I was trying to do a high-speed gimbal tilt up shot over water like I've done many times before and for some reason the mavic just dove into the water.  So this Thanksgiving I went to Mantua Reservoir in Utah and flew around for a while.  On my second battery, I tried to do shot again over the lake.  I was not very far away.  You can see me positioning the gimble straight down to see how close I was getting to the water.  Nothing I haven't done before.  When I seemed ready to start the shot, I pointed the gimble down and started flying as fast as I could in sport mode while trying to slowly tilt the gimbal up like I have several times before.  While looking at my screen it looked like I just lost connection to the drone.  I thought that was odd because I technically had a direct line of sight to it over the water.    I figured it would reconnect soon and/or return to home.  After about a minute I started to see it on my screen again.  Figured it was a normal reconnect but I was a little worried about losing connection over the water again so I started moving it over land just in case it lost connection again.    After it looked like I was over land again, I lost connection again.  I could see basically where it was on the map but no visual imagery.  I didn't hear it start to return to me for a while so I started walking around to where I thought it would be if it decided to land there or if it crashed around there.    I found it had landed fine and was still on.  Just sitting there on a little frontage trail.    Only it was all wet.  But there was no water on the trail.    So I took it home and checked the sd card and was surprised to see that after I had started flying it over the lake, it seems to have decided to dive right into the lake!  It seems like at least the gimbal was underwater for a while but I am not sure if the rest of it submerged.  Also not sure if a submerged mavic can lift itself from under the water.  Maybe the props stayed above water while the gimbal went under?  Anyway, as you can see, it seems to have lifted out of the water, however deep it was, then promptly fall back in it for a moment.    About the second time it lifts out of the water is when I think I see it from my position on my screen, not yet knowing it took a dip.   I can still turn on the mavic but cannot seem to link it to my remote anymore.  But it WAS linked for a few minutes after it came out of the water the second time...  Guess I'll give it another day or two of drying out before I call DJI support again.


Update:  I can now connect to the remote but no imagery is transmitting from the drone to my phone while it is attached to the remote.  I don't think I can control the gimbal anymore and have not tried to fly it yet.  Below is a link to the youtube video I made of the ordeal.

I am now scared to fly over water.  Amazing it got out of the water.  I would think that only the bottom of the drone was submerged.  I wouldn't think the props would have enough power if they became submerged to get it out of the water.  But I am a noob to drones.  

I'm going to start by saying this is just flying stupid.  Did you turn VPS off, cause my best guess is that the water reflection screwed your visual positioning sensors before you switched to sport mode?  Either way, it's an intriguing video, and I'm glad you did it and not me.  

At 1:25 you can see that it was in a shallow area so you lucked out lol

Koia Koia Posted at 2017-12-9 08:55
I am now scared to fly over water.  Amazing it got out of the water.  I would think that only the bottom of the drone was submerged.  I wouldn't think the props would have enough power if they became submerged to get it out of the water.  But I am a noob to drones.

I tend to agree but it was going very fast.  Not sure how deep it got.

Oracle Miata Posted at 2017-12-9 09:23
I'm going to start by saying this is just flying stupid.  Did you turn VPS off, cause my best guess is that the water reflection screwed your visual positioning sensors before you switched to sport mode?  Either way, it's an intriguing video, and I'm glad you did it and not me.

I didn't turn anything on or off that isn't usually on or off.  I have done this shot many times before without issue.  The log shows the sticks at forward motion only,  never downward.  I was several feet over the lake when I started.  Still not sure what happened.

rolling56 Posted at 2017-12-9 09:25
At 1:25 you can see that it was in a shallow area so you lucked out lol

I was lucky but I'm still not sure how.  It lifted itself out of the water without my input.  Not sure if that is in the programming.  When it reconnected to my remote I still had no idea it hit the water.

djiuser_QM6Fcyx Posted at 2017-12-9 09:42
I was lucky but I'm still not sure how.  It lifted itself out of the water without my input.  Not sure if that is in the programming.  When it reconnected to my remote I still had no idea it hit the water.

You are lucky that you have the bird in hand.....in case you need to send in under warranty you need to have it. If it had sank you "probably" would not have found it since you did NOT have line of sight of it. If you had line of sight of it you would have seen it all with your own eyes.

I have no idea what mode it went into but like i said you were lucky.

I remember from the early day's of others' experiences....turn off VPS when flying over water.

This is how I always clean the mud off my Mavic.

Mavic was probably pretty hot....decided to go in for a swim. Tgen co.e back to u

From the video it looks to me like you applied full elevator while it was just barely above the surface of the water, and it's not unusual to lose a little altitude when you do that.

Also not sure if a submerged mavic can lift itself from under the water.  Maybe the props stayed above water while the gimbal went under?

No, it can't. Yes, the props must have still been above the surface of the water.

Guess I'll give it another day or two of drying out before I call DJI support again.

Do you have Care Refresh? If so, this is the time to use it. Otherwise I suspect that they'll tell you to send it in and will just bill you the full cost of a replacement, since DJI considers water-damaged aircraft to be non-repairable.

DroneFlying Posted at 2017-12-9 12:43
From the video it looks to me like you applied full elevator while it was just barely above the surface of the water, and it's not unusual to lose a little altitude when you do that.

Also not sure if a submerged mavic can lift itself from under the water.  Maybe the props stayed above water while the gimbal went under?

If by barely above the water you mean several feet, yes.  Like I mentioned, after having done this shot several times earlier, this is the first time it behaved like that.  

Good point about the care refresh.  Not sure I have that so if I don't, probably going to need a total replacement.  Too bad, since it still flies fine.  DJI support will probably tell me what to do in a couple days.

crashcore Posted at 2017-12-9 13:02
If by barely above the water you mean several feet, yes.  Like I mentioned, after having done this shot several times earlier, this is the first time it behaved like that.  

