What if no proof of cause - what does AAIB do?
Warning: I'm non-professional; not crew, not engineer - just guest and thanks.
I've been wondering what would the AAIB do if they could not demonstrate to a high probability the cause of the accident.
If, for example, the AAIB were convinced, but could not prove, that the fuel quality had been lowered by cold-soaking for an extended period of time and that this had lead, in some unknown way, to the accident, what would they do?
Presumably the AAIB would operate on the precautionary principle.
Might they:
1) Recommend/demand/regulate the avoidance of extended flight-time in very cold air masses;
2) Demand that if aircraft had experienced extended flight-time in very cold air masses then they must loiter for some time in warmer air before descending for landing?
If the AAIB was thinking of 1 or 2 then, I assume, they would have to convince, and then act in unison with, equivalent international agencies - that would take a lot of time and effort. And just imagine how all the other interested parties would react.
Of course, in this scenario the AAIB have until the coming northern hemisphere winter to sort this out.
Has such a situation (i.e. no proof but suspicion of likely cause) arisen before and how did the industry react?
Regards, Tanimbar