engineers fixing broken pieces; how?

[king of nowhere 673]

the wiki says that engineers can fix broken parts.

today, while i was trying a particularly daring jump with my rover, i twisted a wheel on landing

well, i thought, i have an engineer on board, let's see if i can fix it.

but i can't find the option. neither clicking on the wheel nor on the engineer give me any "fix broken piece" or similar option.

what's the deal? why can't i fix the wheel? what can engineers actually fix?

[Demordrah 54]

As far as the game is concerned, that wheel isn't broken, it's just not aligned properly anymore.  That's not something an engineer can fix.

[Gargamel 6,352]

Broken wheels are missing tread.   That's not broken.   It's BROKEN. 

[bewing 3,079]

Right click on the wheel. If it says "Status: damaged" and you have a 3 star engineer, then you can repair it. This is also true for landing legs.