John
Junior Member
Posts: 74
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Post by John on Oct 31, 2020 14:10:33 GMT
Glenn and I recently discussed VNAV via email. I thought others may benefit from the following:
One minute prior to the initial decent point the “Approaching VNAV Profile” message appears. When I see that I push the VNAV button on the autopilot and I turn off the ALT button on the autopilot. I noticed that the ALT button light came back on without me touching it. That would have been my cue to dial the altitude to pattern altitude of my destination. I’ve done that before and it works. This time, however, I reached down and turned the ALT button off again. That worked. The autopilot ignored the altitude and followed the glide slope. As soon as the aircraft departed the cruise altitude setting, the altitude setting changed colors, informing me that I was no longer tracking that set altitude.
What’s great about the VNAV feature is that it knows the pattern altitude of your destination airport without you having to manually set it. When I turned the ALT button off on the autopilot the VNAV feature was flown by the autopilot right down to a pattern altitude that I did not enter. In my mind, that’s a really nice feature. As long as that ALT light is off, it’s going to find that pattern altitude.
To have complete confidence in what I’ve just said, I’ll need a few more runs at this same procedure. Let me know if you find anything different.
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Post by slingpilot on Nov 2, 2020 16:24:27 GMT
Using the G3X Touch, I go to the VNAV and setup the parameters. For me, it’s destination import, altitude I want to be at by how many mile from the airport, and rate of decent. As you do, I get a VNAV alert and depress the VNAV button. I DO NOT have to depress the ALT button, it automatically disengages when the VNAV enables, HANDS OFF. Once it reaches the pre-set altitude, VNAV disengages and Altitude button illuminates and altitude is held.
I’m not tracking a glide slope or on an approach. I use it when approaching an airport, usually having it put me six to ten miles from the airport at pattern altitude.
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