Hello, I have lost my Phantom 4 during a RTH with very unusual behavior and the Service tries to tell me, that it is my fault.

So could somebody please confirm to me that RTH function is useless, due to the fact that it goes straight downwards to the homepoint without keeping its actual height until reaching home?
If so, then the whole function of RTH and setting a minimum RTH in the System is complete useless....

The Case:
Phantom 4 flying at the Beach at 21m height, then RC-Signal loss and the drone starts RTH.
It should rise to 30m which were set in the system but it stops this an flies directly descending home into a tree.
Here the video:
  

Service tells me that  there was a millisecond of signal back and during this I pulled the throttle sticks so that the going up to 30m was aborted.
For sure after this millisecond the RC-Signal was lost again and we could do nothing but just look how it destroys itself while descending into the tree.

Weren't the Drone in it's RTH Function supposed to stay at the actual height of 21m and fly to the start point at this height and after that start descending?
The Manual shows a behavior like this but service guys try to tell me no everything is normal and my fault!!???


This is BS and I have lost my drone due to this BS.
I wanted to sell it to buy a new phantom 4 pro, but now I just have a piece of crap and DJI Support left me an my own.

Is this service? Is this the way they proceed with customers?
It this regular behavior of a drone during RTH? Even if the picture in the manual tells/shows something else?

Hi Christoph... thats horrible!  Sorry you lost your drone.  I hate to see footage of a crash, must have been shocking to you to watch your drone try to munch a tree.

As part of my learning all about the P4, I've initiated RTH a few times now and have never seen it lose altitude while returning.  It seems to do a great job keeping its altitude.  Not sure if this could contribute to the problem you had, but your RTH was initiated over crashing waves... possibly the drone had a hard time assessing its height accurately?  If you did tap your sticks after RTH was initiated, that could definitely cause the bird to not go to its pre-defined height.  I also have to say though, if your drone was 21 meters up when it hit the tree, I don't think it would have cleared the tree at 30m.  I usually give my drone quite a bit of safety space above trees and I probably would have set the RTH height to 50 meters.  Did you not regain control at all when the drone was in RTH?  If you had no communication between the drone and the RC, it seems a bit weird that touching the stick would cause the bird to abort its 30m preset height.

Sorry to hear about your loss Christoph.

The aircraft will stop ascending above 20m (When in RTH mode) if it has detected the left stick is operated at all. And it will RTH at the height it was when stick operated. That height of course being relative to the home point.
Any drop in height might be attributed to sensors needing calibration, or barometer error. In saying that the Obstacle Avoidance seems to detect the tree, as the aircraft stops and then rises as if trying to get over the obstacle. Unfortunately it hit a branch at that point.

Perhaps one of the moderators could have a second look at this for you. It might not change anything, but I have seen cases where a second opinion has worked in the favour of the customer.

There might be something interesting in the log files if you post them, but to me this looks correct behaviour.   RTH on loosing the connection is correct, cancelling the RTH above 20m when using the throttle is correct, unlucky in this case but it is correct and often desirable, stopping to avoid the tree was correct, rising to fly over the tree was correct, the tree having an overhanging branch that the propeller hit was unfortunate but not DJI's fault or your fault.

Even the P4P doesn't have upwards obstacle sensors to avoid overhanging branches.   I do think the P4 could when encountering the tree could have turned around, backtracked for 10m, gone up 10m and then tried to fly over the tree again, but that is not what it does and that would introduce other potential problems, maybe tree avoidance will be improved in future.   Also, maybe DJI could disable the controls for a short while after loosing connection to avoid accidently cancelling RTH.

So I think this was an accident, should be covered by insurance.  If you fly a drone without insurance then you take the risk yourself.

Thanks for posting the video, we can all learn and then fly safer by seeing what can go wrong.  Following the rules for keeping the drone in sight at all times would presumably have avoided this accident?

Hmmm, so the picture in the manual is misleading!?
It shows the drone keeps it height while RTH but eventually it doesn't!

My drone initiated RTH at 21m and was constantly descending. It was at 16m when it hit the tree.
If it would have stayed at its 21m while RTH I would have passed the tree without any problems.

