* I'm reposting this as it doesn't seem to have appeared in the forums? I did have a link to the logs, maybe that stopped it? While flying yesteray, we walked across a field, decided to test how well the RTH worked and for some reason the P4 decided RTH should be 2 miles South of me! Cancelled the RTH so I could take control. The P4 then decided that it was now outside of my 'distance limit' in the app and that IT would keep heading South away from me regardless. With the bird facing me, even on full throttle it continued to head South, it responded to controls but always with a 5mph drift to the South. I got scared as it was heading towards water, so increased altitude so that the VPS wouldn't get confused. Still the drift to the South. Amazingly I got her down, though landed I assume with that 5mph drift Southbound, metres away from trees that it would have hit. No signs of visible damage but it did flip over on landing in the grass. If someone could go through the logs and tell me do I have a defective P4, is it a software bug, or was it pilot error? Rather worried in case this happens again, Conditions were excellent with only a very slight breeze. Is there a way of playing back the csv log for you guys like it does in the GO app? I can  would like others to see this too. All input appreciated, thanks.

Post the link to the logs..

Without flight data it's not possible to do more than just guess.
Go to http://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.

Come back and post a link to the report it provides and some of the experienced people here will probably be able to analyse it and give you an understanding of the cause of the incident

Hello, I'd suggest you to download your flight data from the drone and send them to support.eu@dji.com for the data analysis. Besides, you can also post the flight record (txt file) here.

Same thing happened to me, except the pull was greater than the throttle and no matter how I throttled forward, it continued backwards into a wall. Uploading my log revealed no problems with any systems.

FatedFilmsNC Posted at 2016-5-6 11:28
Same thing happened to me, except the pull was greater than the throttle and no matter how I throttl ...

Same here dude, forward Throttle pointing North and P4 continued South at a stead 5mph. I could move to the East and the West, but always with the same consistent 5mph drag. It WOULD let me move South and did indeed increase speed when I tested, so controls were being received and understood by the drone. Flying North was a no no - always South and always at 5mph it seemed. Only happened after the RTH signal - which I cancelled but was ignored (even though logs show it was cancelled).

Because it thought it was over the 500m set in the DJI Go App the drone just took over, removing full control from the pilot. it was just over 300ft away from take off point, probably only 120ft away from me, but the logs within .1 of a second jump to 6000ft away! No transmission errors, not out of range.

My logs were scary, but at least to me, playing it back seems like I handled it very well and not any pilot error. I'm guessing we can't post logs here since my previous post never seemed to appear publicly :/

Your logs, did a similar thing happen, i.e with the RTH, or drone thinking it was too far away?

DJI-Paladin Posted at 2016-5-6 11:26
Hello, I'd suggest you to download your flight data from the drone and send them to support.eu@dji.c ...

http://www.phantomhelp.com/LogViewer/7J1E3C902VV422TRNRII/

I'll also send them off to the email address you suggest, any reason why my previous thread on this didn't appear?

calls4u2 Posted at 2016-5-6 18:50
http://www.phantomhelp.com/LogViewer/7J1E3C902VV422TRNRII/

I'll also send them off to the email a ...

When did you post your previous thread? What was the thread's name?

DJI-Paladin Posted at 2016-5-6 11:56
When did you post your previous thread? What was the thread's name?

Just this morning, but when I went browsing the forums it never showed anywhere, only had my views counted. http://forum.dji.com/thread-51723-1-1.html

Thanks Paladin, I'd appreciate any advice on this, if you saw the flight logs you'll see that I was very lucky, I'm concerned this is a safety issue, but one that should be easily remedied in firmware/app.

I'm using current firmware. DJI Go app had an automatic update only yesterday - flights previous to that were excellent.

calls4u2 Posted at 2016-5-6 19:06
Just this morning, but when I went browsing the forums it never showed anywhere, only had my views ...

The link works now.

calls4u2 Posted at 2016-5-6 20:50
http://www.phantomhelp.com/LogViewer/7J1E3C902VV422TRNRII/

I'll also send them off to the email a ...

At 10:12 ... home point has reset and distance from home jumped from 337 ft to 6980 ft.
This is the critical point.
WIth the Phantom you can only reset home to either the aircraft's current location or the current location of the controller.
But the new home point is nowhere near either of these possibilities.
The big mystery is, how did this happen as it's not something you can do yourself?

