DJI Drone Help Forum

Dji loses connection falls from sky


#1

As said above i was flying my P4 and it lost connection no biggie it has return to home enabled when connections lost. My P4 did come back but hovered in sky never coming down to normal RTH altitude then as i was trying to figure out how to try to get it reconnected my drone losed power and just drops onto my driveway. Drone is mostly ok except for 1 bent arm from where it landed. I kbow it still flys as i tested right after to make sure but now im scared itll lose connection a drop out of sky again even moreso since scanning questions here asking about drops as well. Any help is appreciated i can also upload flightlog as well if needed


#2

https://drive.google.com/file/d/1sH3NWACAWkqklfoAy7T8RRGpFWwIEYpn/view?usp=drivesdk

Cant upload flightlog directly since new so here is link to drive


#3

Here’s your uploaded flight log:
http://www.phantomhelp.com/logviewer/W7SXS10JRJLNRQKACG82


#4

At the end of your flight log, the Phantom was flying a waypoint mission and moving away from the home point. The details you mentioned are not contained in the flight log.

Does your Phantom still power on? If so, you can retrieve the DAT flight log from your Phantom to see the missing flight details. See this page for instructions on retrieving the DAT flight log. If you’d like other members to review your DAT flight log, then please upload it to a file sharing site and post the download link here.

The missing data will be needed to confirm, but it’s likely the sun was preventing your Phantom from moving forward. The “Braking now. Return sticks to midpoints, then continue flying.” messages in your flight log are an indicator that it was interfering with the front sensors. When that happens, the Phantom will stop and attempt to overcome that obstacle when doing any type of automated flying (e.g. RTH). Disabling the front sensors is the only thing that will prevent that interference.


#5

You will need to retrieve the aircraft .dat file for this I am afraid. Once you lose connection, you also lose telemetry, so where the data ends in this file is prior to any RTH, because there was not one in this file. The data ended @ 4:33.7 and @309 ft away and an altitude of 166 ft.

If you wish to do that follow the instructions on the link below. Once you have the file, upload that to a share site such as Dropbox, Google Drive, etc… and share the link back here. That is really the only way to find out if you had a power shutdown, since you lost signal.

Retrieve V3 .dat from AC


#6

https://drive.google.com/folderview?id=1HOqOLRn1FNfSaoN3Az8NbHZlbYvsC22u

I put the flights from that day on my drive there are 3 the biggest file is the main flight the other is test flight after crash and there was a 0kb one inbetween that may be the crash? Im not really sure


#7

At a quick look, FLY174 sure looks like a shutdown. It apparently shutdown @ approx 15 meters in altitude. Still looking through the other data.


#8

This appears to be the correct flight (FLY174) but it doesn’t exactly match your description from your post. You stated that you lost signal. I think you may have only lost the app. According to the .dat file you had full control of the AC and it was responding to your inputs. Nor did I see an RTH in this data. I will look at The other .dat but this appears to be correct because the data ended as I said above @ an altitude of approx 15 meters. I will see what @BudWalker thinks before I go farther.


#9

So what had happened is it said i had lost connection while on waypoint flight it did RTH but never completed it just hovered above me so i tried some different things and found i could control it back and forth just not up and down and as such it was too high for me to be able to reach so i tried the emergency stop (left joystick down right and pressed the right button) which didnt do anything so i went back to settings in app and tried to get it to connect, even tho i could control drone back and forth the app said disconnected and camera wasnt working or at least streaming at the time to the app later on video i saw right up until it turned off and dropped out if sky from probably like youbsaid about 15 meters


#10

And flight174 wąs the shutdown flight175 was 0kb i think it was from me restrarting drone other one 176 i believe was me testing drone after crash

Also thank you for your help


#11

I’m not sure how you managed to do it but the P4 thinks you commanded the motors to stop. This from the eventLog stream
467.085 : 31807 [L-RC]rc cmd:STD_STOP_MOTOR
467.105 : 31808 [L-FMU/MOTOR] Stop. reason:REQ_RC_NORMAL

At that time the throttle was full back and the rudder was full right. I don’t see how that would have caused the motor stop. I only mention it because you did.


#12

I suspect you took the default Time Axis specs that DatCon offers. Specifically, an upper limit of Motor Stop. That’s why it looked like the log stopped abruptly. Selecting Recording Stop will let you see the rest of the log
image


#13

I had looked at the motor data but not close enough. I saw the Motor Stop CMD in the event log but thought…Hmmm…How is that possible? Anyway, looking back again closer at the motors, this is not the “typical” aircraft shutdown response that I have seen so many times before. Usually this data just stops abruptly. In this instance you can see the stop motor cmd, and the motors gradually slow down. I agree, not sure how the OP managed to do this, but it indeed looks like a commanded motor stop in mid air.


#14

It looks like the OP used the stop motor command. The sticks were in the right position. The only thing we’re missing is whether or not the RTH button was being pressed.

image


#15

There isn’t an indication that the RTH button was pushed. But, that could be because the Go App just sends the command to stop the motors. Or, it could be that DatCon and/or me isn’t smart enough to know where to look.


#16

I don’t think that button is recorded in the TXT/DAT logs. It might be documented in the remote controller logs. In this case though, @Unseen659 might be able to confirm since that’s a pretty odd stick action to forget.


#17

Maybe this statement from the OP as above will clear it up @BudWalker :

_So what had happened is it said i had lost connection while on waypoint flight it did RTH but never completed it just hovered above me so i tried some different things and found i could control it back and forth just not up and down and as such it was too high for me to be able to reach so i tried the emergency stop (left joystick down right and pressed the right button) which didnt do anything so i went back to settings in app and tried to get it to connect, even tho i could control drone back and forth the app said disconnected and camera wasnt working or at least streaming at the time to the app later on video i saw right up until it turned off and dropped out if sky from probably like you said about 15 meters.

Evidently the Emergency stop worked…


#18

Ah, so the OP did mention it. Case closed.


#19

Sorry for late reply I was swamped yesterday bit yes i did perform the emergency stop function but i thought that just canceled flight path commands not fully shutting drone down (arm lights and everything went out like when powering down) and i couldve swore ive done an emergency stop before and it just made the drone stop the action and hover, but i could be incorrect i did test fly it again and it flew fine even with a slightly dented arm lol maybe ill go try to hover a foot off ground and do emergecy stop again to see if i can recreate issue and report back


#20

I’m not so sure that it is. Granted from what we can tell the OP did shut down the motors, but in that instance as he also stated, the Arm LED’s went off as well, which indicates a complete shutdown of the aircraft. Also, the OP stated that the aircraft did RTH, but I cannot find any indication of that in the .dat log. Nor can I find a loss of signal ( Other than the App data lost ). This is quite confusing. I took the .csv log and the .dat log and combined the two for the full flight representation. According to the .dat file the RTH altitude was set to 100 meters. This certainly looks like an RTH, however the AC never climbed to altitude for that. It did turn around and come back but gradually reducing altitude in the process. The only thing I can think of is that the OP had waypoints set for the return. Any thoughts on that? @BudWalker.