etherate
I thought the earlier post with the satellite image of the actual plume was telling. Surely with modern technology of satellite imagery, the airspace closure could be narrowed down significantly to just the areas closest to the plume for avoidance? One wonders if we might be slightly over-reacting just a tad.
As I recall in Eric Moody's encounter (based on the chapter "Strange Encounter" in the book "Emergency") the BA009 flew very close to the volcanic ash cloud and not 700 miles away from the eruption as is most of UK airspace.
With the significantly dispersed cloud tracking over the UK there must be a much lower risk of contamination.
One problem is nobody seems to have any data as to acceptable or permitted levels of ash concentration affecting jet engines.
The other big problem, it now seems to me; is that someone is going to have to make a very difficult decision as to when to re-commence operations against an extremely hard to gauge risk of engine failure caused by volcanic ash penetration. I don't envy those who are going to have to take that one !