Lost Mavic while in waypoint mission

[Oto]

Hello!

Please, need help ASAP to try to recover my lost Mavic.

On October 26 around 11:20 was flying my drone in waypoint mission when it started to drift away, then it switched to ATTI mode and app disconnected. RC showed error SYS WARNING and CHECK APP so I tried to reconnect DJI GO app on my Huawei P9(Android).
While reconnecting lost visual control of UAV but did not panic as was sure that will get back the view from camera and drone drifted in direction of open field where I could land it safely.
Unfortunately when I managed to reconnect app I could enter flight mode but it didn't show any image and there was message "controller error". Tried to restart RC and also reconnected USB which didn't help. So I was left in dark as RC didn't show distance to home nor it allowed RTH as it was still in ATTI mode and didn't switch back to GPS. At some point even tried to switch Sports mode back and forth to reset mode but it didn't help. To not lose direction I only used rudder up to keep it at previous altitude of 75m.
To my relief when battery level reached 15% it somehow waked up the drone and reset mode to GPS and I tried RTH again. To my surprise after a sec altitude sharply dropped to 25m and RC showed message LANDING to which I responded by increasing altitude back to around 60m as was afraid it may land in lake nearby and tried RTH again. Now RTH command worked, RC showed that it is now returning to home with distance to home 2km but then sharply disconnected. This was last info which freeze on RC and RC kept showing CONNECTING. It almost seems that drone crashed which is unlikely as at 60m altutude there are no obstacles or it may experienced a battery malfunction. Drone obviously didn't return to home point and is now lost.
Please check attached logs and help to find out which was last GPS coordinate when RTH was initiated and did it start RTH or it actually continued to land. Checked "lost my drone" menu in app but it shows only home position as last as it seems DJI GO app didn't actually reconnect.

Attaching logs but they are not complete. Also attaching RC blackbox but it seems doesn't contain GPS coordinates. Need help to calculate bearing as at least last distance to home point is known so if initiating RTH succeeded it should have adjusted yaw angle to home location. Also need to calculate how far it could go with 15% left and RTH initiated.

DJI Flight Log Viewer - PhantomHelp.com
DJI Flight Log Viewer - PhantomHelp.com

 

[ac0j]

Lets see if @sar104 or @BudWalker can figure this out.

 

[SpinItUp]

Is that a train track that was flown over? (Edit; yes it obviously is, Note to self)
They have communications along the lines and is probably the source of interference that contributed to the loss. (As it seems to have gone AWOL over it)
I can't find ref; to RTH?
Then again I don't have a subscription to data analysis programs

 

[Oto]

RTH message can be seen only in RC fatal.log as flightrecord is truncated at 60% battery after trying to reconnect DJI GO. Yes there were train tracks right below but expected to be safe at 75m. My mistake that didn't throttle it up to max altitude at 120m immediately which could have help to recover.

 

[Oto]

Is there a tool to visualize the fatal.log from RC controller?

 

[SpinItUp]

The visual from the kmz show the alt as starting at 112m from the ground so that explains that.

Too low.
Looks like you were on the outskirts of an industrial site.
15% battery left at 1.998km from Home with 77m in Alt' is where it shows the craft was rising rather than descending and more than likely dropped due to insufficient voltage, that looks
well-covered area for vegetation/trees. Plus only going by a line from the last known location using GE is nowhere near accurate.
Estimated around 55°52'32.55"N 26°35'54.31"E which could be in an arc from that point.

Were you using litchi?
Dat log is more helpful.

Can't find anything that loads the fatal log.

 

[Oto]

I have also some DAT files.

2018-10-31_7tkrp4pa

Seems it may be dropped into swamp. Stupid, should have allowed it to land and watch if altitude doesn't decrease below 0 which would indicate it is landing in water as it is lower than starting point, now have to do a guesswork.

 

[SpinItUp]

I'm in the process of upgrading my system and don't know whether it's this reason I can't get to open the DAT files or not, so will have to wait until my upgrade is done.
I'm getting
8-10-15-11-54-26_FLY003.DAT is not a valid .DAT file
18-10-26-11-17-53_FLY006.DAT is not a valid .DAT file
Edit; your DAT files are corrupted or something?
Edit, Edit; Okay it was just the header of the file is invalid but not getting much info from it

Both are useless; 003 is in Riga (other flight)
006 is not very useful? I think it's just you getting ready before AFTER (18:00hrs) the waypoints mission where it all goes Pete Tong! (Wrong)

004 & 005 would be the ones with more info?

