. Particularly from those two companies, they are from the best science that could be done by the world’s two largest jet engine manufacturers. They were being pushed by everybody, by British Airways, by the CAA even, on how small they could get the safety factors, because the smaller the safety factor, the more airspace you can fly in. Ultimately, it was their advice, "This is as far as we are going and no further" on safety grounds to jet engines.

Dr Loughlin: Yes. I agree with what has been said previously. The science has moved forward a little but it is not a quick fix. The ICAO Task Force is critical to this, but it is going to take time before results come out of that work. But what has been achieved as a result of April is very strong networks, cross-disciplinary working, and that’s all going to put us in a better position for next time.

The other thing that has happened is that, because of the lack of preparedness, there has been a huge educational effort needed this time around. Certainly next time around it will still be as busy as it was in April but we won’t spend as much time, perhaps, sharing basic information and we will be able to move faster to the more critical issues.

Captain Steeds: I think we are better placed because we now have some better radar up in Iceland so the input into the VAAC model will be better and, therefore, the output from the VAAC model will be better. On the discussion about what the limit is, Rolls-Royce, GE and Pratt & Whitney all agree that it’s 2x10-3. They allow you to fly in any areas, including the famous black zone, which the UK closed, if it is forecast because, like everything else, you get weather forecasts and then you get what actually happens on the day. The engine manufacturers haven’t put any restriction on us flying in areas where there is forecast to be volcanic ash above a concentration of 2x10-3. Their recommendation to the airlines is to avoid visible ash. So, actually, despite Rolls-Royce, GE and everybody else working together, the recommendation that they come back to is the basic ICAO guidance material.

The UK has come up with three zones. You have the black zone, where it is a concentration greater than 4x10-3, and that is closed by NOTAM. Then you have a time limited zone without a time limit, which is an interesting concept, which is a concentration between 2x10-3 and 4x10-3. Then you have the area now up to 2x10-3 and everybody agrees that you can fly in that area without limit.

So am I confident that we have moved forward? My confidence is that with the purchase of the radar the output from the model will be better. Hopefully, that will help us. But, otherwise, I am less confident than my colleagues that we have actually made very much progress.

Dr Loughlin: Could I just clarify one thing. Unfortunately, the radar hasn’t been installed yet. So we are still going to be dealing with uncertainty if we get an eruption in the next few months. But, having said that, the validation of the model, using planes, using ground-based remote sensing and satellite remote sensing, is absolutely critical. But I do think everybody clearly understands what the source-term issues are now and that will help in dealing with things in the interim.

Captain Steeds: Just for clarity on that, I believe I am correct in saying that Europe has moved the radar from Etna up. So we have some improvement in radar but we haven’t got the final improvement.

Dr Loughlin: Yes, okay.

Chair: Thank you very much for your contributions. You will be interested to know that I flew around Montserrat when it first exploded in a naval helicopter, and I was told, "We can’t get any closer, Sir, because it’ll fall out of the sky", which was a salutary lesson. Thank you very much for your evidence.

Examination of Witnesses

Witnesses: Professor Brian Collins, Chief Scientific Adviser, Department for Transport, Dr Miles Parker, Deputy Chief Scientific Adviser, Department for Environment, Food and Rural Affairs, and Professor Julia Slingo, Chief Scientific Advisor, Met Office, gave evidence.

Chair: Thank you for attending this morning. Perhaps you would be kind enough to introduce yourselves briefly.

Dr Parker: I am Miles Parker. I am the Deputy Chief Scientific Adviser at the Department for Environment, Food and Rural Affairs.

Professor Collins: I am Professor Brian Collins. I am the Chief Scientific Adviser, Department for Transport.

Professor Slingo: I am Professor Julia Slingo. I am the Chief Scientist at the Met Office.

Q123 Chair: Our previous session with witnesses slightly overran because I think colleagues found some of the contradictions coming from them intriguing. You all three were at the heart of the matter. Who assumed leadership of this emergency and how did it evolve?

Professor Collins: My understanding is that the Prime Minister took the decision to call a meeting of SAGE and asked John Beddington, now Sir John Beddington, the Government Chief Scientific Adviser, to form up a SAGE group. I believe that was on the Friday. John sent a message to all the Chief Scientific Advisers and others whom he thought could contribute for names of people who could provide the expertise to form a SAGE meeting, and John chaired that first meeting on the following Wednesday. So it was the then Prime Minister’s initiative. I should add, of course, that we were in purdah at the time when this incident occurred.

