Litchi Force Landing?

[Aaron407]

Twice since using Litchi, and seemingly randomly, it has forced my P3S to land with no discernible cause. Yesterday, for example, I was flying with about 50% battery close to home. Within a minute or so, the green "LANDING" notice showed on the screen, and the P3S was forced down. There was no mention or notification about there being a return to home call, nothing regarding low cell voltage, and I hadn't touched anything on the screen (my hands were on the RC sticks). I guided it to a safe landing location, landed, turned off the motors, then immediately turned them back on and did a completely normal flight in the same area without any issues.

Looking in my log, I can see that the flight mode changes from P_GPS to Landing and the flight state changes from 6 to 12, even though there was sufficient battery for the flight. There were no issues shown with the uplink nor downlink signal strength. There were no altitude or distance limits that could have caused this, and I flew the same area and greater altitude on the subsequent flight without any problems. I am also not near a no fly zone or limited flight area.

Has anyone else had this issue with Litchi? The first time was when I was using an older version of the app and firmware in my P3S, but I am currently up to date on both. I haven't had this happen with the DJI Go app, even though I used it for many more flights, so it seems to have something to do with Litchi. I'm curious if I'm the only one, though, as I couldn't find similar concerns when searching the forum.

 

[mdowney58]

What actual battery level % is set for critical?

Sent from my SM-N910V using Tapatalk

 

[Aaron407]

It's set to 15%, which force landed it on the second flight as it should after the critical battery level was reached. I'm just not sure why it force landed the first time. I emailed their customer support, but haven't heard back yet.

 

[Mark The Droner]

I doubt it has anything to do with Litchi. I would look at your battery cells and see if they're balanced.

 

[Aaron407]

There is some variation in the cell voltages, although nothing appeared on my screen to indicate an issue. Cell 1 in my battery seems to fluctuate a bit more than the rest, with regular minor cell deviations and one major deviation in that flight. However, what it considered the 'major' deviation was after it was already triggered to land.

I think you're right about it not being Litchi, though. Their support got back to me and think that it has something to do with the firmware. At any rate, I think I'll be picking up a new battery soon as I'm not overly confident in the one that I have. It's too bad that DJI doesn't offer a better warranty on their batteries as I've only charged mine 25 times or so.

 

[m0rph]

Litchi became buggy in the last versions. My bird also begun to land after one successful waypoint mission. Reason?
Phantom came out of RC signal during that mission. And when it became online, my smatrphone for some reason rebooted! And after this reboot, Phantom tried to land once it finishing the mission.
Solution? If the Litchi crashed or your device has rebooted, do not fly! Land Phantom ASAP. And reboot Phantom, device and RC manually. After manual reboot, i did not have any problems with Litchi.

 

[julien92]

For my very first FPV flight with litchi, I just encontered the exact same issue : GO home + landing without any reason, and with no possibiliy to cancel landing, even if link is OK. I will not fly again with litchi without having understood what happend.

 

[telescott]

Same thing happen to me yesterday. At 40% it did a RTH for no reason. I have it set to 30% warning and 10% critical like normal. No issues before. Is it a DJI firmware issue or litchi?

 

[Mark The Droner]

Sounds like a battery issue to me

 

[telescott]

Sounds like a battery issue to me

Not a battery issue on mine. Band new battery with no issues

 

[Sky Media Drones]

The same problem here.
Two different batteries, new ones, take off and 2 or 3 minutes later was auto landing without apparent cause.
Anybody with the same problem?

 

[julien92]

To me, it is 100% clear it's a litchi issue : with more than 50 flights with DJI GO, I've never faced that behaviour. Yesterday, first flight with litchi and I got this issue.

 

[Mark The Droner]

Then it has to be a bug in Litchi. I can't help because my Litchi is for the P2 and works perfectly. Good luck.

 

[m0rph]

Same thing happen to me yesterday. At 40% it did a RTH for no reason.

How many miles/kilometers away from home point it was during that? Did you fly a mission in Litchi?

 

[telescott]

How many miles/kilometers away from home point it was during that? Did you fly a mission in Litchi?

The quad was 125 feet in the air and 30 feet from me. I had full signal. It rth'ed at 40%. I was doing a follow me with it on my way to the mailbox. I have used it on a mission before but don't know if I trust it now.

 

[m0rph]

That`s very strange. You`d better to read the Phantom`s internal log to see exactly what happened.
My P3 triggered RTH in Litchi only once: during long range autonomous mission. It was 4 km away from home at 50% battery and dedided that it`s not safe to contiue the mission. This is a normal behavior.

 

[julien92]

@m0rph, sorry for the dump question, but how do you get the internal flight logs ? I used to use healthydrone, but not sure that it provides enough information... Thanks in advance !

 

[m0rph]

Check out Retrieving a .DAT from the P3 and use DatCon to convert the *.DAT into *.CSV. Then open it in a OpenOffice for example. Or simply upload somewhere and post here. I`ll try to help.

 

[toegema]

Just wanted to report that I flew two full working days in a row with Waypoint missions, using a total of 18-20 batterys (charges).
Flying Litchi (latest version), second latest firmware on P3P.
No encounters. Just fyi [emoji4]


Sent from my iPhone using PhantomPilots mobile app

 

[Aaron407]

This was the initial reply received from the developers:

"Did you double check the "action on signal loss" setting in DJI Go? Maybe it is set to landing instead of RTH?
In the first log I can see the aircraft is relatively far from the RC at the time when it initiates landing (for a P3S).
I realize it seems you still had signal, but apart from this I am not sure why landing would trigger at such a high battery percentage (maybe entering a no fly zone too, but you said you aren't in one).
I would contact DJI's support, as this is more an issue with the firmware, Litchi itself never commands a landing, or even a RTH (unless asked for)."

My reply:

"Thanks for the feedback. The action on signal loss is return to home, which normally also has the prompt to cancel it if desired. In terms of the aircraft being far from the RC, I have upgraded antennas and have reached 6000' in the past, so the 1100' at the time of the log shouldn't be a problem. There was also no indication on the screen that there was a loss of signal.

I think you're right about the firmware, though, and it might be how it handled the battery. There was some cell voltage variation during that flight, which has the potential to cause a force landing. If that would be the case, is there any way to make this a bit more transparent to the pilot? e.g., provide a cell voltage warning or something to that effect?"

I didn't get a response after that.