VNAV Arm

[dvalle]

Hoping someone can answer this from actual experience on a HDX. Has anyone been able to "arm" VNAV on a GPS approach (when vert is provided on the approach) or "arm" for an ILS in either case when there is NO GS indication? My ability to arm only works after a GS is indicated. The instructions are difficult and actually contradict in two places. I've flown with 4 different planes all with vertical guidance (all with Garmin 430W, 530W, Avidyne 440 and 650) and none will allow arming prior to GS indication.

Thanks
Dan

 

[RVDan]

I only have experience with ILS Glideslope. The AP VNAV won’t arm until the glideslope indicator is within the vertical guidance, i.e., the GS needle is moving down from full up deflection.

 

[airguy]

Dynon will not accept an ARM command for the VNAV until the glideslope indicator appears on the screen.

 

[Ghale]

You can't arm the GPS VNAV until you pass the Final App Fix.

 

[CanardMulti]

I believe that to allow arming the VNAV mode of the AP to capture the glideslope, you must be on the last leg TO the FAF. To only be able to arm AT the FAF would make smooth transition to a stabilized descent much more difficult. Once armed, the VNAV mode will proceed to engage once the GS/VNAV indicator comes alive. Unlike some autopilots, SkyView will only capture the GS from BELOW. VNAV will not arm if you are trying to capture the GS from above.