Note: The Flight Logs and Flight Video has Been Added to this Thread: Today, while flying in a location that I have flown for years I lost GPS signal on my M2P and it evidently went into atti mode.  Unfortunately I was flying in some stiff winds when it happened; over water and near a shoreline with tall trees.  The odd thing is that it displayed 17-18 satelites the whole time this was going on.  The GPS signal never returned for the remainder of the entire flight.  I was about 2 thousand feet out and about 200 feet up when it happened and then suddenly the craft bolted to nearly 500 feet and started drifting fast at the same time, because it was pointed in a headwind I suspect.  Good thing I had practiced flying in atti mode a few years back on my P4, if not I would not have managed to bring it back.  It was like flying a boat in a heavy ocean storm and the landing was crazy!  I could not get it close to anything in the area because it was all over the place, but I managed to get it on the ground.  Don't let anyone tell you differently but the controls do not respond the same in this situation and if this happens with not prior experience then you are out of luck.   

A couple of notations that troubles me: I am disturbed by the fact that the signal never came back at all.  I was using my smart controller and the screen never gave me any information concerning signal loss; only high wind warning.  Also; I don't know about you, but my smart controller tends to disconnect from the app ramdomly, and since I was using the screen to guide me back to my location, what if the darn thing would have disconnected at that time? I know; we are supposed to fly line of sight all the time, but the thing is, in this situation, your line of sight just flew the heck away from you!  

After landing I powered the craft up again just to see if I could get a GPS signal and I flew it around a bit to check it out and it flew fine,  Can anyone point to why the signal failed to come back until after I landed? Yes, I did a compass calibration prior to takeoff, as it pretty much asks me.  

As always, post flight logs if you want help rather than guesses!

parkgt214 Posted at 12-3 17:35
As always, post flight logs if you want help rather than guesses!

Okay; I will try to post them later.

Post the logs here - https://www.phantomhelp.com/LogViewer/Upload/

Hi. Thank you for reaching to DJI Forum. I am sorry for the trouble this has caused. With regards to the said issue. Are you experiencing the same issue in a different location? How strong was the wind during the flight, because strong wind may affect the performance of the said drone. For the DJI Smart Controller are you seeing any error message when you are getting disconnected on the DJI Smart Controller. Please keep us posted for further assistance. Thank you.

DJI should give us the option to fly in ATTI mode.

If you got it back in Atti-mode deserves much kudos, good on the piloting skills.

TrippleDelta Posted at 12-4 14:31
DJI should give us the option to fly in ATTI mode.

Believe me and I think you mean for learning purposes.  Yet, in my opinion, flying a larger and heavier drone like the P4 in atti mode with strong winds is very much different than flying the MP2.  The MP2 acts much like a leaf in the wind and is very hard to control!  When I return home I will post the flight logs and also the video of the ordeal as it took place in real time.  I was very fortunate to get the thing back on the ground.

SD_Pilot Posted at 12-4 16:48
If you got it back in Atti-mode deserves much kudos, good on the piloting skills.

Thanks; like a leaf in the wind and hell to control!

DJI Paladin Posted at 12-4 13:59
Hi. Thank you for reaching to DJI Forum. I am sorry for the trouble this has caused. With regards to the said issue. Are you experiencing the same issue in a different location? How strong was the wind during the flight, because strong wind may affect the performance of the said drone. For the DJI Smart Controller are you seeing any error message when you are getting disconnected on the DJI Smart Controller. Please keep us posted for further assistance. Thank you.

Thanks for responding. One thing also worth mentioning is this: even after getting the aircraft back to the landing areas I noticed that the vision sensors were also not assisting to stabilize the craft even right above the ground, as the wind was still tossing it around.  I flew the drone twice today in different locations and it is working just fine.  The winds during the time of the issue was around 10-12 miles per hour on ground level so I expect higher than 15 or more at my altitude.  I have flown the MP2 in much higher winds on many occasions.  There was not any other information on my screen except the wind warning but again, I became very busy real fast.  I have flown toy drones that does not have any auto measures and they were much easier to handle than the MP2 in attic mode.  IMO the MP2 is not a drone that was built for manual flight!

M Stuart K Posted at 12-4 20:04
Thanks for responding. One thing also worth mentioning is this: even after getting the aircraft back to the landing areas I noticed that the vision sensors were also not assisting to stabilize the craft even right above the ground, as the wind was still tossing it around.  I flew the drone twice today in different locations and it is working just fine.  The winds during the time of the issue was around 10-12 miles per hour on ground level so I expect higher than 15 or more at my altitude.  I have flown the MP2 in much higher winds on many occasions.  There was not any other information on my screen except the wind warning but again, I became very busy real fast.  I have flown toy drones that does not have any auto measures and they were much easier to handle than the MP2 in attic mode.  IMO the MP2 is not a drone that was built for manual flight!

