I was on my 20th flight with my less then 1 month old Mavic Pro and 3:00 minutes into flight I get weak signal and drone crashes. The drone was 250 feet from my location and I could physically see it. I stopped turned to left slightly then all of a sudden I get weak signal warning and the drone banks hard right without me touching the controller gaining speed on its way down until it crash lands. I sent to DJI support and they say it's a magnetic interference non warranty I must pay for repairs. I sync my flight records to show two days earlier I was flying in same spot with zero issues and still telling me sorry case closed non warranty. My co-worker has same drone and was also flying in same area with no problems. I can't understand how a $1000.00 drone can fall out of sky without my control and only answer I get is magnetic interference pay money or we can send crashed drone back to you. I have synced all my flight records.

Ya know, I've been air driving my 2 P3p's for around a year now, just bought the Mavic, have only flown 3 packs so far. I keep it low, slow and close until I am sure of it's stability, especially after each update. I will venture out more and more as I gain confidence in the Quad,

The P3p's are very reliable now, I don't update them anymore (unless I absolutely have to), if it ain't broke don't fix it.

I resigned myself to the fact that DJI Support and/or repair is sometimes non-existent and luckily I have a DJI Authorized repair facility 200 miles from me. I will pay the $89.99 USD diagnostic fee ( which is deducted from the repair cost if you have it repaired ) 1 day shipping UPS, free shipping back and their turnaround time is 3-5 days. ( If parts in stock )

Well worth checking to see if you have the same in your area.

Check if it matches this post: http://forum.dji.com/thread-105008-1-1.html Also download the logs and update them to airdata.com and here so somebody can help you analyzing it.

You can pick up magnetic interference on the ground before you take off. I.e. If you take off from or close to metal objects rebar concrete, electrical wires underground.

1. Ditch the factory USB cable - use the bottom port
2. Fly in flight mode every time
3. Apple is sadly far more stable
4. You'll have zero issues with the above steps...

I would think that I would get a magnetic warning right before it crashes or it would just stop before it just comes down like a rocket. I appreciate the info. Below are the flight records from the crash and two days before in same area with no issues.

http://app.airdata.com/main?share=FypBAM

http://app.airdata.com/main?share=qlroSC

KillMud Posted at 2017-7-31 15:56
I would think that I would get a magnetic warning right before it crashes or it would just stop before it just comes down like a rocket. I appreciate the info. Below are the flight records from the crash and two days before in same area with no issues.

http://app.airdata.com/main?share=FypBAM

I don't see any magnetic interference warnings. I'm calling BS on DJI. The admins here are excellent, and hopefully one of them can clear this up. Also, DroneFlying will probably come along and have you upload your logs for analysis. I'm interested to see what's up with this.

You are one of the few posts that comes along where I don't see immediate pilot error.

Sorry for the crash, could you please provide me your case number so I can look into it?

I would like to know more about you and your mavic to try and help see if i can figure out what happen...
it very abnormal for a mavic to do what you stated.?
I'm not saying your pulling our leg...
i need more info before i can say the Mavic just Loss signal and crashed
Let me help you.!
could you tell me how you start before flight ( start controller ,Start mavic,
did you loss signal or Feed.?
  are you using the factory cables.?
in the controller setting did you set for loss of signal Hover ,Landing, RTH.?
what time of day were you flying.?
what was your battery charge .?
was there Wind.?
after started app you see the arrow that represent Mavic on the map did you notice that they were pointing in same direction.?

KillMud Posted at 2017-7-31 15:56
I would think that I would get a magnetic warning right before it crashes or it would just stop before it just comes down like a rocket. I appreciate the info. Below are the flight records from the crash and two days before in same area with no issues.

http://app.airdata.com/main?share=FypBAM

I think you may have caused the problem yourself by turning away from the drone and blocking the signal. The messages refer to an antenna problem and you said that you had turned away. If DJI also indicate magnetic interference (also indicated by the compass in red) then the combination was probably what brought it down.

