Leo,
Please do not be so insulting to the Dutch.
Sooner rather than later, someone is going to have to take the responsibility for the decision to permit flight through or above a very diluted volcanic ash cloud. That will be an unenviable decision and hopefully it will be based on scientific, measured facts. The Dutch have been the brave ones to take that first step to collecting data for the basis of that decision.
The acceptable level of dilution and distance/time from the source volcano have yet to be decided, BUT THAT DECISION TO FLY WILL HAVE TO BE MADE. The alternative of keeping all commercial aviation grounded for all of whatever the future duration of the Icelandic volcanic activity is simply not imaginable (by me at any rate).
For example, BA 9 still flies over the volcanoes of Indonesia and the low level volcanic cloud is easily visible from altitude when overflying. Remember also that the KLM 744 in Dec 89 and the BA9 in Jun 82 were both relativly close to the source volcanoes and flew through the plumes which were not visible due to darkness.
The examination of the flight data from the KLM trial flight should also include a microscopic examination of the bleed systems and also the surfaces of the windscreens and fuselage. We need to know what was the concentration levels of ash in the trial airspace. We need data urgently to build a knowledgebase of acceptable dilution to the ash cloud. In addition, we need an industry analysis of the level of acceptable risk involved in flying in clear air above the ash. The current ash cloud warning states that there is no significant risk above FL350. Collecting data now will prevent the decision being based solely on financial pressure. That pressure should rightly be feared by each one of us.
Looking ahead, the alternative of staying on the ground until the volcano stops spewing could spell economic disaster for European Union states not to mention the demise of many European airlines.