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P4P+ Random Switching Between Modes During Flight
362 20 2018-6-17
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svjobeth34
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Flight distance : 24915 ft
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Hello all:

My P4P+ has started switching between P mode and Atti mode during flights. All firmware for the batteries, aircraft, and controller is current. For almost all of my flights, I take off and land in P mode.

The first time the switch happened, the aircraft went from P to Atti for a few seconds. When the aircraft was back into P, I landed and rebooted the controller and the aircraft. The aircraft flew fine on two more batteries. On the fourth battery, the switch occurred again. Once again, I landed, rebooted the aircraft and controller, and then flew a fifth battery with no apparent issues.

Later on, I reviewed the flight logs. While I was aware of the two switches i described as having occurred, the flight log showed 11 different times the aircraft lost all GPS contact and two times there was a 'speed' issue. Most of the lost signal notifications were apparently too quick for the switch to happen, as fast as .05 second. Some of the red letter log messages showed 'GPS Position No Match' with as many as 18 satellites linked; others showed the same message with 0 satellites linked. During the longer switches, the voice on the remote controller announced the change to Atti mode. After speaking with several other pilots familiar with the P4P, the consensus is a poor connection between the on-board GPS module and the main board.

This past Friday, I flew again at a different location, approximately two miles away from the location where the switching started. This time, the switch happened multiple times. Unlike before, there were no voice announcements from the controller. I noticed the first switch when the aircraft was over 100' AGL and began moving like a rocket. The other switches were noticed after the Phantom began to drift during flight or hover.

While I agree all pilots should be competent to fly in Atti mode, I would prefer to determine when the flights occur. If this is indeed a hardware issue, is it worth pursuing a warranty claim with DJI? The Phantom was purchased new in January 2018, from B&H Photo in the US.

Thanks!


2018-6-17
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Landbo
First Officer
Flight distance : 502792 ft
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Try to calibrate your compass. Maybe your quad only needs that. Does that not help I think you should send it for repair.

Regards Leif.
2018-6-17
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svjobeth34
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Flight distance : 24915 ft
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Landbo Posted at 2018-6-17 10:29
Try to calibrate your compass. Maybe your quad only needs that. Does that not help I think you should send it for repair.

Regards Leif.

Leif,

Thank you for the reply. I've not gotten a message to calibrate the compass - the compass function shows as normal each time the quad and controller are powered on. As an aside, I'm not certain I understand how calibrating the compass will relate to the GPS stability and holding a link to satellites?

Thank you again -
2018-6-17
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Landbo
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svjobeth34 Posted at 2018-6-17 13:32
Leif,

Thank you for the reply. I've not gotten a message to calibrate the compass - the compass function shows as normal each time the quad and controller are powered on. As an aside, I'm not certain I understand how calibrating the compass will relate to the GPS stability and holding a link to satellites?

I also used the same arguments when my Mavic Pro last summer began switching to ATTI mode time after time. Every time I looked at the compass function in DJIGO4, everything looked nice with little short green lines. After I calibrated the compass I have not noticed ATTI mode since.  But ok, if you do not want to try then I can not help you.  

Compass and GPS have quite a lot to do with each other anyway. The short version is that when the compass does not match the direction the GPS says the quad is flying in, the GPS turns off and the quad is switching to ATTI mode until the two measurements match again.  

Good Luck, regards Leif.
2018-6-17
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svjobeth34
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Landbo Posted at 2018-6-17 16:36
I also used the same arguments when my Mavic Pro last summer began switching to ATTI mode time after time. Every time I looked at the compass function in DJIGO4, everything looked nice with little short green lines. After I calibrated the compass I have not noticed ATTI mode since.  But ok, if you do not want to try then I can not help you.  

Compass and GPS have quite a lot to do with each other anyway. The short version is that when the compass does not match the direction the GPS says the quad is flying in, the GPS turns off and the quad is switching to ATTI mode until the two measurements match again.  

Leif,

I had not considered the correlation between the compass course and GPS lock. I will give the compass calibration a try.

Thank you!
2018-6-17
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Landbo
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svjobeth34 Posted at 2018-6-17 16:41
Leif,

I had not considered the correlation between the compass course and GPS lock. I will give the compass calibration a try.

Yes, try that, you can not ruin anything.

Regards Leif.
2018-6-17
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Geebax
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svjobeth34 Posted at 2018-6-17 16:41
Leif,

I had not considered the correlation between the compass course and GPS lock. I will give the compass calibration a try.

