There seems to be an argument developing about whether the ban was sensible safety precaution, or a hugely expensive and highly inconvenient knee-jerk reaction.
Needless to say, the airlines that are losing money (and vast amounts of it) are starting to get the hump. They now seem to be saying that the risks were exaggerated, that they've conducted test flights with no problem and that the losses are huge and unaffordable. They also seem to be saying that it's all based on theoretical models and little hard data.
The authorities responsible for closing airspace seem to be saying that they go by models, backed up by such hard data as they have, of where the ash is supposed to be and by recommendations from engine manufacturers. I've seen it suggested that engine manufacturers take the stance they do because of they don't have (or can't get) insurance that covers volcanic ash damage, but that doesn't necessarily mean the ash would damage engines, or make then unsafe .... or that it wouldn't. If so, the assertion would seem to be that because nobody has done the research, the data doesn't exist so they can't get insurance, and as a result, Europe's flying is pretty much shut down.
The Met Office certainly seem dismissive of the airline's claims about test flights. They point out that the situation is fluid and constantly changing, that normal aircraft systems can't detect the ash (which is why they use specially equipped research planes) and that the cloud is not a humongous solid block, but a series of clouds, and in layers at different altitudes. The airlines, being unable to detect it, could have been flying where the ash isn't. The problem is, they can't avoid ash in commercial flights if they can't tell where it is.
Oh, and the pilot's association seem to be saying that pilots might or might not fly anyway, since the final decision on (and responsibility for) passenger safety lies with the senior pilot. And quite right too. But .... however professional and responsible pilots are, they aren't experts in volcanic ash damage, and they don't have laser vision to detect it where aircraft nav and weather radar can't. Or I don't think they do anyway.
So ... I don't want aircraft safety in such unusual conditions as this left to the individual judgement of pilots who, however professional and competent they are, aren't qualified to judge on this.
I know the airlines are losing a fortune and some are in financial trouble anyway. But the problem is we don't have adequate data, and we don't have huge resources for gathering it. There aren't many suitably equipped aircraft, there aren't many laser ground stations and satellite data, while comprehensive, isn't detailed enough to give accurate maps, according to reports.
So what can the authorities do?
If they believe there's a serious risk but can't be sure quite how big, or precisely where it exists (and it moves about anyway), are they supposed to allow flights and if one (or more) comes down and kills a few hundred people say "Oops. We thought it was a decent gamble"? They'd get crucified .... and so would their political masters, and in our case, right in the middle of an election campaign.
Personally, I'm inclined to think that however expensive this gets for airlines, it needs to be safety first, second, third and always. Especially given the recorded damage to Finnish F-18 jets and, according to reports of a senior NATO official, similar damage to some NATO F-16 fighters. It certainly seems the alleged damage risk isn't utterly theoretical.
So .... was the ban right?
Should it be lifted because of airline concerns or losses?
Personally, I'm disgusted by the airlines attitude. They seem to think that a test flight or two is grounds for removing the ban. Perhaps some of these executives would care to try sticking one live round in the chamber of a 6-shot revolver, pointing it at their heads and pulling the trigger. If you get away with wit once or twice, or twenty or thirty times, it doesn't mean it's a safe thing to do. It just means you've been lucky for far.
And what they are now proposing seems to be tantamount to Russian Roulette with planes full of people as the stake, with the only difference being that they aren't sure if the round they put in the chamber is live or a dummy. Personally, despite the inconvenience, I'd rather have a horrible time trying to get back from wherever I was stranded than be killed in a crash because an airline executive was wrong about whether the bullet was live or dummy.