If you play back the flight record in the app you will see the new home point and where it is.

There is no record of RTH ever initiating or being cancelled.
Have you practised with RTH before to know how to properly activate RTH?  Was it beeping to acknowledge that RTH was happening?
The flight record indicates that your Phantom was in P-GPS mode the whole time so there's no hint of it drifting away in atti mode.

It will be interesting to find out what DJI's explanation is.
What caused the home point to jump?
Why did the Phantom not respond to your control  inputs?
What made the Phantom go further south? - there was no RTH operating.
You'll have to upload the full flight record from the  Phantom to DJI so they can analyse it.

labroides@yahoo Posted at 2016-5-6 12:26
At 10:12 ... home point has reset and distance from home jumped from 337 ft to 6980 ft.
This is the ...

My guess is that returning to controller point (which I selected as I'd walked across the field towards the drone) got a wrong GPS co-ordinate. That would explain the RTH heading South. The wrong GPS co-ordinates *could* have been due to a pesky wind farm 2 miles to the North?

The big issue here is why the drone would not allow me full control to head North (towards me). No matter what I did, which orientation or how hard I pushed her there was a 5mph Southern drift. My guess is that the distance setting FORCES the drone to RTH (or wherever it thinks home may be!). I had control in all other directions however, thankfully! (You see how I increased altitude when I noticed it going near water).

Perhaps in ALL automated functions there should be a button on controller (we have 2 we can set) that cancels that. Some have suggested I should have switched to ATTI mode, and in retrospect *perhaps* that would have worked, but not having flown the P4 in ATTI mode yet I'd rather do many test flights before using it in a scenario like the above.

Is there anywhere we can upload logs to that would show the same map playback view as the DJI Go app shows me - with controller movements etc? I've analysed the data in a spreadsheet but it'll take more for me to understand the raw data fully.

labroides@yahoo Posted at 2016-5-6 12:26
At 10:12 ... home point has reset and distance from home jumped from 337 ft to 6980 ft.
This is the ...

I'm pretty sure I tried activating RTH manually, maybe that was another command ignored? The logs show more details if viewed as CSV, but awkward to interpret.

IF no RTH was initiated or cancelled then it's obviously something that tells the drone to simply take over (due in this case to it falsely assuming it could travel at the speed of light and get 2 miles away in .1 seconds!)

Anyway it was a bug, the distance has jumped to 6000+ within seconds. DJI need to investigate this.

calls4u2 Posted at 2016-5-6 21:44
My guess is that returning to controller point (which I selected as I'd walked across the field to ...

Lots of guesses there and not many are correct.
A temporary GPS glitch would show uour Phantom a long way from where it was but not change the home point.
The GPS knew where the Phantom was at all times as shown on the map display.
The wind farm 2 miles away didn't cause any GPS issues.

The flight record doesn't indicate that your Phantom was returning to the new home point.
There is no RTH mode in the record.

Atti mode might or might not have been helpful - it's hard to know.
If I was ever presented with a similar situation, I'd want to try resetting home to the location of the controller.
Or if that wasn't possible, reset to the current aircraft location.
If you have a max distance setting and home jumps,  making your Phantom believe it is at  or beyond the  max distance, that's going to make it hard to come home without changing something.

And last ... RTH is one of the  most important  things to learn when you fly a Phantom.
The time you want RTH is not the time to learn.
You have to know how to activate RTH and know it is or isn't working.
There are  3 pages on RH  in the manual and reading and understanding should be compulsory along with practising RTH in a large open area so you know what to expect and how to set RTH and how to cancel.

labroides@yahoo Posted at 2016-5-6 13:08
Lots of guesses there and not many are correct.
A temporary GPS glitch would show uour Phantom a l ...

I've used RTH several times, though each time I've only let it return, then landed the craft manually - Some of the videos I've seen of RTH and autolanding look a little too fast and hard to me. Manual is always in my bag with me, have actually read through the whole thing - probably read again now as I'll understand better!

Only thing different this time was I used RTH button on the controller instead of the app? Since it's not in the log you're making me wonder if it was indeed during *this* flight, I'm pretty sure it was though!

At the time I wasn't even aware the homepoint had changed, when I reviewed the flightlog and couldn't see the RTH point. I zoomed out and there it was! Had I realised I'd have *tried* to reset the home point manually (must find where in the app in case that ever happens again).

