I purchased a new P4P direct from DJI on December 9th, 2017.  After reading these forums I guess that was my first mistake.  This was a Christmas present so it was taken away from me when it arrived and I had to wait until December 25th.  After about 5 flights, it said the IMU was bad and needed to be recalibrated.  It failed this calibration no matter how many ways I tried.  It always said "Sensor bias is too large".  After exchanging emails with tech support, it was determined to be a faulty drone and I needed to send it in for service.  Considering the cost of this unit, I was disappointed to say the least.  The unit was repaired under warranty so that was a positive note.  I received it back on 1/23/18.  I took it out for a flight on 1/24/18.  I launched the craft and allowed it to hover for a few seconds to be sure everything looked ok.  I took it up to 90 ft, turned on the camera and began to move forward.  9 seconds later, the DJI Go app reported that the aircraft disconnected.  The screen stopped displaying video, and the drone no longer responded to the remote.  It continued to fly away.  I hit the RTH button on the remote, but it didn't do anything.  I restarted the DJI Go app, restarted the remote and even rebooted the phone.  The drone never reconnected.  I was flying in a wide open space in the White Mt National Forest.  No power lines, radio towers or cell towers within miles.  I waited 45 minutes to see if it would return to home due to lost signal (as it was set to do in the app) or low battery but it never came back.

I contacted DJI as my brand new, and newly repaired drone has just flown away into the mountains.  The respone was:

"With the record ended without any sign of abnormality, we could not verify what happened afterwards.

We truly appreciate your support for DJI, and especially applied for a 30% off coupon for Phantom 4 Pro without charger and remote:
http://store.dji.com/product/phantom-4-pro-aircraft-excludes-remote-controller-and-battery-charger"


Are you serious?  Two major failures on a brand new drone and they want to generously offer me a 30% discount to buy another?  

Wow that just bought a cloud over my picnic. As I'm just getting ready to buy a P4 Pro and I see a lot of complaining in these posts maybe I'll rethink this sorry about your drone, New Hampshire boy

I see your distance is nearly 6000.  Is this on the same AC, or do you have another?

ALABAMA Posted at 2018-1-26 07:42
I see your distance is nearly 6000.  Is this on the same AC, or do you have another?

Maybe thats from the one and only flight.

Sorry about the loss though.

It was flown prior to the repair.  I am hoping they will do the right thing here, but so far I am very disappointed.  Trying to reach someone who isn't reading from a script and can actually listen to the situation is the most frustrating part.

Been that route too. I feel for you.  Perhaps one of admins can help and get another look at your case from an engineer.

Can you upload your flight log to link below, just click on link and follow instructions and come back here and post link. Might help you get a better understanding of what happened.

http://www.phantomhelp.com/LogViewer/Upload/

http://www.phantomhelp.com/LogViewer/TNSZQG0LOYMPP5LCAV94/

Weird that it never shows that the RTH was never initiated.  Did you turn off your device first?

Wow, that's a nightmare.   What you'd mentioned "It always said "Sensor bias is too large"..sounds strange too - never heard of that.

NH Mountains Posted at 2018-1-26 08:34
http://www.phantomhelp.com/LogViewer/TNSZQG0LOYMPP5LCAV94/

It does seem a bit harsh to offer just 30% , looking at your log warnings only of gps no match, although some here might say this is nothing to do with weak gps, having seen it in many cases it usually shows up when gps is weak or being blocked out.

Although your satellites are reading 11/12 the best indication of gps lock is your bar graph on your telemetry, you should have 4 bars lit up to fly safely.
Number of satellites to fly a drone is or should be 11 guaranteeing at least 6 of either glonass or gps.

Although you log doesn’t show loss of gps and going into Atti mode from what you say this is most likely what happened, you say you also lost video link and RTH wouldn’t work this is another sign of aircraft going to Atti mode, you would have been able to control your aircraft but with difficulty and for a new flyer all the more difficult.

Only other thing I can tell you from what I’ve seen around here, dji’s response to you is the norm when lack of information from your log can be extracted.

The DJI Go app showed Aircraft Disconnected.  Once that displayed, nothing I did would control the drone.

NH Mountains Posted at 2018-1-26 09:16
The DJI Go app showed Aircraft Disconnected.  Once that displayed, nothing I did would control the drone.
[view_image]

But when this happens for more than 3 seconds your Aircraft should RTH but if it lost gps as well then it will just drift, so it was for that reason I think dji were not being really fair to you.
Can you upload the flight replay from your app to see if this would show anything else.

I waited around for 45 minutes to see if it would auto land, but it never did.  I used the sticks on the controller but I could not stop the drone from flying away.  The video is only 9 seconds long and it doesn't show anything abnormal other than the video stopping with the drone in mid air.

NH Mountains Posted at 2018-1-26 09:28
I waited around for 45 minutes to see if it would auto land, but it never did.  I used the sticks on the controller but I could not stop the drone from flying away.  The video is only 9 seconds long and it doesn't show anything abnormal other than the video stopping with the drone in mid air.

