Looks like anywhere from 17.8 - 20.2 inch pounds, depending on screw/nut metallurgy. I have no idea how to interpret the MS & NAS numbers to determine their metallurgical makeup.
Where is the screw going? I have never really seen on our planes where a screw was a super critical fastener. That is pretty much always left up to bolts. In other words, I don't remember ever worrying about torquing screws to some specific value.