I'd like to see DJI's input on this too, as a programmer, debugger, and a guy who spends his days fixing tech stuff, together we can make these things even better!

Anyone who wants to comment on the logs though is very welcome, constructive criticism, tips, etc.. again most welcome and will hopefully help others too.

calls4u2 Posted at 2016-5-6 22:31
I've used RTH several times, though each time I've only let it return, then landed the craft manua ...

It's very common for flyers that haven't practised RTH to have difficulty initiating RTH with the controller button.
You have to press and hold and you get an audible confirmation beeping so you know it's working.
Press again and it cancels.
But if you simply just press the button quickly nothing happens.

Your new home point is exactly 2.2 kms in Simonburn Lane, due south of your original home.
How this jumped is a critical question as it would be impossible for you to have manually reset to a place you and the Phantom are well away from.

calls4u2 Posted at 2016-5-6 06:46
Same here dude, forward Throttle pointing North and P4 continued South at a stead 5mph. I could mo ...

Mine happened during normal flight, about 30 seconds after take off. I am however noticing (on my and other peoples videos) that their distance away in the app DOES NOT equal the true distance away from home point, heck, it says im already 20ft from takeoff point...before starting the motors. This is a common, but very underreported issue. Next time you fly, check to see what your distance meter says before you takeoff, as it is probably saying you are traveling while the drone is still on the ground. I thought this had something to do with the compass or IMU, so i recalibratedboth, but its still happening. I implore everybody to check this next time you fly and report back here if your distance stays at 0ft. before takeoff, or if it jumps around distances, like ive seen on many peoples flight logs. I really dont think anybody has really taken notice to this.

FatedFilmsNC Posted at 2016-5-6 22:50
Mine happened during normal flight, about 30 seconds after take off. I am however noticing (on my  ...

You  are probably noticing the small and variable position error that is a feature of consumer GPS.
The  GPS location is always changing slightly, but mostly within 1-2 metres.
20 feet is possible but this would be uncommon.
It's not possible to correct this but it makes no difference to your Phantom flying.

labroides@yahoo Posted at 2016-5-6 13:38
It's very common for flyers that haven't practised RTH to have difficulty initiating RTH with the  ...

Looks like you right then, I need to reread that manual - I'm not gonna claim to understand everything in there on first read, I hadn't even flown at that point!

So I *didn't* inititate a return to home so that's even more worrying, I do see the home point updated in the logs however, and the rest of the story is detailed in my earlier posts, to summarise, drone though home was 2 miles from my position and wouldn't respond properly as autopilot wanted to take it there regardless of input.

I've not heard anything back from DJI yet, was kinda hoping they'd be onto it and replied, even for additional info as to exactly what the variables were at play here for debugging purposes.

I've just spoken to a guy who did stuff he can't talk about with regard to GPS/Sonar/Radar etc.. Wind turbines wouldn't throw GPS off as there is far too much redundancy built into GPS, as the logs show there are plenty of sats (17) visible.

Short of someone beaming a fake GPS signal at me or the drone this shouldn't have happened. As for the drone refusing my commands, well...

Same guy is also a software developer and from point of programming, it shouldn't be too hard to have an algorithm so it knows that home point (or drone point) can't fluctuate beyond x (y or z) distance per second so it should know somethings wrong. My suggestion would be it stops, hovers, and awaits command - unless the battery is going flat and it needs to descend.

Anyone else care to look at those logs and give me some input? Sadly although conditions looked very good this morning I was too worried about it so went to work instead of flying :p
Logs: http://www.phantomhelp.com/LogViewer/7J1E3C902VV422TRNRII/

DJI-Paladin Posted at 2016-5-6 11:56
When did you post your previous thread? What was the thread's name?

I have an email from DJI asking for more info, how do I get my app username, it's likely just my email address yeah?

Sounds like compass error to me??

R&L Aerial  Posted at 2016-5-7 05:21
Sounds like compass error to me??

This has nothing to do with a compass error.
We've pinpointed the issue (homepoint changed to somewhere two kilometres away and max distance setting would not allow the Phantom to be flown further from the new home point).
The compass can't change your recorded home point and a compass error causes the Phantom to fly curves rather than straight lines - not to fly off to somewhere else.

calls4u2 Posted at 2016-5-7 00:51
Looks like you right then, I need to reread that manual - I'm not gonna claim to understand everyth ...