Q124 Chair: When the Cabinet Office was managing this, was there sufficient expertise there to deal with emergencies like this?

Professor Collins: You suggest that the Cabinet Office had been-

Chair: The Prime Minister himself.

Professor Collins: I see what you mean. I think that is exactly why he asked Sir John Beddington to create a special group around this particular topic because it was immediately seen that it was extremely complex. A large number of disciplines needed to interact with each other to understand the nature of the problem and what the possible solutions might be. That is why he went through John to get an external group of people together, as you have heard in the previous evidence.

Q125 Chair: Had the Government been ignoring warnings about the potential risk from volcanic eruptions?

Professor Slingo: I will go back to your first question because I think it is important that the Committee understands that, as soon as the volcano erupted, as the agency responsible for natural hazard emergencies and well used to dealing with them, we immediately alerted the Cabinet Office, the CAA and the Civil Contingencies Secretariat, and we had a member of staff in the Civil Contingencies Secretariat within an hour. So that had all happened as soon as the volcano erupted. We were well aware of it by Thursday and looking at the meteorological situation and so forth. I was called by Sir John on Saturday and spent Sunday with him in the Cabinet Office.

The processes around natural hazard emergencies and our role as operating and providing the London VAAC got into gear very, very early on.

Professor Collins: That was separate from forming up SAGE.

Professor Slingo: Yes, but a COBRA was called and the Civil Contingencies Secretariat went into full activity immediately with our engagement and providing advice right from the word go. We immediately set our teams in place and the operational process of the forecasting, what we were doing about monitoring, etcetera, etcetera, all went into full swing by the end of that week.

Q126 Chair: Previous witnesses have suggested that the radar evidence that you were relying on from Iceland was not up to scratch. When were you aware of that and when were Sir John and others notified of that?

Professor Slingo: In terms of the radar?

Chair: Yes.

Professor Slingo: We don’t rely solely on any radar evidence.

Q127 Chair: No. I didn’t say you relied solely on it. I asked when you were aware that the radar that you were partly relying on was inadequate.

Professor Slingo: We have always known that in terms of quantifying the source would always be challenging. I think we need to be clear that at the start of this emergency the guidance from ICAO, which goes to the VAACs, is for the VAACs to advise on the ash/no ash boundary. Our duty to the VAAC is to say, "Is there ash there?", not "How much ash is there?" Actually, we were the first VAAC, and indeed the first Met, to have to start producing forecasts about ash concentration as opposed to where ash is. So the issues around knowing the source term really came to the fore as soon as it became apparent that we would have to move from ash/no ash, which is quite constrained by the meteorology rather than the source term, to concentration, which is constrained both by the meteorology and what’s coming out of the volcano.

Going back to your question about characterising the source, we were in very close contact with the Icelandic Met Office, who were working with the Icelandic Earth Science Department, who are very experienced in Iceland volcanoes. We were talking to BGS. We had aircraft reconnaissance of the plume. We had satellite information about the plume. To be fair, it’s not what is coming out of the volcano at the volcano that matters for us. It is what was about tens of kilometres downstream where the big stuff had dropped out and you were left with a fairly stratified plume with the ash that would actually influence airspace. That was what we were looking at all the time. We were not relying that strongly on the radar to tell us about the source because it can’t. It’s not designed to give all the information required.

Q128 Chair: But it has been replaced?

Professor Slingo: There is a new one. There is an Italian one that we talked about, which is en route and will be in place, I believe, next week.

Q129 Chair: In your written submission you mention six-monthly contingency planning exercises. Was the Government really unprepared? There do not seem to be any contingency plans for this event.

Professor Slingo: Yes, we have these six-monthly planning tests and they are done using the current weather conditions so we go through the process. I think when we talk about being unprepared we have to understand that the meteorology that was prevailing at that particular time was almost the worst possible situation that you could get meteorologically. I remember thinking, when it first erupted and looking at the weather maps, we’re in some trouble here because this is not going to change for several days and the flow is bringing the ash almost directly over the UK. It’s very unusual. So the combination of the nature of the volcano and the meteorology put us in a place that, with the best will in the world, even through a lot of six-monthly testing with the real weather conditions at that time, and testing all our processes and all our modelling, to anticipate an event like that in advance is very, very tricky.

