Mavic simply vanished

Rasheedmavic · Feb 28, 2018

I was flying the mavic on an island in Malaysia, connection was strong, it was windy but not too windy! Suddenly connection lost and that was it!

DJI Flight Log Viewer - PhantomHelp.com

Could you please tell me what can I do in this case!! It is very upseting!

msinger · Feb 28, 2018

At the end of your flight log, it shows you held the throttle in the full down position while your Mavic was close to the surface of the water. That caused it to switch to Force Landing mode and land here in the water:

If you want to rescue it from the water, look around the last recorded coordinates at 5.91598245, 102.7237436.

sar104 · Feb 28, 2018

Just to expand on @msinger's explanation, you did not lose connection while flying, you landed it in the water. At 243 s and 48 m you applied and maintained full down throttle. At 263 s it had descended to 0.5 m above the water, at which point continued full down throttle initiated forced landing. At 265 s it landed in the water. After that you lost connection.

galfridus · Feb 28, 2018

Related question - is there a legend somewhere for the values in the various CSV columns? From what I could find the throttle values go from -10,000 to +10,000, yet in this log 364 is throttle down.

ac0j · Feb 28, 2018

If the DJI Go 4 app quits, that is NOT a disconnect. You still had full control from the looks of it, you just didnt know you were still flying it.
Maybe learn to fly your replacement WITHOUT the app so you get a feel for how to control it without the FPV?
Might prevent another loss!

ICHOTT · Feb 28, 2018

Great advice there, let us know if you find it.

Do you remember holding throttle Down and what you were doing to want to do that?

sar104 · Feb 28, 2018

ac0j said:
If the DJI Go 4 app quits, that is NOT a disconnect. You still had full control from the looks of it, you just didnt know you were still flying it.
Maybe learn to fly your replacement WITHOUT the app so you get a feel for how to control it without the FPV?
Might prevent another loss!

I don't think that the app quit at all - it was logging the flight right up until the water landing and the resulting disconnect from the controller.

ac0j · Feb 28, 2018

Maybe he just lost video feed then?
It has to hurt when you find out the accident didn’t have to happen. Sorry it had to go that way for the OP
You know what they say, lessons aren’t cheap and good lessons are expensive!

sar104 · Feb 28, 2018

ac0j said:
Maybe he just lost video feed then?
It has to hurt when you find out the accident didn’t have to happen. Sorry it had to go that way for the OP
You know what they say, lessons aren’t cheap and good lessons are expensive!

The video issues were due to a different problem:

03m 01s 208.3 ft 222 ft Warning Video cache has stopped because there is not enough storage space. You can enable Auto Cache Clear or manually delete cache to get enough space.

maxfaxdude · Feb 28, 2018

Simply another case of pilot error.

joejaxvic123 · Feb 28, 2018

And just like that...poof...she gone!....PFM....

GreggC · Mar 1, 2018

msinger said:
At the end of your flight log, it shows you held the throttle in the full down position while your Mavic was close to the surface of the water. That caused it to switch to Force Landing mode and land here in the water:

View attachment 32404

If you want to rescue it from the water, look around the last recorded coordinates at 5.91598245, 102.7237436.

I'd really like to learn how to interpret flight logs,
For example,
How did you know he held the throttle down ??
Is there a tutorial or video I can study to learn this ??

msinger · Mar 1, 2018

GreggC said:
How did you know he held the throttle down?

You can see the position of the remote controller sticks in the flight log. 364 means the stick was in the full down position.

GreggC said:
Is there a tutorial or video I can study to learn this?

I've never seen such a tutorial.

laurens23 · Mar 2, 2018

msinger said:
I've never seen such a tutorial.

here a plot of the connection status, throttle input and height.

flight-log graph

CsvView/DatCon here you can find the java applet and instructions (tutorial)

everything looks fine. I bet the screen froze, and OP was not flying LOS, OP reacted by pushing throttle down instead of RTH, or manually fly it back.

galfridus · Mar 2, 2018

laurens23 said:
CsvView/DatCon here you can find the java applet and instructions (tutorial)

Note that some of the instructions on this site are flat out wrong, such as the description for throttle:

"Range [-10000, 10000] Neutral = 0. Stick left or down = -10000. Stick right or up = 10000."

sar104 · Mar 2, 2018

galfridus said:
Note that some of the instructions on this site are flat out wrong, such as the description for throttle:

"Range [-10000, 10000] Neutral = 0. Stick left or down = -10000. Stick right or up = 10000."

That looks correct to me - it's describing all four stick inputs, not just the throttle.

BudWalker · Mar 2, 2018

galfridus said:
Note that some of the instructions on this site are flat out wrong, such as the description for throttle:

"Range [-10000, 10000] Neutral = 0. Stick left or down = -10000. Stick right or up = 10000."

You may be referring to the value 10000. The descriptions found at
V3 .CSV column descriptions
are for the .DAT file.

The 364 value you referred to earlier comes from the .txt file. Confusing isn't it? The 364 value originates at the joy stick hardware on the RC. I believe the range is [0, 1632]. From there it goes through the RC software, gets transmitted to the AC, goes through the Flight Controller and finally gets written to the .DAT. Somewhere in there it gets translated into the [-10000, 10000] range.

galfridus · Mar 2, 2018

In the log just above, 364 apparently means full throttle down. I would expect -10,000 based on that site.

Edit: ninja’d, the above makes sense. A similar tutorial for the TXT would be nice.