Triple-echo interfered with surveillance equipment? (10)
I believe the answer is:
helicopter
'surveillance equipment?' is the definition.
(I've seen this before)
'triple-echo interfered with' is the wordplay.
'interfered with' is an anagram indicator.
'triple'+'echo'='tripleecho'
'tripleecho' with letters rearranged gives 'HELICOPTER'.
(Other definitions for helicopter that I've seen before include "Chopper" , "One equipped with blades" , "surveillance equipment" , "aircraft" , "Chinook" .)