Item used when flying bird breaks switch (9)
I believe the answer is:
altimeter
'bird breaks switch' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'item used when flying' is the wordplay.
I cannot really understand how this works, but
an anagram of 'item' is 'time' which is present in the answer.
'when' could be 'e' (I've seen this in other clues) and 'e' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for altimeter that I've seen before include "Plane's height measurer" , "Flyer's instrument" , "Aircraft instrument" , "Instrument that measures the height above ground" , "something in the cockpit" .)