Piloting after releasing right engineer for submarine chamber (6,4)
I believe the answer is:
diving bell
'submarine chamber' is the definition.
(device for lowering someone underwater)
'piloting after releasing right engineer' is the wordplay.
'piloting' becomes 'driving' (both can mean steering).
'after releasing' is a deletion indicator.
'right' becomes 'r' (common abbreviation).
'engineer' becomes 'bell' (Alexander Graham Bell).
'driving' with 'r' removed is 'diving'.
'diving'+'bell'='DIVING-BELL'
'for' acts as a link.
(Other definitions for diving bell that I've seen before include "It lowers one in the main" , "Sea-bottom work chamber supplied air by tube" .)