New to the forums, dji, drones, etc.  I'm pretty techy normally, but this is all new so please bear with me!

After unpacking and setting up the Mavic, connecting to controller/phone app, booting it up, turning on beginner mode, I started my first flight.



I waited for it to tell me there was a GPS lock, and performed the auto-take off.  I hovered around testing the controls, sensitivity etc in about a 5x5 movement area.  I had much more available to me, but that's all the space I covered.  

I then got a LOW BATTERY WARNING (nothing had charged, phone/controller/aircraft all were at 30% or less).  RETURN TO HOME took over due to low battery and the phone took off straight up about 20-30 ft. It then went relatively straight forward another 20-30 feet, into thin tree limbs.  I tried to take control back, but it was unresponsive and continued "testing" the forward direction into thin branches.  After 5 or so seconds of this and a propeller must have broke, and the drone came crashing to the ground.

2 broken propellers, and on of the rear arms broke.  The rear arm BROKE-broke to the point where it was hanging by some wires visible wires.  The break as what I can best describe as "the shoulder"

To see what happened, I pulled flight logs, via HD to get the image below.  I also installed DJI Assistant 2, DatCon, and Dashware.  I was able to pull the .dat file off, and used the other 2 to convert into a .txt and .csv file which I then was able to"view".  I have no clue what is happening in these files and what I'm truly looking at.

So after this mini-saga... I'm looking to learn to properly view the .dat file I pulled, as well as understand what went wrong (user error, firmware, etc).  If ANYONE can help that would be most appreciated!  The only conclusion I have been able to draw (which could be inaccurate) is that when the GPS lock for HOME was recorded, it actually interpreted the location to be in the trees in front of me instead of my true starting point.

The RED DOT is my marking of where I actually took off from.
The space between the house and trees is the deck, which I never left while I was in control.

A couple of things/lessons here:

what happened was you didn't read the manual.

Firstly sorry for your loss, however a couple of lessons learned here:

1. Always fly with charged batteries.
2. Always check the home point on the map when starting the motors, if it's wrong then don't fly.
3. When you get the low battery warning fly the aircraft back to home.

Did you set a height for RTH, what triggered RTH was it low battery, you have given very little information,  maybe a bit more would help understand exactly what happened.

Sorry to hear about your crash.

Other than putting it into BEGINNER mode, I didn't edit any settings.  Looking at the app now (DJI.GO.4 for Android), the critical battery warning shows -5%, and low battery warning shows 0%.

I've been running the simulator over and over here.  Nothing that I can do seems to re-create the issue.

The return to home should auto-land (descend only) if within 20 M.  At no point was I close 20 M from the true starting point.  Also, the map that I believe has inaccurate GPS data (image in OP)  also doesn't show a distance greater than 20 M.  I'm not sure why the return TO HOME was initiated at the power levels that I had, nor do I know why it would ASCEND when so close to the home point.

The total flight was no more than a minnute, take-off to crash.  And I was off the ground, and in-control for no more than 30-40 seconds.  In that time all I did was rotate the aircraft, and move forward a few feet.

Can anyone direct me to log data that would show the controller inputs etc?

fans628b7609 Posted at 2016-12-7 19:21
Firstly sorry for your loss, however a couple of lessons learned here:

1. Always fly with charged batteries.
2. Always check the home point on the map when starting the motors, if it's wrong then don't fly.
3. When you get the low battery warning fly the aircraft back to home.

Lessons learned.  but to respond to this.

1. Charged batteries, I assumed ~30% was enough to test take-off, obstacle avoidance (object 5 ft ahead), and then return to home.  According to the report above, it was triggered after only 43 seconds of flight time!

2. In beginner mode, it wouldn't allow me to take off until GPS lock occurred.  As soon as I hit take off, it notified me of this, then within seconds it notified me that GPS was locked and home point recorded, then it continued the auto-takeoff procedure.  I did assume (I know what they say about ASSUME), that it was accurate, and didn't have more than 30-45 seconds to determine this.  It did appear that GPS was accurate to about 10 M looking back at the report I was able to pull from HD.

3. Low battery warning took over, and the aircraft that was no more than 5 ft off the ground and 5 ft away from me initiated GO HOME and took off into the air 30+ ft then moved towards the trees.

hallmark007 Posted at 2016-12-7 19:38
Did you set a height for RTH, what triggered RTH was it low battery, you have given very little information,  maybe a bit more would help understand exactly what happened.

Sorry to hear about your crash.

Low battery warning auto-initiated the RTH function from what I could tell.

