IFR with KLN89B and AFS-4500

I recently installed a KLN89B to my panel as part of an upgrade to take my RV-7 from VFR to IFR capable.

When I am on an GPS RNAV approach, I see on my AFS-4500 that it is switching from Terminal mode to approach mode as I near the FAF (within two miles), but as soon as I pass the fix, it switches back to terminal mode.

I've confirmed the GPS is working correctly and still in the Approach Active mode with the .3 Nmile CDI standard on the GPS. The GPS is wired to the EFIS via RS-232. Everything else is working and talking to each properly between the two.

Is there a setting on the EFIS that I need to update so that it says in approach mode on an approach?

Vince
RV-7

I don't know anything about the AFS, but I did intergrate a KLN-90B with both a Dynon and GRT. It was my understanding that the CDI scaling information (5 mile, 1 mile, .3 mile, etc.) is only sent on the Airinc output of the King. I don't believe the Aviation format on RS-232 supports this data. The King manuals have an appendix that show each field of data sent on the RS-232 port. I suggest you confirm there whether or not that data is included.

Be advised that the CDI sensitivity is controlled by the EHSI/EFIS. The GPS only provides instructions, but relies upon the EHSI/EFIS to do the scaling based upon it's guidance (it provide the requested scaling in a separate field). Even though your GPS is saying it's in Approach mode, the AFS is likely still scaling the CDI at 5 miles for full scale deflection. You should be able to confirm this by setting the 89 to display CDI. Then Go two dots left or right on the 89's CDI while inside the FAF. Look and see if the AFS is showing 2 dots. I would bet it is showing 1/2 dot.

Larry