HELP! P3 Professional went out of control and crashed.

[Vertigo]

Like I said ... atti mode uses all sensors except GPS and VPS.
When said .. The aircraft only uses its barometer (for stabilisation)
I meant that in P-GPS mode the Phantom uses GPS for horizontal and barometer for vertical stabilisation.
In atti it only has vertical stabilisation -not horizontal.

Dont call it stabilization then, thats the work of gyro and accelerometers and it cant be turned off with a phantom. What you are saying is better described as 'positioning' I guess.

And whether or not it uses compass in attitude mode, or more precisely, whether or not it uses compass data even when it knows and reports its bad data, thats the crux of this discussion. You confidently state it as fact multiple times, despite it being frankly, a really stupid thing to do for DJI, what do you base your assertion on ?

 

[Vertigo]

BTW, thinking it over some more; lets assume it does use bad compass info. If you push the pitch control forward, under no circumstance when not flying in a position mode (PGPS) should it do anything other than pitch forward in whatever heading it happens to be flying. Bad compass data may make it yaw, possibly even like crazy, but pitch and roll control would still work as expected. This is not what im seeing in these video's. I frequently see pitch or roll angle being maxed out while yaw is stable, and I just dont see how bad compass data could do that.

 

[Vertigo]

Digging some more, reading through the manual, I found something interesting:

Read the second paragraph carefully, its the same error the OP had. I really wish someone from DJI would come here and give more details, but it would appear that the phantom tries to recalibrate in flight ? From the wording it sounds like it will use GPS to figure out the direction, which is what a pixhawk does to gradually improve magnetic offsets over time. But this seems little a different and I guess it would make some sense that it would fly around apparently out of control if really its flying around to change its position far enough to measure its heading using GPS localisation, and use that information to recalibrate the compass. If that interpretation is correct, then DJI should make that a lot clearer - and I dont think its the best idea TBH, especially not if you have no control over the process. Climbing high enough to allow these manouvres isnt always an option, particularly not when your batter is low like in the OP's case. Then again, we dont know if (manually) switching the controller to Attitude mode cancels this process, perhaps it does.

 

[syotr]

But switching to atti doesn't shut off the compass.
If they have a small compass error they might get away with it but one like the OP is a different matter.

If the compass is still connected and generating bad data, the data is recorded but ignored by the flight controller in atti mode.

 

[Tenly]

Then again, we dont know if (manually) switching the controller to Attitude mode cancels this process, perhaps it does.

Since the conversation has drifted off topic and we are now discussing Compass, GPS and ATTI mode, I think this is a reasonable place for me to ask for a clarification about what works and doesn't work when we switch the PAF switch to A.

1. Does the GPS get totally disabled? Or just ignored for the purpose of automated flight?
A) Will the GPS coordinates continue to be logged?
B) Will my position on the map continue to be updated?
C) Will no fly zones be enforced?
D) Will Smart Return to Home work (if enabled)
E) Will pressing RTH to invoke Return to Home work
2. Does a Compass that is reporting errors make it difficult/impossible to control?
3. Does an auto-landing still occur at 10% battery? Is there any way to abort that (in any mode)?

 

[Meta4]

If the compass is still connected and generating bad data, the data is recorded but ignored by the flight controller in atti mode.

And if it was ignored, the OP wouldn't have had the problems he did.
His Phantom was in atti mode for almost the whole short flight but it did nothing to tame his wild Phantom.

 

[Vertigo]

And if it was ignored, the OP wouldn't have had the problems he did.
His Phantom was in atti mode for almost the whole short flight but it did nothing to tame his wild Phantom.

His controller was never switched to attitude mode. You assume the flight controller saying its exiting PGPS mode due to compas errors is the same as doing so by flipping the controller switch to A, but the quote from the manual I gave above proves this at least is incorrect. His phantom was not in normal attitude mode, if you believe the manual, it was trying to recalibrate its compass in flight using GPS. How that works in detail, I have no idea, but its quite possible that involves flying large circles apparently erratically and without normal control. And its equally possible that the only real problem the OP had, was that his low battery condition didnt allow this procedure to complete, and he didnt abort it by flipping his controller mode switch.