Did you do the firmware update and initial calibrations? I know when I first got mine my home point was registering in China when I turned it on.

check and see what the RTH altitude is set to in your settings......it will default to this value and ascend regardless of what is above it as the first step in the RTH sequence.

trance728- Posted at 2016-12-7 20:06
Did you do the firmware update and initial calibrations? I know when I first got mine my home point was registering in China when I turned it on.

The phone app did have me UPDATE before it allowed me to continue.  So both app and Mavic should have been up to date.  I did update my controller to the 12/6 firmware today.

As for calibrating, I did not.  I checked the app and calibration said NORMAL.  And again, the GPS did show my backyard so on initial check all seemed well.

I believe the default return to home battery value is 30% and 20% or 10% for critical. Once it hist 30% it will initiate RTH unless you cancel it. At 20 or 10% it will just land on the spot. It's always good even if you are testing to charge the battery up first. Sounds like you had just over 30% when you took off and when it hit 30% it initiated RTH. If you want more details you can go into the main screen and hit the + icon on the DJI Go 4 app and go to flight record, you can sync the flight to the cloud.

There is no use checking RTH settings and battery warning levels unless the aircraft is connected, those settings are pulled form the craft when the GO app connects. I would like to see a screenshot of the flight recorder when you took off. As for the DAT file that is located in the aircraft, you would need to connect your mavic to a PC using the USB cable and download the .DAT file.

Heavysledz Posted at 2016-12-7 20:14
check and see what the RTH altitude is set to in your settings......it will default to this value and ascend regardless of what is above it as the first step in the RTH sequence.

The RTH was set at 98 ft, this is noted in the image i shared in OP.

As for RTH sequence, the manual reads:

Oh and also the Flight Recorder will show you clearly the home point as marked on the map and also your location, might be good to check those as well.

sorry, my computer does not show an image in your OP. Likely due to my work network blocking the image hosting site....

fans628b7609 Posted at 2016-12-7 20:22
I believe the default return to home battery value is 30% and 20% or 10% for critical. Once it hist 30% it will initiate RTH unless you cancel it. At 20 or 10% it will just land on the spot. It's always good even if you are testing to charge the battery up first. Sounds like you had just over 30% when you took off and when it hit 30% it initiated RTH. If you want more details you can go into the main screen and hit the + icon on the DJI Go 4 app and go to flight record, you can sync the flight to the cloud.

There is no use checking RTH settings and battery warning levels unless the aircraft is connected, those settings are pulled form the craft when the GO app connects. I would like to see a screenshot of the flight recorder when you took off. As for the DAT file that is located in the aircraft, you would need to connect your mavic to a PC using the USB cable and download the .DAT file.

Thank you for this info.

After connection, CRIT BAT @ 10%, LOW BAT @30%.

I have both my flight log synced via HealthyDrones, and I have connected the Mavic to PC and exported the .DAT file.  Just not sure how to read this in a digestible format.  If you could help direct me to where I can view the log with my battery info etc on this flight that would be helpful.

Also, I have not been able to find any "flight recorder" info from the camera.  I did not manually activate any recording, but understood that the take-off sequence is captured in some format via the camera.  Do you know where I can find this?

Heavysledz Posted at 2016-12-7 20:30
sorry, my computer does not show an image in your OP. Likely due to my work network blocking the image hosting site....

I've attached the image in another way in OP.  Maybe it will be visible now...

KrAzYKrivda Posted at 2016-12-8 02:05
Low battery warning auto-initiated the RTH function from what I could tell.

What height did you have RTH set at if it only rose 30ft and then flew into trees was that the height you had it set at?

What was the battery level on takeoff?

KrAzYKrivda Posted at 2016-12-8 09:37
I've attached the image in another way in OP.  Maybe it will be visible now...

thanks I can see it now...

KrAzYKrivda Posted at 2016-12-8 02:37
I've attached the image in another way in OP.  Maybe it will be visible now...

Were you were flying looks like a disaster waiting to happen , you took of with almost no battery, your Mavic was trying to climb to RTH height and it looks like while climbing you crashed , did you have OA turned on,  it didn't just go straight into the tree, it went straight up into the tree, or at least that's what it looks like.

Kinda hard to determine what exactly happened, given the incomplete info provided. But, what I see from your first image, is the drones distance from the home point was 19' when RTH was initiated, so as per the manual, it would ascend to 32' and return to the home point, via Forward Vision System.

hallmark007 Posted at 2016-12-7 20:39
What height did you have RTH set at if it only rose 30ft and then flew into trees was that the height you had it set at?

Again, I've attached an image of the manual here.  If you cannot see, please let me know.

It states that between 10-20 M (aka starting at 16 ft) from RTH location, will ascend (if not already at or above) 32 ft, the proceed home.  This is what I'm assuming happened.  