Looks like you were flying close to large metallic objects, i.e. the oil pumps?

sunet last night i also received a STRONG INTERFERANCE warning.
not a breath of wind - LOS, and me and controler facing directly to drone - about 1km out and about 60-80 m high over an area where i have flown many times before.
Immediately i started flying my mavic back to me and after a few seconds - the red notice dissapeared and the green gps mode appeared again.

Survived another scare - but really whats up with this notice - why does it appear - what is causing it ???

DJI Diana Posted at 2017-7-31 18:22
Sorry for the crash, could you please provide me your case number so I can look into it?

CAS-754332-Q9G8B3 Thanks

Jenee 2 Posted at 2017-7-31 20:22
I think you may have caused the problem yourself by turning away from the drone and blocking the signal. The messages refer to an antenna problem and you said that you had turned away. If DJI also indicate magnetic interference (also indicated by the compass in red) then the combination was probably what brought it down.

if the mavic looses connection to the remote, it should rth (or stay and hover, whatever you setup)... not just fall out of the sky...

CharlieFliesDro Posted at 2017-7-31 18:39
I would like to know more about you and your mavic to try and help see if i can figure out what happen...
it very abnormal for a mavic to do what you stated.?
I'm not saying your pulling our leg...

Powered up drone, powered up controller and DJI go 4 app with factory cable plugged into iPhone 7, took off and hovered in area a few moments received weak gps signal warning. I flew around at a low height and speed received good signal and RTH was set. I then started flight with no issues until sudden crash. Middle of the afternoon with 4mph winds take off battery 66%. Did not notice if both arrows were facing up thanks

Jenee 2 Posted at 2017-7-31 20:22
I think you may have caused the problem yourself by turning away from the drone and blocking the signal. The messages refer to an antenna problem and you said that you had turned away. If DJI also indicate magnetic interference (also indicated by the compass in red) then the combination was probably what brought it down.

I didn't turn away from it before the crash I was flying drone forward stopped and turned the drone slightly to the left then received the loss signal and drone crashed. I was also only 260' from the drone and in flights prior was a lot farther away with my back to the drone and no issues

dancopter Posted at 2017-7-31 21:54
Looks like you were flying close to large metallic objects, i.e. the oil pumps?

There was some equipment at the location I was at and in my flight records you can see I was in the exact same area two days before flying with no issues. My co-worker has also has the Mavic Pro and flew his drone in same area before and after my crash with no issues. I would like to think I would get a warning or something before drone doesn't like something and just falls out of the sky.

KillMud Posted at 2017-8-1 02:01
There was some equipment at the location I was at and in my flight records you can see I was in the exact same area two days before flying with no issues. My co-worker has also has the Mavic Pro and flew his drone in same area before and after my crash with no issues. I would like to think I would get a warning or something before drone doesn't like something and just falls out of the sky.

Proof is in the pudd'in, it definetly can happen! Watch this from another post

QuadKid Posted at 2017-8-1 02:00
Proof is in the pudd'in, it definetly can happen! Watch this from another post

https://www.youtube.com/watch?v=mMGZk99cvzM

Definitely crazy I seen it with my own eyes. Mine never disconnected the last warning I was getting was max motor speed reached.

Can you upload those same two logs to PhantomHelp using these instructions? It provides a bit more information than AirData and may shed additional light on what happened. Unfortunately, the really useful data was in the DAT file on the Mavic itself, but if you've already sent it to DJI there's not much chance of getting access to it without having them return your drone.

Also, can you clarify whether the Mavic seemed to still have power on its way to the ground or did it fall straight down? And afterwards were any props missing or broken and was the battery still latched in place?

Magnetic interference may well have played a role in what happened, but it can't / won't affect altitude because the Mavic's height while flying is measured by barometer and VPS, which aren't influenced by magnetism.

