Regarding changed engine thresholds I mentioned:

http://www.nats.co.uk/

I'm putting on my Aerospace engineering hat for this one... I'm irked at the assumption that the ash levels was dangerous for this latest one and the media and everyone went behind it.

From what I've heard through those in the industry; the engine mfr's and airlines were saying the data the Met office and CAA were using was BUNK over the last week and into the weekend. Even DLR (Deutsches Zentrum für Luft- und Raumfahrt e.V)/German Aerospace center sent up their Falcon aircraft Sunday into UK airspace along with a Lufthansa A340 with additional test equipment. Both profiled data above the ash cloud and rumor in the industry from those who profiled the data was that the ash concentrations are NOT as intense as thought once the distance drift from Iceland is taken into account.

In other words we should see LESS airspace closures now that DLR sent REAL data that the CAA used to determine it really isn't an issue. Basically new standards went in place Sunday night/Monday AM.

Now anything within the actual ash plume spout from the Volcano is highly dangerous for aircraft engines - but this level of concentration is RARELY even more than 100NM from the event. Hence when Mt. St. Helens erupted large swaths of US airspace was NOT closed just restrictions placed in areas - even in the 2009 eruption at Mt. Redoubt in Alaska went forward it was controlled and Alaska Air had two days of severe disruptions but once it was determined how to properly determine ash levels flights resumed. CAA/Met office was clueless on this one until this weekend. It's been a month of pure BUNK data being used and it needed to stop.

Too right for Branson and BA to call out the Met office and CAA on this one. Poor assumptions on data were used and flights were cancelled for no reason.