Originally Posted by
Contacttower
Is that the limit that was established last year after the previous eruption?
Yes, although the way the rules have been implemented is very different. Things are now managed within airline SMS (Safety Management Systems) rather than by blanket rulings.
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. The big concern I'd have, because this is another hydro-eruption (through a glacier) is if you've spent any time smelling "rotten eggs" in which case you may have flown through sulphuric acid. If that happens - give the aeroplane a VERY thorough drenching wash, including EVERY steel part of the aeroplane -bolts, engine mounts, brakes, the lot.
G