Thanks to this misleading picture I trusted it would behave like this!

But it seems that all DJI-Products behave in such cases more like:


That is BS and I guess DJI should be at least so fair to send an Info regarding this to all customers and change the manual.
Otherwise maybe I should do their job and share this in all forums and tests of their products.

I am happy to be the guy to pay for this info with my money and my precious time, so that others will know about it........NOT!
I am really pissed!

Christoph_Li Posted at 2016-12-1 14:04
Hmmm, so the picture in the manual is misleading!?
It shows the drone keeps it height while RTH but ...

"My drone initiated RTH at 21m and was constantly descending. It was at 16m when it hit the tree."
What evidence do you have that it descended by 5m?

Watching the video, it appears to keep about the same height, although the ground level increases as you go up the beach so height above ground decreases...

If you upload the log file then we will be able to see more clearly what happened: http://www.phantomhelp.com/LogViewer/Upload/

Unless there was an actual malfunction, then you allowed it to fly into the tree and that would not be DJI's fault.  

Sorry for your loss dude. It is annoying to think a millisecond of a control movement done this. How bad is the drone.... totally un-repairable?

Christoph_Li Posted at 2016-12-1 15:04
Hmmm, so the picture in the manual is misleading!?
It shows the drone keeps it height while RTH but ...

You seem to have been unlucky, but if you did touch left stick down that looks like it caused your problem, also as ardvark said the OA did kick in but when trying to ascend to avoid the tree it just clipped over hanging branches and crashed,
My advice is to talk nicely to dji Ken you might have a small case the way OA worked , but it's worth a try, moderators are very sympathetic to these sort of problems, particularly if you are receptive to them..
Good luck..

DAMN !! It's a Drone NOT a Weed Whacker dude....."Brrrrrrrrrrrruuuupp!!! Too bad there's no audio. Lol. Really sorry honest. You know I NEVER liked the whole auto pilot thing at all. I used RTH once when I first started flying and I lost sight of the drone for the first time behind some big pine trees. Panicked and hit the button but felt more panic when I realized I had not updated my Home point. I dunno I cancelled it and haven't used it since. ESPECIALLY over water or a long way out. Also wonder about what sensors you had enabled when it happened. If I even THINK I am gonna be over marshes or open water I disable ALL downward AND horizontal avoidance systems etc. The Compass and Attitude/GPS sensors should be EVERYONE'S most intimate flight instruments. An odd reflection of sonar/radar or visual sensors etc. has caused many crashes from what I have heard and WHY the hell would I entrust them further by turning total control over to them.

Hi again Christoph, Hallmark gave you some great advice by advising you to play nice with the moderators in this forum.  I've been in this forum for quite a while now (this is the first time I've seen your name) and I can tell you without any hesitation, that you will do MUCH better in this forum if you show courtesy and kindness to the moderators.  They didn't cause your crash, and they REALLY DO try to help. So be very careful not to flame out on them or you will lose their support.  They are humans too and if you want their help (which you really do), be sure to treat them like people that are trying to help.

I'm sorry to hear. If I could get your case number from the Europe Support Center, I can try to get any additional information for you.

Nigel_ Posted at 2016-12-1 16:54
"My drone initiated RTH at 21m and was constantly descending. It was at 16m when it hit the tree." ...

Good Morning @ all and thanks for the replies and your commiseration so far.

I know I may sound a little bit pissed. That's because I am due to the behavior of the german service.

But I don't want to blame anyone here or there for the problems and I am trying to be as kind as possible in such an situation. Sorry if it sometimes seems to be unkind. Its not my intention. But here is something very wrong regarding the drone behavior and also there is a ambiguity in the Users manual leading to misunderstandings in the functionality / capabilities of the drone.

I have the Evidence that it was descending out of my displayed height in the app, out of the record and also the flight logs:
http://www.phantomhelp.com/LogViewer/5F4228CO1QXS1XWEMNL6/#

The complete LOG-Dat out of the drone was uploaded here:
https://we.tl/3VAourJcAi

The beach is also quite flat, at least there is no gap of 4-5m ............