If you want someone to provide an opinion on what happened, go to this site: http://www.phantomhelp.com/LogViewer/Upload/ and upload your flight log, following the instuctions on the site. Copy the link to the log results, then come back here and paste the link into this thjread.
2018-6-17
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svjobeth34
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Geebax Posted at 2018-6-17 16:46
If you want someone to provide an opinion on what happened, go to this site: http://www.phantomhelp.com/LogViewer/Upload/ and upload your flight log, following the instuctions on the site. Copy the link to the log results, then come back here and paste the link into this thjread.

Here is the link to the flight logs after the first mode switching event - I have not had a chance to download the more recent ones. However, the behavior of the drone was the same each time. As I said in my original post, the consenus from those who have reviewed the logs is a poor power connection to the GPS module. After I posted here about the issue, it was suggested that I do a compass calibration. I plan to do that later this week and test afterwards.

The link to the flight logs:http://www.phantomhelp.com/LogViewer/4HZC1A7Y0SS200RPLPGG/

It is interesting that the log only shows the drone in Atti mode for .2 seconds...when my flight experience was (or seemed to be) several seconds...and despite the instances where 0 sattelites were linked.


Thanks!

2018-6-18
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Fontinalis
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Flight distance : 975367 ft
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I experienced same symptoms as you with my first P4P from day one. I flew it with that problem for almost a year before I sent it to DJI under Care Refresh.  It was never really an issue because it was momentary and I was comfortable with ATTI mode. But the last straw for me with the problem was when I started to fly Litchi waypoint missions - they abort if GPS signal is lost, even for a millisecond. If your logs are like mine, you'll see a lot of instances of going from 15+ satellites to zero and then back up within a few milliseconds. This often happened without the Go 4 app notification of switching to ATTI mode. I wish I would have done the refresh sooner. Their diagnosis was  that a faulty GPS module was the root cause and they sent a replacement airframe.

Not saying there might not be some other cause, but if you can't find it with software/settings/calibration it could be hardware.
2018-6-18
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svjobeth34
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Fontinalis Posted at 2018-6-18 11:23
I experienced same symptoms as you with my first P4P from day one. I flew it with that problem for almost a year before I sent it to DJI under Care Refresh.  It was never really an issue because it was momentary and I was comfortable with ATTI mode. But the last straw for me with the problem was when I started to fly Litchi waypoint missions - they abort if GPS signal is lost, even for a millisecond. If your logs are like mine, you'll see a lot of instances of going from 15+ satellites to zero and then back up within a few milliseconds. This often happened without the Go 4 app notification of switching to ATTI mode. I wish I would have done the refresh sooner. Their diagnosis was  that a faulty GPS module was the root cause and they sent a replacement airframe.

Not saying there might not be some other cause, but if you can't find it with software/settings/calibration it could be hardware.

Thanks for the reply -

Mine is doing exactly that - dropping the GPS link frequently for milliseconds...then re-linking. Like you I am comfortable flying in Atti mode, but I strongly prefer to take-off and land in P mode as I am often launching and landing from boats and/or near water. Also, my P4P did not start doing this until several dozen uneventful flights had been made.

I am going to try the compass calibration and see if that fixes things. If not, then I may go to DJI for a warranty claim - although I do not have DJI Refresh...

Thank you again -
2018-6-18
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Aardvark
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svjobeth34 Posted at 2018-6-18 14:01
Thanks for the reply -

Mine is doing exactly that - dropping the GPS link frequently for milliseconds...then re-linking. Like you I am comfortable flying in Atti mode, but I strongly prefer to take-off and land in P mode as I am often launching and landing from boats and/or near water. Also, my P4P did not start doing this until several dozen uneventful flights had been made.

Do you see the same when flying at a different location ?
There are some large steel structures right beside you there, and that is where all the errors are produced.
2018-6-18
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svjobeth34
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Aardvark Posted at 2018-6-18 14:19
Do you see the same when flying at a different location ?
There are some large steel structures right beside you there, and that is where all the errors are produced.

Yes, the most recent flights when the mode switches occurred were in a nature preserve...nothing but forests and fields.

I have flown multiple times at the yacht repair yard where the posted flight log is from. And you raise a valid point - all of the metal structures in close proximity - and after reconsideration of that, that's why I'm thinking the earlier suggestion of a compass re-calibration is worth trying.
2018-6-18
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Geebax
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svjobeth34 Posted at 2018-6-18 14:26
Yes, the most recent flights when the mode switches occurred were in a nature preserve...nothing but forests and fields.

I have flown multiple times at the yacht repair yard where the posted flight log is from. And you raise a valid point - all of the metal structures in close proximity - and after reconsideration of that, that's why I'm thinking the earlier suggestion of a compass re-calibration is worth trying.

The compass is not the issue, and calibrating it will neither cure the problem nor help it in any way. There are no errors in the log that can be attributed to the compass, they are all to do with the GPS receiver system.

