Lost my Mavic 2 Pro in the Gulf of Mexico

[Thomas B]

Well, lets see, I commanded is up 5 feet while in reality it dropped almost 8 feet. Se that's a delta of 13 feet. Yes, I did expect it to hold altitude better than that on a very calm day.

So someone mentioned it "uses infared for ranging, not ultrasonic" Why would they not take a sonar altitude reading into account for safety sake? All of these protections and it ignores a sonar reading of .3 and drifts 13 feet in altitude.

All speculation. Bottom line I was stupid and it cost me. I knew I was taking a risk but I had too much faith in DJI having flown many hours in my Phantom 3 pro. It didn't have any protection but I don't think I ever got altitude loss like this. I've already replaced the drone and have flown a bunch more times. I can't say I'll be skimming the water anymore but I did get some great video of it on that trip.

Here's some raw footage from the night before. I was playing around with settings, speed, height...It didn't like the dusk light and I would get the "Auto braking Center Sticks" a lot. I would have expected that on my next morning flight when it was committing suicide but it had other plans.

2019_11_09_17_00_12.mp4

drive.google.com

I don't need to hear how stupid I am to have flown like this but go ahead if you must. Army Strong, I can take it.

One thing to note... and your last vid in this thread appears to show it, is the gradual slow descent often when seen flying the M2P rapidly over any surface. Noticed you made several height adjustments.
Glad your back in the air!

 

[PhantomFandom]

I don't see how I did anything wrong and have asked DJI to look at the logs. I expect them to go with the "sonar protection not guaranteed over water" or something like that but it seems stable in the log. Why didn't the drone react to the sonar altitude? I don't see "sonar altitude" in the CSV log but it is in the graph of the airdata.com log analysis info.

I am sorry you lost your M2P and that night footage was quite impressive. However, I think in this case I can't blame DJI when they tell you this was totally pilot error. The manual specifically states that the sensors may not be accurate over water. You were flying at high speed while barely skimming the water. If you can see prop wash on the surface (which is seen in the video) then you are definitely too close to the surface.

I fly over water all the time. However getting that close to the surface is just dangerous. If/when I get any lower than 10 feet above the water surface, I make sure I am flying very slowly and well within VLOS. The procedure I use is to have a very low sight angle so basically my eyes are near to the water level and definitely below the drone's height. Otherwise you don't have the necessary perception to see how low the drone truly is. Water is not only tricky for the drone but also on human eyes. When you are over water (especially calm water) you have no means by which to judge altitude and depth perception is terrible as well.

Also never watch the screen when flying like this. Eyes always on the drone itself.

You did say that you expect the technology to be better than this. However, I don't think that is the case. Basing altitude hold on barometric pressure is only accurate to some substantial margin of error. Depending on the infrared sensors over water is a known limitation and can't be trusted. That is why I try to never fly below 10 feet and usually well above that.

 

[MAvic_South_Oz]

The manual specifically states that the sensors may not be accurate over water.

Or in fading light (2nd video post 13).

Also never watch the screen when flying like this. Eyes always on the drone itself.

This.

 

[ajaxflysquare]

Hope that is a good lesson learned, most fly a good 10' minimum over water, and even then watch it like a hawk.



Well, THAT'S convenient !!
You should be able to go straight out and order a new drone body & battery !!

Whenever I fly over large bodies of open [ocean] water here in Florida I've always maintained a minimum altitude of 35 ft. At that altitude you can focus down on almost any size object.

 

[RayOZ]

It didn't rise on its own - in fact it didn't rise at all until commanded to at around 23 seconds. The vision-based height increase at 15 seconds, with no associated barometric rise, is just the level of the beach falling off to the water. The aircraft remained in approximately level flight.

That was just my interpretation of the first trend.

 

[Simmo]

Check out the Blue line..

 

[RayOZ]

Yes. But throttle was released but it was still ascending.

 

[Simmo]

Yes. But throttle was released but it was still ascending.

No, look at the relevant delays in the graphs, they all match....

 

[big shasta]

Thanks everyone for the input. I know what I was doing was risky and my ignorance of the limitations of the aircraft caused me to take more risk than I realized.

I did increase altitude manually and the craft rose about 5 feet. When I replay the flight I can see left stick input to increase altitude and it did in fact rise in response to my command (at least it did on the altitude display). It then descended into the flat calm gulf of mexico. There was absolutely no wave action or wind, it might as well have been a lake.

After much back and forth with DJI, they were unable to find the flight log on their server even though I did have it sync'd. I sent them my entire flight log folder and they were able to analyze the flight. I was surprised how responsive they were for this issue. Getting back to me within hours. After I send them the logs yesterday morning, I got an email from them last night and they are covering the replacement 100%. They have offered me a coupon code valid in their DJI store for replacement of the aircraft and battery (no remote or charger). Their verbiage in the email:

The unfortunate incident that occurred to your aircraft has been confirmed as a warranty case according to our data analysis. If the aircraft couldn't be retrieved, we would like to offer you a 100% off coupon code for Mavic 2 Pro (without the remote controller and battery charger), which can be used on DJI's online store:

I understand this could have been interpreted differently, especially with their disclaimers for flying over water and I'm fortunate that they are replacing it. I will be far more cautious in the future.

 

[nhoj_yelbom]

Lol 34 seconds

 

[GotLift?]

...Here's some raw footage from the night before....

Well you did capture some nice sunset footage! I did notice that at about 21s in that you can see propeller induced waves on the water. To me that means danger; increase altitude.

 

[jumblemon]

Nicely handled by DJI. They could have refused the claim with some legitimacy.

That’s why I buy DJI not a lesser brand.