GTN650 messages

[Matthew]

I think we have some experts here:

I've seen these messages pop up after landing and during taxi. Usually it's just the Steep Turn message, but yesterday it was the Steep Turn and the VNAV together.

I was doing practice approaches so I had an approach loaded. I am pretty sure this happened after I did my final approach of the lesson, an ILS into R36, then circle to land on R18. I took off the hood and had to extend downwind a ways for other traffic (towered airport) so I got outside the circling protected area. I'm pretty sure either I or my CFI unspsended the 650, but I'm pretty sure we didn't tell it to guide the missed approach since this was going to be a full stop landing.

My guess is the Steep Turn message and the VNAV excessive track angle are related, that the GTN is still trying to calculate guidance even after landing and after I've turned off the rwy.

This particular airplane does not have an autopilot.

Any other ideas?


And then there was this one. I can't remember the phase of flight when this one popped up. I was trying to navigate to a fix, get on an airway, go to another fix, get off the airway, and do a VOR-A approach. There's a pretty good chance that particular flight plan wasn't completely entered properly, I really fumbled around with it. When I reviewed it on the map screen it looked OK, but that doesn't mean there wasn't a gap in it somehow.



I'll ping my CFII to see what she remembers about that flight plan. Right now I'm thinking I just entered something wrong. We were kind of making that route up "on the fly".

 

[asicer]

Did you leave it in suspend mode after you got to the MAP?

 

[Matthew]

Did you leave it in suspend mode after you got to the MAP?

I don’t think so. I’m pretty sure I bailed out of the ILS approach about a mile short because of traffic, then entered a left downwind. Tower wanted me to extend downwind for other traffic on final. I think one of us unsuspended, probably my CFII. When it’s suspended you get the two menu buttons: one to unsuspend and the other to activate the missed procedure. When those are displayed you can’t use the screen to see traffic. I’m pretty sure my CFII unsuspended in order to monitor traffic. Since we were in the pattern there was no need for guidance anymore. This is why I’m wondering if it was still trying to direct me somewhere and with the maneuvering either in the pattern or on the ground it generated those messages.

 

[midlifeflyer]

The steep turn is mostly about speed. Basically, the unit is set for a maximum, "normal" bank angle. Needed bank angle increases as speed increases, so at some point the combination of turn radios and speed will generate the message.

There are several conditions for VNAV to be available. Most apply to the autopilot but there are GTN-specific ones in the AFMS. One is that there are no VNAV altitude constraints in the flight plan. The one that probably applies here is that the descent would exceed the default flight path angle - basically too steep. Again, that can definitely be about being too fast.

Beyond that, I'd need to actually see it to understand it.

 

[Matthew]

The steep turn is mostly about speed. Basically, the unit is set for a maximum, "normal" bank angle. Needed bank angle increases as speed increases, so at some point the combination of turn radios and speed will generate the message.

There are several conditions for VNAV to be available. Most apply to the autopilot but there are GTN-specific ones in the AFMS. One is that there are no VNAV altitude constraints in the flight plan. The one that probably applies here is that the descent would exceed the default flight path angle - basically too steep. Again, that can definitely be about being too fast.

Beyond that, I'd need to actually see it to understand it.

Here are the messages and more background. This flight was about a week ago. I filed, so that’s why there is a squawk code. Did an approach or two somewhere, then on the way back we were getting so beat up by turbulence I did a visual approach back home since there wasn’t much point in trying another approach. I was pretty much worn out by then. I can’t remember if I was being vectored back home or had been given a direct-to. I loaded a visual approach so I could see how the Garmin would display it. With everything going on, and being visual, I didn’t activate it. After landing and during taxi these messages popped up.

I do remember seeing the steep turn message yesterday after landing, that was after the ILS 36 that terminated with a circle to 18. That’s what I described earlier. And I’ve seen it before.

 

[Eric Pauley]

I wouldn’t worry about either of these. During the circle you were probably off track in a way that it couldn’t compute a path back under bank constraints.

 

[Matthew]

I wouldn’t worry about either of these. During the circle you were probably off track in a way that it couldn’t compute a path back under bank constraints.

That’s what I think, too. But I’m still trying to think like a 650.

 

[Pinecone]

Since you flew an ILS, the GTN may still have been in Localizer CDI on the Nav Page. That can get you some screwy things showing up.

 

[asicer]

When it’s suspended you get the two menu buttons: one to unsuspend and the other to activate the missed procedure.

Actually, the two options should be "unsuspend (activate missed)" and "stay suspended". If you stay suspended, it should stop giving you those weird messages.

 

[Matthew]

Actually, the two options should be "unsuspend (activate missed)" and "stay suspended". If you stay suspended, it should stop giving you those weird messages.

I’ll have to pay closer attention.

 

[asicer]

I’ll have to pay closer attention.

Look for a "SUSP" annunciation along the bottom row status bar. If you don't see that, it's trying to steer you back on course.