Only thing it may show is bar graph for gps, but you should be able to see this yourself, your Aircraft would have eventually landed when it reached low battery critical battery but how far it went would be hard to tell.

Sorry for your loss, i know the feeling, exact same thing happened to me last year...
Sent you a PM...

NH Mountains Posted at 2018-1-26 08:34
http://www.phantomhelp.com/LogViewer/TNSZQG0LOYMPP5LCAV94/

Did you do any calibration before flying with the new one?

I don't see anything in the log to explain what happened, so the offer of 30% isn't surprising, but if it was a first flight with the replacement then I think you should ask for the for the case to be reviewed based on it being a first flight.

Something I don't understand is the rather large pitch and acceleration up to 27mph at the end of the log when it is reporting that you only pushed the right stick forward very gently, something seems wrong.   After that there is the question of why it disconnected at such close range, but there is no data in the log to support your story there.

Nigel_ Posted at 2018-1-26 10:48
Did you do any calibration before flying with the new one?

I don't see anything in the log to explain what happened, so the offer of 30% isn't surprising, but if it was a first flight with the replacement then I think you should ask for the for the case to be reviewed based on it being a first flight.

It might explain increase in speed if aircraft was in Atti mode small movements like the one in the log can cause speed to increase greatly in Atti mode going downwind, in fact it would probably be the only explanation for this increase. I do realise log shows pgps mode this is why I asked to see the app screenshot to see if gps bar graph was showing weak gps.

Wow... you won the reversed jackpot

hallmark007 Posted at 2018-1-26 11:32
It might explain increase in speed if aircraft was in Atti mode small movements like the one in the log can cause speed to increase greatly in Atti mode going downwind, in fact it would probably be the only explanation for this increase. I do realise log shows pgps mode this is why I asked to see the app screenshot to see if gps bar graph was showing weak gps.

The GPS location is changing all the way to the end of the log and looks correct so I think the GPS was working up to the end of the log.  My guess is that it failed at the same time the communications failed and the aircraft then went to atti and since it was already doing 27mph it would have continued without any braking for a fair distance before the wind took it further.

Looking at the sticks again, they do seem to make sense, I got them mixed up on my first look.

So apparently no fault up to the end of the log and thus with no evidence we only have the owners word for there having been any fault.

If it wasn't a first flight then I would say it was a case for insurance to deal with.

I appreciate you taking the time to look at the log files.  Everything I saw in there seemed to mirror what occurred right up to the communication loss.  One thing I was curious about...does the remote control keep any sort of log file?  If so, is this accessible to the end user?  I would like to see what the controller saw happen.

NH Mountains Posted at 2018-1-26 14:49
I appreciate you taking the time to look at the log files.  Everything I saw in there seemed to mirror what occurred right up to the communication loss.  One thing I was curious about...does the remote control keep any sort of log file?  If so, is this accessible to the end user?  I would like to see what the controller saw happen.

I’m not sure about P4Pro RC ,but there is in Mavic RC, maybe amid will come along and help out.

hallmark007 Posted at 2018-1-26 15:29
I’m not sure about P4Pro RC ,but there is in Mavic RC, maybe amid will come along and help out.

It cotinued to fly away? very odd because if you lose signal the bird should stop and RTH should kick in..maybe a hardware issue after DJI repair?

PowerBand1 Posted at 2018-1-26 16:10
It cotinued to fly away? very odd because if you lose signal the bird should stop and RTH should kick in..maybe a hardware issue after DJI repair?

If it looses signal and gps it will just fly away, I think this is what happened.

NH Mountains Posted at 2018-1-26 07:59
It was flown prior to the repair.  I am hoping they will do the right thing here, but so far I am very disappointed.  Trying to reach someone who isn't reading from a script and can actually listen to the situation is the most frustrating part.

Sir, sorry for the trouble it brings. Please tell me your case number, we will look into the case and help you solve the problem. Thanks for your support.

you have a obsidian , NH Mountains ?

Nigel_ Posted at 2018-1-26 12:37
The GPS location is changing all the way to the end of the log and looks correct so I think the GPS was working up to the end of the log.  My guess is that it failed at the same time the communications failed and the aircraft then went to atti and since it was already doing 27mph it would have continued without any braking for a fair distance before the wind took it further.

Looking at the sticks again, they do seem to make sense, I got them mixed up on my first look.

Well the thing is, these are flying machines! When the computer or other hardware in the drone malfunctions, all sorts of things can happen.
It could drop out of the sky, or it could fly off into the distance never to be seen again.
If the flight log in the remote/phone just ended, well this indicates that a piece of drone hardware has malfunctioned, especially seeing as the drone was so close and signal strengh shows good up to the disconnect.

It is not like this is an isolated case. It seems that every day there is a drone that flys away or falls out of the sky for no reason at all.

