If you had a sheath knife, why would you dissassemble a pocketknife?
As Mona suggested, perhaps to use the blades to make fishing spears.
Nice catch on the Javanese knife Ashley. If the Javanese knife is there we haven't found it - yet.
Or maybe she decided not to take in on the Pacific flight after all.
Or maybe she did and she somehow lost it before she took up residence at the Seven Site.
Or maybe one of the colonists found it and kept it.
Or maybe the person who died at the Seven Site and seems to look so much like Amelia Earhart was someone else we've never heard of.
Or there are probably a hundred other possible reasons the Javanese knife hasn't turned up.
But it would be nice if it did.