NASA's Terra satellite captured an image of the ash plume from Iceland's Eyjafjallajökull volcano Tuesday morning, April 20, 2010, as it flew overhead from its vantage point in space.

The Irish Aviation Authority and the Civil Aviation Authority of the UK on Tuesday sanctioned the resumption of full service on a phased basis in all Irish and UK airspace from 2100 hours Tuesday night, to Europe, North America and the UK.

The IAA has warned that the lifting of the restrictions is subject to the ash cloud, currently positioned between Iceland and Ireland, not moving over Ireland and no further aggressive volcanic activity. It is expected that flights today will focus on positioning aircraft and crews and full service by the airlines may take up to three days to recover. Passengers should consult airline websites before travelling to the airport for flights.

Following the agreement of the European Transport Ministers on Monday, the Irish Aviation Authority, UK Civil Aviation Authority, and UK NATS have agreed on a safe model to allow flight operations to resume in both countries. Eamonn Brennan, IAA CEO, said: "We welcome this agreement, which balances safety priorities with the need of the industry. This provides the foundation for a long term solution to the volcanic ash issue, however we need to be careful over the next few days as we are concerned that the ash cloud currently positioned between Iceland and Ireland may drift over the country. Ireland is one of the closest European countries to the exclusion zone which is shown in the Eurocontrol Air Ash Concentration Charts."

You can view the areas zoned by Eurocontrol as of 1800 on Tuesday 20^th April 2010. Restrictions in Irish airspace ended at 2100 hours Tuesday in ‘Zone 2' as per the Eurocontrol definition:  

• ZONE 2: In low contaminated areas, States should allow airlines to operate, fully supported by shared data, including advice from the scientific community (meteo, volcanic ash proliferation etc.) including safety assessments, supported by tests  under the oversight of the competent Safety Authorities;

The aircraft engine manufacturers have been consulted and detailed technical guidance has been developed in conjunction with CAA and IAA. This has been issued to airlines and maintenance organisations. This includes a risk management regime and additional maintenance. Each airline will have to comply with guidance material that will include additional reporting, maintenance inspections and regular ash ingestion assessments.

Ryanair said on Tuesday that it has decided to cancel all of its flights between Ireland and the UK until 1300hrs on Friday 23^rd April in order to use these UK and Irish based aircraft to operate extra flights from the UK to Continental Europe; and from Ireland to Continental Europe from 1300hrs on Thurs 22^nd April to clear any backlog of disrupted passengers travelling between Continental Europe, the UK and Ireland.

Ryanair travel update

Aer Lingus said Tuesday that it would cancel operations for today, Wednesday, up to 1:00 pm Irish time

Aer Lingus update

Met Éireann said on Tuesday that Iceland’s Eyjafjallajökull volcano is now primarily emitting lava and steam, and the ash emissions decreased considerably for a time. Ash emissions at the volcano for much of Monday reached altitudes of just 2km, whereas over the weekend the ash plume was reaching altitudes of 8km or 9km; by Tuesday however the plume height once more reached altitudes of 4km to 5km. The higher the ash plume extends, the further it travels; lower ash plumes will travel more slowly, and the ash will deposit out of them (fall to ground) more quickly.

The weather service said the source of the ash plume of relevance to European aviation virtually ceased for the latter part of Sunday and for much of Monday. This offered hope, for a time, that the concentrations in the atmosphere over Europe would thin out significantly over the coming days, and led to the authorities planning to permit some flights over Europe to resume on Tuesday and Wednesday. However, late on Monday evening, volcanic activity increased in strength again, with the plume reaching altitudes of 4km to 5km. This development led to the re-assessment by the aviation authorities early on Tuesday.

Apart from changes and developments in the emissions of ash from the volcano, the weather patterns are expected to change significantly through Friday and Saturday next, introducing a strong south or southwest wind over Ireland which will direct any ash emissions to the north of Iceland and away from the bulk of Europe.

The volcano has forced the cancellation of over 60,000 flights across Europe since it erupted last Wednesday.