Airport and Runway selection question.

ty1295

New Member
Joined
Jan 10, 2020
Messages
11
The other day I was out flying and learning how the airport/runway direct to AP feature worked. I was able to do 3 "approaches" and found it to be a very good tool. I found 2 things that still have me a bit confused.

On one of the approaches it appears I active the VNAV too close to the runway, so the AP only did the navigation direction but did not do any altitude changes, even though the altitude preselected based on threshold height.

Based on the above I tried to arm the VNAV portion 20+ miles out, using HDG bug to intercept the extended centerline of the runway. What I noticed there is it would not allow me to select the VNAV until we were closer to the airport.

Is there a range of distance to airport that is needed to both capture the vertical?

It would still be awesome for a good how to video on this feature, and I am hoping in the future it can be selected as part of a longer flight plan and not just direct to.
 

Dynon

Dynon Staff
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Jan 14, 2013
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Woodinville, WA
The limit is 5 minutes from the top of the descent for VNAV arming. Outside of that limit, it will be unavailable.
 

steve m

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Feb 10, 2020
Messages
48
Location
Asheville NC
The limit is 5 minutes from the top of the descent for VNAV arming. Outside of that limit, it will be unavailable.

Follow up question on this 5 minute VNAV arming.

If I am flying say 150 knots and get the VNAV to engage then slow down to say 120 knots (extending my time to greater than 5 minutes due to slowing down) will the VNAV disengage?

Thx

Steve
 

Dynon

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Woodinville, WA
80% sure on this answer - if the glidepath went away (which I think may be possible in the scenario you outline, most likely when you're at the outer edge of your glidepath appearing envelope), then the AP would fail down to alt hold mode (and annunciate the mode change visually and audibly.)
 
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