perhaps better characterized as limited or minimal damage.
Depends on the viewpoint; turbine bucket with ash sticking to it does not affect engine performance much. Replacing or scrubbing it might prove costly and time consuming.
Yes I did my "test" flight, thank you for asking.
Ever helpful ATC confirmed that my penetration of VA alert area was solely upon my discretion. I would have appreciated that even more, if they choose some earlier moment to tell me that than post-landing taxiing.
No, the engines did not flameout, stall, show glowing around intakes or props, spout fire from exhausts or increased their respective ITTs erratically & rapidly. There was no st Elmo's fire visible on the screen, it was noon anyway, and no strong sulfuric odour was present.
As I have made the post-flight written confirmation of the above mentioned facts, the maintenance stated that just flying through suspected VA contaminated area does not warrant complete post VA penetration maint procedure and cleared the machine for further flights.
At least now I won't get the bill if the overhaul comes before planned time.
Regarding see and avoid: in severe CAVOK one can discern layers of dirt in the atmosphere. Now I know what I've seen yesterday over mid Italy - it looked exactly as photo on the page 3 of German Falcon flight report. There was no practical way of going around this one, it stretched from the horizon to horizon. And I can tell that regarding my routing, Met office's prediction of VA spread was frighteningly correct.