In poem airborne soldier dies horribly, way off course (8,4)
I believe the answer is:
paradise lost
'in poem' is the definition.
'paradise lost' can be an answer for 'poem' (epic poem by John Milton). I am not certain of the 'in' bit.
'airborne soldier dies horribly way off course' is the wordplay.
'airborne soldier' becomes 'para' (paratrooper).
'horribly' indicates anagramming the letters (a horribly wrong version of the letters).
'way off course' becomes 'lost' (off course means lost).
'dies' with letters rearranged gives 'dise'.
'para'+'dise'+'lost'='PARADISE LOST'
(Other definitions for paradise lost that I've seen before include "disaster on cosmic scale" , "Poem by 1" , "Work by Milton" , "long poem" , "work from the 17th century" .)