mm_flynn I understand your redundancy logic theory. Nice one! Never really cnosidered that. Although as you say, each engine is likely to be affected in a similar way and to a similar degree. So is it not cutting the redundancy logic a little fine? Can it not be considered possible that another engine may suffer similarly within a short period of time following an ash encounter?
Normal redundancy works because failures are much more random and occur from tiny differences in quality of manufacturing or unusual isolated interaction with other components and therefore the time scale for failure is very wide and varying.
But if what peter says is true then if you are likely to see problems within 100-500 hours then that is much too small a window to expect isolated and seperate issues. What I mean is that if one engine dies 105 hours after an ash encounter, there has been reasonably significant damage. It is therefore correct to assume another engine will suffer the same fate within a very short period.
Yes, engine monitoring should highlight longer term issues long before they become a problem, so I don't expect we will see engines failing spontaneously in 2 or 3 months time. I just hope we don't have repair bills which cripple the industry more than another couple of days of waiting for the ash to clear would have done. And an engine change takes a lot longer than 2 days....