In PNG we used to refer to it as a BN3 for some reason but that was not correct.
Pinky, from memory it was designated as a BN-2A. And if you think a normal Trislander (also known as a try and land 'er) is ugly, wait until you see one set up for geophysical survey work with extended nose & cables hanging off it everywhere. SALTMAP had one - we used to call it the flying clothesline!
DF.