Hi everyone.
Unfortunately, my first post will be a sad one.
I have been flying DJI drones for a couple of years, starting with the Phantom 3 and switched to the awesome Air a couple months back.
The last flight behavior of the drone after updating to the latest firmaware (0400) was ... a bit strange.

I flew about 3 batteries without any issues. On the 4th one I was hovering about 3 feet off the ground (big open field), making fast horizontal left/right passes at about 30-40mph in sports mode. Suddenly, the Air stopped responding to any controller inputs. It was about 30 feet away and did not loose connection. I did not get any interference warnings either. The little one did not stop. It proceeded full horizontal speed ahead closer and closer to a wooden fence. I could only watch it hitting the wodden fence full force ahead. I thought it was gone completely because the impact was so huge. When I checked the logs on the DJI app I can clearly see the drone stopped responding to stick movements, and just kept flying (it shows me stopping any inputs, then me trying to move the drone into the other direction - it just kept going).

Does anyone have a clue how this could happen?

I have uploaded the flight logs here but don't see anything out of the ordinary.  
http://www.phantomhelp.com/LogViewer/3BDBZ5LXYN71YU6NJKUF/
Reminds me of a case here on this forum where a member's drone just flew into a building without any stick inputs.
This happened on a open field, I have flown there many times.
Any help / insight would be appreciated. I have opened a case with DJI. I wonder if they can remotely trouble shoot and let me know if this is a warranty issue or user error. I have also provided the dat file to them but haven't heart anything besides them asking me to send it in.

Btw, I am AMAZED that the drone did not break up in 1000 pieces on impact. It needs a new white top plate, new props (of course), however, it does not lock on to GPS any more, so something is broken

Thanks for your help / guidance everyone!

I am sorry for your issue. It seems that you are not alone.

This friend had similar issue

Hey fansa,
This looks very similar to what happened to me. Thanks for sharing. Wondering if anyone else has encountered this.

I have similar problem. When I switch from Sport mode back to GPS for landing. I also turn on APAS and MA just around 20 meters away. The connection is good but MA stop on there and not respond to my stick command. I try push stick different way and still no response. Finally I activated RTH and it fly back. At this point it started to respond to stick command again.

Hi there, I'm sorry to hear about the accident. I have managed to get your case number via your DJI forum account, this has been forwarded to the related support team, they will reply your email and provide the further help soon, please be patient to wait for the update. If there is anything else we can assist you with, please feel free to let us know, we'll here for help.

Note to myself: do not use Sport mode till firmware fix.

Thanks DJIDiana,
Good to know you guys are active here on the forum. Much appreciated...
Do you want me to send it in or wait until I hear something back from you? Are you able to determine remotely if this was user error or unit defect? I have sent the link to the DJI assistant DAT File previously but please let me know if you need the link again.
Thanks again for your help! Everyone, I highly recommend not using the sport mode on the Air for now...

Hi Diana,
This is the only response I got so far - not very helpful. Is there no way you can check the logs and DAT File remotely? Do I really need to send the MA in for that? What would you like me to do?

Hello Florian,

Thank you for your email.

Unfortunately, only our Service Team from our Repair Center can help you check the flight logs of the unit.

If you have any questions, please feel free to contact DJI North America Technical Support, Mon-Fri 9:00AM - 5:00PM (PST) via the following three channels:

DJIFlo2 Posted at 2018-5-7 06:54
Thanks DJIDiana,
Good to know you guys are active here on the forum. Much appreciated...
Do you want me to send it in or wait until I hear something back from you? Are you able to determine remotely if this was user error or unit defect? I have sent the link to the DJI assistant DAT File previously but please let me know if you need the link again.

It is recommended to send in the drone firstly for data analysis and a thorough evaluation, we will have professional team who will help to figure out the reason, thanks for your understanding.

Just a few other users who seem to have the same problem, MA intermittently unresponsive after last firmware update:
https://forum.dji.com/forum.php?mod=viewthread&tid=147538
https://forum.dji.com/forum.php?mod=viewthread&tid=146987
Also, user GDL seem to have similiar issue in my post:
https://forum.dji.com/thread-147265-1-1.html

Mindy, Diana, I will send it in. Again, I was hoping to get an initial read from you guys before but it does not sound like it

DJIFlo2 Posted at 2018-5-8 14:13
Just a few other users who seem to have the same problem, MA intermittently unresponsive after last firmware update:
https://forum.dji.com/forum.php?mod=viewthread&tid=147538
https://forum.dji.com/forum.php?mod=viewthread&tid=146987

Currently, we cannot tell the issue was caused by the firmware upgrade, it still needs to be analyzed case by case, please send in for data analysis and damage assessment, our repair team to get it sorted out, thank you.

