Altitude loss on forward throttle, every time
1721 14 2020-2-14
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snowgepard
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Russia
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Hi to all,

My Mavic 2 Pro is losing altitude when I apply forward throttle and that happens mainly in the P mode and sport mode. In tripod mode, it is kinda holding stable altitude but I assume that it has to do with the very low speed in tripod mode interestingly it doesn't happen at all at backward throttle what so ever, I've tried that several times already. All that is so extream that it passes the minimum landing altitude threshold, almost before contact with the ground so I'm forced to stop and even introduce with the stick incline movement to avoid docking on the ground. I Have recalibrated all systems several times over the past one month including controller, compass gimbal and IMU over phone and desktop as well. As well do I calibrate my compass before all flights to make sure that no magnetic interferences from the transport might bring the drone in trouble. furthermore, I did try this behavior in different terrains like asphalt and very big grass fields, it doesn't seem to make any difference.
I have updated to the latest current firmware version V01.00.0510 and even reinstalled it, but no changes.
I'm pretty much frustrated and don't know, what to do next or else.
this issue accrued absolutely out of nowhere approximately 1 month ago, I was actually at the beginning thinking it might be normal and I just didn't notice it before but when a friend of mine purchased the same drone I saw how his Mavic 2 pro was flying without any issues at all and understood that something is not right with mine.
After some research, I found out that other users in different forums and as well here, have or had the same or equal issues. Is this all a soft or hardware issue?

I already contacted the DJI support about it and even send them a mail with all the details. Request number (2602676).

I have downloaded the flight logs from the Mavic 2, I've seen that some users are very experienced with reading them. Please, guys, I need your help?
I need to understand what's happening with it.

2020-2-14
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Labroides
Core User of DJI
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I calibrate my compass before  all flights to make sure that no magnetic interferences from the  transport might bring the drone in trouble.
That won't have any effect on your issue and it's unnecessary anyway.

I found out that other users  in different forums and as well here, have or had the same or equal  issues. Is this all a soft or hardware issue?
I haven't heard of any Mavic 2 owners with this issue.

I have downloaded the flight logs from the Mavic 2, I've seen that some users are very experienced with reading them. Please, guys, I need your help?
If you want help, how about sharing some flight data from a flight that demonstrates this issue?
2020-2-14
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snowgepard
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Russia
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Hi Labroides,
2020-2-14
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snowgepard
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Russia
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Hi Labroides,


thank you so much for the really quick reply....

I calibrate my compass before  all flights to make sure that no magnetic interferences from the  transport might bring the drone in trouble.
That won't have any effect on your issue and it's unnecessary anyway.
Well I understood that now as well

I found out that other users  in different forums and as well here, have or had the same or equal  issues. Is this all a soft or hardware issue?
I haven't heard of any Mavic 2 owners with this issue.

I have downloaded the flight logs from the Mavic 2, I've seen that some users are very experienced with reading them. Please, guys, I need your help?
If you want help, how about sharing some flight data from a flight that demonstrates this issue?
of course, I would love to do that, just don't know how to upload an over 2 GB file, maybe via google drive?


2020-2-14
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Labroides
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of course, I would love to do that, just don't know how to upload an over 2 GB file, maybe via google drive?

Forget the 2GB .dat file.
All we need to see is the much smaller .txt file.
2020-2-14
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HedgeTrimmer
First Officer
United States
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Your flight log data file should be whole lot smaller than 2GBs.  

See this link for uploading flight log file, processing log file, and viewing output:  https://www.phantomhelp.com/LogViewer/Upload/

When you get successful output, post the Link to output back here.
2020-2-14
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snowgepard
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Russia
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well, that was me being an idiot, didn't know that everyone is talking actually from the flight data form the app and not from the drone itself.
Anyway here is the link:

https://www.phantomhelp.com/LogViewer/6MRD3FZY1XL215KPNU8H
2020-2-14
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Labroides
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My Mavic 2 Pro is losing altitude when I apply forward throttle and that happens mainly in the P mode and sport mode.
Looking through your flight data for some examples where you had the left stick (throttle) centred and pushed the right stick forward, I find:

