Crashed my Phantom 4 Pro please help

[tapevans]

Hi guys, SORRY for the huge post and l know this has been done before but l have a few questions for you pros out there.

l crashed my Phantom 4 pro when l was on a mountain.
So what happened was l took off vertically as normal but on the way up it seems to have lost GPS signal and stated to pan right off, there was no Wind warnings or anything but it all happened in 14 seconds so I'm trying to now piece together what i did wrong or what the the drone did but I'm leaning towards me because iv not once had a drama with the drone prior even in some high winds. originally thought it was a strong draft on the mountain top that caused it but l have been reading threads and seems when it looses GPS it goes into ATTI Mode, now on the flight record it showed a few warnings being:

(Warning: In fight, working IMU encounters heading exception, please switch to ATTI mode if aircraft behaves abnormally)
(warning: Compass Error. Exit P-GPS Mode)
(warning: weak GPS signal. Positional accuracy may be compromised. please fly with caution)

No being that it happened to fast and l didnt understand what what happening (My Bad) l wasn't looking at the screen but trying to recover the drone by eye but i was unable to before it went bad in a few seconds.

saying that l was on a trip so l managed to get the drone working as the main damage was the shell and Yaw arm which l straightened and l had snapped one side of the landing gear so l reattached the antenna wires and doctored it all up and besides flying on a slight angle she is all systems go.

So today l went and tried to fly it in ATTl mode to see what that does without gps and it was very similar to the crash fly in the way that the smallest breeze caused it to drift but holding altitude and l had to fly it myself (first time in the mode, my bad l know now) but when l switched modes it showed a warning saying (flight mode set to Atti: set flight mode to GPS to ensure safety) but not when l went back to P-GPS mode but it does show it in flight record on top left.

During crash record it also shows that it went from GPS Mode into ATTI mode and stayed there until it crashed but it showed it had 9 sats but no bars and said weak GPS signal on the record screen. i tried to cover it but didnt work or l messed it up.

Question: do you think from these warnings below it was purely pilot error or something else as l cannot get the drone to show these warnings again on purpose as it would need to loose GPS signal on its own rather then me switching it over. WHAT DO YOU THINK?
(Warning: In fight, working IMU encounters heading exception, please switch to ATTI mode if aircraft behaves abnormally)
(warning: Compass Error. Exit P-GPS Mode)
(warning: weak GPS signal. Positional accuracy may be compromised. please fly with caution)

Thanks Guys Sorry again about the Explanation but want you to have the full picture. cheers

 

[Technical Bob]

Did you do a compass calibration before you flew ?

 

[tapevans]

Hi Bob no l didnt l only do them when prompted too.

 

[Meta4]

Hi guys, SORRY for the huge post and l know this has been done before but l have a few questions for you pros out there.

The pros will need flight data to be able to say anything helpful.
Go to DJI Flight Log Viewer
Follow the instructions there to upload your flight record.
Come back and post a link to the report it provides.

And what can you tell us about where you launched from.

 

[tapevans]

l have just used Airdata link and also DJI Flight Log Viewer.
launched from a high altitude area but there was no wind.

DJI Flight Log Viewer - PhantomHelp.com
Airdata UAV - Flight Data Analysis for Drones

 

[Meta4]

l have just used Airdata link and also DJI Flight Log Viewer.
launched from a high altitude area but there was no wind.

Your Phantom gets 5 ft off the ground and gets a compass error.
What was the surface that you launched from?
How close was the Phantom to any cars or ather steel objects?

 

[Meta4]

it seems to have lost GPS signal and stated to pan right off, there was no Wind warnings or anything but it all happened in 14 seconds so I'm trying to now piece together what i did wrong or what the the drone did but I'm leaning towards me because iv not once had a drama with the drone prior even in some high winds. originally thought it was a strong draft on the mountain top that caused it but l have been reading threads and seems when it looses GPS it goes into ATTI Mode, now on the flight record it showed a few warnings being:

Your Phantom never lost GPS signal at all but you got a compass error one second after lifting off.
The Phantom is getting conflicting directional data from the compass and the GPS and because it can fly without GPS but can't without compass, it ignores the GPS data and your Phantom is then in atti mode.
In atti mode, it has no brakes, no position holding and can drift on the breeze.
If you are not used to controlling in atti mode, it can be disorientating when the compass is OK but weird things can happen when the compass is messed up by launching from close to steel.

