I can see why the questions about acceptably safe ash levels went unanswered. From the safety standpoint the manufacturers surely are the right people answer that question, NOT the operators.
Agreed. But surely the operators have a responsibility to ensure that they operate within the engine manufacturer's guidelines?
If the manufacturer's existing guidelines are anomalous to the operating situation(s), then operators must surely be obligated to clarify these guidelines with the engine manufacturer BEFORE they put their aircraft up.
CJ