I decided to fly a test scenario to see what would happen if the EFIS should "die" while on a flight plan with the AP engaged. I have a single screen AF5600 system, GTN650, and TruTrak DF II VSGV.

When I pulled the appropriate breakers, the AF5600 totally shut down, but the ARinc Interface module, the 650, and the AP were continually powered up. When the AF5600 went down, the AP indicated "GPS Flag" and it went to wing leveler and Alt Hold mode. Is this what should have happened?

Somehow I expected the AP to start talking to the 650 "directly" via the ARinc Interface.

Thanks,
Dick