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Unable to lower down Air 2

chukovskij

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Hi, I flight actively last 3 weeks in mountains, everything was fine in general although 2 times I wasn't able to lower down (due to force landing trigger) Mavic Air 2 and had to run uphill to land it safely. And once I have multiple disconnection/reconnection issues although drone was close to me and in direct visibility. Could you please explain what was going on.

It was often hard to find a flat area in the mountains, so I usually launch and land the drone from/on my hand.
The first 2 cases were in foggy conditions, but the fog was thin.

1) Case #1. I launched the drone, then went downhill. The drone was flying above the lake, the weather was a bit foggy but the fog was thin, when I tried to lower it down a bit closer to the lake surface it didn't go down and suggested to do auto-landing. I tried to lower it down above me, but the same thing happened. So I have to run uphill to land it at a higher altitude. I assume it is my fault and maybe it cannot fly below take-off relative altitude. File: fly074.dat

2) Case #2. I flight a bit after takeoff, returned it back to me (was standing at ~ same altitude), but the drone rejected to go down and was hanging 5-15 meters above me suggesting auto-landing. So I have to run to some higher place to land it. This case not clear for me because my altitude was the same and I expected drone to lower down back to take-off altitude. File: fly076.dat

3) Case #3. This case is related to RC multiple disconnections, the drone was lost for several seconds and reconnected again. Not sure why it happened, maybe some wi-fi interference in mountaineering base camp, but I didn't get any strong interference warning. I stand on the stone roof and the drone was flying not far from me, at a bit hight altitude. File: FLY095.DAT
 

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There can be problems, with other models, forcing a landing i.e. impossible, if the drone is attempting to RTH to somewhere else, would that fit any of these situations?

If you are moving about it is probably wise to keep updating the home point to the controller's location, you'll probably need the phone's location services switched on to do that.
 

chukovskij

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> if the drone is attempting to RTH
There were no RTH attempts. Maybe due to thin fog, obstacles detection system decided that ground was close. Not sure how to check this in DAT file.

> If you are moving about it is probably wise to keep updating the home point to the controller's location
Thank you for the advice. So it is ok to fly lower relative to take-off altitude?
 

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Hi, I flight actively last 3 weeks in mountains, everything was fine in general although 2 times I wasn't able to lower down (due to force landing trigger) Mavic Air 2 and had to run uphill to land it safely. And once I have multiple disconnection/reconnection issues although drone was close to me and in direct visibility. Could you please explain what was going on.

It was often hard to find a flat area in the mountains, so I usually launch and land the drone from/on my hand.
The first 2 cases were in foggy conditions, but the fog was thin.

1) Case #1. I launched the drone, then went downhill. The drone was flying above the lake, the weather was a bit foggy but the fog was thin, when I tried to lower it down a bit closer to the lake surface it didn't go down and suggested to do auto-landing. I tried to lower it down above me, but the same thing happened. So I have to run uphill to land it at a higher altitude. I assume it is my fault and maybe it cannot fly below take-off relative altitude. File: fly074.dat

2) Case #2. I flight a bit after takeoff, returned it back to me (was standing at ~ same altitude), but the drone rejected to go down and was hanging 5-15 meters above me suggesting auto-landing. So I have to run to some higher place to land it. This case not clear for me because my altitude was the same and I expected drone to lower down back to take-off altitude. File: fly076.dat

3) Case #3. This case is related to RC multiple disconnections, the drone was lost for several seconds and reconnected again. Not sure why it happened, maybe some wi-fi interference in mountaineering base camp, but I didn't get any strong interference warning. I stand on the stone roof and the drone was flying not far from me, at a bit hight altitude. File: FLY095.DAT

Did you consider switching into Sport Mode : ; that way you know immediately if it was the sensors being confused with the water and the fog ?

Phantomrain.org
Gear to fly your Mavic in the rain
 
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So it is ok to fly lower relative to take-off altitude?
There is no limit, that I know of, as to how far below the homepoint etc. you can descend, i.e. I believe you could take off from the top of a 1000m cliff and fly down to its base if that is what you wanted to do, DON'T land.
Whether you'd have the battery capacity to get back up to the top of that cliff is a different matter, lol.
 
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chukovskij

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> Did you consider switching into Sport Mode : ; that way you know immediately if it was the sensors being confused

I know that it could help, but I don't remember whether I tried it or not. I see a switch to a sport mode in 074 DAT file, but don't understand was it helpful or not. It was 2 weeks ago and AFAIR after some attempts, the safest solution seemed just to run uphill to the desired altitude and land it.

In case #2 I just run uphill again and didn't tried sport mode.

