Have you tried Assist?...
NA160, "SCREW, FAIRING WASHER, ASSEMBLY, 6AL-4V TITANIUM ALLOY, TORQ-SET, FULL THREAD, 1100MPA TENSILE, METRIC"
In particular, the NA160 castellated nut. We have a former Rumanian air force airplane, and it has metric bolts, screws nuts etc. They are specified as "NAxxx", in particular the wing attach uses NA160 castellated nuts. The problem is that there seems to be no spec for NA160. We can have the fastener made if we have the spec, but so far we don't have that.
AIA's NA specs aren't it. I've looked at NA0160, and the title refers to it as a "star washer", so clearly there is US DoD/NASA specs on one hand and AIA NA specs on the other. I presume there are other sources for the specs (the Organisation Formerly Known as aecma, for example).
Anyway, we are trying to find them, and its getting really, really frustrating. Any advice, help, etc would be greatly appreciated.
The problem exactly.
The part number is definitely referring to a castellated nut, but as "NA160", which is clearly not a "screw,fairing washer" and not titanium. So the problem is identifying what the standard they are referring to is, and how it got there. FWIW, the parts manual (for the IAR823) was written in 1972, so there is plenty of reason to think the standard was superseded, number changed, etc.
The plane, BTW, is an IAR 823, made by IAR Brasov. Its a really great plane if we can get the wings back on and the rest of the restoration tasks done.