Random In-Flight Switches to from 'P' Mode to 'Atti' Mode...

[svjobeth]

...and then back to 'OPTI' or 'P' mode. Phantom 4 Pro+, current firmware.

Happened the first flight of five, two or three times, while well away from obstacles, potential interference sources, etc., at altitudes of 100' - 125', and about 500' from the RC. Landed the AC, rebooted both AC and controller, and had no further issues.

Curious if anyone else has seen this before. Thanks!

 

[Loz]

Not experienced it, doesn’t sound good and it’s not normal. I’m guessing AC was loosing GPS fix and dropping into ATTI mode as a result? Best I’d suggest is upload flight log and hopefully a kind and capable member could look at them and provide some clarity on what’s happening. Anything new occurred to cause this that you know of?

 

[Neon Euc]

Odd thing is when I personally check airdata the flight log says that a lot, it switched back and forth to ATTI mode but nothing appears on my screen. And had no issues with that. Been happening with the P3S in the past and also my P3A (all 3 of them that I had exchanged in the past) this may be normal if the OP is getting the reading from airdata. Or does it happen on screen ?

 

[svjobeth]

Thanks for the replies -

Loz: after some thought, I wrote it off to being a hiccup with the satellites. We see that from time to time on our boat. That would do exactly as you suggested; dropping the GPS and going into 'Atti.' Nothing new with the A/C or other gear. Flight was at a location I'd flown previously with no issues. I'm traveling now and the A/C is back at home. I'll fly when I get back and see what happens.

Neon Euc: The switch between modes showed up on the RC screen and the DJI lady announced "Atti Mode" each time it happened. I checked the controller, thinking perhaps I flicked it out of "P" and the mode switch was set to "P." Within a few seconds, the A/C was back in "P." I hovered for a bit, then resumed my course. The switch happened a couple more times, in the span of less than a minute. At this point, the A/C was flying in "P" mode and I landed without it switching again. After the reboot of the boat A/C and controller, no more switches.

I'll look through the logs when I'm back and see what I can see. Thanks again, and if anyone else has seen this, I'm interested to hear.

 

[WetDog]

This happens on my P3Ps from time to time. It's annoying because I stop and check the telemetry, make sure I'm not near something I shouldn't be - but nothing untoward happens. It may be like svjbeth theorizes - just quick dropouts on the signal - although the P4 with it's dual GPS *should* be less sensitive to this than my relatively ancient P3Ps.

 

[svjobeth]

This happens on my P3Ps from time to time. It's annoying because I stop and check the telemetry, make sure I'm not near something I shouldn't be - but nothing untoward happens. It may be like svjbeth theorizes - just quick dropouts on the signal - although the P4 with it's dual GPS *should* be less sensitive to this than my relatively ancient P3Ps.

The GPS network faltering - that's the only explanation I can see, given the randomness of the event. And yes, even though the P4P *should* be less sensitive to drop-outs of satellite signals, etc., we have, as I mentioned, seen this happen with our boat navigation systems...and I would hazard a guess they're quite a bit more sophisticated than the DJI systems.

 

[WetDog]

Aliens. I'm sure it's Aliens blocking the satellites. Makes sense.

 

[Meta4]

The GPS network faltering - that's the only explanation I can see, given the randomness of the event. And yes, even though the P4P *should* be less sensitive to drop-outs of satellite signals, etc., we have, as I mentioned, seen this happen with our boat navigation systems...and I would hazard a guess they're quite a bit more sophisticated than the DJI systems.

The GPS satellite network isn't faltering and that's not the only explanation.
Any GPS issues would be limited to just one satellite, not the whole network.
I've been flying Phantoms and using GPS for >20 years and I don't see anything like what you describe.
It sounds like a hardware problem with your GPS antenna or a connection to the mainboard.

Go to DJI Flight Log Viewer
Follow the instructions there to upload your flight record from your phone or tablet.
Come back and post a link to the report it gives you.

 

[svjobeth]

The GPS satellite network isn't faltering and that's not the only explanation.
Any GPS issues would be limited to just one satellite, not the whole network.
I've been flying Phantoms and using GPS for >20 years and I don't see anything like what you describe.
It sounds like a hardware problem with your GPS antenna or a connection to the mainboard.

Go to DJI Flight Log Viewer
Follow the instructions there to upload your flight record from your phone or tablet.
Come back and post a link to the report it gives you.

I'm finally back in town and am going through these steps to retrieve and upload the flight records.

On the P4P+ remote controller, I go through the steps to get to the DJI/dji.pilot.pad.FlightRecord folder. I open the folder and all I see are lots .txt docs which are filled with code...and a folder full of .dat files...a SynchResult folder and an Uploads folder which is empty.

Which file do I upload for the correct flight and flight data? Thanks!

 

[Meta4]

I open the folder and all I see are lots .txt docs which are filled with code...and a folder full of .dat files...a SynchResult folder and an Uploads folder which is empty.
Which file do I upload for the correct flight and flight data?

You are looking for a txt file for the data and time of the flight of interest

 

[svjobeth]

You are looking for a txt file for the data and time of the flight of interest

Thank you. Will upload in a few minutes.