Without even seeing the flight data I can bet that the compass error is to blame here. Rule #36 (or whatever rule #) when DJI drones are considered is to never perform compass calibration on spot, even when clearly demanded by the app. Move the drone somewhere else instead and check compass reading at different location. Calibrate the compass in magnetic interferences free environment once and forget it, unless you travel hundreds miles far. Calibrating at suddenly troubled spot usually results with such erratic behaviour.

I am not saying that the compass was an issue but I have experienced the so called “batti” mode before and this was nothing like that. I was well into my flight when this happened and from my experience the batti mode subsided in a short while and I literally had not control in batti.

M Stuart K Posted at 12-4 19:56
Believe me and I think you mean for learning purposes.  Yet, in my opinion, flying a larger and heavier drone like the P4 in atti mode with strong winds is very much different than flying the MP2.  The MP2 acts much like a leaf in the wind and is very hard to control!  When I return home I will post the flight logs and also the video of the ordeal as it took place in real time.  I was very fortunate to get the thing back on the ground.

Not only for the learning process but also to maintain your skills as a drone pilot.

M2 has atti mode.  You can code it to be in Atti instead of tripod.  I prefer tripod because when I fly tight I need the 6-pos OA.

" what if the darn thing would have disconnected at that time?"

We have hopefully remained prepared for the worst.

Stuart,  Are you in Southern California?

https://www.faasafety.gov/files/notices/2019/Nov/SCORE_19-04_GPS_Flight_Advisory.pdf

https://www.faasafety.gov/files/notices/2019/Nov/YPG_AZ_19-17_(Revision_1)_GPS_Flight_Advisory.pdf

M Stuart K Posted at 12-5 03:12
I am not saying that the compass was an issue but I have experienced the so called “batti” mode before and this was nothing like that. I was well into my flight when this happened and from my experience the batti mode subsided in a short while and I literally had not control in batti.

" I did a compass calibration prior to takeoff, as it pretty much asks me."  

So, was there a compass issue or was not? I'm confused ...

Regarding the Nightmare Incident: Hopefully this is the right link to the flight logs.  I see now that it was not exactly in atti mode but worst than that!  I was lucky to get the darn thing back on the ground in one piece because it had constant ESC errors during the flight, even until I landed.  I will post the video in a couple minutes:
Here is the link to the logs:

https://app.airdata.com/share/aFkkeb

M Stuart K Posted at 12-8 07:52
Regarding the Nightmare Incident: Hopefully this is the right link to the flight logs.  I see now that it was not exactly in atti mode but worst than that!  I was lucky to get the darn thing back on the ground in one piece because it had constant ESC errors during the flight, even until I landed.  I will post the video in a couple minutes:
Here is the link to the logs:

Here is the link to the video of the flight from about the time the malfunction started until I managed to get it on the ground.  I have flown in this location for a couple of years.  

rwynant V1 Posted at 12-5 11:23
Stuart,  Are you in Southern California?
https://www.faasafety.gov/files/notices/2019/Nov/SCORE_19-04_GPS_Flight_Advisory.pdf

No. I was in Tennessee at the time.

Matthew Dobrski Posted at 12-5 13:04
" I did a compass calibration prior to takeoff, as it pretty much asks me."  

So, was there a compass issue or was not? I'm confused ...

Actually no. Take a look at the flight log and video that I posted a few minutes ag.

Hiya,

Had a look at your flight. Wow, good on the controls to bring your MP safely to the ground.

GPS signals and reception stayed OKE during flight. (15 and more all the time, 5 bar reception)
All flight in P-GPS mode.

What i see in the log: mismatch between speed v.v. caculated GPS speed. Same for yaw heading values craft and gimbal yaw. Mismatch often due to incorrect yaw data (data wrong or calculationon data wrong).
So at the end in line an IMU error, only no IMU errors in the log wich is a bit weird.

cheers
JJB

JJB* Posted at 12-8 09:58
Hiya,

Had a look at your flight. Wow, good on the controls to bring your MP safely to the ground.
[Image]

Thanks for taking a look. So does the ESC errors have much to do with loss of control functionality?  Also, I continued to fly the craft on a daily basis for the remainder of the week with no issues at all, so would you say that it was a glitch?  All I saw was a bunch of esc errors but you derived IMU, so what do you suggest?  

M Stuart K Posted at 12-8 10:28
Thanks for taking a look. So does the ESC errors have much to do with loss of control functionality?  Also, I continued to fly the craft on a daily basis for the remainder of the week with no issues at all, so would you say that it was a glitch?  All I saw was a bunch of esc errors but you derived IMU, so what do you suggest?

