Second gear required for take-off (4)
I believe the answer is:
skit
'take-off' is the definition.
(both can mean a send-up or parody)
'second gear required' is the wordplay.
'second' becomes 's' (common abbreviation).
'gear' becomes 'kit' (kit is a kind of gear).
'required' means one lot of letters go next to another.
's'+'kit'='SKIT'
'for' is the link.
(Other definitions for skit that I've seen before include "take-off" , "Turn" , "Short satirical performance" , "Satirical drama" , "Hoax; satire" .)