 

[svjobeth]

This is the log:

DJI Flight Log Viewer - PhantomHelp.com

 

[Meta4]

This is the log:

This flight shows an intermittent GPS problem.
The GPS sat count drops to zero a number of times during the flight.
The flight data doesn't show P-Opti mode but if you were in atti mode (which would have happened whenever you lost GPS) and your Phantom was close enough to the ground for the VPS to work, the Phantom would have been in P-Opti mode.
If the lighting was good and the ground surface had a distinct pattern or texture, VPS would have maintained position holding.
The GPS count dropped to zero at:
0:12.1 - 0:18.3
1:31 - 1:31.3
1:32.2 - 1:34
2:02.9
2:03.9
2:04.5 - 2:05.5
2:06.2 - 2:09.3
3:06 - 3:09.5
3:14.7
3:17.2 - 3:19.5
Some of these were too brief for the app to register as Atti or P-Opti mode.
The cause would be a fault in the GPS receiver or a loose connection from the GPS to the mainboard.
Was this a one-off event or is it still happening?

 

[svjobeth]

This flight shows an intermittent GPS problem.
The GPS sat count drops to zero a number of times during the flight.
The flight data doesn't show P-Opti mode but if you were in atti mode (which would have happened whenever you lost GPS) and your Phantom was close enough to the ground for the VPS to work, the Phantom would have been in P-Opti mode.
If the lighting was good and the ground surface had a distinct pattern or texture, VPS would have maintained position holding.
The GPS count dropped to zero at:
0:12.1 - 0:18.3
1:31 - 1:31.3
1:32.2 - 1:34
2:02.9
2:03.9
2:04.5 - 2:05.5
2:06.2 - 2:09.3
3:06 - 3:09.5
3:14.7
3:17.2 - 3:19.5
Some of these were too brief for the app to register as Atti or P-Opti mode.
The cause would be a fault in the GPS receiver or a loose connection from the GPS to the mainboard.
Was this a one-off event or is it still happening?

Thanks for the data analysis.

After landing and rebooting everything, I flew the remainder of that flight and 4 others with no issues whatsoever. During the second flight that day, I intentionally switched from P to Atti mode while in flight for a few minutes, then back to P mode again. There were zero issues when I manually switched between modes. Otherwise, all the flights that day, 5 in total, were done start to finish in P mode.

Since it didn't happen at all on the other flights that day, it seems at the moment to have been a one-off event. However, as I was in and out of town for a few weeks, and because of poor weather conditions when I was here, I haven't flown since the date this happened. I'm hoping to get the AC back in the air within this week.

Thanks again!

 

[Rick218]

Aliens. I'm sure it's Aliens blocking the satellites. Makes sense.

Big brother tracking your every move.... using your camera too most likely!!!

 

[svjobeth]

Big brother tracking your every move.... using your camera too most likely!!!

Haha, well Big Brother's gonna get real bored, real quick...

 

[svjobeth]

Rather than start a new thread, I'll just post here...again.

Today marked the first set of flights made since I experienced random switches between P and Atti modes while flying. Once again, I had at least two random mode switches. (I say at least two, as the flight logs from the last flight showed several modes shifts occurred, with most happening too quickly to be noticeable with the drone.) I'll post flight logs later in the weekend, after charging batteries, etc.

With the events of my last flights in mind, I watched the GPS signal on the remote very closely. One thing I noticed was that the number of satellites showing on the display, anywhere between 4 and 19, varied quickly. The change was literally in the blink of an eye. The first mode shift happened during my second flight. I only noticed because the AC, at about 130' AGL, took off like a rocket and began drifting off course. I brought the bird back down below treetop level, back in P mode. As I was prepping to land, it shifted to Atti mode again. Unlike the first time this happened a couple months back, this time around Ms. DJI was silent.

And this time, I experienced something of a 'soft' crash landing. Before I could get control, the drone flew into a tangle of young vines behind me, and three feet off the ground right at the edge of the woods. Fortunately, the brush acted like something of a 'net;' aside from a few juicy leaf stains and one nicked propeller, the AC is fine. I flew three more batteries with one other shift event. On that one, Ms. DJI spoke up and the AC went back into P mode after a second or two. After that, I did one or two takeoff and landings in Atti mode, then switched to P mode, back to Atti, and again to P, all while in flight. No further issues.

The consensus seems to be this is a hardware issue. The drone was bought new from B&H Photo in January this year. I'm considering whether or not to approach DJI with a warranty claim.

Thanks everyone for your past and future input.

 

[Yeadonites]

My new P4P has similar issues. It will often stay in ATTI mode for a little while until it settles down and relinks to GPS, or I land and take off again. It seems to loose GPS lock when I perform a rapid pan or a fast AC movement to reframe a shot/redo a move.

 

[svjobeth]

My new P4P has similar issues. It will often stay in ATTI mode for a little while until it settles down and relinks to GPS, or I land and take off again. It seems to loose GPS lock when I perform a rapid pan or a fast AC movement to reframe a shot/redo a move.

That seems odd...I wouldn't think it should do that at ll. It's either in one mode or another. What could it do to 'settle down' and then switch modes?

My issues started happening after dozens of uneventful flights. Each time it's happened, I've generally been flying straight and level, or straight while ascending/descending. No 'aerobatics,' or quick maneuvers. After the first event yesterday, I did some rapid moves, just out of curiosity, and she stayed in P mode and performed beautifully.

 

[Yeadonites]

It only seems to happen when I use my iPhone. If I use my non-cellular iPad I’m fairly sure it’s been fine. And I know that my iPhone has real GPS problems. So I guess the transmitter gets it’s GPS position from the device attached to it. But why would that affect the drone?