Test aircraft theory
A quick thought on sending aircraft up to measure this and that and measure turbine wear and damage.
1. It appears its hard to measure quantities from what I've read on here so far but I have no idea about the subject, and furthermore, no idea if the people's comments I read had any idea or not.
2. The concentration of ash in a particular part of the sky is changing second by second. So really what good is any data that is collected. In 4 hours time, it could be vastly different turning a 'safe' zone into something worse.