As far as I understand force landing was enabled because I held the stick down while the drone rejected to descend.
 

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Meta4

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Hi, I flight actively last 3 weeks in mountains, everything was fine in general although 2 times I wasn't able to lower down (due to force landing trigger) Mavic Air 2 and had to run uphill to land it safely. And once I have multiple disconnection/reconnection issues although drone was close to me and in direct visibility. Could you please explain what was going on.
This kind of thing is usually related to the downward facing sensors and the fog you mentioned might be a factor.
It should be quite easy to check the flight data to confirm whether this was the case.
Post the txt files (rather than .dat files) and I can have a look for you.
 
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boblui

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case #1

after 410 seconds into the flight, the drone did not respond to throttle-down commands :

1596947596360.png

This was because the drone detected something very close to the bottom, just 0.2 ~ 1 meter away so the landing protection mechanism kicked in. If you hold the throttle fully down for more than 1 second or so, landing will be triggered. This has happened two times in the time period above. I believe landing was not executed because the "ground" was seen as not flat enough for the purpose.

At this point the drone was about 1 meter below the take off point. If you are sure that the drone was still well above the terrain beneath it, the drone must have misrecognized the fog as the ground.
 
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chukovskij

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case #1

This was because the drone detected something very close to the bottom, just 0.2 ~ 1 meter away so the landing protection mechanism kicked in. If you hold the throttle fully down for more than 1 second or so, the landing will be triggered. This has happened two times in the time period above.

the drone must have misrecognized the fog as the ground.
Thx, for the explanation, I've reproduced the same plots by myself, so now I understand how to interpret


I believe landing was not executed because the "ground" was seen as not flat enough for the purpose.
In both cases, I got landing countdown and managed to press "Cancel" on phone screen


just 0.2 ~ 1 meter away so the landing protection mechanism kicked in. If you hold the throttle fully down for more than 1 second or so, the landing will be triggered.

I believe landing was not executed because the "ground" was seen as not flat enough for the purpose.
Ok, fog is unfriendly environment, but clouds could approach fast enough in the mountains and cover the area for some time. What I'm supposed to do in such cases?
- Should "Sport" mode help to force ultrasonic height confusion? AFAIU I cannot disable ultrasonic sensor warnings for Air2 in the app.
- If landing is triggered and I will not manage to stop it, what the drone is supposed to do if the surface is not suitable for landing, e.g. stone blocks / rocks or lake?
I'm I right that lake is likely to be flat enough to landing and as for stones, it should hover close to them and reject landing?
- Does left stick down command skips flat area check? (In the other thread I was recommended to do it for hand landing because "land" button in my case sometimes results in error msg that area is not suitable for landing without any force landing choice)

> 3) Case #3. This case is related to RC multiple disconnections
Could you please show how to check RC disconnections issues in case #3 or tell which params to check?
In other days/locations, I didn't have such issues, only here although it was close to me and in direct visibility. Is it some radio interference or attempt to capture drone control or etc?

P.S: Not 100% sure that 095.DAT is the log with disconnections, I have several log files for that.
 
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boblui

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In both cases, I got landing countdown and managed to press "Cancel" on phone screen
On my M2P, I have seen landing countdown only in forced landing due to severly low battery :

1597048227242.png

Your case is obviously different. I can only guess that the landing countdown was due to the cameras at the belly unable to see any clear textures so it was not sure whether it was close to the real ground.

On my M2P, if the ground is seen but found to be uneven, this message will appear. I have the option to do force landing but there is no coutdown :

1597046828398.png


Ok, fog is unfriendly environment..... What I'm supposed to do ....
- Should "Sport" mode help ....
I don't have the Air 2 but with my M2P, turning off the VPS will solve the problem but the pilot will need to manaully control the rate of descent until the drone touches the ground. I am not sure whether switching to sport mode will have the same effect on the Air 2. On M2P or Mini, switching to sport mode has no effect on the bottom sensors.


- If landing is triggered and I will not manage to stop it, what the drone is supposed to do if the surface is not suitable for landing.... "land" button in my case sometimes results in error msg that area is not suitable for landing without any force landing choice....
The design of the Air 2 seems to be different from that of M2 in this regard, I will leave it to owners of Air 2 to answer this question.


> 3) Case #3. This case is related to RC multiple disconnections
Could you please show how to check RC disconnections issues in case #3. In all other flights, I didn't have such issues, only here although it was close to me and in direct visibility. Is it some radio interference or attempt to capture drone control or etc?

