Auto pilot interface question

[art.pileggi]

I have a 5600 connected to a Trio Pro Pilot. When I have the AP set to LAT-NAV and VERT-ALT the Trio shows GPSS and GPSV signals and will not let me control anything while I am in TRK mode. If the 5600 is set to LAT-HDG and VERT-OFF the Trio still shows GPSV signal and will not let me control the vertical while in course mode. Is the 5600 an all or nothing device?

[Rob Hickman]

If the EFIS AP mode is LAT:HDG and VERT:OFF the EFIS is sending zero FPM to the AP. Not sure about the Trio, the TruTrak is either following the EFIS (LAT and VERT) or following the AP head. From an operational complexity standpoint it does not make a lot of sense to have half the AP following the EFIS and half following commands from the AP control head.