Lean and topple over part of aeroplane (7)
I believe the answer is:
cockpit
'aeroplane' is the definition.
(thesaurus)
'lean and topple over' is the wordplay.
'lean' becomes 'cock' (I can't justify this - if you can you should give a lot more credence to this answer).
'and' says to put letters next to each other.
'topple' becomes 'tip'.
'over' is a reversal indicator.
'tip' in reverse letter order is 'pit'.
'cock'+'pit'='COCKPIT'
'part of' acts as a link.
Can you help me to learn more?
(Other definitions for cockpit that I've seen before include "Place for aircraft's pilot and crew" , "Flightdeck" , "Navigation room" , "Pilot's place in aircraft" , "Compartment for aircraft pilot" .)