Hi Mindy,
I will sent it in.
Thanks for your help!
Much appresciated

DJIFlo2 Posted at 2018-5-9 06:15
Hi Mindy,
I will sent it in.
Thanks for your help!

You are welcome, appreciate your understanding very much, please keep us updated if there is any further issue during this process.

Is it official any problem after the update???
So frustrating!

SBasso Posted at 2018-5-10 08:10
Is it official any problem after the update???
So frustrating!

May I know what issue do you encounter with the latest firmware? Could you offer more details for better assistance? Thanks in advance!

DJI Susan Posted at 2018-5-10 21:09
May I know what issue do you encounter with the latest firmware? Could you offer more details for better assistance? Thanks in advance!

Of course!
Sorry about the late answer.

Its lacking on Satellites at all the time...
(It takes very long time to reach 7/9 of them)
My comments is based on places where I used to fly the drone

It's turning to the left itself, usually when ascending.

I tried to downgrade the firmware from my laptop, unfortunately was not possible, so I refreshed and the issue still on. I also noticed that my RC does not connect to the DJI Assistant 2

I do not feel safe on flying it!
Very disappointing!

SBasso Posted at 2018-5-15 00:02
Of course!
Sorry about the late answer.

Sorry about this. May I know how long will the drone reach 7-9 satellites? Regarding the turning and ascending issue, does it appear frequently? If yes, please kindly export some sample of the flight logs, we'll analyze the exact status. Thanks in advance!

DJI Susan Posted at 2018-5-18 01:52
Sorry about this. May I know how long will the drone reach 7-9 satellites? Regarding the turning and ascending issue, does it appear frequently? If yes, please kindly export some sample of the flight logs, we'll analyze the exact status. Thanks in advance!

Yes, after the update each time it happened.
Forgive me, I would love to share the logs but i have no clue how to do it...

SBasso Posted at 2018-5-18 12:28
Yes, after the update each time it happened.
Forgive me, I would love to share the logs but i have no clue how to do it...

Please connect your drone with DJI Assistant 2 and export the flight data for further check. You can upload it to dropbox and post the link here. Here is the video for your reference:

Update:
DJI replaced the drone for free. They sent me a new one (with a very ancient firmware prior to the official firmware numbering ).
A big Thank You to DJI for this excellent service and quick turn-around. I know you are getting a lot of negative reviews but I have always had great experience with your service!
The only issue that remains is that I need the battery also changed since it is not working any longer and you sent back the old broken one.
Also, how do I know what exactly happened? I know the MA stopped responding and just kept flying but why? Is it safe to fly with the latest firmware?
Thanks again DJI for this excellent service.
Flo

DJIFlo2 Posted at 2018-5-28 09:02
Update:
DJI replaced the drone for free. They sent me a new one (with a very ancient firmware prior to the official firmware numbering ).
A big Thank You to DJI for this excellent service and quick turn-around. I know you are getting a lot of negative reviews but I have always had great experience with your service!

Flo, thanks for your update and glad to know you have received the drone. The battery issue will be forwarded to the local team to look into, we will have someone to contact you about what to do next.
The accident has nothing to do with your operation and we have got it sorted out, no worries about the future flight. It is suggested to update the firmware to the latest version.

My drone just crashed while doing a controlled landing from around 300 meters. At one point it just stopped recording and went into a free fall. No wind, no warnings, as if the battery power was cut off. Unbelievable. It hit my house and broke a piece of wall of it! I was scared it might kill somebody. I think it might be the firmware. Sent to DJI for repair and analyses but the repair progress still shows it’s being delivered even though UPS delivered it yesterday.

puharic Posted at 2018-5-28 23:49
My drone just crashed while doing a controlled landing from around 300 meters. At one point it just stopped recording and went into a free fall. No wind, no warnings, as if the battery power was cut off. Unbelievable. It hit my house and broke a piece of wall of it! I was scared it might kill somebody. I think it might be the firmware. Sent to DJI for repair and analyses but the repair progress still shows it’s being delivered even though UPS delivered it yesterday.

