Schoolchild's instrument put under stairs in black box? (6,8)
I believe the answer is:
flight recorder
'black box?' is the definition.
(I've seen this in another clue)
'schoolchild's instrument put under stairs' is the wordplay.
'schoolchild's instrument' becomes 'recorder' (I can't explain this - if you can you should give a lot more credence to this answer).
'put under' says to put letters next to each other.
'stairs' becomes 'flight' (flight is a kind of stairs).
'recorder' put after 'flight' is 'FLIGHT RECORDER'.
'in' is the link.
Can you help me to learn more?
(Other definitions for flight recorder that I've seen before include "black box" , "may help to determine cause of accident" , "One revealing cause of crash" .)