"drone thought home was 2 kilometres from my position and wouldn't respond properly as autopilot wanted to take it there regardless of input."

Almost ... as there was no RTH operating, the Phantom was not trying to go to the new home like it would have if you had initiated RTH.
But the max distance setting wouldn't allow the Phantom to be flown any further away from its new home location (toward the original home location).
This accounts for the control difficulty.
The cure would have been to disable max distance and manually fly it back ... or reset home to where you were ... or to reset to the Phantom's location and manually fly it back.

The main question is why did the home point jump?

labroides@yahoo Posted at 2016-5-6 16:11
This has nothing to do with a compass error.
We've pinpointed the issue (homepoint changed to some ...

Good day mate, say what you will but most flyaways are compass related. From what I've read in the first post in this thread a phantom 4 flew away.

labroides@yahoo Posted at 2016-5-6 21:15
"drone thought home was 2 kilometres from my position and wouldn't respond properly as autopilot w ...

I've seen a couple similar events in the Phantom 3 forum with home points changing mid flight.

Back in January, flying a P3, I was somewhere I really didn't want to get much out of a 50m radius and set the maximum flight distance to 50m. I then decided I did want to go a little further and found that the maximum safe distance couldn't be changed mid flight - I had to land and shut down the motors. If this is still the case, I'm fearful we lose control should the phantom's home point change mid-flight sufficiently to take it beyond maximum safe distance from the new home point. Scary....

R&L Aerial  Posted at 2016-5-7 06:24
Good day mate, say what you will but most flyaways are compass related. From what I've read in the ...

1.  Most "flyaways" aren't flyaways
2.  Just read my analysis in this thread and it explains exactly what happened.  
There is no indication anywhere in the flight record that there was any compass related problem.

The compass is poorly understood by many flyers and gets blamed for many more things than it is responsible for.

labroides@yahoo Posted at 2016-5-6 17:06
1.  Most "flyaways" aren't flyaways
2.  Just read my analysis in this thread and it explains exactl ...

According to DJI ken ALL flyaways are pilot error. Or maybe it was DJI Tim? He said he's never heard of a properly set up quad flyaway.

What type of tablet are you using?  It sounds like the device passed bad position data when you tried to reset the home point to the current controller positoon.  Because the new home point was due South of the old home point. it sounds like Longitude was passed correctly but Latitude had an error.  The error is very close to .02 degrees of latitude.

I want to see what DJI has to say about this just reading this scares the life out of me.

projeffrey11 Posted at 2016-5-7 07:30
I want to see what DJI has to say about this just reading this scares the life out of me.

Me too! Having the home point change mid flight  to a location outside your maximum flying distance is akin to a black hole popping up to suck the aircraft into!

I had this happen 2 times tonight. On the first flight the p4 was up 200 feet and I flew about 800 feet away when I switched to sport mode and tried to bring it back it just stayed in one place. I switched out of sport and it still would not move then started drifting to the north. at this point the controller lost signal and RTH was initiated. when signal came back it was still drifting slowly and acted like it wanted to respond and would start to but then couldn't and just kept drifting to the north. it finally hit critical battery level and landed itself safely in the middle of the road where i found it. however the flight log shows when it landed that it was still above 500 feet. Kansas is flat as can be and I can assure you the street i live on is only a couple feet higher or lower than where it landed.

I brought it home and put in a new battery and powered up and all my settings in the app were off from where i had them. for instance it was measuring in metric again and the sensors were all turned off. I set them back to normal and took off. I was in normal mode and all was good. at just over 400 feet up and 1000 feet away I switched to sport mode again and it stopped responding and started to drift. I tried to bring it down or back and it would do nothing I could climb and turn in circles that was all. again RTH did not work and it drifted north. I got in the car again and went after it and it landed in the parking lot of the grocery store.

I am not sure how it could be pilot error on all of these when even the RTH won't bring it back. I have a p3 professional and when I fly it I have never had an issue.

jstjohnz Posted at 2016-5-7 12:51
What type of tablet are you using?  It sounds like the device passed bad position data when you trie ...

But he didn't reset home point at all - that was a surprise that the Phantom threw at him.
And the new home point was exactly (magnetic) south so the longitude is not the same as the original home point.

