Mavic 2 crash into Lake of the Ozarks, help w/ data analysis?

[fishtek]

? Hey all,

Lost my Mavic 2 Zoom this past Sunday down on Lake of the Ozarks. It is kinda an amazing story that almost had a happy ending. On Saturday I was filming my son get up on ski's for the first time and had ActiveTrack enabled and panned out to the side to get a profile however wasn't watching the drone itself that closely due to all the excitement and as it flew sideways filming the skier it strafed into some tree branches and then fell, into the lake! I immediately thought it was a goner, but others convinced me we should try and find it. So we used the "Find my drone" in the app and were actually able to locate the GPS location where it said it went down, and there were some leaves in the water around the spot. We waded into the water about 5 feet deep, and low and behold the drone was sitting under the surface in about 2 feet of water on a boulder. It was under water for 25 minutes according to the DJI app.

Pulled it out and took lense, rotors and battery out (I didn't have any allen wrenches small enough to take the drone itself apart), but then put it under a fan for the rest of the day and night, rotating it occasionally.

I still figured it wasn't going to fly again after being under water for 25 minutes, but late into the next day, I decided to give it a shot. Put in a new battery and it fired right up, I had it hover for a bit above the dock and tested things out like the camera and video, I then flew out over the water where some of our group were lounging in blow up rafts and did a couple of "quick shots", rocket and then circle. I then pulled it backwards away from them and up a little bit and hovered for a few seconds, it was then that I looked over and the front (I think) of the drone just dropped and then drone just went straight down into the water. I couldn't believe it, after getting that second chance I figured all was good, however something must have been compromised perhaps?

I swam to the spot and dove down to the bottom (about 12 feet in this area) to try and find it, but it was too dark and I couldn't get it back.

I'm curious if anyone can look at the data and tell if one of the rotors stopped or maybe broke?

I attached the DJIFlightRecord and I also uploaded over here: DJI Flight Log Viewer - PhantomHelp.com

So lessons learned, I think the drone is pretty amazing to have even worked at all after being under water for 25 minutes, I wish I had inspected the props a bit closer after hitting the tree, and I suppose investing in those silly drone floaties when flying over water would be a good idea, since the drone can apparently take a bit of water and keep on going.

Thanks for peeking at the data and giving your opinion.

 

[Fly Dawg]

I'm curious if anyone can look at the data and tell if one of the rotors stopped or maybe broke?

Very well could be a lost prop. You were applying full forward elevator, then applied full back elevator within 1 second. That is where it appears a prop came off. No way to know for certain from the data, but it "appears" that way to me.

 

[parkgt]

I wonder if you let it dry out long enough. I doubt all the water had a chance to evaporate completely in less than a day.

I would have given it several days sitting in a warm spot with some air movement; same with the dunked battery.

How carefully did you check the props from the first crash or did you put on your spares?

 

[sar104]

Very well could be a lost prop. You were applying full forward elevator, then applied full back elevator within 1 second. That is where it appears a prop came off. No way to know for certain from the data, but it "appears" that way to me.

View attachment 78122

This is one of those cases where you have to look more closely. The RC was operating in Mode 3, not mode 2.

The front right motor failed, but I don't think it lost a prop - the period of the resulting motion is too long. I would guess that it was damaged by the previous immersion.

 

[John Kyte]

Fellow Lake of the Ozarks here and sorry to hear about your loss. Hope you can still find your Mavic and have DJI care. I lost my Spark in a lake and couldn’t retrieve it so my DJI care was worthless so I didn’t purchase it for my Mavic Air. We are so lucky to have such an awesome place to fly our birds. Good Luck on getting your Mavic back.

 

[fishtek]

How carefully did you check the props from the first crash or did you put on your spares?

I had all the rotors off while I let it dry under the fans, but I do wonder if your right perhaps I didn't look closely enough when putting them all back on, and that is what ultimately doomed me on the 2nd fatal flight.

This is one of those cases where you have to look more closely. The RC was operating in Mode 3, not mode 2.

The front right motor failed, but I don't think it lost a prop - the period of the resulting motion is too long. I would guess that it was damaged by the previous immersion.

