Hi,

After 3 months, 23+km distributed over 50 flights with flawless operation, my drone went beserk today

What makes it extremely sad for me, is that I've taken such great care of the drone and kept it completely clean and scratch free, now it's cosmetically not the prettiest looking.

So, I set everything up, as usual, turned the controller and drone on, let it warm up, and get good GPS signal and home point. As soon as I lifted up, the drone started drifting sideways, so i compensated a little bit, and at first didn't think much of it (maybe wind), until a second later, when it started drifting way more and seemed to be gaining speed (accelerating) I still had control with the controller, so I made it go higher, so it would go above our heads, and not through them, and when I saw there was no chance of regaining control, i came as low as I could, so a wooden fence would stop it near us, and not have the drone go even faster into the unknown, or into the sea/harbor (300-400 meters from us) and initiated the emergency cut motors command before it hit the fence, and seemed to save my propellers.

After that, when gathering all the pieces and reassembling everything, i tested if the drone works (safe area, low altitude) and it did, but seems not to be as stable as it used to.

The logs (which I can upload later) will confirm, that the drone moved and gained speed without any commands from the controller and that there were no errors. All conditions for flying were good (No strong winds, clear sky, good GPS, stable compass and IMU readings).

I've lost a lot of confidence in the drone, that i had before and was amazed at the engineering work behind it.

Damages: mostly cosmetical, except as the battery fell out at the crash location, the battery clamp sockets on the drone side seem a bit bent and I'm afraid it will jepordize the battery staying secured in the future. Also will need to do further testing, but it seems to drift a bit more, and struggling to keep still/stable.

What's also strange is, that in my flight log, the drones initial facing direction seems opposite of what it actually was.

This is my little sad story.

EDIT:

I've been travelling and was unable to deal with all this earlier.

Uploaded the log available from the app to: http://www.phantomhelp.com/LogViewer/9TVU5N3F45PJ4CN6P2CY/
Unfortunately that log does not seem to display any information regarding the controller inputs, so for this scenario seems not too useful.

More information in the HealhyDrones log: http://healthydrones.com/main?share=wXcNNi but can't find control inputs on this one either..

I was unable to upload to a reader or read the flight logs (.BAK file) I got straight out of the drone with DJI Assistant via my computer, but I uploaded them to dropbox, and they can be downloaded here: https://www.dropbox.com/s/xpa2lm ... 1-03-05%5D.rar?dl=0 (hope it's the correct one )


Anyhow, on my own inspection it seems that without any Compass errors and the compass calibration screen giving no interference (all green) on the map (in the app) the drone's direction seems the opposite of what it was, and I figure the drone wanted to correct it's location because of wind movement and what not, trusting the compass, but correcting in the wrong direction, hence trying to correct even harder and gaining more speed in the wrong direction..


Here are some images of the drone after the accident. The pictures were taken right after getting home, I've managed to clean it a bit but not completely.
The nooks holding in the battery have gotten bent, theres a lot of scratches and dents, the colored scratches don't want to completely clear off (the one at the battery nook location is extremely weird).

Sorry to hear! Are you saying you had altitude control, but the rest of the controls were unresponsive? That would be odd! If you had yaw control it would have been possible to have the obstacle avoidance stop it, provided it was in P mode.

glad you saved it from worse damage

by any chance did you calibrate the compass onsite before the flight?

Sounds like the compass or GPS data was in error. Just because your not getting a error of some type, doesn't mean the data (GPS or compass) is not corrupted. Where you flying somewhere new for you, maybe there's was some type of magnetic interference in that area.

Alari,

The symptoms you are describing - drifting immediately after takeoff, ability to control aircraft with RC stick commands but random drifting making it very difficult to fly - I have experienced after calibrating the compass of my Phantom 3 Pro while holding it over concrete with rebar. The metal rebar in the concrete can play havoc with compass calibration and the result is a bad compass calibration and bad drifting. I learned this lesson the hard way many months ago, so I have never had this problem with my Phantom 4 as I learned to NEVER calibrate the compass or take off with the quadcopter on concrete surfaces or structures with rebar.

Were you flying in a new area today? Did you happen to be on a concrete parking lot, driveway, street or sidewalk when you calibrated or launched your P4 prior to the flight where it exhibited extreme drifting?

Another possibility - were you in an area with nearby cell towers, satellite dishes or other signal transmission equipment? Such equipment can also interfere with the flight control electronics in any DJI aircraft.

soundbyte58 Posted at 2016-8-8 02:00
Sorry to hear! Are you saying you had altitude control, but the rest of the controls were unresponsi ...

