Garmin TO/GA functionality during missed approach

[Richard Connell]

That variability in time to transition FD modes results from the AGL at which you pressed the TO/GA button. If you press the TO/GA button at LPV approach minimums, it is going to sequence flight director modes as soon as a positive rate of climb is achieved. If you press the TO/GA button just prior to actually reaching the runway (very low AGL), the system holds wings level (GA lateral mode) until you have both achieved a positive rate of climb, and flown away from the ground to a reasonable threshold.

I think you will find that pressing the TO/GA button at LPV approach minimums will lead to a very quick transition of flight director modes. If you are in a situation you are pressing the TO/GA button beyond approach minimums, the system will hold you wings level for a bit longer, before it begins any kind of lateral GPS course correction, even if it is very slight.

Thanks,

Justin

Thanks Justin. Makes sense

 

[Bavafa]

One other behavior that was rather new/unexpected to me;
A couple of days ago, I was on an ILS practice approach and I pressed the TO/GA button at the miss point. The plane behaved as expected by the way of pitching up and climbing straight and level at which point I disconnect the A/P and talking to ATC to get another approach in. Once finished talking and looked back at the 650xi, it was on the GPS mode. So, it seems that it had flipped from VLOC to GPS automatically which I didn't think it would do that.

I did not try it again that day to reconfirm, but if this is new and automatic, then it is a nice feature/function.
Of course we all know that if you are on the GPS and load an ILS plan, it will automatically flip to VLOC once you have an active needle.

 

[rdamazio]

Here's how mine is wired, in case that helps:

 

[Richard Connell]

One other behavior that was rather new/unexpected to me;
A couple of days ago, I was on an ILS practice approach and I pressed the TO/GA button at the miss point. The plane behaved as expected by the way of pitching up and climbing straight and level at which point I disconnect the A/P and talking to ATC to get another approach in. Once finished talking and looked back at the 650xi, it was on the GPS mode. So, it seems that it had flipped from VLOC to GPS automatically which I didn't think it would do that.

I did not try it again that day to reconfirm, but if this is new and automatic, then it is a nice feature/function.
Of course we all know that if you are on the GPS and load an ILS plan, it will automatically flip to VLOC once you have an active needle.

so I think what’s happening here is that the GPS overlay that seems to accompany the ILS also has a GPS missed approach. So when you TOGA you are activating a GPS missed approach. We only have 2 ILSs here and they both do the same thing.
So it transitions to the GPS for lateral guidance.
I haven’t actually done this in practice though because we almost never get the published missed at my local so it’s always fly runway heading - but the GPS missed procedure is on the screen ready to go.

 

[Bavafa]

so I think what’s happening here is that the GPS overlay that seems to accompany the ILS also has a GPS missed approach. So when you TOGA you are activating a GPS missed approach. We only have 2 ILSs here and they both do the same thing.
So it transitions to the GPS for lateral guidance.
I haven’t actually done this in practice though because we almost never get the published missed at my local so it’s always fly runway heading - but the GPS missed procedure is on the screen ready to go.

Richard,
I had tried this in the past as part of my practice but I don't remember that it flipped from VLOC to GPS automatically and for my check list, I have a item to do this manually.
On my next next flight, I will repeat this again and pay attention to see if/when this transition take place.

 

[Richard Connell]

Richard,
I had tried this in the past as part of my practice but I don't remember that it flipped from VLOC to GPS automatically and for my check list, I have a item to do this manually.
On my next next flight, I will repeat this again and pay attention to see if/when this transition take place.

Great. Will be good to hear.
I’m pretty sure it’s at the MAP if you’ve pushed TOGA (unsuspend) prior.
I do know that for my local if you are hand flying and don’t push TOGA prior to the MAP you’ll get the same message at the MAP “activate gps missed approach” for both an ILS and an RNAV.
In that scenario if you remain suspended then the CDI will stay in VLOC.