ACTANTS AND ASH CLOUDS

The risks raised by the ash cloud that swamped Europe in April/May 2010 could be thought of in terms of a set of actants (things, people, institutions anything entity really that has the ability to act upon and be acted upon by other entities). Relations between these actants are not fixed but change as the interactions between the actants change. Some relations and actants are harder to change, more entrenched, than others but all are capable of change even if this change is more painful to some than to others.

Figure 1 illustrates the main actants involved in the ash cloud story. The actants are presented as simple boxes but this hides a great deal of differentiation within each box. All airlines, for example, are not the same and or, initially anyway, were they response to the ash clod. Some airlines complained bitterly after a few days of grounding, others took the air in uninstrumented flights to ‘prove’ the safety of the airspace. Likewise, the government is likely to have had different factions pushing for grounding and for letting flights take place. All the actants relations end up focusing on airspace, the theatre in which the drama is played out.


Figure 1 Main actants in ash cloud drama

Importantly, none of the boxes is isolated; many of the boxes are intricately interlinked. Some of the links are relatively straight-forward. The Met Office and CAA, for example, are linked in a very formal manner. The CAA have set criteria for dust concentrations deemed safe. The Met Office provided that information based on computer modelling and data from instrumented flights. The Met Office may also provide the CAA with information on hazardous weather conditions but again the link is formal and highly structured. The link between the met Office and government is more of an economic link, the government paying for an impartial service, whilst the CAA has a regulatory link to the government in setting the legal parameters of responsibility for the airlines. Links need not be singular in nature. The airlines pay tax to the government (economic link), but also lobby on environmental issues and apply pressure when they interests are threatened.

The whole network trundles along, changing and developing as the actants interact, each trying to make the whole network function for their benefit. Each actant has a role in the network. The Met Office has a ‘scientific’ role of monitoring, the CAA a regulatory role, the airlines an economic role. This does not mean to say that each actant will not press into service different aspects of their character in pursuit of their goals, in their attempts to align the network and how it operate to their benefit. The Met Office tries to monitor the ash concentrations, measure and characterize the ash partilces and transmit this information effectively to all actants. The resultant grounding of flights, based on the CAA interpretation this information, meant the network wasn’t functioning in a manner that matched the desires of the airlines. The airlines tried to usurp the role of the Met Office by undertaking their own ‘tests’, flying unistrumented planes into the ash cloud and then transmitted this information through the network and beyond. The airlines tried to take on a role where they collected and transmitted information about the ash to parts of the network where that information could be understood in a way that benefited them. The general public could understand a plane going through an ash cloud and coming out the other side – could they understand complicated mathematically models that predicted ash concentrations? The airlines played to the general public, part of a wider network, to influence the government and CAA, part of the immediate network focused on the UK airspace.

Expanding the network out, it is relatively easy to include other actants (Figure 2). The CAA insisted that they were setting limits based on advice from VAAC and engine manufacturers. It didn’t take long before the economic relation between engine manufacturers and airlines resulted in the release of new information from the engine manufacturers as to the limits of operation in ash. Similarly, the wheel network could be expanded out to include the general public. There is however a danger with this type of analysis. You must always be aware that drawing a box around group doesn’t mean that that group is real or that that group is static. Entities evolve and are differentiated. Airlines are not all the same nor they necessarily behave in the same way to each hazard that they encounter. Likewise, the general public will not necessarily act as a mindless mass if given certain information. What this type of analysis does do is to help to clarify what entities are involved, how they are related and how they use these relationships to try to align the whole network to their benefit.


Figure 2 Expanding the network: VAAC and engine manufacturers

Icelandic Volcano: How Much Ash Is Dangerous?

Figure 1 Image ash plume from the Eyjafjallajökull volcano

I hate flying. No that is not quite true: I hate the thought of crashing, of a massive heavy metal object plummeting 30-odd thousand feet to the ground with me in it. I do fly though, I have to for work and for holidays, so I may not be the person you most want to sit next to on a plane. Having just made it back from a second year field class in Malta when the Eyjafjallajökull volcano erupted ejecting ash to between 20,000 and 30,000 feet, you can imagine I watched the news with great interest.