That being said, if we were just required to provide ash/no ash guidance, which is what the London VAAC was required to do, we did a fantastic job. Despite what other witnesses have said-I have the evidence and we showed it at the CAA conference-the comparison between the model’s forecast of the extent of the ash cloud and what we observed very clearly from satellites and from other ground-based observations was incredibly accurate. So I think we were doing a really good job with what we were required to do at that time.

Q130 Gavin Barwell: I have three questions for you about the working of SAGE. First of all, in terms of transparency, neither the membership nor the minutes of the SAGE meetings have been published. Why is that?

Professor Collins: I discussed that with Sir John Beddington about two hours ago. He, of course, is reporting to you later. There isn’t a secretariat in the context of the way this particular SAGE group was put together because of it being led from No. 10 at that particular point in history. So John is well aware that the record is not yet published. It is in preparation. I think you need to ask him whether there were factors that he felt were appropriate at the time that would have suggested it shouldn’t be published.

Gavin Barwell: You didn’t. We will do that.

Q131 Chair: Can you see any reason why it shouldn’t have been in the public domain?

Professor Collins: I can see some sensitivities, yes, but I believe you should ask Sir John what they are.

Q132 Chair: I am asking you what your view is.

Professor Collins: I don’t want to answer that question in a public domain.

Q133 Stephen Mosley: Did you have to sign non-disclosure agreements as part of your conditions?

Professor Collins: I am an adviser to Government so I don’t have to sign a non-disclosure agreement. Did others?

Q134 Stephen Mosley: Did others?

Professor Collins: Yes.

Stephen Mosley: They did. Okay.

Q135 Gavin Barwell: My second question is about the timing of the SAGE meetings, so that the first meeting actually occurred on the day that UK airports re-opened.

Professor Collins: That was the Wednesday.

Q136 Gavin Barwell: 21 April?

Professor Slingo: Yes; that’s right. The full SAGE met on Wednesday.

Q137 Gavin Barwell: There was a telephone conference the day before, I think?

Professor Collins: Yes, there was.

Q138 Gavin Barwell: The full meeting was the day they re-opened. Was there a reason that it took that time to get the SAGE meeting for the first time?

Professor Collins: You were involved before that.

Professor Slingo: As I said, I was involved with Sir John on the Sunday. We had discussions then, with myself and Sue Loughlin, whom you have just talked to, and we were asked to provide suitable names to represent the meteorology and the volcanology, particularly across academia and people who had not got vested interests. So by Monday I had provided Sir John with a list of names that I believed represented well the research aircraft community that you have heard from, from the academic community in terms of LIDAR technology, scattering processes, all that sort of atmospheric physics community and the meteorological weather conditions-type community. Sue Loughlin did the same on the volcanology. Those phone calls were then made on the Monday. There was a teleconference and that group met on Wednesday. It is hard to do it much faster than that.

Q139 Gavin Barwell: I will press a little bit on that. Obviously, the decisions that were being made in terms of shutting down UK airspace had a very significant impact on individual companies and on the UK economy as well. Is the time it took to identify those people perhaps an indication that this wasn’t a risk that had been particularly anticipated? If you look at some of the other things that are on the Government’s risk register, is there already drawn up a view that, "If this happens, these are the people we would get on to SAGE" and you would get a meeting quicker? Is that why it took a little time?

Professor Slingo: I think that’s probably a fair comment, yes.

Q140 Gavin Barwell: My final question on SAGE is about the process for appointing people and whether you feel, with hindsight, that the right balance of expertise was on there from the start. I think we got the impression from our previous evidence session that, at least initially, there weren’t necessarily people with engineering experience in terms of the operation of engines and what the tolerances might be.

Professor Collins: At the first meeting it is perfectly true to say, because those people were seriously busy dealing with their activity, and there aren’t many of them, that at the first meeting they weren’t present. Sir John and I had private meetings with the Chief Engineer of Rolls-Royce in the gap between the first meeting and the second meeting of SAGE. He was represented, as were the CAA engine experts, at the next meeting. So from that point on, as a result of identifying that that was a community we needed at that table, the answer is correct. Yes, we moved as quickly as we could.

