Stopped during auto-takeoff.

Phantom 4 Pro/Adv
1

Hello,

I have posted on the DJI forums, but figure posting here is probably a good idea too.

I’ve just bought a P4Pro secondhand, having used a friends and wishing to gain experience.
I was flying it yesterday and it had been working fine. I swapped the battery and everything seemed fine, so I told it to auto-takeoff.

A few seconds in and fortunately only about 50 cm’s from the ground (actually looking at the logs nearer 2m), it completely stopped and just dropped. This was on soft moorland so no damage has occurred.

As soon as it hit the ground it started back up by itself (the music ditty played). LED1 of the battery was either sold or flashing yellow and the rest were green. (The manual doesn’t have this listed)

The battery was fully charged, securely clipped in (I’ve only had it a few days and am paranoid about making sure!) and the firmwares are on the latest version (according to DJI Assistant).

I manually lifted it to a few cm’s to see if I could make it re-occur and I cannot.

I raised a case with DJI, and was somewhat dismayed to get a stock response of “we don’t do data analysis out of warranty.”

To be fair, they did suggest I can send it in for paid-repair, which is fine, but I would have expected maybe, “yeah send us the logs and we can tell you if it needs to come in for a repair or if it’s a faulty battery or something”

I had expected interest to be taken as, whilst it’s not damaged, there could be useful clues as to what caused it to fail.

I’ve uploaded the log file to phantomhelp and it just shows it was in auto-takeoff and nothing else.

I have all the logs of the unit (including the .DAT) but not sure if it’s any help if DJI won’t look at them.

The logfiles are here:
https://drive.google.com/drive/folders/12GM1esr82Cg4qZZC39GkKDhXtn0o0ChJ?usp=sharing

Has anyone experienced something similar or anyone any suggestions?

Thanks for looking,

Ben.

2

The following is mentioned in the DJI Warranty:

“Please note that data analysis service will not be provided after warranty expiration.”

I don’t see anything in your logs that explains what happened. Since the startup tone sounded, it appears the battery abruptly disconnected and reconnected.

3

Thanks for the reply and looking at the logs - appreciate it.

“Please note that data analysis service will not be provided after warranty expiration.”

I accept that - I’m just surprised a responsible manufacturer is that dismissive given the circumstances. There are manufacturer liability issues for something like this and being as dismissive as they are implying that they aren’t interested in why a device they made fell out of the sky.

Since the startup tone sounded, it appears the battery abruptly disconnected and reconnected.
Yep, but have checked everything. There are no signs of arcing/burning, and the battery was 100% and seated and both clips checked.

I’ve tried to re-create and so far cannot get abnormal behaviour.

4

In most (all?) countries, you’re likely going to find you are solely responsible for what happens after your aircraft leaves the ground (even if it malfunctions). That’s why best practices and/or rules exist (like flying within VLOS & never flying over people) and company’s offer liability insurance. If liability is of great concern, you should definitely look into buying insurance to protect yourself.

Good to hear!

If you’re not doing this already, make sure the battery is properly snapped into the battery compartment (on both sides) before each flight. And make sure your batteries don’t have a lot of play (room to wiggle) when snapped into the battery compartment. Some P4 batteries don’t fit well for some reason. That should at least prevent the possibility of the battery from disconnecting mid-flight.