I saw the disconnection in the chart and it last for about 5 seconds. Before disconnection, the uplink and downlink signal strength were at their maximum ( 5 ). After that, there were some events saying that the radio connection was resumed. It is highly unlikely that the disconnection was due to interference considering the proximity of the drone to the RC and the lack of any interference warning messages. I am afraid I don't have any clue on the reason behind.
 
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chukovskij

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On my M2P, if the ground is seen but found to be uneven, this message will appear. I have the option to do force landing but there is no coutdown :

View attachment 110133
I often get the same warning during hand landing (when using 'land' button on the screen), but in rare cases there is only "OK" button and no force landing choice.


I saw the disconnection in the chart and it last for about 5 seconds. Before disconnection, the uplink and downlink signal strength were at their maximum ( 5 ). After that, there were some events saying that the radio connection was resumed. It is highly unlikely that the disconnection was due to interference considering the proximity of the drone to the RC and the lack of any interference warning messages. I am afraid I don't have any clue on the reason behind.
Thx, you are right, it was like you described. Sudden disconnection and re-connection in several secs with full signal + also camera live view freezes in next flight in that area. I thought the drone would try to RTH, maybe disconnection wasn't long enough for starting RTH. Which `states` do you use to see these 1) disconnection 5 sec event and 2) lack of any interference warnings
 

boblui

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Which `states` do you use to see these 1) disconnection 5 sec event and 2) lack of any interference warnings

Related data fields are shown in the chart below. Disconnection occurred during the period from 301.2 to 305.9 secs

1597056075864.png

Events before and after the disconnection can be seen in the exported csv file. Some of the messages are only displayed in the .TXT flight log file. You may check it as well.

1597056503250.png
 
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BudWalker

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On my M2P, I have seen landing countdown only in forced landing due to severly low battery :

View attachment 110136

Your case is obviously different. I can only guess that the landing countdown was due to the cameras at the belly unable to see any clear textures so it was not sure whether it was close to the real ground.

On my M2P, if the ground is seen but found to be uneven, this message will appear. I have the option to do force landing but there is no coutdown :

View attachment 110133



I don't have the Air 2 but with my M2P, turning off the VPS will solve the problem but the pilot will need to manaully control the rate of descent until the drone touches the ground. I am not sure whether switching to sport mode will have the same effect on the Air 2. On M2P or Mini, switching to sport mode has no effect on the bottom sensors.



The design of the Air 2 seems to be different from that of M2 in this regard, I will leave it to owners of Air 2 to answer this question.




I saw the disconnection in the chart and it last for about 5 seconds. Before disconnection, the uplink and downlink signal strength were at their maximum ( 5 ). After that, there were some events saying that the radio connection was resumed. It is highly unlikely that the disconnection was due to interference considering the proximity of the drone to the RC and the lack of any interference warning messages. I am afraid I don't have any clue on the reason behind.
Mr_controller:ctrl_level is, I believe, the confidence that the FC has in it's location solution. It was called navHealth in version 3.7.6 and before. Mr_controller:sig_level follows ctrl_level closely but is not identical.
 

wauwau0977

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just to add on this. had the very same. i run the latest firmware on a mavic air z.

i can definitely confirm: sport mode did not help. it was kind of scary, i thought i don't bring it down. this was an issue since i was in trees and the only way back was lower it first.

what helped as a workaround was to initiate landing procedure, bring it down, then cancel it again...

i live in a foggy area...

cheers,
pt
 
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commrus

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just to add on this. had the very same. i run the latest firmware on a mavic air z.

i can definitely confirm: sport mode did not help. it was kind of scary, i thought i don't bring it down. this was an issue since i was in trees and the only way back was lower it first.

what helped as a workaround was to initiate landing procedure, bring it down, then cancel it again...

i live in a foggy area...

cheers,
pt
hi im having same problem with my air 2 today (sept. 24, 2022) after a hand launch from a 3 story building and attempting to go back from same point 3floors and descending the drone is very tricky its just hovering around 40 feet above and doesnt respond to a throttle down input. so i need to force land and cancelling until its near me for a hand grab. is this something to do with telemetry that drones require to take off from ground level from now on? i was having no problem with my other air 2s. is it a sensor calibration or merely a firmware problem? any findings about this causing it? i have no problem with ground takeoff and hand landing the throttle down is responsive. your thoughts is highly appreciated. thanks

h.
 

Meta4

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is this something to do with telemetry that drones require to take off from ground level from now on?
It makes no difference what level you launch from or land at.

i was having no problem with my other air 2s. is it a sensor calibration or merely a firmware problem?h.
It won't be a firmware issue.
The obvious thing to do is post your flight data so someone can look at it and find the cause.

Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report on the flight data.
Come back and post a link to the report it provides.

Or just post the .txt file.
 
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