Flat area wherein the plane crashed? (5)
I believe the answer is:
Here is my best explanation:
'flat area wherein the' is the definition.
I can't tell whether this definition defines the answer.
'plane crashed?' is the wordplay.
'crashed?' indicates anagramming the letters (I've seen 'crash' mean this).
'plane' anagrammed gives 'PANEL'.
Can you help me to learn more?