Why hsa the buffer zone of 60 miles been removed?
From eurocontrol:
"To this end charts showing areas of potential concentrated contamination have been produced in close coordination with London Volcanic Ash Advisory Centre. These charts enable States to establish NO FLY zones where necessary. Ongoing work by the UK Met Office and the UK CAA has confirmed the effectiveness of the model used to determine the areas where ash concentration could be above engine tolerance levels. For that reason, the 60 nautical mile "Buffer Zone" which was initially added has been removed from charts published as from 11-1200 UTC. States retain the prerogative to add the 60nm buffer if they believe it is necessary to do so."