The GPS data I could gather believed I was 19 ft from home.  However, the DJI.GO.4 app contradicts the manual and says that it will initiate landing if you are within 20 M, whereas the attached image (manual) states this will only happen during 5-10 M.

bighi Posted at 2016-12-7 20:46
What was the battery level on takeoff?

If you could direct me into gathering this data, I'd be happy to share!

hallmark007 Posted at 2016-12-7 20:55
Were you were flying looks like a disaster waiting to happen , you took of with almost no battery, your Mavic was trying to climb to RTH height and it looks like while climbing you crashed , did you have OA turned on,  it didn't just go straight into the tree, it went straight up into the tree, or at least that's what it looks like.

Ha, yes the image would appear that way.  I only anticipated flying a few feet here and there just to see the controls.  Hence not being concerned about low battery, or the trees.

Also, as I've stated, the image attached in OP is what the FlightLog is showing.  In reality, the GPS was not accurate to the foot.  I took off from the center of my deck (the red dot in OP).  The deck alone is roughly 15 ft X 30 ft with open airspace.  The trees do not impede the airspace i took off from until I proceed about 30 ft forward, and about 30 ft upward.  

So based on the screenshot the home point was recorded 1 sec after RTH initiated. So from what i can see you had not enough battery, RTH kicked in almost immediately and the home point was not set till after RTH initiated.

damaltor Posted at 2016-12-7 20:56
Kinda hard to determine what exactly happened, given the incomplete info provided. But, what I see from your first image, is the drones distance from the home point was 19' when RTH was initiated, so as per the manual, it would ascend to 32' and return to the home point, via Forward Vision System.

Yes thank you! You and I are on the same page here.  I was hoping for someone to help me understand that.  The manual basically says it will preform this if 10-20 M away.  The app, which I assume was more up-to-date and accounted for changes in firmware, states that landing occurs up to 20 M away.  (Manual states this only up to 5 M away).

If anyone could clarify this discrepancy, or even test on a DJI Mavic that would be helpful.  Test what initiating RTH does when 8 ft in altitude and 19 ft in distance.  Manual says it will rise 32 ft then go home, app is telling me that it will land.

fans628b7609 Posted at 2016-12-7 21:01
So based on the screenshot the home point was recorded 1 sec after RTH initiated. So from what i can see you had not enough battery, RTH kicked in almost immediately and the home point was not set till after RTH initiated.

You may have misread that log.  It reads top to bottom.  In BEGINNER MODE you cannot takeoff until RTH point is set.  I attempted to auto-takeoff, but it haulted, locked GPS, set home location, then took off.  ~40 seconds later RTH was activated.

Hopefully this is seen, since I wish to clarify what I'm looking for:
1. Can anyone confirm using up-to-date Mavic and DJI Go 4, when RTH is initiated @ altitude =8 ft and distance = 19 ft?  What does app screen say, what does Mavic do?

2. For my 1 minute flight, how can I see my battery stats (controller, Mavic, etc), and inputs?  (I'm assuming somehow a GPS update occurred causing the Mavic to believe there was a ~15 ft change, although hopefully inputs can confirm there was no physical movement, and why was RTH force triggered ...)


3. How can I view any visual data from this flight if I never manual initiated any recording?

Even if it might sound funny to you: I think you set some new world records.

The fastest demolishing crash after unpacking the Mavic. AND
The shortest flight ending in a demolishing crash.

Congratulations contestant.

fansae63899d Posted at 2016-12-7 21:55
Even if it might sound funny to you: I think you set some new world records.

The fastest demolishing crash after unpacking the Mavic. AND

Please be sure to factor in that I only was in control for ~30 seconds!  That should help that record stand for a long time :-)

KrAzYKrivda Posted at 2016-12-7 19:17
Hopefully this is seen, since I wish to clarify what I'm looking for:
1. Can anyone confirm using up-to-date Mavic and DJI Go 4, when RTH is initiated @ altitude =8 ft and distance = 19 ft?  What does app screen say, what does Mavic do?

!. You've already posted the page from the manual that what happens in RTH mode at different distances.
2. You can play back your flight in the flight records and that will tell you the telemetry data.
3. Visual data you can only playback if you were recording, and then playback the video.

DJI-Ken Posted at 2016-12-7 22:32
!. You've already posted the page from the manual that what happens in RTH mode at different distances.
2. You can play back your flight in the flight records and that will tell you the telemetry data.
3. Visual data you can only playback if you were recording, and then playback the video.

Thanks for the reply.

1.  Spoke to DJI customer support, they claim (as APP states) that it will ONLY descend if within 20 M.  Manual I posted says it will ONLY descend if within 5 M.  These do not agree, and I'm wondering what others in real-world experience since 2 DJI sources vary.

