"Jon A." wrote in message
...
On Fri, 31 Dec 2004 07:36:16 -0400, "Juan Jimenez"
wrote:


"M" wrote in message
oups.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.

Any work that alters (that includes drilling, cutting, riveting),
needs a 337.

There is one exception, that I know of. Check AC 43.9-1E.