Does no one here have a contact at DJI that could give us an authoritative answer?

 

[syotr]

And if it was ignored, the OP wouldn't have had the problems he did.
His Phantom was in atti mode for almost the whole short flight but it did nothing to tame his wild Phantom.

His controller was never switched to attitude mode. You assume the flight controller saying its exiting PGPS mode due to compas errors is the same as doing so by flipping the controller switch to A, but the quote from the manual I gave above proves this at least is incorrect. His phantom was not in normal attitude mode, if you believe the manual, it was trying to recalibrate its compass in flight using GPS. How that works in detail, I have no idea, but its quite possible that involves flying large circles apparently erratically and without normal control. And its equally possible that the only real problem the OP had, was that his low battery condition didnt allow this procedure to complete, and he didnt abort it by flipping his controller mode switch.

Does no one here have a contact at DJI that could give us an authoritative answer?

You will never get a definitive answer from DJI on anything with regards to how the algorithms work.
I can't believe they would be stupid enough to use compass data that they know is bad. Anyone who has a P3 could test this by doing an intentional bad calibration and flying in atti mode. I can do it with my P1 but it does not automatically switch modes. I have on two occasions saved it from a flyaway by switching to atti mode but I have no flight data to indicate that the compass was the problem. In both instances, I had successful flights in the same spot before losing control.

 

[Vertigo]

They dont have to disclose the algorithms, but surely its not a trade secret whether or not the phantom deliberately flies 'out of control' in this situation, while its recalibrating in flight, and whether or not manually switching to attitude mode would bring it back under control and ignore erroneous compass readings. That should be in the user manual to begin with.

 

[MikeyOnline]

And if it was ignored, the OP wouldn't have had the problems he did.
His Phantom was in atti mode for almost the whole short flight but it did nothing to tame his wild Phantom.

Possibly. But it's also possible that he had other issues that caused the erratic flight. In the log, it is constantly switching back and forth between GPS_Atti and Atti. We don't know what would have happened had the OP manually switched to Atti mode and it stayed there for the last part of the flight. Would that have allowed regaining control? I don't know.

Mike

 

[syotr]

Possibly. But it's also possible that he had other issues that caused the erratic flight. In the log, it is constantly switching back and forth between GPS_Atti and Atti. We don't know what would have happened had the OP manually switched to Atti mode and it stayed there for the last part of the flight. Would that have allowed regaining control? I don't know.

Mike

Like a stopped clock that is correct twice a day, the compass heading may match the GPS calculated heading at some points when flying around erratically, causing the flight controller to switch back to GPS mode and assume the compass is correct. I wonder if the FC switching back to GPS mode contributed to the problem when staying in atti mode might have saved it.

 

[sethtinsley]

Lipo batteries do NOT develop a memory - Old technology NiCad batteres do.
There was no need to hover to run your batteries down

Thanks for the information.

 

[sethtinsley]

Toilet bowl effect is indicative of a compass problem. Hubsan had a firmware upgrade for its H501s and the forums were full of the same complaint. I had the same problem and finally the drone just flew away. There were plenty of videos of it but it was never quite so scary as when I saw it happening to my own bird.

It was very scary and I'm glad it didn't fly into a person in the area, I could have done nothing to stop it though obviously.

 

[sethtinsley]

I recently lost a phantom in the lake. I did not have the bird to send in. I filled out the same questionnaire as you and sync'd my flight records.

After a 2 week review - they replaced by phantom, camera, battery and props at a 100% discount - so if someone tells you they they won't replace a bird that you can't send them - they're wrong. It might not happen often - but I'm proof that it cab happen.

In any case - my issue was different than yours. I'll bet that after a review of your data, they'll offer you at least 30% off of a replacement drone and possibly even 50%. I've also heard that if you complain about the discount they offer, they'll someone's make it better with a "final offer".

I do hope that they do something for you though. Although the conventional forum wisdom says not to fly with anything but a fully charged battery - I don't think the operating manual says any such thing.

