I lost my Mavic Mini today and it was most likely my fault. I know that some of you on this forum can do a detailed review of the data. I would greatly appreciate it if you could confirm my suspicions, just let me know what file (txt or dat) to sent you and how.

  

I was using the drone to take some photographs of the cliffs near my home, so I was flying over water (nearby lake). The Home Point was on a narrow beach (lake level was down due to winter) and somewhat covered by tree branches, so I set the RTH altitude at 50 ft. to allow the drone to return under the trees. My thought was that I would keep the drone in direct sight and always maintain the RTH flightpath to the Home Point over water, not over any land/trees. However, during the photo taking I believe that I maneuvered it around a slight bend where it lost contact. Despite my attempts to reestablish contact I couldn't regain control so I initiated RTH, but it never returned. I suspect that it struck some trees that protruded from the bend (over 50 ft. high) and fell into the water. A search of the bank was impossible due to overgrowth and dangerous slope. Attempts to reconnect with the drone were unsuccessful despite being within 50 ft. of the suspected crash area which I hiked to later. My quick interpretation of the data captured would make me believe that the drone struck something (“motor is blocked”) and then fell (last altitude recorded was 11 ft. below the Home Point). If that is a true altitude reading then the drone was under water as the Home Point was no more that 1 ft. above the lake level. Was it still transmitting under water?

  

I've really enjoyed this drone so I'm already working on a replacement. Tough lesson learned but one I will not forget.

Most likely it has hit a tree. If you set the RTH height to 50 feet, and it begins to return when it is higher than 50 feet, it will not descend to 50 feet first, the RTH height sets a height that it will go to as a minimum. If it is already higher than that, it will return at the current height.

Sorry about your loss.  Yes, there are others here that are very good at reading the data, and presumably one of them will jump in here.

Setting RTH altitude to be below the trees is asking for trouble in my opinion.  Better to set it above any possible obstacle.

Even if the drone was not in the water (stuck in the tree that it hit), unless you get there fairly soon, the battery will run down.  If it was under water, good bet it will be even less time.  Radio signals can get through water - but VERY poorly.

Log is posted at https://www.phantomhelp.com/logviewer/JXH4GRPPF9BTFGAG06Y8

This link shows your flight on Google Earth.
https://app.airdata.com/kml?flight=11e158e494b46e94d6d2dce077e2c8c8&default_color=ff00ffff&default_width=2&color_width=3
It makes what happened pretty clear.

the drone struck something (“motor is blocked”) and then fell (last altitude recorded was 11 ft. below the Home Point).
The pitch, roll and compass data in your flight data shows the colision starting at 533.8 seconds.
From then the drone slows rapidly, it bounces around, rolls and tumbles downwards.
The motor blocked messages don't show until 535.1 sec, when the drone has fallen 19 feet.

If that is a true altitude reading then the drone was under water as the Home Point was no more that 1 ft. above the lake level. Was it still transmitting under water?
Your drone cannot transmit from under water and was not still in contact from 10 feet down.
There are two factors affecting the altitude data from the barometric sensor in this flight.
It's common and normal to see some variance over the time of a flight so that the accuracy of the 49 ft altitude that was showing on your screen could easily have +/- 10 feet.
And the IMU sensors often give false data after an impact.

Labroides Posted at 3-14 16:38
This link shows your flight on Google Earth.
https://app.airdata.com/kml?flight=11e158e494b46e94d6d2dce077e2c8c8&default_color=ff00ffff&default_width=2&color_width=3
It makes what happened pretty clear.

Thanks so much for your analysis. From what you said and the file you sent, I'm convinced that the drone hit a tree and fell into the lake.  As others mentioned earlier, I should have set the RTH altitude much higher with the assumption (proven correct) that the drone would possibly have to travel over some land to return to the Home Point. Perhaps others can learn from my mistake.
Thanks Again!
Doug

Geebax Posted at 3-14 13:56
Most likely it has hit a tree. If you set the RTH height to 50 feet, and it begins to return when it is higher than 50 feet, it will not descend to 50 feet first, the RTH height sets a height that it will go to as a minimum. If it is already higher than that, it will return at the current height.

You make a good point that I hadn't considered. I kept the drone around 50 ft. altitude so it would return to the Home Point under the tree branches. If I had positioned it well above the 50 ft. altitude, it would have returned at that altitude and possibly missed the tree(s). Then when the mode changed to Auto Landing I could have guided the drone around the tree branches to land at the Home Point.

Hello there Cravites. I am sorry to read and to know what happened to your DJI Mavic Mini. Since this unfortunate incident happened and you have lost the said drone. I would recommend for you to contact our DJI Support Team at https://www.dji.com/support?site=brandsite&from=nav for further assistance. We have a team that will do there best to help you and give out the best resolution for the said issue. Again, I am sorry for your loss and thank you for your understanding.