Yes that is true I do have my sticks setup a little different from the defaults.

Fellow Lake of the Ozarks here and sorry to hear about your loss. Hope you can still find your Mavic and have DJI care. I lost my Spark in a lake and couldn’t retrieve it so my DJI care was worthless so I didn’t purchase it for my Mavic Air. We are so lucky to have such an awesome place to fly our birds. Good Luck on getting your Mavic back.

Yeah, this was my first time down on the Ozarks and it really is an amazing lake, my family certainly had a great time!

Thank you all for looking at the flight log, I really appreciate it.

 

[Anthony Richardson]

? Hey all,

Lost my Mavic 2 Zoom this past Sunday down on Lake of the Ozarks. It is kinda an amazing story that almost had a happy ending. On Saturday I was filming my son get up on ski's for the first time and had ActiveTrack enabled and panned out to the side to get a profile however wasn't watching the drone itself that closely due to all the excitement and as it flew sideways filming the skier it strafed into some tree branches and then fell, into the lake! I immediately thought it was a goner, but others convinced me we should try and find it. So we used the "Find my drone" in the app and were actually able to locate the GPS location where it said it went down, and there were some leaves in the water around the spot. We waded into the water about 5 feet deep, and low and behold the drone was sitting under the surface in about 2 feet of water on a boulder. It was under water for 25 minutes according to the DJI app.

Pulled it out and took lense, rotors and battery out (I didn't have any allen wrenches small enough to take the drone itself apart), but then put it under a fan for the rest of the day and night, rotating it occasionally.

I still figured it wasn't going to fly again after being under water for 25 minutes, but late into the next day, I decided to give it a shot. Put in a new battery and it fired right up, I had it hover for a bit above the dock and tested things out like the camera and video, I then flew out over the water where some of our group were lounging in blow up rafts and did a couple of "quick shots", rocket and then circle. I then pulled it backwards away from them and up a little bit and hovered for a few seconds, it was then that I looked over and the front (I think) of the drone just dropped and then drone just went straight down into the water. I couldn't believe it, after getting that second chance I figured all was good, however something must have been compromised perhaps?

I swam to the spot and dove down to the bottom (about 12 feet in this area) to try and find it, but it was too dark and I couldn't get it back.

I'm curious if anyone can look at the data and tell if one of the rotors stopped or maybe broke?

I attached the DJIFlightRecord and I also uploaded over here: DJI Flight Log Viewer - PhantomHelp.com

So lessons learned, I think the drone is pretty amazing to have even worked at all after being under water for 25 minutes, I wish I had inspected the props a bit closer after hitting the tree, and I suppose investing in those silly drone floaties when flying over water would be a good idea, since the drone can apparently take a bit of water and keep on going.

Thanks for peeking at the data and giving your opinion.

 

[Anthony Richardson]

As I am a.new member from the UK I will keep it short.
Really sorry to hear of the sad loss of your drone. Having been both an electronics engineer and a diving instructor, if I may I would like to make some observations.
Firstly, I would have given the craft at least 7 days to fully dry out in a well ventilated area but having a slightly elevated temperature.
Secondly, if you must flyover water of any kind, why not fit some small
polystyrene floats to the underside somehow, even with duct tape.
I was in the Osarks area some 42 years ago and my wife and I had a wonderful time. I would still go search for the wreck even now. It is sometimes quite surprising how parts will survive especially in fresh water.
Good luck Tony Richardson, COLCHESTER, Essex , UK.

 

[AntDX316]

Very well could be a lost prop. You were applying full forward elevator, then applied full back elevator within 1 second. That is where it appears a prop came off. No way to know for certain from the data, but it "appears" that way to me.

Yeah, probably not changing the props was bad. Prob had a crack in the front where it hit but it stayed on. Gradually the crack became bigger and came off but it seemed stable but it could be the IMU being confused. Towards the very end, the attitude indicator was going pretty crazy. I had my Phantom 4 Pro V2.0 do the same as what the attitude indicator was showing on the Camera but when I examine the logs, it was stable. I assume it's because I calibrate the compass part 2 sideways but now I do it nose down and it never came back since.