There may have been things you could have done differently or better when the incident occurred - but I don't think you did much of anything that contributed to the errors. As someone else mentioned - the compass errors should have cleared up when you flew away from whatever was interfering - unless you actually calibrated your compass on all that metal (did you?).

One other thing I dug up and sent them is the cached video from DJI Go. If you can retrieve that file - post it here for us to look at - and send it in to DJI as supplemental evidence. If you are using an iOS device, connect to iTunes, then on the right hand side of the screen - find the DJI Go app listed and look at the directory structure. You should see your "flight record" folder and you should also see a "videocache" folder. Go into the videocache folder and find the file that matches the flight in question. Copy it to your computer and then upload it! When you submit it to DJI, make a vague suggestion that this video file contains more evidence that you did not do anything wrong - and let them figure out what you meant by that!

Good luck. I know exactly how you feel right now. Don't wait for an email from them. Call them every 5 days asking for an update or if they need anything else from you. My case took 2 weeks. I've heard of others taking as much as 8 weeks.

Wow, that is definitely a relief to hear that it's possible but I will just wait it out and see. The battery thing is the main lesson learned here although I will reiterate that I was aware of the battery and made the mistake of taking off with sole intentions to burn the battery down, not for a distance flight. Now i know, horrible idea.
I did not calibrate it on the metal, but I have a strong idea of where the what the metal was that caused the interference.

I did my best to recover knowing what I know, but unfortunately that wasn't enough. I am attempting to upload the video from the videocache folder but I'm not seeing one from the final flight. I wasn't recording during it and I believe thats why. I would like to upload the video from my logs on the app to also show the mayhem the aircraft was commencing, is there a way to do that?

Here is the screenshot the the log I speak of...

Yes I feel defeated regarding the situation, but I'm doing all I can to get back to where I was with the drone prior to the incident. Thanks for the positive advice and thoughts!

 

[impilot51]

I land on my neighbors steel shed a few times and have never noticed this. Land and take off actually.

My guess is that it's actually aluminum rather than steel. Aluminum is not magnetic, thus no compass issue.


Sent from my iPhone using PhantomPilots mobile app

 

[MikeyOnline]

You should offer a $5 prize to whoever successfully accomplishes this...

Make it $500 and I'll try it.

Mike

 

[Susruth]

Someone should copy this whole thread and mail it to dji and ask them to clear this and bring an end. More the posts more confusion.

 

[flyNfrank]

Got it, thanks for the advice. The ticket is turned in and is in process, I'll post the outcome whenever I get it. I will definitely use that argument if needed. Thank you!

I want to let you know now that it's best not to have any expectations on this claim. You may want to start now thinking the worse may happen. And if they offer a discount, ask if the discount is for a brand new aircraft and what accessories are included. Make sure you old one is returned.

 

[flyNfrank]

How can you tell if it's refurbished?
I just received a replacement for one I lost. How can I tell if it is new or refurbished?

Other then looking at the serial numbers you can't tell. The refurb they sent me looked a new one that had just came off the production line. They told me ahead of time what I was being sent, which then lead to me getting the cost reduced a great deal.

Just keep in mind the deals out on the market that include a battery, extra props, a microSD card, and a R/C with charger. So if you are paying $400+ for just a aircraft, you are getting jacked.

 

[Tenly]

Other then looking at the serial numbers you can't tell. The refurb they sent me looked a new one that had just came off the production line. They told me ahead of time what I was being sent, which then lead to me getting the cost reduced a great deal.

Just keep in mind the deals out on the market that include a battery, extra props, a microSD card, and a R/C with charger. So if you are paying $400+ for just a aircraft, you are getting jacked.

Their list price is $709 US + shipping for a Phantom 3 Professional, a battery and a set of props (no RC, no charger). This is what I was sent for free. At that price, I would assume that it's brand new.. The equivalent package for the P3 Advanced is $559 US. The description on the DJI store does bit include the word refurbished. My package arrived in a solid brown box labeled "Parts and Components".