IMO ESC and NotEnoughPower errors has nothing to do with this kind of control functionality, but mayby if the motors individually has power problems than it can have effect on steering ofcourse.

What you can do ; well IMU calibration ofcourse (calibration of IMU and Compass never harm a drone if done properly!)

Low temperature doesn`t help the battery to perform great.

So just be carefull next flights, but as you have flown already some flights after this witthout issues....

Happy many landings,
Cheers
JJB

M Stuart K Posted at 12-8 08:27
Actually no. Take a look at the flight log and video that I posted a few minutes ag.

OK, let's make sure we're on the same page:

Q1. Was there a request to perform compass calibration prior to take off?
Q2. Did you performed compass calibration as requested?

Matthew Dobrski Posted at 12-8 12:44
OK, let's make sure we're on the same page:

Q1. Was there a request to perform compass calibration prior to take off?

Yes to both!

M Stuart K Posted at 12-8 14:40
Yes to both!

And that was a mistake! That's what I'm trying to tell you.

1. Surprising compass reading anomaly at the place well tested before and known as a trouble-free should be investigated first. There's a number of reasons for magnetic or RF interference with compass, i.e. strong marine radar possibly present at nearby marina(s).
2. Performing compass calibration in magnetically polluted environment may - and most likely will - result with wrong calibration.

Confused compass produced such erratic movements of your drone, probably fighting your somehow panicky sticks commands. Strong wind wasn't helping at all ...

Of course this is only my educated guess, as I've experienced occasional warnings as well, demanding compass calibration of various type and model DJI drones. It was discussed to death many times before, with conclusion NOT to perform compass calibration without investigating the cause first. It was said loud and clearly to perform compass calibration once only in magnetically clean environment and forget about it until you travel several hundreds miles away. This common practice, however, evolved slightly with arise of Mavic class drones and introduction of more advanced compass technology. Mavics are more sensitive to location changes and require periodical compass "excercises", mentioned in manual.

That said, some pilots are reporting increased "eagerness" of DJI Go4 app to display compass error warnings. Here's what to do when it happens:

1. While still on the ground, open the sensors page to examine IMU and compass reading bars. Abandon the lift off if compass readings are abnormal.
2. Shut the system down, restart and check the readings again. Move somewhere else if compass reading is abnormal and repeat the procedure.
3. Perform compass calibration only if the warning is persistent at different locations, and only at location where magnetic interference are not likely to be present.

Matthew Dobrski Posted at 12-8 19:30
And that was a mistake! That's what I'm trying to tell you.

1. Surprising compass reading anomaly at the place well tested before and known as a trouble-free should be investigated first. There's a number of reasons for magnetic or RF interference with compass, i.e. strong marine radar possibly present at nearby marina(s).

Thanks for your feedback. Actually, I had traveled hundreds of miles before taking off at the point of the issue.  I fly there about twice yearly while there on business but it is about 6 hours from my home.  

I will make an assumption that your educated guess is as good as any, but the fact is I have calibrated compasses in some of the worst locations many many times and this is the only incident I have had with any device I have flown, and I have flown a lot.  In the end, it is not a perfect device and is prone to errors, so I guess it was just my time.  Yet, it would be great if I could find out the actual cause of issue.  For example: why was all sensors disabled, including the vision sensors when I was close to the ground?  The craft continued in its nearly uncontrollable behavior and never gained any steady position.  For now, I will practice what you suggest as I move forward.  Thanks again.

M Stuart K Posted at 12-9 04:35
Thanks for your feedback. Actually, I had traveled hundreds of miles before taking off at the point of the issue.  I fly there about twice yearly while there on business but it is about 6 hours from my home.  

I will make an assumption that your educated guess is as good as any, but the fact is I have calibrated compasses in some of the worst locations many many times and this is the only incident I have had with any device I have flown, and I have flown a lot.  In the end, it is not a perfect device and is prone to errors, so I guess it was just my time.  Yet, it would be great if I could find out the actual cause of issue.  For example: why was all sensors disabled, including the vision sensors when I was close to the ground?  The craft continued in its nearly uncontrollable behavior and never gained any steady position.  For now, I will practice what you suggest as I move forward.  Thanks again.

Oh, now I see why the bird demanded compass calibration! Well, like you said it's a complex piece of machinery and occasional glitches are inevitable. Let's hope it was an isolated hiccup ...

Matthew Dobrski Posted at 12-9 11:51
Oh, now I see why the bird demanded compass calibration! Well, like you said it's a complex piece of machinery and occasional glitches are inevitable. Let's hope it was an isolated hiccup  ...

Thanks