Aerocruze 100/TruTrak Question

SoCal 182 Driver

Cleared for Takeoff
Sep 11, 2019
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SoCal 182 Driver
Assume I'm flying an RNAV approach. I've got the Aerocruze 100 set for GPSS, and the RNAV approach loaded into the GPS. As I enter the approach course, I'm above the glide slope, and the autopilot goes from "ARM" to "FLAG."

Once the autopilot goes to "FLAG," can I still have the autopilot handle lateral guidance, while I manually hand-fly altitude? If so, what do I need to do with the autopilot to allow me to hand-fly altitude while it handles lateral guidance. As I "RTFM," it seems that the best way to handle this would be to switch the autopilot to TRK mode (assuming I'm on the approach course), and then hand fly the altitudes, but I'd appreciate hearing others' thoughts, comments and suggestions.

It is possible to put a switch to disable altitude, but it’s not approved by the STC. You would have to adjust the altitude to altitude preselect and select a vertical speed.
It needs to be below the gludeslope to change from Flag to Arm.
It needs to be below the gludeslope to change from Flag to Arm.
I've found that once it goes from ARM to FLAG, it won't go back to ARM, or go to CPLD, simply by getting below the glide slope. My experience has been that once it goes to FLAG, it won't change.
I’m not sure on this. Technically, it goes to Flg every time before it goes to Arm. It just changes so fast that you only see a flicker of Flg before it goes to Arm. Once it sees itself above the glideslope, Flg stays on. You may need to toggle mode twice to retry the Arm once below the glideslope.
I don't know the autopilot or your GPS box, but . . . My guess is you still have the navigator outputting an LPV glide path. Try deselecting LPV and using just LNAV, VNAV. The autopilot may well ignore the VNAV signal which is different from the vertical part of a an LPV.
Almost this exact scenario happened to me last week. In fact I found this thread when i was looking for others experiences. I have an older version of the trutrak, the RV-10 AP, so YMMV. For my model of AP it must be in Alt hold for the GS to arm. Approach control kept me high and when they cleared me for the RNAV approach, I was above the glideslope on GPSS steering. THE AP was displaying GS FLAG. The lateral gps guidance continued and I controlled vertical guidance with the VS buttons. I descended below the glideslope to try to get the GS to arm, but even with quickly putting it into alt hold when I was below the GS, the GS Flag persisted so I controlled the vertical navigation with the VS to stay on glideslope.
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