DroneFlying Posted at 2017-8-1 02:55
Can you upload those same two logs to PhantomHelp using these instructions? It provides a bit more information than AirData and may shed additional light on what happened. Unfortunately, the really useful data was in the DAT file on the Mavic itself, but if you've already sent it to DJI there's not much chance of getting access to it without having them return your drone.

Also, can you clarify whether the Mavic seemed to still have power on its way to the ground or did it fall straight down? And afterwards were any props missing or broken and was the battery still latched in place?

Definitely can see a lot more warnings with PhantomHelp. Looks like I got compass error before crash. Why wouldn't that warning show during flight. Seems like I got the error and continued maneuvering around at slow speeds with errors until crash. When it crashed it gained speed till it hit and power stayed on. Two props were broke off and battery was still latched in place. When I found it I shut it down. Both logs below thanks!

http://www.phantomhelp.com/LogViewer/ZV1FWO91U6V5UEURG3IJ/

http://www.phantomhelp.com/LogViewer/ACE075MM5N8Q5V6CRKV4/

KillMud Posted at 2017-8-1 04:03
Definitely can see a lot more warnings with PhantomHelp. Looks like I got compass error before crash. Why wouldn't that warning show during flight. Seems like I got the error and continued maneuvering around at slow speeds with errors until crash. When it crashed it gained speed till it hit and power stayed on. Two props were broke off and battery was still latched in place. When I found it I shut it down. Both logs below thanks!

http://www.phantomhelp.com/LogViewer/ZV1FWO91U6V5UEURG3IJ/

By any chance did you take off from a vehicle, such as the roof, hood, or bed of a truck?

DroneFlying Posted at 2017-8-1 04:51
By any chance did you take off from a vehicle, such as the roof, hood, or bed of a truck?

No I took off from the ground my truck was with in 10' from where I took off.

KillMud Posted at 2017-8-1 05:01
No I took off from the ground my truck was with in 10' from where I took off.

Well, there does appear to have been some kind of magnetic interference before takeoff, so it must have been something underground. And the loss of control / start of the crash appears to have taken place here, though I can't see anything in that location on the map. I suppose it's possible that this could have been a bird strike, but that would be a strange coincidence given that you were already having trouble due to the magnetic interference. Did you see anything that it might have collided with around the time you lost control? If not, the only other thing I can think of is that one of the propellers was damaged or faulty at the time.

DroneFlying Posted at 2017-8-1 05:07
Well, there does appear to have been some kind of magnetic interference before takeoff, so it must have been something underground. And the loss of control / start of the crash appears to have taken place here, though I can't see anything in that location on the map. I suppose it's possible that this could have been a bird strike, but that would be a strange coincidence given that you were already having trouble due to the magnetic interference. Did you see anything that it might have collided with around the time you lost control? If not, the only other thing I can think of is that one of the propellers was damaged or faulty at the time.

I could see the drone at time of crash but was not looking at drone was looking down at controller. Did not see no birds or anything when I looked up from controller during crash but I guess I can't completely rule it out. Definitely a bummer was completely out of my control in a blink of an eye. DJI is saying they found no hardware issues and will not cover any costs. When I call them it seems like I get no where except waiting on analysis or I need to pay for repairs or they can send the damaged drone back. Thought I could get more help or info on here appreciate the info and feedback.

TroutboyNZ Posted at 2017-7-31 14:42
1. Ditch the factory USB cable - use the bottom port
2. Fly in flight mode every time
3. Apple is sadly far more stable

BS   (for this problem)      

The weak signal could also be due to electromagnetic interference.  I'm unable to examine the DAT files from my current location, but looking at the AirData log, it appears that at the time Weak Signal was reported, you were flying at about 20 ft altitude near the derrick.  Was the derrick operational?  Gas or Gas-generator/Electric?  On the previous flight your altitude appears to have been much higher.  Could be buried material on the site.  DroneFlying, did you see any unusual motor-rpm discrepancies that might indicate prop damage? Maybe one motor that went to much higher rpm?  