Perhaps DJI needs to have a smarter built transmission link(with its own independent power source) back to the controller, so in the case of on board systems failing, the drone can still transmit data back to the remote, eg "CPU faulire" "power failure" "receiver failure" "captured by aliens"
Also it could transmit information from the g-force sensors etc for a crash log.

When things go bad, these things fly off into the sunset and if it is a hardware failure, then the user should not be burdened with the cost.

It is a white, not obsidian which in this case is a bad thing.  There is 3 feet of snow on the ground where I was flying.  A white drone tends to blend in under those conditions.

I have started to find other threads on this board that talk about the same thing happening, drones falling from the sky.  There should be slightly more logging done.  I agree with you 100%. A backup power source that could send a single extra message or two would make a world of difference.  Having the remote controller do logging (if it doesn't already) could also be a big help as that is almost always the piece that does not fly away. <snicker>

NH Mountains Posted at 2018-1-27 05:34
I have started to find other threads on this board that talk about the same thing happening, drones falling from the sky.  There should be slightly more logging done.  I agree with you 100%. A backup power source that could send a single extra message or two would make a world of difference.  Having the remote controller do logging (if it doesn't already) could also be a big help as that is almost always the piece that does not fly away.

Did you respond to post #26 above?  If not then reply to it with the details requested...

There is a decent log of what happens, including what the controller was seeing, and normally this answers the questions and provides good evidence, but if you loose communication then it is impossible to log what happens after.  Sometimes it is also impossible to know why communication was lost which makes it impossible to know who was at fault.  Without proof of a manufacturing fault you can't normally use a warranty and then it becomes an insurance issue.

In this case, because the aircraft was new and effectively on it's test flight, I would expect DJI to accept your story, maybe the reason they didn't is because it was a replacement. Let us know the outcome...

Yes, I replied in a PM.

NH Mountains Posted at 2018-1-29 02:46
Yes, I replied in a PM.

Hi NH, sorry for the late response since Elektra is off duty recently, case number received with thanks, I fully understand your frustration and we sympathize with your situation, while according to the remaining flight records, there was no abnormality before the record interrupted. I have transferred your concern to data analysis team to see if there is anymore we can do for you, the team will send you email, please check later, thank you.

After 2 1/2 long days of trudging through the woods, I finally found the drone.  It was completely buried in the snow with only a piece of the prop sticking out.  It looks to me like it fell out of the sky.  The battery was still full.  The video on the SD card mirrors the video on the phone.  9 seconds long.  The data analysis team has been completely unhelpful.  They keep repeating the same thing.  There is no proof it failed, so it is your fault.  Here is 30% off another expensive paperweight.  

It was the aliens that did it....

NH Mountains Posted at 2018-1-30 03:22
After 2 1/2 long days of trudging through the woods, I finally found the drone.  It was completely buried in the snow with only a piece of the prop sticking out.  It looks to me like it fell out of the sky.  The battery was still full.  The video on the SD card mirrors the video on the phone.  9 seconds long.  The data analysis team has been completely unhelpful.  They keep repeating the same thing.  There is no proof it failed, so it is your fault.  Here is 30% off another expensive paperweight.  [view_image]

i´m disappointed too...

Recently my Spark slowly landed in the water while I was sending him up (using remote controller).

I sent it to DJI and yesterday they wrote me saying that it is not covered by the warranty (it seems that they did not see the recording of the flight), and they offered me one in exchange for U $ 390 (a new one costs U $ 399), besides I disagree on the guarantee, because before taking off I waited GPS signal, the sky is clear and there was no sensor error, etc ... I received a discount offer of $ 9, do you believe it? 9 dollars !!

This month I bought a Mavic, but I plan on selling it before something happens and they ignore it.

NH Mountains Posted at 2018-1-30 03:22
After 2 1/2 long days of trudging through the woods, I finally found the drone.  It was completely buried in the snow with only a piece of the prop sticking out.  It looks to me like it fell out of the sky.  The battery was still full.  The video on the SD card mirrors the video on the phone.  9 seconds long.  The data analysis team has been completely unhelpful.  They keep repeating the same thing.  There is no proof it failed, so it is your fault.  Here is 30% off another expensive paperweight.  [view_image]

It's a great news that you retrieved the drone in the end, the previous data analysis was based on the flight records in APP, please contact our support to export the data log inside of the drone for further analysis, thank you.

FelipeNG Posted at 2018-1-30 14:32
i´m disappointed too...

Recently my Spark slowly landed in the water while I was sending him up (using remote controller).

FelipeNG, we are so sorry for the accident, may I have the case number please so that I can check more details for further support? Thank you.

DJI Mindy Posted at 2018-1-30 21:33
FelipeNG, we are so sorry for the accident, may I have the case number please so that I can check more details for further support? Thank you.

Shure!

CAS-1323170-J3P6M2

Thank you!!

FelipeNG Posted at 2018-1-31 11:29
Shure!

CAS-1323170-J3P6M2

Well received, thank you so much! This has been forwarded to the local team to investigate. We will look into it and help you get an update soon.