Introduced quiet official before pilot departs (8)
I believe the answer is:
prefaced
'introduced' is the definition.
('preface' can be a synonym of 'introduce')
'quiet official before pilot departs' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'official' becomes 'ref' (match official in football, say).
'before' means one lot of letters go next to another.
'pilot' becomes 'ace' (term for military pilot).
'departs' becomes 'd' (common abbreviation e.g. train timetables).
'p'+'ref'+'ace'+'d'='PREFACED'
(Other definitions for prefaced that I've seen before include "Introduced (by)" , "Led up to" .)