Griffith Posted at 2017-8-1 06:44
The weak signal could also be due to electromagnetic interference.  I'm unable to examine the DAT files from my current location, but looking at the AirData log, it appears that at the time Weak Signal was reported, you were flying at about 20 ft altitude near the derrick.  Was the derrick operational?  Gas or Gas-generator/Electric?  On the previous flight your altitude appears to have been much higher.  Could be buried material on the site.  DroneFlying, did you see any unusual motor-rpm discrepancies that might indicate prop damage? Maybe one motor that went to much higher rpm?

DroneFlying, did you see any unusual motor-rpm discrepancies that might indicate prop damage?

I didn't even ask for the DAT file because my interpretation of his original post was that he already sent the Mavic to DJI, but after rereading it I guess it's not entirely clear if he sent the drone itself to them or only contacted them about the crash.

KillMud Posted at 2017-8-1 05:35
I could see the drone at time of crash but was not looking at drone was looking down at controller. Did not see no birds or anything when I looked up from controller during crash but I guess I can't completely rule it out. Definitely a bummer was completely out of my control in a blink of an eye. DJI is saying they found no hardware issues and will not cover any costs. When I call them it seems like I get no where except waiting on analysis or I need to pay for repairs or they can send the damaged drone back. Thought I could get more help or info on here appreciate the info and feedback.

As Griffith mentioned, there's a file stored on the Mavic itself with an extension of .DAT that has a lot more information about the flight. If you still have the Mavic and are willing to extract and upload the DAT file we may be able to get more insight into what happened. The instructions for retrieving it are here and if you're able to access it you'll need to upload it to DropBox and provide a link to it in this thread. The correct file will have a time stamp that corresponds to when the flight occurred and will be at least tens of megabytes in size.

QuadKid Posted at 2017-7-31 14:19
Ya know, I've been air driving my 2 P3p's for around a year now, just bought the Mavic, have only flown 3 packs so far. I keep it low, slow and close until I am sure of it's stability, especially after each update. I will venture out more and more as I gain confidence in the Quad,

The P3p's are very reliable now, I don't update them anymore (unless I absolutely have to), if it ain't broke don't fix it.

Basically what I'm doing, low, within sight and playing safe after this most recent FW upgrade.

BadBert Posted at 2017-8-1 01:43
if the mavic looses connection to the remote, it should rth (or stay and hover, whatever you setup)... not just fall out of the sky...

what's exactly what I thought...it's designed to do jsut that...RTH once connection is lost. Craft dropping out of the sky could be caused by several variables for sure.

KillMud Posted at 2017-8-1 04:03
Definitely can see a lot more warnings with PhantomHelp. Looks like I got compass error before crash. Why wouldn't that warning show during flight. Seems like I got the error and continued maneuvering around at slow speeds with errors until crash. When it crashed it gained speed till it hit and power stayed on. Two props were broke off and battery was still latched in place. When I found it I shut it down. Both logs below thanks!

http://www.phantomhelp.com/LogViewer/ZV1FWO91U6V5UEURG3IJ/

i do not understand why there is a altitude discrepency between VPS alt and IMU alt.
Even assuming that is normal or to be expected then i next do not understand why that descrepency varies as it does in the log view.
I would think that if the differnace is say 2m then that should remain constant but these flight logs show a constant variation at the start the differance becomes greater through the flight and difficult to understand towards the end.
I am guessing that take off w/o gps link resulted in VPS activation which i think is only good to a certain height.
Then gps linked in whilst in flight/ hovering. and perhaps a conflict arose between gps and Vps -
VPS then turns off (1.51s) then on again at (2.487s) then off again at 2.574s - all the while sufficient satelites connected.
  
why turn on and off - i wonder what its AI logic was for this action?
Perhaps a conflict arose between gps and Vps ??

