Altitude setting different than the AP setting

[d3mac123]

HI, I am trying to get familiar with my HDX and I noticed that after setting my altitude to 3200ft (see attached), the AP ALT kept showing 3100ft. Any ideas why?

 

[Rhino]

Don't you need to be in TRK+ALT to get it to follow the bug?

 

[d3mac123]

Thanks @RV8JD - I will take a look. This is different that what I was used to when I had my other plane with the D120 and the AP head. All I had to do was to change the bug and the AP would follow

 

[Bob Y]

It will if you’re in “Simplified” mode vs. “Expert”.

 

[Rhino]

Does the default vertical speed come with a preset value from the factory, or is it set to zero until you change it? I know there has to be a value for it to track the bug.

 

[Bob Y]

In Simplified Mode you set the VS default. In Expert Mode, it uses the current VS when it’s engaged until changing it with the bug knob. If using the Nose Up/Down buttons to change altitude, I believe the default is 500 ft/min, which can be changed. See attached from the User Guide.

 

[Dynon]

Advice above is sound. To summarize:

• In simplified mode, the AP chases the bugs, and of story. Simple!
• In expert mode, pressing ALT will hold the current altitude that you were at the moment you pressed the button. This is reflected in the AP status area. Changing the altitude bug will not immediately initiate a climb or descent, or change altitude mode, until you enable a change in direction via VS or IAS climb/descent mode. This is to allow pilots to set their next altitude target in advance while continuing to hold altitude. This means that the bug won't always match the AP alt hold target.