While restrictions on European airspace will ease from 20 April, Eurocontrol expects that a 'no-fly' zone will still affect around one-third of the current airspace area considered contaminated by volcanic ash.

Speaking at a briefing in Brussels today, Eurocontrol director for co-operative network design Bo Redeborn said the 'no-fly' region had yet to be defined and would take into account updated ash forecasts issued every six hours.

"The no-fly zone is based on satellite images where we know the concentration of ash is high," he says, adding that there will also be a buffer zone established.

Western Europe appears to be the area most likely to remain subject to restriction, says Redeborn, although he cautions that the situation is fluid.

He is unable to provide precise details of the extent of the no-fly zone, owing to the changing conditions. But he says the Nordic states, plus southern and eastern Europe, will probably be least affected by the ash cloud.

"Once a no-fly zone is agreed, we'll make sure no-one is allowed to file a flight plan that penetrates this zone," he says, adding that the area off-limits to aircraft should be reduced to about one-third of the current region of contamination.

European authorities are planning to re-open sections of airspace from 08:00CET (06:00UTC) on 20 April.

Source: Air Transport Intelligence news