DJI Drone Help Forum

Phantom 4pro - help with analyzing crash log

Please help me understand why my drone fell into the water. Suddenly and straight down. I’m not sure if motors were on or if the drone turned off first. I think I heard the motors while it was falling. It took a second or two. https://www.phantomhelp.com/logviewer/KFHRG8PDFQBHFYA40NYV. DJI care - ECQMSKZXH1U6AN57. Thank you.

This appears to be a battery ejection. This has been noted numerous times with P4’s. Notice at the very end of the log you were traveling backwards, when you issued a full throttle up and full forward elevator.
It was at that exact point, the bettery ejected. All other data is nominal

Thanks for fast response. Does it mean that it was somehow my fault? Can you shade more light on it as still do not fully understand what happened. I’m pretty confident that I did not perform any full joystick operation like full throttle up. What battery ejection is? Thank you.

On many P4’s…if the battery latch is weak or defective in some manner, the battery will “Eject” either completely fall out of the aircraft or disconnect power. This has happened numerous times from the data that I have seen. And yes, if you look at the graph above, you can clearly see the RC inputs almost instantanously before signal loss. That hard manuever accentuated the dislodge I would surmise. That said however, there are occassions where the batttery will simply disconnect without those hard manuevers. In the P4 V2 series, the latch design was changed…Pointing to IMHO, a design flaw which DJI has never claimed officially.

I feel that this is exactly what happen to me. My question is if it is this issue does DJI cover it or are you just out the drone?

Thanks again for the explanation. It would make sense but I’m confident that I did not make that sharp maneuver with both joysticks full up/forward. I was slowly setting the drone in the right position to start recording and moving forward towards raising sun. In general I do not make any sudden and extreme moves like that. I’m also sure that there was a click and there was no gap between the batter and the drone. It could have been battery ejection due to faulty battery latch and it could have been caused by that “full throttle up and full forward elevator” maneuver, but I did not trigger that maneuver. It looks like we’ll never know what caused that.

I need to buy a new one :/. DJI care expired already like a year ago. I feel awful and scared that similar thing may happen again with the new one.

This is my concern, I don’t want to buy another product that could be faulty… Also it doesn’t sound like DJI covers these type of failures.

That is possible. That final point of data “could” be related to the surmised battery ejection. If you care to look farther in to this, the device .dat may provide additional info, although doughtful. See this link to retrieve the file. You can upload that here and we can take a look.
Retrieve V3 DAT

Here is the file and big thanks for help. I could not upload here as new users cant do that … whatever.

Looking at the .dat file. It does indeed appear that the spikes in the .txt file were anomolies from the battery disconnect. They are not present in the .dat. That said, it does not change the fact that this was a complete and immediate shutdown. Everything still points to a battery dislodge or sudden and complete power failure. As in the .txt file, the data looks normal until that point so I think we are still looking at a battery disconnect.

Thanks so much. I feel better knowing that it was rather no my fault. I should have bought some other insurance after DJI care expired tho. I wish I’ll have better luck with v2. Take care.