And whatever metal that might be in that yard is not significant enough anyway as when the errors occured, you were at about 100 feet in altitude. The problem is more like with the GPS system, it appears to be receiving a good number of satellites, but the data it is passing along to the navigational system is rubbish. There is no simple answer to this, it could be a bad connection between the GPS receiver and the main board inside the aircraft, it could also be a faulty GPS sub-system or it may be a blip in the firmware. I would suggest you send it to DJI for repair.


2018-6-18
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DJI Thor
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I agree with suggestions above, please try to calibrate the compass, and wait for the status goes to Ready to Go. Besides, you can also try different open areas for testing. If it happens frequently, I suggest that you send the drone in for diagnosis. If it is a warranty case and within the warranty period, the repair will be covered by DJI.
2018-6-24
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svjobeth34
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DJI Thor Posted at 2018-6-24 19:02
I agree with suggestions above, please try to calibrate the compass, and wait for the status goes to Ready to Go. Besides, you can also try different open areas for testing. If it happens frequently, I suggest that you send the drone in for diagnosis. If it is a warranty case and within the warranty period, the repair will be covered by DJI.

Thank you DJI Thor, I can give the compass calibration a try later this week.

If that doesn't resolve the issue, I will open a warranty ticket with DJI. The P4P+ was purchased in January, this year; the problem was first encountered in April.
2018-6-25
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svjobeth34
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svjobeth34 Posted at 2018-6-25 02:56
Thank you DJI Thor, I can give the compass calibration a try later this week.

If that doesn't resolve the issue, I will open a warranty ticket with DJI. The P4P+ was purchased in January, this year; the problem was first encountered in April.

I tried to calibrate the compass, but couldn't get into a calibration menu.

The DJI GO app has not prompted me to calibrate the compass, or to perform any calibration at all. When I go into the 'Aircraft Status' menu, it shows the compass as 'Normal.' Tapping on the compass line makes a 'click' sound, but no menu opens for calibration. Am I missing something?

I did fly three flights on three fully charged batteries. The aircraft mode did not switch on it's own during any of the flights. On the third flight, I switched between P and Atti mode, with no issues.

Any other suggestions?
2018-6-27
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djiuser_PEp4mLwh74c7
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You may fly the drone with strong GPS interference: concrete, metal tower, power plant, or high building. I eperienced the same situation when I flew my drone on a concrete road. When it happens, it alwasy remind you to calibrate your campass and IMU, but it nerve works.
2018-6-27
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DJI Thor
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svjobeth34 Posted at 2018-6-27 08:21
I tried to calibrate the compass, but couldn't get into a calibration menu.

The DJI GO app has not prompted me to calibrate the compass, or to perform any calibration at all. When I go into the 'Aircraft Status' menu, it shows the compass as 'Normal.' Tapping on the compass line makes a 'click' sound, but no menu opens for calibration. Am I missing something?

If the issue did not happen in your recent flights, it could be related with the flight environment.
As for the compass calibration, you can trigger it under the Main Controller Settings: connect the drone, RC and app, Go Fly, the upper right three dots, Advance Settings, Sensor. See if it helps.
2018-6-28
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svjobeth34
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Flight distance : 24915 ft
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DJI Thor Posted at 2018-6-28 04:59
If the issue did not happen in your recent flights, it could be related with the flight environment.
As for the compass calibration, you can trigger it under the Main Controller Settings: connect the drone, RC and app, Go Fly, the upper right three dots, Advance Settings, Sensor. See if it helps.

Thank you for the information.

I flew again this morning, fully charged battery, and had no problems with the drone switching modes. I flew normally on P mode and Atti mode, and was able to switch the modes myself without a problem.

The flight environment most certainly may have played a role. The first time I experienced the mode switches, I had taken off from a concrete pad, which I though had been built around wooden forms. I have since learned the concrete is steel reinforced.

I will try the compass calibration again, just to be certain.
2018-6-28
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DJI Thor
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svjobeth34 Posted at 2018-6-28 07:25
Thank you for the information.

I flew again this morning, fully charged battery, and had no problems with the drone switching modes. I flew normally on P mode and Atti mode, and was able to switch the modes myself without a problem.

Thanks. Should you have any further questions, please feel free to contact us at any time, we're glad to help.
2018-6-28
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Labroides
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svjobeth34 Posted at 2018-6-28 07:25
Thank you for the information.

I flew again this morning, fully charged battery, and had no problems with the drone switching modes. I flew normally on P mode and Atti mode, and was able to switch the modes myself without a problem.
If your Phantom hovers in place without turning, the compass is fine.
Recalibrating the compass won't "fix" anything.

Any other suggestions?
If people understood what calibrating the compass actually does, they might stop recommending it as a universal cure-all.

2018-6-28
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