Gnx375 with KAP 140

[Hopsl]

Question for anyone with experience on GNX 375 and the KAP140 flying coupled LPV approaches... I need  to know when the message pops up on the 375 asking you to “enable apr output”. Is it a fixed distance  from the FAF? Also, according to 3-89 in the 375 manual,  I have to be in HDG mode and then arm APR on the 140 only after  I acknowledge the “enable apr output” message. Am I reading that correctly? 

Thanks for any help

[carusoam]

see if this helps you get closer...?
 

BK has their user manuals online... some days...?

 

two buttons that are helpful....

• heading mode... allows the AP to follow a GPSS signal...
• approach mode... changes the AP tuning to fly a tighter / more jerky pattern.... tightness at the cost of jerkiness...

 

• When to enable the approach is typically before some distance prior to the FAF point... to allow it’s pea sized brain to do some calculations....
• the KAP140 has an even more pea sized brain that only allows approaching the final course from certain angle limitations... the 150 is a step up in this regard.

Fuzzy memories of a non-current IR’d PP... not a CFI...

Best regards,

-a-

[Bob Weber]

My probably equally fuzzy memory recalls this:

The 140 and 225 were early "digital" autopilots, I believe they were on the list in the Garmin manual that required it to be configured to prompt you to "Enable Approach Output".

I flew so few of them for certification that they would catch me off guard.

I'm thinking it prompts you when it transitions from TERM to LPV, this is when the navigator throws an approach enable command to the autopilot among other things.

Multiple things happen at this point to both the navigator, as well as the autopilot.

In APPCH mode, the autopilot begins a regiment of intercept, capture, and track functions.

These differ from NAV mode by changing intercept angles, limiting bank angles, and enabling vertical guidance.

I found over the years that the last item has always made people nervous, and rightly so.

I have a feeling this was the reason for the requirement.

Hopefully this sheds a bit more light.

Fly safe,

Bob Weber

 

Edited December 18, 2019 by Bob Weber