I think I had the full controll, but as it had gone beserk, and went it's own way sideways, gathering speed, I didn't notice any changes from my doings other then the height change, which I used to save it. As it seems it was going crazy, not sure avoidance system would've been able to correct that, since as far as the drone knew, it was doing everything correct, otherwise I don't think it would've been running away at all.

kirk2579@aol.co Posted at 2016-8-8 03:47
glad you saved it from worse damage

by any chance did you calibrate the compass onsite before the f ...

Nope, the flight was ~10km from my last flying location, compass overview was showing stable green, so I was following the rule, I've caught from posts here, that no need to do compass calibrations unless you're going farther than 100km and it's showing fine

wmcvey Posted at 2016-8-8 07:50
Sounds like the compass or GPS data was in error. Just because your not getting a error of some type ...

The strangfe thing is, that the couple minutes after the crash, when I tested the drone cautiously, I was in the same location, where minute3s before it was beserk..

david.p.mann@ea Posted at 2016-8-8 07:58
Alari,

The symptoms you are describing - drifting immediately after takeoff, ability to control air ...

Hi,

Difficult to fly is a bit of an understatement, as based on the speed everything went down, it was near impossible, even reacting with the altitude corrections I used to save everything was a miracle. It'll be more clear after I get the logs up

For me, I'm not even able to calibrate with magnetic interference and on concrete, it just won't calibrate and throw a calibration error, forcing me to do the calibration again, but the location was ~10km from my home and usual flying place, where I calibrated the last time, and I've been following the no need to calibrate every time rule (unless moving 100km away and/or the compass sensor status isn't stable and green)

I was on a street in the city yes, but the same way I've been dozens of times, and after the accident when I was testing, it was the same location the drone had lost it's mind just a couple minutes back.

I have experienced this. Mine was caused by calibrating the compass while surrounded by buildings. Noob mistake back then.

Anyway, when I lifted off and hovered 2 meters off the ground, the drone immediately started to twitch and drift. I had full control and I can attest to the fact that it was wickedly hard to counter the seemingly random drift. It's like a madman is at the controls. I was able to take it down, thankfully, without crashing.

Learned a valuable lesson in compass calibration.

Sorry for your crash, Alari. Have you contacted our tech support in Europe service center?

For future reference,  if you go to atti mode when this happens,  you will have a better chance of control.  That's assuming it was compass or imu error.

Kneepuck Posted at 2016-8-8 05:41
For future reference,  if you go to atti mode when this happens,  you will have a better chance of c ...

I was guessing he might have been in attitude mode to begin with, my first thought when reading, but thats just a guess

Alari Posted at 2016-8-7 22:49
I think I had the full controll, but as it had gone beserk, and went it's own way sideways, gather ...

I know that in the heat of the moment it can be difficult to keep,your wits about you. But one of the most common causes of crashes is when a pilot uses CSC to bring down an aircraft that still had a possibility of being flown. I am not saying that this is what happened to you only that it has happened to many people in the past. There is an old saying that pilots observe when facing an in air crisis. AVIATE, NAVIGATE,COMMUNICATE The first one is true for drone fights as well. I look forward to seeing the logs.

I'm curious about the "full control" comments.  If you have full control and the drone is drifting then why not simply fly the drone to a landing?  Not that this is the case of the pilots above, but everyone should learn to actually "fly" a quadcopter without stabilization because electronics and stabilization systems do fail and are subject to interference at times.  Too many newbies are buying quadcopters with stabilization systems and they really never learn to "fly" these machines.  Then something happens in which the pilot actually has to control and fly the quadcopters without the benefit of stabilizattion and...well...we know what happens many times.  I'm glad I've been flying RC helicopters and airplanes for several years, which certainly prepares me if stabilization fails on my P4.

After reading this, I think I am going to cut down my compass calibrations!  So far, I do a compass calibration every time I fly the P4.

Most of the times though, I am on a beach.
So once we hear the lady voice telling us the New Homepoint has been established, then we are good to go?

MD_Icarus Posted at 2016-8-10 03:31
After reading this, I think I am going to cut down my compass calibrations!  So far, I do a compass  ...

Personally I calibrate my compass only when going several hundred miles away. Sometimes if not travelling it could be several months without a calibration. But if you add or remove anything metal or get the aircraft close to any metal then it requires a calibration.

DJI-Ken Posted at 2016-8-9 15:50
Personally I calibrate my compass only when going several hundred miles away. Sometimes if not tra ...

Do you mean if the P4 is on and in my car, which is full of metal, then I should do a compass calibration the next time?

