Copilot D-180 as BusMaster for AP

[johndavies]

I am starting the panel on an RV-7A. I have a question with regards to a D-100 and AP-74 (pilot position) D-180 (copilot position) setup and the new autopilot. If I make the D-180 the Bus Master in the copilot position (and hence have the AP and AP74 work through it) will the operation be transparent to the pilot with the D-100 in front of him. In other words will the pilot position work exactly as if the D-100 in front of him were the Bus Master with regards to AP-74 and AP functions on the screen while say the D-180 (copilot position) displays just EMS data. My logic is that I am uncomfortable with the idea that if I lose all Flight instruments in front of me I also lose Autopilot just when I need it. However I AM comfortable with the idea that if the D-100 in front of me fails I still have Autopilot AND flight instruments on the copilot side and if the D-180 fails I lose AP but still have a full EFIS in front of me. Am I understanding how DSAB works correctly?

 

[dynonsupport]

There's a tiny limitation in 5.0 (which will go away in 5.1), which is that the item that the AP74 is adjusting via the value knob is best viewed on the master. Also, the AP74's value knob will adjust other numerical plus/minus things on the master if you're buried in a menu on the master.

However, generically, know that you can set up either of those units to be master, no matter where things are physically placed. Also know that the Master's "EFIS" will be the one driving the AP. This might be slightly confusing if the AP is running off a screen which isn't showing its EFIS.

 

[airguy]

Ok - similar question. Now that we know either unit (D100 or D180) can run the AP, let's say I have my preferred panel installed with a D100/D180/AP74 and I'm running the AP off the D100 and that unit dies in flight. How much heartburn is entailed in switching the AP to drive off the D180 in the air?

 

[dynonsupport]

Because of the need to reconfigure DSAB and then calibrate the servos, this can only be done on the ground. From flight to flight, consider our AP like any other - controlled by a particular device.

 

[airguy]

Because of the need to reconfigure DSAB and then calibrate the servos, this can only be done on the ground. From flight to flight, consider our AP like any other - controlled by a particular device.

Clear - hence the need to use the D180 as AP master, so that in case of failure you lose either the AP, or the EFIS, but not both.

 

[dynonsupport]

If you used the D180 as master, and the D180 fails, you have no EMS and no AP, but you still have EFIS on the D100.

If you use the D100 as the master and it fails, you still have EMS and EFIS on the D180.

With a D100 and a D180 you never lose your EFIS to a single unit failure.