Everayla Posted at 2016-5-7 17:26
I had this happen 2 times tonight. On the first flight the p4 was up 200 feet and I flew about 800 f ...

Interesting - post your flight data anad I can analyse it to see if what happened was similar.

Go to http://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.
Come back and post a link to the report it provides

labroides@yahoo Posted at 2016-5-7 02:59
Interesting - post your flight data anad I can analyse it to see if what happened was similar.

Go ...

Log 1Log 2
Hope I did this right.

Seems a few similar threads online part day or two. My go app updated the day it happened to me, maybe something there? Definitely think we'll be getting an update to app/firmware soon. I'm gonna go check the change log for the app.

Everayla Posted at 2016-5-7 17:26
I had this happen 2 times tonight. On the first flight the p4 was up 200 feet and I flew about 800 f ...

I had a look at the first flight and to clear up a few things ...
Your home point did not jump - It stayed the same for the whole flight.
The flight data doesn't show landing above 500 feet.
It ends with 25% battery at a height of 616 feet and the Phantom hasn't descended.  After signal was lost, the Phantom must have descended but there is no record for this part of the flight.

The explanation for the flight isn't obvious and I've had to guess a little to come up with something that may explain what happened.
I'm wondering what the wind was doing?
When RTH initiated at 6:14 the Phantom was 620 feet up and was only making 3-4 mph and travelling NW in a straight line.

620 feet is a long way up and the wind up that high would have been significantly stronger than at ground level.
RTH is slower than normal flight (22mph)
If the wind at that level was around 25 mph and from the southeast, that would explain the Phantom appearing to drift to the NW.

Staying up at 620 feet, your Phantom was exposed to high winds and in RTH it could not travel fast enough to get home.

The solution would have been to be aware of the wind strength and direction and not send the Phantom so high.
For RTH you should have brought it down lower where there was less wind and/or taken over and flown it yourself faster than RTH.
Disabling the object avoidance will allow your Phantom to do about 35 mph in GPS mode - about 50% faster than with it on.

labroides@yahoo Posted at 2016-5-7 13:38
I had a look at the first flight and to clear up a few things ...
Your home point did not jump - I ...

Out of interest labroides, in RTH mode, if the altitude is higher than your set RTH altitude, which takes precedence? I'm assuming it'll fly above you and then descend, which is the opposite of if you're below your 'safe' RTH altitude? OR will it try diagonals if it's higher?

Any opinion on my logs as to what I (personally) could have done better to control what happened with mine?

Incidentally, is there a current way of playing back flight logs on computer the same way the app does it on tablet/phone?

calls4u2 Posted at 2016-5-7 23:37
Out of interest labroides, in RTH mode, if the altitude is higher than your set RTH altitude, whic ...

The Phantom will never descend to RTH.
If it is at or above RTH height, it will just com back at the height it  is.

I gave some ideas that might have worked in your situation up in post #24 above.

labroides@yahoo Posted at 2016-5-6 21:15
"drone thought home was 2 kilometres from my position and wouldn't respond properly as autopilot w ...

Ah yeah, thanks, I did see it

Concern is since it wasn't responding as would be expected, could I do any of those things? Is there something in the coding that if distance > limitset then only allow certain features? Is the limit setting ignored in A/S modes??

Can we change the max distance setting while the bird is in the air? i.e see some posts for older phantoms where you need to land and power down to change this?

Would it have honored any *new* RTH points since the bird thought it was so far from where it thought I was? (this would be same as someone glitching their way *beyond* what was set as a limit, which would also include altitude? - It's likely they've coded against such an occurrence?)

How would I reset the phantoms location? I've now enabled all multiple flight mode in the app, so manual flying enabled, Whether it would have let me change mode (even if enabled in the app) outside of the distance limit is something I don't want to test!

I think the home point jumped due to phone GPS, can think of no other explanation, and since the birds location seems VERY accurate, I would have to assume the GPS coding in the app and the bird would be the same. Okay maybe they tweaked it and introduced something - possible but not so likely.

Incidentally, I also tried the pause button while drifting, but didn't make any difference.

Thanks for your input labroides, I've also learned a bit from reading your other posts elsewhere, i.e compass calibration side effects etc

Looking forward to hearing what DJI has to say about the logs and what fixes could be implemented, most beginners/novices will set themselves limits, and they are the very people who would find it difficult in such a situation.