@ DJI-Jamie.
Thanks for your help. Unfortunately this is a little bit more complicated. At the Moment I do not have a case number, because I refused until now to send back the wrecked drone to the german service center.

This has a few reasons but the strongest reason is... lets say the service center in Germany has not the best reputation out of the experience of many many users well documented on the internet.
They always first say send it in and then they charge money for the repair or give customers false promises etc...
Don't misunderstand me I don't want to make any  unjustified bashing of anybody, I had a long discussion with them, at the beginning very friendly.

But from the first moment on I just wanted to have one info:
Is this a regular behavior of the drone during RTH descending in height?

They said send us the drone for further analysys.
I said I will do this after they give me a first feedback and arguments what they expect to extract more out of the damage drone then the data provided so far? If there is any more analyzable data I would like to get the info so I can backup it for me too before I give away my only evidence... the drone.

I have send them all information's, videos, synced my account, send the Log-Dat-file etc......
They still did not respond to my request/question regarding the unusual descending behavior during RTH.

Then I told them hey, just send me your report draft and your findings so far out of all my data and then I will send them the maybe the drone.
Their answer was suddenly that it was an operator error and that its my fault and I would have to pay for the repair....because I had short time connection back and pulled the stick.

Sorry but for what reason did they even ask me to send it back when they already new that it was my error? For charging me money for the repair?

If a short touch of the stick stops the drone from ascending during RTH (which is some kind of normal behavior of every user when he looses connection, trying to see if he gets it back by touching the sticks!!!???) and lets it start RTH directly descending and ignoring any height limitations, then something has to be rethought by the designers/ software programmers or this whole function and praying down -> adjust a correct RTH-height before flight is some kind of useless.
And at the same time they can also update their completely unclear user manual which led to this problem/misunderstanding.
And as a last point they should inform every owner of a DJI Drone that their drone shows this behavior deviating to the manual description.

I am now just the guy with bad luck loosing its drone due to this.
Maybe further generations will have more luck with updated Software/user manuals! Me not!

donogl Posted at 2016-12-2 07:12
Good Morning @ all and thanks for the replies and your commiseration so far.

I know I may sound  ...

The logfile suggests that very shortly after it started Home, you pulled the throttle down telling it to descend and kept it pulled down until after the crash and it was lying on the ground.

There are big bits of log missing as there was no communication, so it is hard to work out exactly what happened and maybe that interpretation is wrong.  To help try and understand the log correctly, can you explain why the throttle is held down during the last 17 seconds of log records while the aircraft was returning home and after the crash?   Or maybe it wasn't and the log is wrong?   Or maybe I am reading the log wrong?

Hi Nigel_,
thanks for the answer. Does the log say exactly this?
I have never seen those information'snor has the german support told me something like this.
That is very interesting.

I have the Drone since it`s launch and I was one of the first guys receiving it.
Since then I have made a lot of flights and would say I am not a noob in drone flying since I was also already flying drones before.

I would never pull down the Stick over 17 Seconds in a row because I lost connection. Maybe I forgot that I fell asleep and pulled the stick with my nose?
That must be some kind of wrong data or signal from the Remote Control.

donogl Posted at 2016-12-2 13:57
Hi Nigel_,
thanks for the answer. Does the log say exactly this?
I have never seen those informati ...

The data is incomplete so I can't see that you held the throttle down for 17 seconds continuous, only that all the entries in the last 17 seconds show it pulled down.   Possibly after you lost the connection you held the control in one hand and accidently pushed the throttle while running to see what happened?

Just trying to understand the data and find an explanation, not placing blame anywhere, yet...

I can tell for sure that the stick was not pulled downwards the whole time even due to the shocking situation...... .

donogl Posted at 2016-12-2 14:18
I can tell for sure that the stick was not pulled downwards the whole time even due to the shocking  ...

If your aircraft can still be powered up you may be able to download a copy of the .dat file from the P4 using DJI Assistant 2 which DJI could perhaps analyse and make a decision. Or at least you could keep a copy for your own records before sending in.

