I don't have any idea what a "head down tail up" thread might be, but I suspect it might be not be considered dignified in polite company! Oh, the coin fip thing. Allright.
MINIMUM zero fuel weight
Is this an officially recognized term or isn't it? Or is it like calling an aeronautical chart a map? Or a jet engine a motor?
We know what you mean, even though that is not the properly recognized term.
How about it? I'll promise to give up now!
Best,
Westhawk