response to WHBM's many questions to us all.
1. This comparison is irrelevant...... why? wind.
2. The indon incident, cost millions of dollars and nearly killed 400 people, if we told you that the concentration of ppm was x, how do you come up with a figure that is safe? You cannot.
3. See answer number 1.
4. no good answer here but, Enroute avoidance is slightly different from flying through what is known to be there. eg Depart into the ash, fly through it, land in it. Domestic European flight.
5. just a stab at this answer but ICAO rules prevent ATC from allowing you to use the airspace when ash is known or forecast. Perhaps in other parts of the world, ie indon, they don't subscribe to these parts of ICAO. I know that Australia picks and chooses what ICAO rules to adopt. That is why this volcano is different.
6. Hawaii may have been using a piston engine aircraft, or again may not have had laws preventing the flight.
7. Erm, Russia is more west than western europe. This argument is like saying why the hell is Kazakhstan and China still flying.
A return fire question to you. How many deaths need to spared for you to say that the ban was worth it?