Working as a test pilot's a big leveller (6,5)

'pilot's a big leveller' is the definition.
I don't know anything about this answer so I can't tell whether this works.

'working as a test' is the wordplay.
I cannot quite understand how this works, but
'as' could be 'in' (I've seen this in other clues) and 'in' is found in the answer.
'a' could be 'an' and 'an' is found within the answer.
'test' could be 'try' (synonyms) and 'try' is present in the answer.
This explanation may well be incorrect...

Can you help me to learn more?