Sorry for the accident, may I have your case number so that we could check the current status? Thank you.

DJI Mindy Posted at 2018-5-29 00:38
Sorry for the accident, may I have your case number so that we could check the current status? Thank you.

Hi Mindy! Thanks for your reply. The case number is in your Inbox

Mindy, thanks so much! I am just curious... what was the issue? I am sure you know

MPuharic Posted at 2018-5-29 03:47
Hi Mindy! Thanks for your reply. The case number is in your Inbox

PM received with thanks, we will escalate your case to the local team to look into and keep you updated soon, please wait patiently, thank you.

OK, Thanks!

Today I received a quotation for the repair od my crashed Air - around 700€ or a replacement for 89€ per DJI Refresh. But before deciding I’d like to know WHY the aircraft crashed in the first place. Was it something I did if they decided to just send me a quotation without mentioning the warranty? If so I’d like to know what it was I did wrong. The aircraft was in landing mode. No warnings. Then it just plummets to the ground. What about the requested analytics? What do you think who can I contact to get answers?

MPuharic Posted at 2018-6-4 06:39
Today I received a quotation for the repair od my crashed Air - around 700€ or a replacement for 89€ per DJI Refresh. But before deciding I’d like to know WHY the aircraft crashed in the first place. Was it something I did if they decided to just send me a quotation without mentioning the warranty? If so I’d like to know what it was I did wrong. The aircraft was in landing mode. No warnings. Then it just plummets to the ground. What about the requested analytics? What do you think who can I contact to get answers?

Hi, Puharic, thanks for getting back to us, it seems no data analysis was conducted in your case, I will contact the local team to make data analysis to locate the crash reason, we will have someone to keep you contacted, please wait patiently, thank you.

DJI Mindy Posted at 2018-6-4 20:14
Hi, Puharic, thanks for getting back to us, it seems no data analysis was conducted in your case, I will contact the local team to make data analysis to locate the crash reason, we will have someone to keep you contacted, please wait patiently, thank you.

Thanks for your help! I received an e-mail from Technical with questions inquiring when and how the crash happened. My reply was followed up by an e-mail informing me that the Analysis will take 4-8 working days, which seems a bit long, but I presume the team is busy. Hopefully, the results will bring some clarity to the case.

MPuharic Posted at 2018-6-4 23:15
Thanks for your help! I received an e-mail from Technical with questions inquiring when and how the crash happened. My reply was followed up by an e-mail informing me that the Analysis will take 4-8 working days, which seems a bit long, but I presume the team is busy. Hopefully, the results will bring some clarity to the case.

Glad to know you have been reached, thanks for your understanding, we will do our best to figure out the reason as soon as possible, there will be someone to keep you updated via email, thanks for your patience.

OK guys, just to give you a final update on my Mavic's repair: yesterday I was notified by DJI that after diagnosing and testing my Mavic they were going to do a free repair. A few hours later I got a shipment notice with a tracking number so it's already being delivered. I'm really happy all of it turned out the way it did but I must say I'd be happier if I knew what was the cause of the crash. I mean, there's definitely gonna be some reluctance from my side flying the drone having in mind what happened. I suggest DJI to follow-up on this, like say if they fixed a firmware glitch or a hardware malfunction or whatever. Just to assure their users it's not gonna happen again.

MPuharic Posted at 2018-6-8 01:29
OK guys, just to give you a final update on my Mavic's repair: yesterday I was notified by DJI that after diagnosing and testing my Mavic they were going to do a free repair. A few hours later I got a shipment notice with a tracking number so it's already being delivered. I'm really happy all of it turned out the way it did but I must say I'd be happier if I knew what was the cause of the crash. I mean, there's definitely gonna be some reluctance from my side flying the drone having in mind what happened. I suggest DJI to follow-up on this, like say if they fixed a firmware glitch or a hardware malfunction or whatever. Just to assure their users it's not gonna happen again.

Puharic, glad to know the repair was covered by warranty, hope you will receive it soon and test the performance.
Per the data analysis, the accident has nothing to do with your operation and you should not worry about it, and we will also keep improving our products in software and hardware to make you have a better experience, please let us know if there is any other issue.