RC Lost Contact with Drone; Couldn't Re-Establish

[jclarkw]

Most recent flight of Mavic Air 2 with RC231, it was out about 9000 ft and I started having intermittent connection problems. This didn't worry me much, since I was still line-of site and had previously reached a range of 15,000 ft without communication difficulty, but maybe there was strong radio interference. Suddenly the RC lost contact with the drone and could not re-establish. I tried moving to a higher location, power cycling my iPhone, power cycling the RC, all to no avail.

Fortunately the drone did return to launch point as it should, after what seemed like forever, but even after I could see it and it landed at my feet, I still couldn't re-connect. Not until the drone was powered off and back on could I regain control. Playing back the flight log from the phone showed that, after a number of complaints about signal, the last line of the log was, "Aircraft not connected with RC," followed by a bunch of other errors. I have not yet tried to examine the on-board flight log, if indeed we mere mortals have to tools to do so.

My questions are:
1) Is this behavior normal during an extended interference or signal-strength problem?
2) Is there anything else I could have done to re-establish connection?
3) Is there any way to prevent such a disturbing event from recurring?

Best Regards to All -- jclarkw

 

[GadgetGuy]

1. Not normal
2. Nope
3. Fly somewhere else

 

[slup]

Agree with the earlier answers for 1. & 2. but don't think it's as easy as stated in 3.

We have seen issues like this before... no reestablished connection even at really close distance & the only thing that have helped have been to restart the AC. This points much more to AC firmware issues than the location by itself.

Haven't seen any firm solution for this in general yet... but one tip could be to do a refresh of the AC firmware.

Also...

"Aircraft not connected with RC," followed by a bunch of other errors.

...it would be good to know more about those "...followed by a bunch of other errors". Share the mobile device stored .TXT flight log from the flight, that might give some clues.

Go here -->DJI Flight Log Viewer | Phantom Help & upload the .TXT log, then share the link they provide. (Scroll down a bit there on the first page & they describe how you retrieve the .TXT log)

 

[Capt KO]

Have you updated new A2 firmware that includes RID? Sounds like a good time to do it.

 

[jclarkw]

Have you updated new A2 firmware that includes RID? Sounds like a good time to do it.

Yes, but I haven't rechecked to see if there's now a newer one... jclarkw

 

[jclarkw]

Agree with the earlier answers for 1. & 2. but don't think it's as easy as stated in 3.

We have seen issues like this before... no reestablished connection even at really close distance & the only thing that have helped have been to restart the AC. This points much more to AC firmware issues than the location by itself.

Haven't seen any firm solution for this in general yet... but one tip could be to do a refresh of the AC firmware.

Also...



...it would be good to know more about those "...followed by a bunch of other errors". Share the mobile device stored .TXT flight log from the flight, that might give some clues.

Go here -->DJI Flight Log Viewer | Phantom Help & upload the .TXT log, then share the link they provide. (Scroll down a bit there on the first page & they describe how you retrieve the .TXT log)

Thanks for the tip; I'll refresh the firmware. Meanwhile log can be found at;

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Sorry about not copying the whole message. I haven't figured out an easy way to do that yet in FlightReader. -- jclarkw

 

[slup]

Thanks for the tip; I'll refresh the firmware. Meanwhile log can be found at;

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Sorry about not copying the whole message. I haven't figured out an easy way to do that yet in FlightReader. -- jclarkw

All the errors in the end of the log was only RID related... can't see how that could prevent a re-connect once the AC was closer to the HP.

Here the total message stream out from the log...

 

[GadgetGuy]

All the errors in the end of the log was only RID related... can't see how that could prevent a re-connect once the AC was closer to the HP.

Here the total message stream out from the log...

View attachment 170096

Mandatory RID FW creates a whole new set of traps for the unwary in the software code when anything else goes awry, much like GEO does after a disconnect in flight, where unlocks suddenly have to be reauthorized in mid-flight, after a reconnection. It was so much simpler when we only needed to worry about a LOS disconnect that would quickly reconnect after the the drone started RTH! GEO and RID have created land mines that we have to now have to try to successfully navigate through, before and during flight!

 

[jclarkw]

...but one tip could be to do a refresh of the AC firmware....

slup -- How do you accomplish this? I tried updating from the DJI Fly app (through iPhone and controller), but it did not find any updates and does not seem to offer to re-install the AC FW. -- jclarkw

 

[slup]

slup -- How do you accomplish this? I tried updating from the DJI Fly app (through iPhone and controller), but it did not find any updates and does not seem to offer to re-install the AC FW. -- jclarkw

Try with DJI Assistant 2 on your computer. Go here --> Mavic Air 2 - Downloads - DJI & download it (scroll down a bit)... you have versions for both Windows & Mac there.

Hook your MA2 up to your computer with a USB cable, turn the drone on, & once it turns up in DJI Assistant 2 you should be able to refresh the FW.

​

 

[marinsd]

This happened to me when the drone briefly went behind a small outcropping and went out of VLOS (I was focused on the screen following a rower). But it DID respond to a RTH command.

 

[jclarkw]

Agree with the earlier answers for 1. & 2. but don't think it's as easy as stated in 3.

We have seen issues like this before... no reestablished connection even at really close distance & the only thing that have helped have been to restart the AC. This points much more to AC firmware issues than the location by itself...

Is there any useful information on the drone itself relative to this problem?

I finally got the DJI advisors on their forum to understand what my problem was. (Too many words, I guess.) They've had me upload the flight records from my iPhone to Dropbox for review. Maybe I'll get something to share here...

Meanwhile it occurred to me that, since the RC/drone never reconnected after they lost contact, there shouldn't be much more in the MCDatFlightRecords or si_cache files than you saw in the decrypted text flight record (below). Therefore I looked at memory (both internal and SD card) in the drone itself, supposing there would be other kinds of flight records there. Should there be?

Anyhow I didn't find ANY files there with the a date even close to that of the flight in question, although there are a lot of .THM and .SCR files in SD Card:\MISC\THM\100. Do these have any use to us? -- jclarkw

 

[thanducha]

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