Pilot raised issue before event (4,5)
I believe the answer is:
Here is my best explanation:
'event' is the definition.
Both the answer and definition are singular nouns.
Perhaps there's an association between them I don't understand?
'pilot raised issue before' is the subsidiary indication.
'pilot' becomes 'trial' ('trial' can be a synonym of 'pilot'**).
'raised' says the letters should be written in reverse.
'issue' becomes 'emit' (I've seen this before).
'before' is a charade indicator (letters next to each other).
'emit' backwards is 'time'.
'trial' put after 'time' is 'timetrial'.
(Other definitions for time trial that I've seen before include "cycling event", "Race against the clock", "Cycling event" and "test".)