I have already Uploadet the dat. File.
The Link is somewere above in an older Post

The data is in the lower right hand corner for the stick movements. Under throttle you can see the command for throttle down right after return to home started. :/ This is what DJI was talking about when they said that you sent a command.. Hopefully they can find more data from the aircraft that shows interference.

Mobilcams Posted at 2016-12-2 23:37
The data is in the lower right hand corner for the stick movements. Under throttle you can see the c ...

It does look like it was sent the command and the value changes as though the stick was being moved a little while being held part down.

I don't see anything else unusual.

I'm not sure the command is actually relevant to the outcome anyway.  The issue is that it met a tree, tried to fly up and over but got caught on an overhanging branch.  Unfortunate, but it is an accident and not a fault so it is an issue for insurance not warrantee.   Flying out of signal range, behind hills/buildings/trees etc is risky.

This is not OK. I still did not command the drone to descend during RTH so it would have Not hit the branch.

So thats it?
My fault?
Drone descending during RTH?
Useless function and completely misleading user manual!

So that's it.
DJI Drones behave like this!
Thanks for the Info..............

donogl Posted at 2016-12-5 10:09
So that's it.
DJI Drones behave like this!
Thanks for the Info..............

As far as I can see from the log and the video, the aircraft behaved as described in the user manual.  

DJI appears to have come to the same conclusion, and they are able to see the complete log since they can decode the big log from the aircraft.

Many people use the RTH function successfully and the obstacle avoidance has brought many aircraft back safely when otherwise they would have had an accident, but we all know that it isn't infallible, especially when it comes to trees with overhanging branches.

We can't expect DJI to replace every aircraft that is involved in an accident under warrantee if there was no actual fault, they offer optional insurance to cover that.

"So that's it."
What more are you expecting?

I was expecting a statement that the drone is not supposed to descend during RTH because that is not described in the manual etc.....
I did not command the drone to descend and if it would have behaved like shown/written in the manual (keeping the same height during RTH) then the drone would be 5m higher when reaching the tree and then with OA it would have passed it without a crash.

Again, I never commanded it to sink and I never hold the throttle stick downwards for all the time!!??
Why should I do this???

But Hey it`s OK.
I just can learn for myself that some kind of magic/mysterious ghost signal can appear and kill my DJI-Drones at any time and that I should just safe the money and become the beta-tester of another Drone-manufacturer.
Thanks and Bye!

donogl Posted at 2016-12-5 23:02
I was expecting a statement that the drone is not supposed to descend during RTH because that is not described in the manual etc.....
I did not command the drone to descend .

The phantom will always accept stick commands during an RTH scenario where is a active radio connection. I guess you were in the unfortunate situation you were already just past the 20m mark and that connection was restored very quickly away after RTH was initiated and you didn't notice the app message. The manual (whilst I agree could be clearer) does actually state as much.

As to whether you did or didn't pull down the throttle I won't speculate about what may have actually happened, the only thing that DJI has to go by are the logs.

So it does not react to my command to abort RTH because of no connection but it does react to stick commands I never made because there was some mysterious form of connection only accepting imaginary throttle down commands which I allegedly made constantly over a long time.

The Story is getting better and better. :-)
Maybe Aliens from mars came down and tried to steal my phantom?

Hey guys its OK. Lets stop the discussion here, it just steals my nerves.......
I learned for myself never to buy a DJI Product again and that's it.
Expensive lesson learned!

Nevertheless thanks for the Help/Answers, even if they are very unsatisfying.

How bad is the damage, if do not mind me asking?

donogl Posted at 2016-12-5 02:09
So that's it.
DJI Drones behave like this!
Thanks for the Info..............

