"Peter Clark" wrote:


Have you tried changing the baro in flight to some number of inches
off the real pressure to see just how far the system is mis-reading
the baro? That will tell you something.

Yes. On the ground I have set the xponder to squawk altitude and turned the
altitude preset on the KAP 140 up until it gives the "1,000 ft. before"
warning. That happens at 13,000 ft.

I'll have to go pull my wiring diagrams out since I don't recall off
the top of my head, but does the KAP140 actually get it's graycode
from the GTX, or does it get it from one of the outputs on GIA#2? Have
they tried swapping GIA#1 and GIA#2 to see if there is any difference?

The GIA2. The GIAs have been swapped and the problem stays.

--
Dan
T-182T at BFM