Slippery Sam’s post takes us back where I began this thread – it echoes my own views entirely. From everything else that has been said by contributors to this thread, it seems that:

a. MAYDAY is indeed in the vocabulary in the US, but just isn’t used very much, for reasons which aren’t clear to me. (Maybe this is more of a military/civil difference than a US/UK one?).

b. It wouldn’t have made a lot of difference in this case, because the crew could obviously tell from the controller’s responses that he understood, sympathised, and was on their case! (But I still think the other aircraft on frequency were a potential distraction, though I don’t know enough about the circumstances to judge whether that could have been headed off).

c. One possible reason an explicit MAYDAY call was not made is that the crew were very, very preoccupied with priority #1 – FLY THE AIRCRAFT. We can all approve that principle, I hope. That doesn’t mean it isn’t a useful tool that ought to have been deployed, at least in the ideal world. That’s the world that Sully didn’t have the luxury of living in for those few minutes.

NTSB have raised a similar point in other reports. I just wonder if they will feel diffident, in this high-profile case, about making what some might see as negative criticism; I hope not. More likely, they will stick to their professionalism and say ‘Mayday would have been a good idea (though it wouldn’t have made a whole lot of difference in these specific circumstances)’. That will be the cue for volumes of hysterical reaction from non-flyers, most of it missing the point of the second part of the sentence. But that’s just me showing my prejudice about journalists!