DroneFlying Posted at 2017-8-1 07:14
As Griffith mentioned, there's a file stored on the Mavic itself with an extension of .DAT that has a lot more information about the flight. If you still have the Mavic and are willing to extract and upload the DAT file we may be able to get more insight into what happened. The instructions for retrieving it are here and if you're able to access it you'll need to upload it to DropBox and provide a link to it in this thread. The correct file will have a time stamp that corresponds to when the flight occurred and will be at least tens of megabytes in size.

DJI has my Mavic I'm going to pay the money to get it repaired today before they decide to send it back to me still damaged. Once I get it I can get the DAT file uploaded thanks.

Griffith Posted at 2017-8-1 06:44
The weak signal could also be due to electromagnetic interference.  I'm unable to examine the DAT files from my current location, but looking at the AirData log, it appears that at the time Weak Signal was reported, you were flying at about 20 ft altitude near the derrick.  Was the derrick operational?  Gas or Gas-generator/Electric?  On the previous flight your altitude appears to have been much higher.  Could be buried material on the site.  DroneFlying, did you see any unusual motor-rpm discrepancies that might indicate prop damage? Maybe one motor that went to much higher rpm?

The pump jacks were not operational but there was some equipment that was operational on the location. Maybe underground stuff as well it's hard to tell. My first flight on the location I was 16' higher in the area it crashed. I was running at very low speeds that I think I should of got a warning or something before it crashes out of the sky thanks.

Bekaru Tree Posted at 2017-8-1 08:53
i do not understand why there is a altitude discrepency between VPS alt and IMU alt.
Even assuming that is normal or to be expected then i next do not understand why that descrepency varies as it does in the log view.
I would think that if the differnace is say 2m then that should remain constant but these flight logs show a constant variation at the start the differance becomes greater through the flight and difficult to understand towards the end.

There's nothing really abnormal in the VPS vs. IMU altitude readings in his logs. The VPS height comes from a sensor on the bottom of the Mavic and the IMU from a barometer, and it's actually pretty rare for them to have exactly the same value.

KillMud Posted at 2017-8-1 09:12
DJI has my Mavic I'm going to pay the money to get it repaired today before they decide to send it back to me still damaged. Once I get it I can get the DAT file uploaded thanks.

Well, to be honest you aren't likely to get back your original Mavic if you pay for a "repair"; what they'll send you will almost certainly be someone else's refurbished Mavic, so there's not much chance of getting the DAT file from the flight off what you get back.

DroneFlying Posted at 2017-8-1 09:36
There's nothing really abnormal in the VPS vs. IMU altitude readings in his logs. The VPS height comes from a sensor on the bottom of the Mavic and the IMU from a barometer, and it's actually pretty rare for them to have exactly the same value.

Ok, thanks - i accept that about VPS and IMU variance.

Now i am confused by how a barometer, which distinquishes variance in air pressure can be used to determine height? any ideas on that?

DroneFlying Posted at 2017-8-1 07:12
DroneFlying, did you see any unusual motor-rpm discrepancies that might indicate prop damage?

I didn't even ask for the DAT file because my interpretation of his original post was that he already sent the Mavic to DJI, but after rereading it I guess it's not entirely clear if he sent the drone itself to them or only contacted them about the crash.

Sorry, I just noticed the PhantomHelp URL.  Looks like a lot of Compass Errors near the crash site.  I also noticed  a bunch of Error (9) entries.  Any idea what that is?

Griffith Posted at 2017-8-1 10:43
Sorry, I just noticed the PhantomHelp URL.  Looks like a lot of Compass Errors near the crash site.  I also noticed  a bunch of Error (9) entries.  Any idea what that is?

I seen those as well and couldn't tell you what they were I was not getting 9 errors on the screen during the flight

Bekaru Tree Posted at 2017-8-1 10:24
Ok, thanks - i accept that about VPS and IMU variance.

Now i am confused by how a barometer, which distinquishes variance in air pressure can be used to determine height? any ideas on that?

Barometric pressure and altitude are directly related.  A rise of 1000 feet in altitude will result in approximately 1 inch of pressure change (decrease) on a barometer.  That's why barometric pressure is usually given as "corrected to seal level".