This should be no issue for a small piston-engined aeroplane, firstly because the air into the engine is filtered, and secondly because the combustion chamber temperatures are too low too melt the ash.
One can only applaud that CAAs and Transport Ministries have learned from last year's debacle. I recall trying to convince a knowledgeable Belgian ATC officer into pulling some strings to get a VFR clearance for a business trip I had planned months in advance, using the above argument. He told me "I know, and it's embarrassing to say, but orders to close the airspace to VFR traffic too came straight from the cabinet
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