Good point about the care refresh.  Not sure I have that so if I don't, probably going to need a total replacement.  Too bad, since it still flies fine.  DJI support will probably tell me what to do in a couple days.

If by barely above the water you mean several feet, yes.

Looking at the video starting around 0:30 -- especially at around 0:32 -- it's clearly much closer than that as it's flying forward.

If you'd like to provide a link to the TXT file (log from you mobile device) on PhantomHelp I'll take a look. An even better record of what happened can be found on the DAT file, and if you retrieve it from the aircraft, upload it to DropBox, and provide a link to it here someone will take a look and can shed more light on what occurred. The instructions for retrieving the TXT file are at the link I provided, and the ones for accessing a DAT file are here.

If you are too close to the surface when you hit full throttle, you'll get wet because the nose drops and the tail raises to give it forward motion.

DroneFlying Posted at 2017-12-9 13:28
If by barely above the water you mean several feet, yes.

Looking at the video starting around 0:30 -- especially at around 0:32 -- it's clearly much closer than that as it's flying forward.

Thanks for that link, very interesting.  

http://www.phantomhelp.com/LogViewer/BJ5W7CDI6UYM61X9RRM0/

So I think it all started to go south around here:

9m 36.7s        Sport        16satellites        14.8ft        0ft        34.2mph        2,467.1ft        66%        11.357V        3.786V        3.786V        3.786V        0V        Weak signal. Avoid blocking the antennas and keep the antennas parallel to and facing toward the aircraft during flight.

I agree the 14.8ft is probably not 100% accurate but I think I at least started moving forward at that altitude.  But you do have a point about seconds 30-32 on my video.  Looks way lower.  



I'll work on the DAT next.  Good tips.

AG0N-Gary Posted at 2017-12-9 14:33
If you are too close to the surface when you hit full throttle, you'll get wet because the nose drops and the tail raises to give it forward motion.

Totally agree.  But from all the evidence I can see I was at least several feet above the surface.  That said, I do not rule out the possibility that the nose could drop that far after hitting full throttle.  And the flight log txt appears to show it actually gaining altitude.  I'll believe anything at this point.

I'm starting to think this might have been the first time I tried this in sport mode.  The log shows me doing it fine in regular mode earlier.  Live and learn.

I am going to have to call B.S. on this with no disrespect intended. You either have Flossie’s for the drone or it was a very skillful hover over the water.   Come on come clean with us and let us know how it was really done. I have been able to hover my Mavic PP right over water with camera pointing down all I had to do was go 3 inches lower and dunk the bottom half of front legs the rest of the drown is just barley above water except for the camera dome which if the camera is pointing straight down then it appears as if you are filming under water.  I have not gone the extra 2-3 inches but this video gives me the idea on how to make a cool video of a new drone that’s both a submarine and a flying drone.   Let’s see what I can do and I will get back with y’all.  Thanks. Wheelyboyd

MediaElite Posted at 2017-12-9 10:25
I remember from the early day's of others' experiences....turn off VPS when flying over water.

I’m new to all this so is it basic practice to turn off VPS over water?

MavicTribe Posted at 2017-12-9 20:47
I’m new to all this so is it basic practice to turn off VPS over water?

Yes, or at least disable landing protection. The idea is that the sensor might interpret the water as solid ground, and pulling back on the throttle (left stick) can cause it to land in the water because it mistakenly thinks it's over solid ground and that you're commanding it to land.

crashcore Posted at 2017-12-9 19:08
Thanks for that link, very interesting.  

http://www.phantomhelp.com/LogViewer/BJ5W7CDI6UYM61X9RRM0/

Yes, that does appear to be the point in time when it hit the water. Notice how the altitude goes from 14.8 feet down to -1391 in less than a second? I think that's the barometer being submerged. And speaking of which, keep in mind that the barometer is just an estimate -- and sometimes not a very accurate one -- of the Mavic's height relative to the takeoff location. The VPS height is much more accurate when it's able to work, but that requires solid ground within a certain number of feet below the Mavic.

I'll work on the DAT next.

Thank you. I am still interested to see it because I'm curious as to why it went into Auto Landing mode when it hit the water. I have a theory but I'd like to see whether it's supported by the data.

Brianboyd1969 Posted at 2017-12-9 19:27
I am going to have to call B.S. on this with no disrespect intended. You either have Flossie’s for the drone or it was a very skillful hover over the water.   Come on come clean with us and let us know how it was really done. I have been able to hover my Mavic PP right over water with camera pointing down all I had to do was go 3 inches lower and dunk the bottom half of front legs the rest of the drown is just barley above water except for the camera dome which if the camera is pointing straight down then it appears as if you are filming under water.  I have not gone the extra 2-3 inches but this video gives me the idea on how to make a cool video of a new drone that’s both a submarine and a flying drone.   Let’s see what I can do and I will get back with y’all.  Thanks. Wheelyboyd

Wish it was just B.S.  I imagine it is going to cost several hundred dollars to repair or a full replacement.

DroneFlying Posted at 2017-12-10 05:25
Yes, that does appear to be the point in time when it hit the water. Notice how the altitude goes from 14.8 feet down to -1391 in less than a second? I think that's the barometer being submerged. And speaking of which, keep in mind that the barometer is just an estimate -- and sometimes not a very accurate one -- of the Mavic's height relative to the takeoff location. The VPS height is much more accurate when it's able to work, but that requires solid ground within a certain number of feet below the Mavic.

I'll work on the DAT next.

Let DroneFlying do his magic and see what happened. Keep Mavic in LOS more often. I know people say BS to LOS but a lot of times they are the ones (cry babies) coming here for help to find the AC.