She assembles helmet parts (5)
I believe the answer is:
ethel
'she' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for ethel that I've seen before include "Lethe (anag) -- Barrymore or Merman" , "Trying not to be seen" , "chapel" , "Female name" , "Lady" .)