 

[Oto]

Yes DAT file seem to be only from preparation for takeoff as it is last time DJI Go was connected properly.

 

[Jackcutrone]

These reports of controller glitches causing failures is scary. I recently had the Go4app disconnect during flight though the rc was still connected. Will try to post later to get some ideas.

 

[lertsek]

We're getting all these horror stories on Halloween?

 

[DanMan32]

Go 4.3.0 (or was it 4.3.1) for Android was buggy where it would often crash on 2nd or 3rd flight in a session. No app crashes since updating to 4.3.2.
Then again I haven't flown more than 2 flights straight due to one reason or another.

 

[Meta4]

This was last info which freeze on RC and RC kept showing CONNECTING. It almost seems that drone crashed which is unlikely as at 60m altutude there are no obstacles or it may experienced a battery malfunction. Drone obviously didn't return to home point and is now lost.
Please check attached logs and help to find out which was last GPS coordinate when RTH was initiated and did it start RTH or it actually continued to land. Checked "lost my drone" menu in app but it shows only home position as last as it seems DJI GO app didn't actually reconnect.

... Need help to calculate bearing as at least last distance to home point is known so if initiating RTH succeeded it should have adjusted yaw angle to home location. Also need to calculate how far it could go with 15% left and RTH initiated.

The only data you've given shows less than a minute of flight around 60% battery level.
That's no help at all if you want to find your drone and I can't work out much from your explanation.
The home point is not lost while in flight but if your drone has a yaw error, it can't use GPS to hold position of to return home.
You need flight data from later in the flight to have any chance of getting help.
The only useful information from the data is that it was showing a yaw error and drifting in atti mode.
A yaw error is usually quite serious and can cause the drone to be uncontrollable.
The cause is usually launching from a steel or reinforced concrete surface.

These reports of controller glitches causing failures is scary. I recently had the Go4app disconnect during flight though the rc was still connected. Will try to post later to get some ideas.

There's no hint of a controller glitch here.
Occasional disconnects are not unusual and are not necessarily anything to be concerned about.

We're getting all these horror stories on Halloween?

There are always tales of drone misfortune but what's important is what causes the incidents.
Almost all turn out to have been preventable.

 

[SpinItUp]

Yes DAT file seem to be only from preparation for takeoff as it is last time DJI Go was connected properly.

Wrong
It (006 DAT) shows 18:00 hrs which is after you lost it so it was during your realisation the mission ain't gone to plan.

I find this more entertaining (but seriously more informative) than flying my drone.
That industrial site must've been bouncing communication waves all over the shop.

 

[BudWalker]

Yes DAT file seem to be only from preparation for takeoff as it is last time DJI Go was connected properly.

FLY007 is the associated .DAT from the second .txt that you submitted. Can you provide that? There is a chance it will have some data that will help locate the Mavic Pro. If there are other .DATs after that (FLY008, FLY009, etc) please provide those as well.

 

[Oto]

Will check if there is other DATs.
Today went to site and did some search&rescue in my calculated locations(from RC fatal.log) and SpinItUp provided. No luck yet either it drowned or is hanging in the tree. Would have let it to land it may have been recovered easly. Tomorrow will try again.

 

[Oto]

There are no other TXT or DAT files unless they are missing because of some filesystem corruption.
Can other DJI GO logs under Android DJI\LOGS be decrypted which seem to be BASE64 encoded but also encrypted? Seems older logs from year 2017 were plain text.

 

[SpinItUp]

If they were I doubt they'd be any use or reference to the flight.

 

[Oto]

Some seem relevant for example older map logs has location for home point(addHomeMarker) and maybe it locates flight also.

Need a volunteer for a test. What distance could Mavic travel if RTH is initiated at 60m(with RTH altitude set to 50m) and remaining capacity of 15%? At which bat level it starts force landing for this altitude?

 

[SpinItUp]

Some reading to do may help?
Edit; @15% I think it forces autoland or at least RTH so from there it will be straight lining it home
Guy did a test for a MA so battery time is going to be different.