It wasn’t a visible cloud. More like a cloud of heavy large droplets. Quite sticky too – covered the camera faceplate quite well, as the video shows.
I did wonder if it wasn’t some chemical emission – Italy is covered in chemical factories.
The cockpit air comes from outside but via convoluted routes.
Dan wrote:
Simply put, how can ash get toasted, melting… again?
That is exactly what happened to the BA747’s engines. The ash particles glazed the whole turbine wheels with thick residue.
The fighter airplanes who flew somewhere in Scandinavia during the event also had lots of residue.
A quick check of my logbook shows 102 movements (1 landing + 1 takeoff) @ CTA, and 97 @ PMO, in very different conditions, over the course of some 20 years. Add to that a few circling Mr Stromboli, transiting or overnighting different strips in Sicily.
Some of them flights performed whilst Mr Etna was emitting visible smoke (and ash sometimes), with VA notams on, and off.
Believe half of what you see and nothing of what you hear 
And I was probably “unlucky”, but never witnessed any of the stuff described in this very thread.
Dan wrote:
And I was probably “unlucky”, but never witnessed any of the stuff described in this very thread.
Maybe. Or in the right place. VA mostly is not dangerous if you are in visual conditions and can see the volcano miles and miles away. If VA is around, I’d expect quite a bit of a reduction in visibility, like a brownish haze. Add to that in our case a noticable smell.
That is what it looked like when we flew in 2010. It was pretty much like in haze, but the colour was different and one could smell it too.
