SamuraiBlue
Captain
Now open water operations are limited to fairly calm sea conditions, in fact when conditions where rougher during past rescue operations, it was common to lay down an "oil slik" so that waves were prevented from breaking by the film of light oil overlaying the sea.
So amphibs are limited to calm water, protected bays etc, for optimal use, as the sea state deteriorates you would only operate to make an emergency landing. I would note that the floats are fixed and very robustly configured, so air evacs etc are no doubt a part of her mission. Oil platform, even ship resupplies, would also fall under that umbrella with a light boat being used for "transfers", a neat airplane, and one I would love to get a little time in!
Is 2.8m~3m swells considered calm?
According to Wiki AG600 can land in water with 2.8m swells and US2 can land on 3.0m swells.