Fighter plane brought in faulty, not initially operational (9)
I believe the answer is:
effective
'operational' is the definition.
(thesaurus)
'fighter plane brought in faulty not initially' is the wordplay.
'fighter plane' becomes 'f' (abbreviation e.g. F-16 etc.).
'brought in' is an insertion indicator.
'faulty' becomes 'defective' ('defective' can be a synonym of 'faulty').
'not initially' means to remove the first letter.
'defective' with its first letter taken off is 'efective'.
'f' put within 'efective' is 'EFFECTIVE'.
(Other definitions for effective that I've seen before include "Powerful" , "Accomplishing a purpose, efficient" , "Practical and productive" , "Competent - impressive" , "Practical or operative" .)