Hi. Lukily I did not lost it. I have the Mavic Air.

On a foggy morning I wanted to break through the fog and capture the sunrise. I waited a few moments for RTH to update. After confirmation that RTH was set I started flying. I ascend 6 meters and flew 21meters in front. 12 satelites. I stayed there for a few seconds and started slowly going up to break through the fog. I went up 120 meters (max. altitude) but no sunrise visible. Still dense fog. 14 satelites, distance 22 meters. I hit the RTH buttom and command was accepted. But nothing happend. Just stayed there hoovering. Suddenly I heard a voice saying "Landing". I've paniced and tried to get it home asap trying first to decend so I could see it. I pushed the down stick but it was coming down much to slow. After some very long minutes I could retrive it and land.
BUT. Why did RTH not work??

Flightrecord: https://www.phantomhelp.com/LogViewer/4A3B14BX0MW10TVNLJKF

First of all , you are flying illegally. You lost visual site of your drone.  Secondly , taking it through fog intentionally is not smart.  Fog is a cloud.  A cloud is moisture.  Not the brightest move..

See in here if this helps https://store.dji.com/guides/how-to-use-the-djis-return-to-home/

Perhaps as you ascended the wind blew the drone back a little - if RTH is activated within 20m radius is will land where it is. I presume this happened or the sensors were confused by the fog (which is why DJI advice not to fly in it).

Thanks to all your replies. I won't do it again for security reasons.

Yep. 21meters away is easily within the parameters where RTH will land where it is at.
Suggest you test out RTH actions/options in a wide open field and no clouds (or fog).  Play with different settings and distances and see how RTH works.

Hi Tino,

Had a look at your log and imo something else causes the slow landing.

I can see that you had your Landing Protection ON. This is usefull when hovering at low height, 100% down stick and the MA goes into a smooth slow landing. In the log that`s a ForceLanding.

Flying in the fog your MA VPS height sensor did measure some height, just before that ForceLanding 0.3 meters.When a user applies 100% for stick down for some moments with and low VPS altitude and Landing Protection ON ; DJI software thinks that you want to initiate a landing at low altitude.
Happily you had enough battery power left to bring her down from 120 meters at slow landing speed.

Trying to speed up the descennd with 100% down stick does not help.

What to do ?  To stop the ForceLanding pull 100% up, than disable Landing Protection. Now you can bring the MA down with normal down speed.

At your first RTH your MA did turn towards home heading, but stayed than at position.
It did not lowered altitude, guess that has soemthing to do with the VPS height measuring height.
Same for the second RTH, but than MA was already heading OK.

During ForceLanding (at 5m20.8s) a LowWarning : "Downward altitude sensor data error. Please contact DJI Support for help".

Just see if this error is returning the next flight, if it has to do with fog/moisture guess no problems next time.Just have a sharp lookout on this.

cheers
JJB

Your battery percentage likely fell below 15%, which is why it proceeded to land..

JJB* Posted at 8-11 01:27
Hi Tino,

Had a look at your log and imo something else causes the slow landing.

JJB. Thanks for your analysis.

What made me nervous was the fact that at the RTH MA faced direction to home but did not come back.
Next flight I will test it out in open field. I also contated support and they adviced me to relink the controller what i did. They also adviced to update the firmware with DJI Assistent 2. I tried to do this and also with the DJI GO 4 APP the Firmware semms be up to date, DJI Assistent says it's not. But when I try to update with DJI A2 it dowloads the update but then gives an error message and aborts update.

Anyway. Next couple of times I will fly with more caution and not far away. Just in case.

Thank you again and have a nice sunday.
Tino

David Martin Graff Posted at 8-11 03:21
Your battery percentage likely fell below 15%, which is why it proceeded to land..

This was not the case. In the end I still has 50% battery.

TinoC Posted at 8-11 04:01
This was not the case. In the end I still has 50% battery.

You should reset the drone using DJI Assistant 2 and reinstall the firmware update to the latest version, also reset the firmware of your Remote Controller and repeat RTH functions several times to see if the error reoccurs and if so I'd contact DJI Support.

David Martin Graff Posted at 8-11 18:57
You should reset the drone using DJI Assistant 2 and reinstall the firmware update to the latest version, also reset the firmware of your Remote Controller and repeat RTH functions several times to see if the error reoccurs and if so I'd contact DJI Support.

I tried to do this.  With the DJI GO 4 APP the Firmware seems be up to date, DJI Assistent 2 says it's not. But when I try to update with DJI Assistent 2 it dowloads the update but then gives an error message and aborts the update.

this happened to me too in a way and I need to find out how to prevent this from occurring again. My Air2 s shot up to 1200  feet! when I hit rtn is shot uo more. then it just hovered. This went on for minutes  finally I brought the drone down several hundred feet and it still just hovered. soon it ran out of battery at  2500 feet away from me.  I could not get it to approach home at more then 2 mph so it force landed.    I am very lucky it landed somewhere I was able to reterive it.

I am brand new here so I am not able to start my own thread that is why I am posting here.   I really do not want to lose my $1000 drone.

Can someone explain why RTN would cause my Air 2S to shoot up to 1200 feet and then just hover and not follow any commands?  When I brought it down to 200 feet I was able to get it to approach home manually, but only at about 2mph!  Finally though it started to pick up some speed just as it was force landing.   Very strange. Why would this happen?   I was really dreading that I was going to lose my drone and I was watching it force land not sure exactly where it was but I was able to have enough control to get it to land in a parking lot.

Why would a Air 2 S shoot up to 1200 feet? Why would it then just hover and not follow commands? Why would it not RTN?  

I thought RTN is a fail safe mechanism to the the instrument home.

MANTRAIN Posted at 11-28 01:25
I am brand new here so I am not able to start my own thread that is why I am posting here.   I really do not want to lose my $1000 drone.

Can someone explain why RTN would cause my Air 2S to shoot up to 1200 feet and then just hover and not follow any commands?  When I brought it down to 200 feet I was able to get it to approach home manually, but only at about 2mph!  Finally though it started to pick up some speed just as it was force landing.   Very strange. Why would this happen?   I was really dreading that I was going to lose my drone and I was watching it force land not sure exactly where it was but I was able to have enough control to get it to land in a parking lot.

Hi,

best to get help/advice is to upload your flightlog for this flight.

Use this link > https://www.phantomhelp.com/LogViewer/Upload/
Post the upload linl on here.

Or just put a cloud-link to your flightlog here.

cheers
JJB