Time                        Height          Difference
11:49.7 - 11:58.3   14.8 - 13.0   -1.8m
12:02.9 - 13:21.8   18.7 - 18.1   +0.3m
13:50.8 - 13:58.8   19.2 - 18.8   -0.4m
14:03.6 - 14:11.9   18.4 - 18.6   +0.2m
14:53.6 -  15:02.5  23.4 - 23.1   -0.3m
16:29.5 -  16:48.1  22.9 - 22.4   -0.5m
17:13.7 -  17:21.2  2.0 -  2.5    +0.5m
17:38.3 -  17:49.4  0.7 -  0.8    +0.1m

Apart from the first observation, all were within +/-0.5m which is the vertical position holding accuracy shown in the specs
Hovering Accuracy Range    Vertical: ± 0.5 m (with GPS positioning)
There is a mix of positive and negative changes in altitude rather than a general negative trend.
Sport mode was not used in that flight so I can't comment on what happens in Sport Mode.

2020-2-15
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snowgepard
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Russia
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Hey Labroides,

thank you already for your really nice support and help, I can't really explain my self why it doesn't show up on the log files since it is way more serious and visible in real life.
here I have a link of a video from that day (drone perspective), I'm trying to shoot a video today also of the drone from my perspective to show you what I mean because the drone is dropping altitude way more than .5m .   I really appreciate the help

2020-2-15
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HedgeTrimmer
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United States
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Does the same problem happen when flying over land (that is not covered by snow)?
2020-2-15
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snowgepard
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Russia
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HedgeTrimmer Posted at 2-15 19:31
Does the same problem happen when flying over land (that is not covered by snow)?

Pretty much on any terrain, as I already mentioned I tried it on asphalt cleaned roads pretty much on all kind of places. I was also thinking about it at the beginning that it might be related to the snow or the ice, but it possible can't  be because I've seen another Mavic 2 PRO just  a week ago from a friend of mine flying like a smooth perfect bird without any issues at all.  
2020-2-16
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JJB*
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Hi

Snowgepard,

Had a look at your fligt as well, after reading your text.

When i see the VPS height data ( see chart),   i see that at few moments in flight VPS height is dropping. (at aprox. my ID 1500 almost 4 meter down).

Problem is that i cannot tell if your drone really droppend that height, simply beacuse it is a measured value wich if wrongly measured (possible above some surfaces, like ice) does not reflect the actual height fluctuations of your drone.

But as you said that you saw it loosing height, VPS shows what you have seen.

Solutiuon ; don`t fly low over water, ice and other surfaces wich disturb the VPS height sensor.

cheers
JJB
analysis1.png
2020-2-16
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snowgepard
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Hey JJB,

thanks for the reply, is there any explanation from your side with regard to the normal behavior of the MAVIC 2 PRO from my friend. I mean I'm really absolutely ready to agree to any problem solution like that if other drones would behave the same, but first - the other drone is not doing that on exactly the same surface and second I have tried it on other surfaces as well.

Thanks again, I really appreciate all your help and analyzing skills  guys....
2020-2-16
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JJB*
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snowgepard Posted at 2-16 05:33
Hey JJB,

thanks for the reply, is there any explanation from your side with regard to the normal behavior of the MAVIC 2 PRO from my friend. I mean I'm really absolutely ready to agree to any problem solution like that if other drones would behave the same, but first - the other drone is not doing that on exactly the same surface and second I have tried it on other surfaces as well.

Hi,

Are all the settings in Go app for both drones the same?  Is the Autolanding Protection option enabled?If this setting is disabled you can fly the drone into the ground, if will not stop automatically.

I do not have a MP2 myself, so cannot tell from own experience if or what could be wrong with your MP.


cheers,
JJB


2020-2-16
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snowgepard
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Russia
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JJB* Posted at 2-16 05:39
Hi,

Are all the settings in Go app for both drones the same?  Is the Autolanding Protection option enabled?If this setting is disabled you can fly the drone into the ground, if will not stop automatically.

Well auto landing protection is activated.... and by long enough holding the throttle stick and not trying to correct for the altitude loss my drone would pretty much fly in to the ground. --- I mean I didn't check the camera settings of his drone but I guess it is in any case irrelevant, but as far as all the flight settings and sensors goes all settings are the same.

I wanted to make some more clips from the drone today but didn't have the time to, but I hope can get tomorrow more footage and log data especially demonstrating the sport mode as well what is behaving really wired very occasionally.
2020-2-16
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