2. Can you point to a more specific source so I can figure out how to do this.  In app, the flight record view only shows me 5-10 lines of almost identical info to my OP image.  Where do I go to get the deeper detail and view it?

3. It was my understanding that there were video/images taken to "match" and "align" the craft on RTH.  I guess I misunderstood.  Thanks for clarifying.

KrAzYKrivda Posted at 2016-12-7 20:45
Thanks for the reply.

1.  Spoke to DJI customer support, they claim (as APP states) that it will ONLY descend if within 20 M.  Manual I posted says it will ONLY descend if within 5 M.  These do not agree, and I'm wondering what others in real-world experience since 2 DJI sources vary.

1. I don't have a Mavic on hand to see what the app states, but the manual states it will descend within 5m.
On the P4P and older aircraft it's 20m.

2. Your original post image is from Healthy Drones, it's a 3rd party site that does not have totally accurate data and you should not rely on it. From the home page in the GO app, tap the top left icon (paper airplane) and that takes you to your flight records and you can see data from each flight. If you ever delete the app or use multiple devices make sure you tap the top right icon (cloud) so all your flight data is synced with the DJI servers.

Did you calibrate the compass?

It was a very short flight, I think your aircraft was trying to head back home but it was not reading its heading right, hence it headed out into the trees.

Check the logged flight and verify that the recorded heading matches what it really was.

DJI-Ken Posted at 2016-12-7 23:20
1. I don't have a Mavic on hand to see what the app states, but the manual states it will descend within 5m.
On the P4P and older aircraft it's 20m.

2.  Dji.go.4 is different.  Though your direction helped.  

It ended up being in top right corner, press the + button.  3rd option down has the button I've been looking for for the past 3 days! Thank you!

KrAzYKrivda Posted at 2016-12-7 21:31
2.  Dji.go.4 is different.  Though your direction helped.  

It ended up being in top right corner, press the + button.  3rd option down has the button I've been looking for for the past 3 days! Thank you!

Ya, sorry about that, I should have given you GO 4.0 directions.

With the help of finding the flight data think most of my questions are answered.  

For those still curious and following along...

The GPS and compass were clearly off.  my battery started at only 17%, and triggered a return to home af about  13%.   ignoring bad calibration this is issue one. shouldn't have occured until 10%.  From this point on until it was clear it was about to crash, there was 0 user input.
2nd and biggest issue is the it appears the Mavic follows what is written in manual for RTH and not on App (and apparently what older models do)  this means that when Mavic is 5 M to 20 M from home, it will rise to at least 32 ft then return home.  App and older models will LAND if within 20 M, no ascending.

When Mavic began to ascened, it was directly vertical.  however due to poor GPS on start, as it rose, the data also showed that the GPS believed it was moving sidewas away from home.  in reality, the higher it rose the more accurate the GPS became to its true location.  in the 25 ft ascent, it believed it had also moved ~15 ft away.  

At this point it proceeded to return to where it believed "home" was.  when it began heading for the trees, you can see there was input from user to DESCEND however the Mavic seemed to remain locked into RTH (issue 3).  

It then hit a branch a few times, broke a propeller, and feel from the sky.

THE END

Please give the link where you took the screenshot from. Much easier.

Anyway, screenshot shows everything. E = homepoint, does not match your real takeoffpoint = user error, did not check on the screen if it is correct.

Sad, but yeah... user error. Next time, check, double check and do not take off if not correct or land and wait for more accurate GPS.

Did you calibrate your compass in an area clear of metal and with no metal, cellphone, etc. on you before flying?  I thought that the Mavic required this on first flight, so hopefully the answer is yes.  

Also, with respect to the "Red Dot"  While it's useful to know where you actually took off from, what direction the drone actually travelled, etc., the only things that really matter to the Mavic are where it THINKS it is (GPS), what heading it THINKS its flying (compass), what altitude it THINKS its at (VPS and Barometer), and what amount of battery it THINKS it has (I believe battery can jump around quickly when getting near 0).  It looks like you used healthydrones, which can help you get the data on what the Mavic thought was going on.  

One thing you didn't include was your GPS count.  If you took off immediately as soon as Beginner Mode would allow, I wonder if you might have had a low GPS count upon takeoff, accounting for the poor home point precision.  If your satellite count increased during the time you were flying, its possible your position shifted further from the original home point than you physically flew (ie you may have only flown 5 feet, but after the GPS resolves better, the Mavic thinks you have traveled 20 feet).

So in addition to verifying your home point is properly set, another lesson (in addition to all the others above) is to make sure you have a high number of satellites before taking off.