Mavic Pro2 Lost Connection

[JimWest]

This isn't quite a crash or flyway, but it could have ended up as either. I was flying this morning when I suddenly lost my connection to the AC. The drone was less than 100' away and around 30' altitude when I suddenly lost all contact. It started the automatic return to home, ascended to around 100', but then I lost contact a couple more times, during which it ascended to about 200', which was the maximum flight altitude I had set, and stayed there. Not responsive to any controls. Eventually, if I remember right, I was able to cancel the return to home, and land without any damage. My big question is why I lost contact, and more important--how to avoid it happening again. I don't know if its possible to determine this from the attached txt and dat files. Any help is very welcome!

 

[Meta4]

I suddenly lost my connection to the AC. The drone was less than 100' away and around 30' altitude when I suddenly lost all contact. It started the automatic return to home, ascended to around 100', but then I lost contact a couple more times, during which it ascended to about 200', which was the maximum flight altitude I had set, and stayed there. Not responsive to any controls. Eventually, if I remember right, I was able to cancel the return to home, and land without any damage. My big question is why I lost contact, and more important--how to avoid it happening again. I don't know if its possible to determine this from the attached txt and dat files.

The flight data can't explain why you lost contact.
It doesn't show whether you had the antennas oriented properly toward the drone or whatever else might have been a factor.
But the RTH issue looks to be an issue with obstacle avoidance preventing the drone from flying towards the west.
Was the sun low and in the west?
If you had cancelled RTH and manually flown a slightly different course or disabled obstacle avoidance, it should have done whatever you wanted.

 

[JimWest]

Thanks for your comments.
The sun was in the east, three hours after sunrise, so I don't see that as an issue. There were no other obstacles that I can recall, so I'm inclined to think the obstacle avoidance was, as they say, "fake news."
In any case, my main worry is about the repeated loss of contact. I suppose its possible that my antennas were not oriented properly, but I've been flying for over a year and have never completely lost contact like this. Now it has occurred four times in a six and a half minute flight, along with an uncommanded ascent from 100 to 200 feet during one of those lost contact periods. I'm worried that something more is wrong here.

 

[Meta4]

The sun was in the east, three hours after sunrise, so I don't see that as an issue. There were no other obstacles that I can recall, so I'm inclined to think the obstacle avoidance was, as they say, "fake news."

Here's a brief summary of the flight data.

At about 3:07 the RTH stalled and the drone just stopped..
At 3:08.7 you had a string of Braking to avoid obstacle warnings with the drone facing 247 degrees.
The obstacle avoidance recognised something on that bearing as an obstacle.
The drone only started moving again after RTH was cancelled and the drone turned away.

At 4:09.8 another RTH following loss of signal was stalled, again facing home (247 degrees) just as before.
The data shows that you gave some left stick down just before losing signal and the Mavic responded properly.
But when signal was regained 36 seconds later, the data shows left joystick input value of exactly 422 for almost a minute and the drone not descending.
This looks suspicious, it would be very difficult to hold the stick exactly at that position for that long.
There is more (believable) left stick down after 5:04.4 but the drone stayed stalled until 5:56 when you cancelled RTH again.

along with an uncommanded ascent from 100 to 200 feet during one of those lost contact periods.

The most logical explanation for the "uncommanded ascent" is that obstacle avoidance identified an obstacle and tried to climb over it.
OA had previously identified something in that direction as an obstacle, perhaps a bright reflection?
There was something in the west that upset the OA system.