Physical Weathering plane option missing?

[Dragoon!]

I seem to be missing this feature, as stated in the manual. I'm running a US Disc/Steam version. My plane options end at 'visible weathering'. Is this option in the current version? Am I missing something?

Also, I had a question about it. Does it effect engine performance? Or is it just a random failure enabler? If it's just a random chance that your wing will fall off, I don't think I'd use it, but if it affected revs/bhp and made each plane unique, in a way, I'd be interested to use it.

Thanks.
D