Q141 Stephen Mosley: Having heard Professor Collins’ earlier answer, my question is probably best off being pointed at Sir John Beddington when we talk to him. Can I just come back on something that we had in the first discussion? It was just the issue that Mr Stringer was raising about the difference between the model and the actual evidence, when you sent the aeroplane up there. We are told that you might have the answers as to the actual levels of ash that you discovered when you went up there. Could you just let us know? Did you find ash, what concentrations were they in and did they fit in with what the model was predicting?

Professor Slingo: When we moved on to having to talk about how much ash we believed was in the atmosphere, those measurements became crucial. From the point of view of was there ash/no ash, the reconnaissance flights in the early part of the emergency were finding ash where we expected it to be. As I have said, we then had to move to saying how much ash was up there. The other point about this particular event and the meteorology is that we had a high pressure system so the ash was layering. It was being stratified into layers with quite large amounts. So for us it was more about, "What’s the peak concentration? What is the risk of exposure?". So we were required to talk about peak concentrations. So the red and black areas, which we have been hearing about, which were the 2x10-3, 2x10-4g/m3, those, not just from the aircraft but also from our ground-based instruments-this is LIDARs, aerosondes and so forth-all suggested that we were pretty accurate, within an order of magnitude, which, when you think about the range of values that you could get in a situation like that, showed we were pretty close on the peak concentrations.

That was a very important point for us because, even if we can’t characterise the source, we can back-calibrate the source by the monitoring that we had in place over the UK, from aircraft and, indeed, from satellite observations. There are ways-it is quite scientifically challenging-that you can retrieve concentrations. We had scientists working on that throughout this episode.

I think a fair assessment is that, for the peak concentrations, we were within at most an order of magnitude and probably better than that. So the ash was there. It was at the levels pretty much that we were predicting it to be. That is a remarkable achievement considering that we had to move from saying "Is ash there?" to "How much?" within, literally, five days.

Professor Collins: Yes.

Professor Slingo: I can assure you my scientists were working long hours with no breaks for several weeks. It was a very challenging period for us.

Professor Collins: Could I just pick up on a question that Mr Stringer asked earlier about accuracy of measurement? The accuracy, as you have just heard, order of magnitude, that was about as best you could achieve.

Professor Slingo: Yes.

Professor Collins: The margin between where the safety limit was set and where we knew ash damage would occur in an engine, as described by the consortium of engine manufacturers, who, you have just heard, got together to decide what that number would be, left another factor of 100 between what they saw as damaging to the peak concentration that the measurement that the Met Office had said. So we combined all those uncertainties together in that process within about 10 days of the volcano going up, from a standing start. I don’t know whether that actually answers the question you were asking, but I felt it was relevant to the uncertainty that maybe you were left with.

Q142 Graham Stringer: I will come to a question I’ve not yet asked. Is this work peer reviewed and publicly available, where you say that you are accurate within an order of magnitude?

Professor Slingo: Of course it’s not peer reviewed yet, because this was new science. The papers are being reviewed now in the literature, so we have a series of papers that cover the observations, that cover the models, that actually even cover some of the sensitivity tests that we have been doing with the models to try and look at the range of uncertainties that might have arisen due to not knowing the particle size distribution accurately and not knowing the vertical structure of the source term.

In terms of observational evidence, we were putting that stuff out on our website at the time along with the five-day forecasts of the plume concentrations that we were asked to do by Government. So all that information is freely available. The observations were on the website. So those of a scientific bent could have looked at them and seen evidence of this layering that I’ve talked about and some of the evidence for the sorts of concentration values.

Professor Collins: There was also an event that was held jointly, which you have already heard about, sponsored by the CAA and SAGE, which was attended by a very wide audience. All of the science and all of the considerations that SAGE had been talking about was discussed on that day. The airlines were there in force at the most senior level.

Q143 Graham Stringer: When you are talking about being accurate within an order of magnitude, what are you talking about? Are you talking about getting the level at which the ash was accurate so that you knew precisely where the layering was or are you talking about concentration?

Professor Slingo: I am talking about peak concentrations.

Q144 Graham Stringer: But not, actually, the location of it in a vertical axis?

Professor Slingo: We can’t be entirely accurate about the vertical location because of the way the model is constructed and the computational cost. We could put many more vertical layers in. But, again, you have to say to what degree can you evaluate that and is that useful information? Later on, and actually during the whole event, we were looking at between what flight levels the ash was situated. That’s fairly important information. But to say exactly in the vertical where these layers were a day or two ahead is extremely difficult, but, even with that, we have good evidence that the model was doing a remarkably good job. These layers were descending slowly towards the surface, the old ash layers, and the model was capturing all those processes. The meteorology is a major driver.

