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  1. Username Protected
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       #1  

    VNAV gotcha- on G1000 NXI, Phenom 100

    A couple times now, having engaged VNAV for an arrival, with the correct lower altitude in the alerted box, Vpath appearing in white on the FMA, the aircraft simply did not go down as advertised.
    it happened again, despite my making sure all parameters were met.
    of course, I did what I had to do as the AP ‘human monitor’.
    Other times, it works just fine as advertised.
    Anyone else experienced this and if so, is this just a Garmin thing or AP thing?
  2. Username Protected
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    #2  
    There is timer on the 1000. I do not know the exact time .I have been told 5 and 10 minutes. If that much times has elapsed since pressing the VNAV button, will not descend, though it all looks normal until it just does not descend.

    My habit on these is to press the VNAV button twice (OFF than ON) when the “1 minute warning (When the system indicates one minute until descent and descent path appears)” goes off. This will reset the timer and ensure that she actually descends.

    I am not sure but think this may NOT occur with NXI. In the Garmin 3000, this does not occur, at least in the fairly new one I operate.
  3. Username Protected
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    #3  
    I fly a 2010 Phenom 100 which was upgraded to NXi. When I was trained, my instructor said wait until TOD is less than 5 minutes to press the VNAV button. That has been my practice and it has always worked.
  4. Username Protected
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       #4  
    Quote Originally Posted by (Username Protected) View Post
    I fly a 2010 Phenom 100 which was upgraded to NXi. When I was trained, my instructor said wait until TOD is less than 5 minutes to press the VNAV button. That has been my practice and it has always worked.
    while I was aware of that 5 min timer limitation, it’s possible that I pressed VNAV earlier, although I would have thought not.
    But, it’s a good reminder and I will be sure to watch that and if it happens again, will report back here!
  5. Username Protected
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       #5  
    Quote Originally Posted by (Username Protected) View Post
    There is timer on the 1000. I do not know the exact time .I have been told 5 and 10 minutes. If that much times has elapsed since pressing the VNAV button, will not descend, though it all looks normal until it just does not descend.

    My habit on these is to press the VNAV button twice (OFF than ON) when the “1 minute warning (When the system indicates one minute until descent and descent path appears)” goes off. This will reset the timer and ensure that she actually descends.

    I am not sure but think this may NOT occur with NXI. In the Garmin 3000, this does not occur, at least in the fairly new one I operate.
    That’s a good technique!
  6. Username Protected
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    #6  
    I have had the same thing happen and concur about the five minute timer. You can input the target altitude into your flight plan, but the key is to press the VNAV button anytime within five minutes of the descent beginning.
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    #7  
    I fly Lear 75’s now, and it doesn’t have the timeout on vnav. It drives most everyone crazy that I don’t engage the vnav until I’m close to TOD. Old habits die hard.
  8. Username Protected
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    #8  
    Quote Originally Posted by (Username Protected) View Post
    There is timer on the 1000. I do not know the exact time .I have been told 5 and 10 minutes. If that much times has elapsed since pressing the VNAV button, will not descend, though it all looks normal until it just does not descend.

    My habit on these is to press the VNAV button twice (OFF than ON) when the “1 minute warning (When the system indicates one minute until descent and descent path appears)” goes off. This will reset the timer and ensure that she actually descends.

    I am not sure but think this may NOT occur with NXI. In the Garmin 3000, this does not occur, at least in the fairly new one I operate.
    +1 on this technique that (Username Protected) taught me during my initial. The flows taught by (Username Protected) Aviation are huge.

    VNAV on when cleared to descend via (just so you have the light as a reminder), VNAV off/on when you hear the audible alert.

    Never had a problem with this and it gives you another thing to use as a reminder!
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    #9  
    (Username Protected), you will know if the armed VPATH will capture or not when the one minute audio alert sounds “Vertical Track” and the white armed VPATH annunciation is NOT blinking. If the white armed VPATH annunciation blinks when you are 1 minute prior to TOD then it is alerting you that it will not capture. There are only two reasons for the blinking. 5 minute timer expired or a lower altitude has not been selected. To stop it blinking so it can capture, just press VNV button once (if it’s the timer) or set a lower altitude if it’s because of altitude.

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