Dude....donogl! What's you're deal man? You have been throwing a tantrum since your first post. Go back and read what you've posted and tell me how you sound. I understand how you feel...everyone on this forum understands...and they have all been trying to help you out. A couple posts even nicely told you to change your whiny-baby attitude. Its not even that you're a jerk, its that you sound like a tantrum throwing little baby. Do you not understand that everyone here is your friend? Do you not understand that everyone here would like to help you...which includes many individuals associated with DJI that could help you out considerably, if not in terms of a straight up return, at least in terms if getting the phantom fixed. Suck it up, buttercup! Act like an adult...strive for maturity. The bottom line is that you pulled down on the throttle stick. I know it, you know it, everyone else knows it. And, they were still offering to help. But you just can't keep it together. Come on, man...knock it off. You're embarrassing yourself. Breathe. Think about how you're gonna feel about your behavior during this incident a month or three from now. You can look back and be proud of how you handled a horrible situation, or you can look back with embarrassment. Also, think about how your tantrums and shitty attitude affect everyone else offering to help you. Behaving like that, no one wants anything to do with you.
In light of my rather harsh lecture (that you didn't ask for, I know), I feel horrible about your situation and hope that your drone gets fixed and back in the air soon. The way you treat others will likely have a big role in how all of this plays out.

fansae514b87 Posted at 2016-12-7 00:08
How bad is the damage, if do not mind me asking?

Props and one wing/Body Is Broken and deformed. One Motor is completely defect and not turntable by hand.
Electronical problems with GPS and with defective electronical contacts...... etc.
After hitting a rock falling down 16m it fell inside the Sand/Beach and all engines and the whole drone is full of sand.......

@ Fleabus
Dude......! Whats your problem?
I always learned on the internet to not feed the trolls but ........
I can go back over and over again and the only thing I see is that I never offended anybody here... called nobody a jerk....... in contrast to you. Maybe you should go back and reread this whole thing?
Or at least rethink your behavior before you comment the behavior of other people?

Just because I start laughing about the explanations here does not mean that I am offending anybody here.
Like I wrote in my last post before I wanted to end the discussion here was: Thanks for the support/answers even if unsatisfying.  

I could also start really become a whiny baby but for what? I would have every reason after being ripped.
But the only thing I am posting here over and over again are facts and questions.

Fact No.1: My Drone descended during RTH and that was not commanded and that was the reason for the crash!
Fact No.2: I never commanded it to descent nor have I ever hold the throttle stick downwards for the whole time while RTH
Fact No.3: I do know that I did not hold it down because this would make no sense! Its nice that you seem to have other information's and you can speak for all others that you know I was holding it down. Did I miss something and you were with me on vacation in Thailand, standing beside me when the accident appeared?

But for sure it is impossible that the drone was descending on its own, like this Posts/Problems here are impossible that the drones ascent during RTH by themselves:
http://www.phantompilots.com/thr ... ou-seeing-it.97645/

Quote:
"Just did a flight and reset my units to imperial for easy comparisons. RTH altitude set at 130 feet. I tested RTH three times as follows;

1) I hit RTH at 500 feet away at 35 feet altitude. The craft climbed to 130 feet flew back to home at 130 feet and landed.
2) I hit RTH at 950 feet away at 80 feet altitude. The craft climbed to 130 feet flew back to home at 130 feet and landed.
3) I hit RTH at 2100 feet away at 80 feet altitude. The craft climbed to 130 feet, started back home but continued to climb to about 260 feet until about 1000 feet away then began descending until it hit 130 feet above the home point then landed.
EDIT- more data
4) I hit RTH at 5400 feet away at 100 feet altitude. The craft climbed to 130 feet, started back home but continued to climb to about 800 feet until about 2000 feet away then began descending until it hit 130 feet above the home point then landed.
5) I hit RTH at 5400 feet away at 100 feet altitude. The craft climbed to 130 feet, started back home but continued to climb to about 600 feet until about 1500 feet away then began descending until it hit 130 feet above the home point then landed. This time I had the RTH obstacle avoidance box unchecked. I had control of the camera tilt on the trip back to home. "

My drone was also over 1000ft away. Maybe it has something to do with this?

What's your explanation for this? I guess you know this too and were standing beside those guys when their drones started rising high up to the sky without the command?

@ DJI-Admins here:
I am still asking here for support and comparison of the cases ascending/descending during RTH.
At least I would like to see the throttle stick commands records of the people with the ascending during RTH Problem out of your analysis to confirm that their records show no signal changes while the drone is rising...
Thanks in advance for the support!