 

[Fly Dawg]

You had multiple error notifications immediately from takeoff and throughout the flight. I would suspect the same as Meta4 mentioned. The .dat file from the aircraft will tell more of the story. Not a lot of useful information in this log to make a determination. However, with all of the errors you had, one could speculate what the problem was.

 

[tapevans]

Hi guys thanks for all that info, in the picture attached it’s saying weak gps signal? I really felt like l had no control over the craft I should have been able to fly it in the opposite direction it was headed but maybe due to compass failure it flu in the direction of the trees. I’m sending it to dji for them to take a look. I know l can replace the damaged parts but it’s more I’m concerned if there is an internal problem it could happen again. I would have been 5 Mtr from car but l always am and l know there was large power lines about 1 km down the track but wouldn’t have thought that be enough to mess it up. Maybe it was hopefully either way dji can tell me something. I have learnt a lot from this experience and I’m just happy l still have a drone to fix. Thanks for all the help.

 

[Meta4]

Hi guys thanks for all that info, in the picture attached it’s saying weak gps signal? I really felt like l had no control over the craft I should have been able to fly it in the opposite direction it was headed but maybe due to compass failure it flu in the direction of the trees. I’m sending it to dji for them to take a look. I know l can replace the damaged parts but it’s more I’m concerned if there is an internal problem it could happen again. I would have been 5 Mtr from car but l always am and l know there was large power lines about 1 km down the track but wouldn’t have thought that be enough to mess it up. Maybe it was hopefully either way dji can tell me something. I have learnt a lot from this experience and I’m just happy l still have a drone to fix. Thanks for all the help.

"Weak GPS Signal" is a badly worded error message.
There's no such thing as a weak GPS signal and your Phantom had full GPS reception the whole time.
The message is to alert you that the Phantom is ignoring GPS because of the compass error.
Your powerline had no effect at that distance.
The symptoms shown in the flight are the same as this one which is what happens when the launch is from a steel or reinforced concrete surface:
Looking for Trouble ??

 

[tapevans]

Ok so simply put l must have launched to close to my car? Being a metal structure it has thrown out my compass, as the ph4 took off it has had a mind of its own even in attitude mode hence why l couldn’t get it to fly in the direction l wanted away from the trees?

 

[tapevans]

Ok so simply put l must have launched to close to my car? Being a metal structure it has thrown out my compass, as the ph4 took off it has had a mind of its own even in attitude mode hence why l couldn’t get it to fly in the direction l wanted away from the trees?

So because there were no errors prior to actual takeoff does that mean That the ph4 thought the compass was ok until it got to a point of altitude after takeoff when the magnetic surface was no longer that it got confused due to the change in magnetism?

 

[Timinator]

If it goes into atti mode then ya gotta fly the aircraft! It ain't gonna hold its position and will drift so you actively have to counteract the wind.

 

[pe9999]

Did OP day he launch near his car? So the mag issue caused the crash.

 

[andy_k]

what was the bedrock? Granite can cause huge (magnetic) issues if it has high iron content

 

[tapevans]

Thanks for the info everyone. It’s off to dji so they can take a look. I’ll post back once they have does an assessment. Cheers

 

[Blade4]

what was the bedrock? Granite can cause huge (magnetic) issues if it has high iron content

Glad somebody finally mentioned this. In many mountainous areas there’s a lot of ferris in the rock.

Once in a while sectional charts will post areas of extreme magnetic disturbance and you can also find that in a briefing if you ask for it from flight service.

 

[Blade4]

Thanks for the info everyone. It’s off to dji so they can take a look. I’ll post back once they have does an assessment. Cheers

Thank you for posting this. Another lesson learned for all of us. New and experienced.

 

[tapevans]

Hi Eveeyone so DJI have after doing an Assesment decided to do my repair under warranty for free which I’m stocked about. I don’t have much info on what they found to be the cause of the crash but maybe when it arrives home in a few days it will have some paper work attached. Overall I’m very happy with dji they keep you posted on what’s happening and you can monitor the steps as they go. Job was about $520 to repair and mainly that’s the price of the battery. I was super surprised about just how inexpensive there genuine parts are and l found some a lot cheaper then aftermarket online. Anyways happy with the outcome and thanks again everyone!

 

[Timinator]

Excellent news! Good to hear you're back in the air soon.