MD_Icarus Posted at 2016-8-10 04:05
Do you mean if the P4 is on and in my car, which is full of metal, then I should do a compass calib ...

Probably, What's the reason for having it powered up in your car?

OrlyP Posted at 2016-8-8 08:48
I have experienced this. Mine was caused by calibrating the compass while surrounded by buildings. N ...

Hi, I'm doing very late replies as I was travelling and didn't have any chance to deal with the drone anyway

I had my drone already calibrated from earlier, and as I was not far from the previous locations, where everything was alright, and compass interference at the new location was green, I just let it be. (I've heard that the save calibration trip range is even 100km)

Anyhow, seems that yes, the compass was wrong, and when the drone was trying to correct its position, it corrected in the wrong direction, trying to correct harder (also in the wrong direction) and you can see where it's going

DJI-Paladin Posted at 2016-8-8 09:49
Sorry for your crash, Alari. Have you contacted our tech support in Europe service center?

Hi, thank you!

I've been traveling and couldn't deal with the drone during the time, but now am back. I'll be contacting the technical support tomorrow (Monday). Is there anything I can do on my side to make things go smoother?

I updated the original post with a lot of data, hope it's a good start.

Kneepuck Posted at 2016-8-8 11:41
For future reference,  if you go to atti mode when this happens,  you will have a better chance of c ...

Thank you for the idea, it seems like that could've helped, but as everything happened so quickly, unfortunately I didn't come to that think of that myself.

Heebus Posted at 2016-8-8 15:11
I was guessing he might have been in attitude mode to begin with, my first thought when reading, b ...

Hi, no I was in the GPS and every other assisted mode

soundbyte58 Posted at 2016-8-8 18:46
I know that in the heat of the moment it can be difficult to keep,your wits about you. But one of  ...

Hi,

As it seems that the compass information was inverted and the drone was trying to correct it's position (in the wrong direction) and increasingly so, it was very hard to predict where it was moving, the only thing that worked correctly was altitude changing.

I didn't use the CSC (to try and ease the crash as much as possible) until the drone was half a second away from hitting a fence, and I had brought it as low as I could. (again I had basically no control) and I believe switching to ATTI mode could've been of help, like suggested here by Kneepuck, but unfortunately I didn't think of that myself at the time.

Also updated the original post with the logs, but I myself am unable to find the information regarding controller inputs and drone direction that You see when checking the log on the app.. Maybe someone more experienced than I is able to

Cheers!

Alari

I had similar experience early on in flying, beginner mode was on and home point jumped by 2 miles... Drone wanted to get back to that (false) home point and acted very much like you describe. I too managed to land, but got mine back very safely. I don't see home point acting strange in your logs, so different reason, but the description of how drone behaved was all too familiar.

calls4u2 Posted at 2016-9-12 10:16
I had similar experience early on in flying, beginner mode was on and home point jumped by 2 miles.. ...

Hey,

Yup, no home-point issue, the connection was good and stable throughout.. As I mentioned, it seems that the compass had it's direction reversed (without any errors or notifications and interference was nonexistent - green), because on the map it displays the opposite direction than what it was really facing, and the drone likely was trying to correct it's position trusting the compass input, and correcting in the wrong direction, furthering from the location it wanted to go, and accelerating even harder (in the wrong direction) to get back where it was - unsuccessfully..

I'm no stranger to disrupting RTH, unluckily that was not the case..

I thought the P4 had redundancy dual imu ect,  to avoid miscalculations like that (if that was the case)

Sorry to hear what happened and this thread is long for me to read through each of the comments to make sure you answered it. But i had a similar issues yesterday when i flew my drone in A mode when it just decided to go off on its own. I had to quickly switch it back to P mode and get control and bring it down. Not sure if that was the issue.

udayramakrishna Posted at 2016-9-12 19:04
Sorry to hear what happened and this thread is long for me to read through each of the comments to m ...

A  mode is attitude mode, thats normal in that case, it drifts with the wind in that mode

plasrobin Posted at 2016-9-12 19:33
A  mode is attitude mode, thats normal in that case, it drifts with the wind in that mode

It drifts with the wind, i have read but trying to auto fly itself to about 500ft like it was in sport mode was funny. I am not sure if that is also the expected behavior. There was not much wind when i was flying this.

udayramakrishna Posted at 2016-9-13 01:38
It drifts with the wind, i have read but trying to auto fly itself to about 500ft like it was in s ...

In sports mode it will still track a straight line if you do not touch the aileron or rudder. It's in GPS mode.