Scientific advice and evidence in emergencies - Science and Technology Committee Contents

Memorandum submitted by the Airport Operators Association (SAGE 39)


  1. The Airport Operators Association (AOA) is the trade association that represents the interests of British airports and is the principal body with which the UK Government and regulatory authorities consult on airport matters.

2. Our mission is to influence governments and regulators, at national, European and international levels, in order to secure policy outcomes that contribute to conditions for sustainable growth in the airport sector.

  3. Our airport members, some 70 in number, represent the UK's international hub, major regional airports as well as many serving community, business and leisure aviation. AOA actively brings these members together to share expertise and develop common approaches across the full spectrum of airport issues.

  4. Working closely with our members, partners and other stakeholders we play a lead role in promoting aviation security, economic development, and environmental sustainability.


  5. At the start of the crisis, members observed poor coordination between the parties involved, namely: the Volcanic Ash Advisory Centre (VAAC), the Met Office, the CAA and National Air Traffic Services (NATS). Moreover, there appeared to be no direct input from the government.

  6. As a result, in the first few days, nobody appeared to take responsibility for restricting flights. NATS's response was to close controlled airspace for six hours at a time, when the reality was that nobody would be flying for days. More realistic announcements on how long airspace would be closed for would have been much more helpful.

  7. This reflected the highly cautious attitude taken by those responsible for resolving the problem and those advising them at the start of the crisis. While this might have been expected at the very start, of what was after all a new situation for the UK, we do not think the parties should have continued in this vein.

  8. Moreover, while the International Civil Aviation Organisation (ICAO) had plans for a response to volcanic ash in airspace (see point five, below); such an event had never been considered for the UK and consequently there was no analysis, or contingency planning.

  9. As the authorities addressed events, it soon became clear that the ICAO volcanic ash plans were outdated. They relied on assumptions that later proved not to have been based on scientific evidence.

  10. Moreover, no scientific tests or certification had ever taken place to analyse and assess the ability for aircraft or engines to safely withstand flight in ash contaminated air.

  11. What also seemed surprising was that—to the public—the UK and European reaction to the crisis appeared to be unique, yet volcanic eruptions have occurred in other parts of the world with regularity, and the disruption to air traffic routes has been far less extensive. The reaction in the UK and Europe seemed highly disproportionate. Part of the reason for this was the businesses of UK and European airspace, whereas in other part of the world, aircraft can simply be diverted in the event of a volcanic eruption.

  12. Official forecasting by the Met office was also found to be heavily lacking. Airport operators required a good and stable forecast to work with their airlines to plan operations that would continue and those that would be cancelled for the following day. However, often, forecasts issued in the morning could change completely from the night before. This meant that flights were not cancelled in a timely manner, but rather at short notice. As a result of this poor forecasting, many airlines began to make decisions based on their own assessment of conditions.


  13. The solution to the crisis came about as a result of three factors. Two factors involved the use of scientific evidence. The three were:

    (a) The sheer scale of the problem. The inability of land and sea transport alternatives to cope. This left thousands of stranded passengers and in effect public crisis in both real and PR terms. The crisis provides clear evidence of the massive reliance on air transport for the UK.

    (b) The increasing airline impatience with the airspace closedown and their willingness to test-fly aircraft through areas where there were, or were supposed to be, ash clouds.

    (c) The decision of the CAA to take the initiative in resolving the crisis, by involving engine manufacturers, airlines and others in working out safe rules. This resulted in wide areas of airspace to be opened up.

  14.  The CAA embarked on a very rapid attempt to conduct some form of scientific certification with the engine manufacturers. This showed how different agencies can work together to achieve quick solutions, when clear leadership is shown.

  15. The CAA led it because the European Aviation Safety Authority (EASA) team didn't seem to have the expertise—a concern given the fact that that EASA is also now taking command of ATC and Aerodromes. Since the event, the EU has begun to implement clearer means of responding, as a Single Sky entity, to such an event. In spite of several years of development of both Single Sky and the existence of EASA, it was clear that a joint European was lacking.

  16. In the end, the resolution of the crisis involved hard evidence from engine manufacturers about the ability of their products to withstand moderate ash cloud exposure, and from the airlines about their level of confidence in being able to fly their aircraft safely.


  17. Question 3 is about obstacles to timely scientific evidence to inform policy decisions. The key weakness in managing and responding to the dynamic situation reactively was the poor accuracy of the forecasting models and also the models used for weather prediction, particularly winds. At one point, the London VAAC had issued no-fly zones, only for the Toulouse VAAC to discredit it by issuing advice that those over France did not exist.

  18. There are fundamental differences in the ash forecasting models used throughout the world, in spite of it being a global response plan. An example is that on some models, ash is assumed to disperse or sink to ground after three days, whereas the UK model continued to calculate forecasts using ash data that was several days old and increasingly likely to be inaccurate. In addition to the principles of the modelling, the lack of ability to take scientific measurement must have been a significant detriment to making improved forecasts.

  19. This meant the public and policy messages throughout were often unclear, delivered by a range of agencies or bodies, and most frustratingly, often conflicted or changed over time.

  20. Very few aircraft were equipped to take samples and measurements (and certainly not any of the commercial aircraft offered and used by a number of airlines and manufacturers) and the sparse coverage by Light Detection & Ranging (LIDAR) equipment severely hampered both the ability to check the accuracy of the forecasting and to add scientific data to improve the process of predicting ash concentration.

  21. Q4 mentions sources of scientific advice and a research base. It should be remembered that research comes at a high cost. What was experienced during the ash crisis was a once in 100-years event—how much effort and investment could reasonably be considered justified? Research involving aircraft engines is inevitably very costly—the work on biodiesel residue on aviation fuel is evidence of that (now at least two years into a programme, but one that is still not fully funded to get to a clear conclusion with all the relevant aircraft and component manufacturers).


  22. In considering where improvements could be made for future resilience, we propose that it is in the forecast modelling and the LIDAR coverage. Neither will make a perfect arrangement for forecasting or to directly permit flight in more dense concentrations, but they are reasonably deliverable.

  23. In conclusion, the crisis was solved by the CAA demonstrating clear leadership and using scientific evidence to derive a workable solution to the problem of closed airspace. There is no reason why such a solution would not work in any future crisis: it will work better when such leadership is shown from the outset.

Airport Operators Association

12 October 2010

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