Jet sat outside to fly from rank (4)
I believe the answer is:
inky
'jet' is the definition.
(I've seen this in another clue)
'sat outside to fly from rank' is the wordplay.
I cannot really understand how this works, but
'from' could be 'in' (I've seen this in other clues) and 'in' is found within the answer.
The remaining letters 'ky' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for inky that I've seen before include "Like writing fluid" , "Leaked on by pen" , "Black; drunk (Aus. sl.)" , "Coloured black" , "Completely dark" .)