"M" wrote in message
ps.com...
I'm considering adding a second (backup) electric AI. The primary AI
is vacuum driven so is the DG.
Two questions: 1. Does adding a backup electric AI require an 337?
Not necessarily. A repair station may be able to perform the work based on a
work order approval, since it's not really a major alteration. Ask your
local avionics shop.
2. Does the electric AI needs to be TSO'ed?
That I don't know, but aren't you adding this to improve safety of your
aircraft? From my point of view, that should make the answer obvious.
Juan