Volcanic Fall out?

[Larry Reese]

I don't believe the ash need be visible to the naked eye to potentially bring down aircraft. The clogging/pasting and abrasive properties will still chose the fan disks to pulp, particularly if a high concentration pocket happens to be flown through. I'm sure the airlines and most other air operators (governments and such) feel the risks and the accelerated maintenance needs even without a catastrophic failure simply aren't worth it.

LR