Descending below altitude of take-off elevation?

[Hugabeen]

Hi fellow Mavic Pilots,
I have searched threads and forums and the manual to find a solution to this problem but haven't found any clear answers. Perhaps it's been covered before but I'm not having much success finding it. I'm trying to figure out what I'm missing in my settings that prevents me from descending in elevation below the point of launch. This is an intermittent issue. I have had no problems with this in the past until a few months ago (possibly after a firmware update?) and was able to launch at a canyon rim or riverbed and descend downward to shoot below my launch elevation. Now, the aircraft won't allow me to do this unless I disable downward vision sensors. I'm a fairly experienced pilot having flown DJI drones including the P2V+, P3P, P4P, Mavic Pro, Mavic AIr, Mavic 2 Pro, Spark, Mavic Mini and the Inspire 1 recreationally and professionally since 2014. But I'm also human and aware that I am fully capable of stupid and making mistakes. Any relevant and new insight would be very much appreciated.

 

[Not A Speck Of Cereal]

Now, the aircraft won't allow me to do this unless I disable downward vision sensors.

What specifically does it do? Does it just stop at that elevation? If so, can you move the craft laterally (left right fwd bwd)?

Do you get visual or audible warnings from the app?

But I'm also human and aware that I am fully capable of stupid and making mistakes.

Ain't we all.

Chris

 

[Hugabeen]

What specifically does it do? Does it just stop at that elevation? If so, can you move the craft laterally (left right fwd bwd)?

Do you get visual or audible warnings from the app?



Ain't we all.

Chris

Aircraft operates perfectly normal laterally and vertically however once the altitude indicator reaches a negative number it stops all downward motion. It's as if there is an imaginary barrier. There are no warning indications on the screen of my mobile device indicating an error. This is even after calibrating Vision sensors on the computer at home. It's just really puzzling because it's a new problem I have never encountered before.

 

[Not A Speck Of Cereal]

Interesting. The only time I've had that -- aircraft smearing against what could have been a glass wall -- was when it encountered a NFZ (and that was horizontal, not vertical). But you say this goes away when you turn off the vision positioning sensors, so it can't be that.

I'm interested to see what others come up with.

Chris

 

[oldfiredrone]

In the past I have had the issue of not being able to fly at negative altitude below the home point, with the Go 4 App. Since 2017, I have used the Litchi App as my primary flight controller. I live at a cliff’s edge, 100’ above a lake. I now have the Mavic 2 Pro, that I fly with the Litchi App. Yesterday, I flew to a negative 40’ below the home point. Negative altitude has not been an issue using Litchi.

 

[cgmaxed]

Aircraft operates perfectly normal laterally and vertically however once the altitude indicator reaches a negative number it stops all downward motion. It's as if there is an imaginary barrier. There are no warning indications on the screen of my mobile device indicating an error. This is even after calibrating Vision sensors on the computer at home. It's just really puzzling because it's a new problem I have never encountered before.

Strange. My Mav Air 2 doesn't do that. It descends normally. It just gives a negative altitude value.

 

[Meta4]

Strange. My Mav Air 2 doesn't do that. It descends normally. It just gives a negative altitude value.

The behaviour reported by the OP is not normal.
Recorded flight data would have probably explained the cause of the issue.

 

[Auggie]

I flew my second mission ever on a very tall hilltop and descended below the Home Point to cruise the school and playing field below. Not sure how much further below Home Point. I think I heard a verbal warning. I haven't looked into the flight logs this second session but now I'm curious and will peruse it this evening...