Aerospace technology to change with intervention of several years? (9)
I believe the answer is:
altimeter
'aerospace technology' is the definition.
(device on an aircraft)
'change with intervention of several years?' is the wordplay.
'change' becomes 'alter' (synonyms).
'with intervention of' indicates putting letters inside.
'several years?' becomes 'time' (a period of time).
'alter' placed around 'time' is 'ALTIMETER'.
'to' acts as a link.
(Other definitions for altimeter that I've seen before include "something in the cockpit" , "equipment for pilot" , "Plane's instrument" , "Flyer's instrument" , "Plane's height measurer" .)