Dear DJI Support,
I'm really frustrated about the DJI after-sales service and technical support.

First, my Mavic had a warranty defect and after 3 flights had to be returned for a new one and I had to pay 150USD for the transportation because DJI doesn´t have international warranty? How is that possible!


And then, the new one, after a couple of flights, went by itself against a wall. So, I sent it to repair and got this report and an invoice of 213USD to pay for the repair:
"1.  At t=787.14s, unit switched to Atti mode as user lower the altitude of unit into a small alley and GPS signal was blocked
2.  Observed satellite count dropped as unit approached the alley
3.  Unit had no GPS lock nor avoidance in Atti mode and would drift
4.  At t=789.45s, relative height=3.5m, unit drifted backward into a wall of the alley and crashed
Conclusion: Poor flight environment disabled P mode. Unit drifted to obstacle and crashed
Impact location: -16.3976903 -71.5369039
Non warranty
We apologize for the inconvenience, but that is the result of the analysis from our analysis team."


Which I replied promptly with a full explanation of what happened:
1. The unit was controlled since lift-off from the same position, for 13 minutes, with all the needed conditions to fly, including GPS signal and obstacle sensors on;
2. The unit was controlled to land on the same place used to lift-off, where all systems were okay, including GPS signal;
3. The unit wasn't in a "small alley" as stated in the remarks, it was at the beginning of a pedestrian street around 5m wide with buildings on both sides, roughly between 6m and 8m tall, clearly not tall enough to block the GPS signal (see images below);
4. The obstacle avoidance sensors were never turned off by the user;
5. As stated in the remarks, the unit drifted backwards, and it drifted around 5 meters, more than 15 times the diagonal size of the Mavic open, including its wings, which is totally unacceptable, even without GPS;
6. The unit not only drifted backwards, it also lifted. It was only 2 inches from the floor when it lifted 3,5m and then went backwards to the wall
7. The weather conditions were perfect, without any wind that could push the aircraft backwards
Following all the reasons above, please review your report and include the repair under the warranty period of the product since the crash was clearly motivated by a malfunction of the aircraft.


I've been waiting for a month for an answer, without success, and this week, after another email from mine insisting for an answer DJI support told me that the decision was final! How is that possible? How can DJI run away like that from a clear equipment error?


My case no. is CAS-706614-Q1T8F7

Please review this subject...

Post the flight records, that's the only way to tell for sure.
But it does sound like user error, poor choice of flight environment, not correcting the drift when GPS lost.

Looking at the photographs of the "alley", I have to say this looks like a clear pilot error situation.  Do you even know the technicalities of how GPS works?  Depending on how far toward the horizon the satellites you are locked on to are located, if you aren't at an elevation equal to or greater than the height of the edges of those roofs, you will likely have very poor horizontal resolution.  The most accurate horizontal positioning will be where you can see the satellites closest to the horizon.  If you were down "in the alley" low to the ground, you had no decent GPS signal.  You may have had a high number of birds showing, they they may have all been very high in the sky overhead.  This would likely give much less horizontal resolution.

Thanks for the replies.
Considering the lost of the GPS signal the sensors on the aircraft shouldn't work to avoid crashing?
And how was the GPS signal OK to take off and landing and it only started drifting 2 inches from the soil, upwards and backwards?
Thank you.

Sorry for the crash, I understand how you feel, and it may be a hard lesson, but I have to say that this is a pilot error, the drone went into ATTI mode because of the poor flight environment, it wouldn't be able to automatically avoid the obstacles. As you can see the manual below.

Thanks for the help. Forum works way better than the actual support.

tcpinto Posted at 2017-8-19 01:15
Thanks for the help. Forum works way better than the actual support.

Thank you for bringing this to our attention, we'll forward it to the management and will keep improving to provide you all better service.