Aside from hearing news of the second year Berlin fieldclass who had to trek across Europe to the Belgium coast to get back, my interest was caught by the debate, carried out with more than a hint of repressed anger, between the Meteorological Office, the Civil Aviation Authority, the government and airlines. The Met Office view is outlined through their press releases (http://www.metoffice.gov.uk/corporate/pressoffice/volcano.html) whilst the BBC archives provide details of the chronology and debate, at least the public aspect of it (http://search.bbc.co.uk/search?go=toolbar&uri=%2F&q=icelandic+volcano and hunt around for something of interest).


Figure 2 Map of extent of ash cloud impact. Source: Metetorlogical Office

The particular angle I was interested in, however, was how this diverse set of actors came together because of a specific geophysical event and how what was viewed as ‘safe’ changed as the travel chaos unfolded at airport across Europe. Eyjafjallajökull itself could be seen as an actor in its own right with its own spatial extent, temporal behaviour and characteristics such as size and shape of ash particles released. The other actors in the drama, the Met Office, the CAA, the government and the airlines were all entwined in a complex web of relationships that focused on the definition of what was a safe level of ash for flights.

The definition of safe level was central to everything that happened in late April and early May 2010. Having never had such a massive eruption with a set of meteorological conditions that pushed the ash plume over the major flight paths across most of Europe the organisation assigned responsibility for safety fell back on the ‘safe’ position of stating a of stating a zero tolerance level (a little ash was allowed in the standard threshold of a concentration of 200 microgrammes per cubic meter), no ash you could fly, any ash (above standard threshold) you couldn’t. Given the damage that ash plumes had caused for aircraft engines in the past this seemed a ‘safe’ position.


Figure 3 British Airways engine after a run in with a volcanic ash plume in 1982. Image: Eric Moody, British Airways

But how did the CAA know this. Advice is provided by VAAC (Volcanic Ash Advisory Centres – see http://www.ucl.ac.uk/news/news-articles/1004/10041901 for an outline of the global warning system and its history). But how do they know? There may have been 80 incidents since 1982 but the Icelandic eruption was something different because of the geophysical conditions, a continuous stream of ash and meteorological conditions that meant it affected European airspace. The other actors in the network, once the duration of the hazard became clearer, did not passively sit there and accept the CAA advice and the Met Office evidence. BA, for example, undertook a ‘test’ flight through the ash cloud and, emerging safely the other side, declared they felt there was no danger. Likewise, as travel chaos grew, the airlines questioned the evidence upon which the advice was based. The focus of their attention was the use of modelling rather than monitoring to predict ash cloud movement. Despite using such modelling techniques to predict weather patterns that airline use, the ash cloud models were heavily criticised for not matching the reality the uninstrumented ‘test’ flights of the airlines showed.

The definition of ‘safe’, a fixed thing you might think, became a subject of negotiation within the network based on the interest of each of the actors. The details of the zoning of the ash cloud can be found at http://www.metoffice.gov.uk/corporate/pressoffice/2010/volcano/forecasts.html. Black zones have 20 times the standard threshold ash concentration (concentrations of over 4,000 microgrammes per cubic metre), grey zones have concentrations between 10 and 20 times the standard threshold (concentrations of 2,000-4,000 microgrammes per cubic metre). The standard threshold of concentrations of 200 microgrammes per cubic metre was used to define the edge of red zones. Each zone had associated with a it an additional definition – red zones stated the concentration was as used in official VAAC products. To operate in grey zones airlines had to present the CAA with a safety case that included the agreement of their aircraft and engine manufacturers. Black zone were stated to be zones where the required tolerances of engine manufacturers were exceeded.

So is ‘safe’ a fixed term, something that is unaltered by circumstances, by context? The above summary would suggest not. ‘Safe’ levels of ash became a term that could be defined, redefined and negotiated between the actors. Scientific evidence, which you may think could decide the issue, was itself open to debate and discussion. In my next blog about the ash cloud I will look at this negotiation of evidence in more detail