A royal pain about the crash! (5)
I believe the answer is:
prang
'the crash' is the definition.
(I've seen this before)
'a royal pain about' is the wordplay.
'a royal' becomes 'r' (abbreviation).
'pain' becomes 'pang' (pang is a kind of pain**).
'about' indicates putting letters inside.
'r' going inside 'pang' is 'PRANG'.
(Other definitions for prang that I've seen before include "Car accident, usually not too serious" , "Minor accident" , "Plane or car crash" , "knock" , "Car collision" .)