There is a key point here as well. Our global weather forecasts are, arguably, the best in the world alongside the European Centre for Medium-Range Weather Forecasts in Reading. The meteorology that drives the dispersion of the ash was actually a really key factor in also getting the concentration and the structure of this major ash plume right. The weather forecasts at that time were extremely good so it is the combination of state-of-the-art atmospheric dispersion modelling with state of the art global weather forecasting which gave us quite a lot of confidence in what we were doing and what we were saying.

Q145 Graham Stringer: The Royal Aeronautical Society, the Airport Operators’ Association, British Airways and Manchester Airport have all criticised your lack of responsiveness to their criticism that the inputs into the model were poor. How do you respond to that criticism?

Professor Slingo: We know that the uncertainty in the source term is an issue. We were looking at that and adjusting it on a six-hourly basis with the advice we were getting from the Icelandic Met Office, the Icelandic Earth Sciences Department, BGS-

Q146 Graham Stringer: I don’t quite understand that. There was a limited amount of source information, wasn’t there, from Iceland around when the volcano went off? How could you change that?

Professor Slingo: I think Sue Loughlin talked about the relationship between the height of the-there are various things. You can look at the height of the plume. You can also look at the lightning activity within the plume. We were also using that to give us some idea of the intensity of the volcano. We have satellite observations. We had information downstream, certainly coming into the UK, which would give us an idea of whether we had the mass amounts anything like right. As I said, we were in an order of magnitude on peak concentrations.

In terms of the changing nature of the source, the volcano was changing after the first eruption quite rapidly at times. We were re-doing our forecasts on a six-hourly basis and adjusting the source term as soon as we had any change in information about the activity. That, on occasion, meant that there were what appeared to be random changes in the forecast from one six hours to the next, but that’s the nature of the beast you are dealing with. You can’t forecast volcanic activity in the same way that you can forecast the weather.

Q147 Graham Stringer: I understand that. Maybe I am not making myself clear. The criticism was that the actual information from the source was poor quality going into the model.

Professor Slingo: Yes.

Q148 Graham Stringer: Those organisations, in all their submissions, are critical that you were unwilling to accept that the data input was itself inaccurate, not that the model didn’t work.

Professor Slingo: I totally disagree. We have been very clear right from the word go that a major constraint on the accuracy of the ash concentration forecast has to be in the definition of the source term. We are all agreed. It’s a major recommendation. At the Met Office we have done a major review of what happened during that emergency and one of our strongest recommendations is to get a better handle on not so much what’s actually coming out of the volcano in the vicinity of the volcano but what exits finally in this contained plume that enters into the free atmosphere downstream of the volcano.

We have a couple of additional recommendations. One is that we need an aircraft that can really get into these plumes. With the CAA and DfT we are just completing the tendering process for fully instrumented aircraft, a civil contingency aircraft, that will be on 24-hour call, fully instrumented. It’s a turbo prop. It’s not a jet so it can fly where our BA 146 could not fly safely. That will be ready early next year to go. So that will be invaluable in telling us to the north of Scotland what’s coming our way because actually that is far more useful to us than knowing exactly what’s coming out of the volcano at the volcano.

Then the other thing is that we have what we call "sondes" that can be launched from the surface or dropped from an aircraft which have a package of instruments on that look at aerosols. They look at particle sizes, composition, mass concentrations. At the time of this event we had three of those instruments available. They are research instruments. They were used, and that is part of the evidence that we had for knowing what the peak concentrations are. We now have 20. We can deploy those from the surface or we can drop them out of an aircraft through the plume. So, for me, we understand that that is a major constraint on the confidence of the ash concentration forecast and we are acting on it. So we’ve never denied that there was uncertainty there.

Q149 Chair: Dr Parker-I think this is more or less agreed-there are other areas where safety considerations are paramount where we expect the producer to collect data on behalf of Government. In this case, isn’t there an argument for the airline industry collecting data on behalf of Government?

Dr Parker: If you are referring to the environmental issues-

Chair: Yes.

Dr Parker: No, they are not, really, because most of them are happening at ground level rather than at the upper layers.

