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That’s too bad..
Which is the absolute bomb! I use the VNAV feature in the 750 all the time.
We tried last night (I'm the buddy in the OP) to get the VNAV to work for the RNAV approach. We were at 9500 and set the AP altitude bug to the FAF (5100) altitude, engaged VNAV well before capturing a segment of the approach and the plane did nothing. It followed the lateral course, but stayed at 9500 the entire way until I had to click off the AP and manually descend to get it to capture the GP in APPRCH mode.
Been there and had to slip so hard to the runway that the fuel unported in the low wing and I got a fuel level alert!
I am no expert (only got my instrument last year) but in my setup with the 375 and the Trutrak Vizion 385 I use the waypoint function in my 760 (which is coupled to the 375) to set the desired altitude at the IAF waypoint and the Vertical Speed required (VSR) user field display to display the required rate of descent to put in the Trutrak. I then put the desired altitude into the Trutrak in GPSS mode and set the VS to match the computed VSR, a bit clunky but it seems to work out, the AP arms and then couples to fly the approach.
Ok, maybe we're all using different terms. I'm talking specifically about the "VNAV" button on the Garmin 507 AP panel. Not the generic concept of VNAV. I can get the Garmin to capture the Glide path exactly as you describe from below by using only the "APPR" (approach) button on the AP controller before the FAF. It seems to ignore the actual VNAV button on the panel if you select that.Been there and had to slip so hard to the runway that the fuel unported in the low wing and I got a fuel level alert!
However these GPS will in fact provide VNAV approach guidance. The approach must be activated, and the VNAV armed. You are responsible to descend below the glide path guidance before the FAF on your own (the Approach will usually set you up for that). The VNAV will engage once it captures the glide path from *below*! It will never attempt to dive and acquire the GP from above, at least my Dynon AP won't.
a different panel here, but the APR button I believe arms both Lateral and vertical guidance for the approach. It's a sort of shortcut for pressing NAV and VNAV buttons one after another. probably we are all saying the same thing - the vertical guidance won't work on these lower end units outside of capturing the approach GP.
Thank you. Yep, I watched the YT vid above and it confirmed the GNX-375 does not have VNAV as a feature. Bummer. I wish I had known - I might have gone to the 650 instead. Oh well.
Yes sir. All clear now. Thanks! We were pulling our hair out last night trying to figure out why nothing was happening.
Brad,
Steve is correct... when used with an IFR navigator that doesn't provide its own enroute VNAV functionality, the G3X system can provide basic enroute VNAV guidance to a single flight plan waypoint. This functionality is basically equivalent to the VCALC feature offered by those navigators, but better integrated with the complete system. There's really no practical reason to use the VCALC feature on an IFR navigator if you have a G3X system.
When told to cross 'joblow' at xxx ft being able to do that with the VNAV and AP is almost as good as sex
Maybe it is just me, but unless one is doing scheduled air charter service, or routine heavy IFR, I think the GNX375 is just fine. The advantage of the GNX375, for experimentals, is that the GPS and adsb transponder are integrated, so it saves an expensive extra box. I only need to calculated Vnav once per flight. what else am i going to do while Otto is flying, watch a movie on my starlink/GDU460 display(with video in)? Now this is truly like an airliner