Q150 Chair: So you see a different between ground level activity and things in the air?

Dr Parker: Our concerns were entirely with what might have been deposited in water, in breathable air or on the ground.

Q151 Chair: I know that was your concern. On many of your ground-based activities you require industry to collect regular data and feed it into your models. Isn’t there an argument that says the same should apply for the airline industry in terms of helping out on things like this?

Dr Parker: I find it difficult to see how they could. We were happy to get information from whatever source it was available, but in this case I am at a loss to know what it is they could contribute.

Q152 Chair: Did the BA test flights have a wider scientific value? Should we encourage them to do more of them?

Dr Parker: Again, I take your point but they didn’t give us the sort of information which would have told us what the ground level conditions were going to be. So in that sense, no, they are not helpful.

Q153 Stephen Metcalfe: Very briefly, because I am aware of the time, firstly, do you think the current emergency is over, secondly, is it going to happen again, and, thirdly, are we better prepared and what have we learnt from the previous experience? That is for all three, really, I suppose.

Dr Parker: Okay. Very quickly from my end, in technical terms, it’s only over when the Icelandic geologists tell us it’s over. In terms of what was actually happening on the ground, we have had zero results in a long while. So we feel it’s over in that sense.

Have we learnt a lot? Yes, a good deal, and it’s been helpful in building up our knowledge of who are the right people to call on at the right time.

Are we better prepared? I think we had most of our preparations in place. We had a risk assessment based on an earlier volcanic explosion which related to the veterinary issues we might have faced. Our biggest difficulty at the time was finding somebody to analyse fluorine in samples. We managed that quite quickly. Yes, I think we learnt some useful lessons there.

Professor Collins: I think the answer for the particular volcano that erupted in April is yes because it isn’t erupting now. Iceland is one of the densest parts of the planet with regard to where volcanoes exist. So will it happen again? Certainly. When? I haven’t a clue, but it absolutely certainly will happen again.

Are we better prepared? My observation is that we were pretty well prepared in a lot of disjointed areas. What this episode showed us how to do, and quickly, was to bring those disjointed areas together in a very constructive and collaborative way to deliver as quickly as possible a solution that got us out of a situation that could have been unsafe and we didn’t know, so we erred on the side of safety, to a situation that we now know to be safe, but we still need to do a lot more work.

Are we better prepared? Absolutely, because we now have that community working together and it is still continuing to work, as Julia has just said, on a number of the critical aspects were there to be another volcano in the near future.

Given the resource constraints, we, I think, have to look to the market, going back to the Chairman’s question just now. We do have to look to the market just a wee bit more than perhaps we have done in the past to help us with the experience of what actually happens when aircraft fly through airspace which has got stuff in it, whether it is volcanic ash, ice or anything else. We need to get the science of observation in airspace better coupled to the experience of aviators who fly through it. That is a piece of work that, maybe, we haven’t done as much of yet as we should do. In the current economic climate, if you say to anybody "Add to your cost base", that’s not going to go down well, but, nevertheless, we ought to be addressing it.

Professor Slingo: Yes, the current emergency is over, but I think it would be wrong for us to take our foot off the pedal in terms of the research, the development of the forecasting capability, the monitoring systems, because, for sure, this was a wake-up call of how bad it could be. Next time, of course, the meteorology may be a lot more friendly. We may not be hit with such a difficult situation. There is no doubt, certainly within the Met Office, that we are pushing ahead with improving the forecasting process and particularly recognising the need to actually say something about concentrations now, which is going to be very demanding for us.

Q154 Chair: All of those three answers have financial implications-

Professor Slingo: Yes.

Chair: -yet we still owe money to NERC?

Professor Collins: We do because the NERC aircraft existed which, of course, had it not existed we would have been in much more difficult straits. It is worth considering that the fact that we put 30 years’ worth of investment into atmospheric science, into meteorology, into modelling, into volcanology through our science base, gave us the ability to react very quickly. I agree we have a financial short-term issue to resolve but actually the fundamentals of continuing to invest in making sure we are not vulnerable in the future are probably more substantial and maybe slightly trickier. That’s the current ICAO road map for what is happening. We are, from an aviation point of view, still working extensively and collaboratively on an international front to ensure that not just our airspace but European airspace, with respect to Iceland, is much better understood in these circumstances.

Chair: Thank you very much for your time.