Water Crash... Is this the VPS issue im now reading about?

[Andrew F]

I have lots of videos like this. Way too much fun and VPS / sonar helps keep me dry - so far!
Sharks Snacking.MP4

 

[Bunny Too]

Correct me if I am wrong, but VPS only tries to work when your AC is what, 15 meters above the water?

So wouldn't it be safe to fly over water if you fly your AC more than 15 meters above water with your VPS on?

Yes, and only certain conditions affect it however I think I would still turn landing protection off

 

[ChasiTail]

DJI is very good at covering their rears from any possible warranty issues. Your one of the few people that have actually retrieved a Mavic that went into the water, I am really hoping that once you dry it out you can retrieve the DAT file.

Hats off to you for the quick work and keeping your nerve. What happened to you is becoming far to common. DJI needs to fix the problem and return the stick up as a means of stopping this from happening. Putting the solution in the sports button is not a good idea, it is just not something most people will think of hitting when they unexpectedly descending into water.

Rob

I actually sent it in to DJI. I put in a bag of rice and silica for past 2 + days after the water landing. It apparently didn't like the bath it got and wouldn't work. Even if it had come back from the dead, I would always be afraid of a failure when flying and I don't think that would be very safe flying with questionable reliability.. So I started a case with DJI and mailed it off just before I made my original post. I have the DJI Refresh, as I'm new to flying and thought it would be good to cover myself if I hit a tree or something.. Never thought it would happen over a wide open lake. Still cant believe we hooked it before it sunk. So it'll be interesting to see how it goes with DJI.

I just hope others who read this do it before they encounter something similar, as its a very expensive lesson learned if you cant retrieve your downed drone.

 

[Egika]

Correct me if I am wrong, but VPS only tries to work when your AC is what, 15 meters above the water?

So wouldn't it be safe to fly over water if you fly your AC more than 15 meters above water with your VPS on?

Not quite. It works until a certain height over areas that have a distinctive pattern (also the height depends on the speed)!
It could still be malfunctioning at greater heights over water giving false readings even at greater heights.

 

[Andrew F]

The manual lists the following (using the search term "water"):

• Operate the aircraft with great caution in the following situations - flying over water [...]
• Forward and Downward vision systems may not function properly when flying over water
• The general hint to avoid bodies of water

By stating that the sensors may not function properly, all different things can happen. And that is exactly what you experienced. First the rise and then the automatic landing by full stick down...

I agree with you that DJI did not warn you specifically about what could happen if the VPS went berserk together with a landing protection. The more automated functions they put in to these things, the more combinations of stuff that could happen there are...

The "may" is a rather important word. Regardless, there is a big difference between having difficulty determining elevation and shooting up 150 feet and entering a forced landing mode. It "should" be an easy matter for DJI to compare disparate readings and react properly. Clearly the Mavic doesn't just instantly drop 30 feet. When these confusing readings kick in, we should get a warning - not fly for the lives of our Mavic! Haha. They can fix this.

 

[JLane]

Correct me if I am wrong, but VPS only tries to work when your AC is what, 15 meters above the water?

So wouldn't it be safe to fly over water if you fly your AC more than 15 meters above water with your VPS on?

This is what makes me wonder if this really has anything to do with the water, or if it's just the general faulty VPS issue that has been so common in the past. The OP states the Mavic ascended to 150'. I find it hard to believe that the water's surface is able to throw the sonar sensors off so badly from 150' way, enough to cause the sensors to think there's something just inches away. It doesn't quite make sense to me.

 

[Egika]

The "may" is a rather important word. Regardless, there is a big difference between having difficulty determining elevation and shooting up 150 feet and entering a forced landing mode. It "should" be an easy matter for DJI to compare disparate readings and react properly. Clearly the Mavic doesn't just instantly drop 30 feet. When these confusing readings kick in, we should get a warning - not fly for the lives of our Mavic! Haha. They can fix this.

Think of objects coming close from below... If set to avoid stuff from below the bird will go up whatever the reason. Also the barometer could be wrong...
There'll always be situations in which you like a different behavior. That is why it is so important to not rely an all automated functions but also add some studying, training and common sense...

 

[Strafe1]

I fly with VPS on over water - which is primarily the ocean - because I want the added safety net in case I get too close. It's easy to lose perspective and I pay attention to all indicators.

This is interesting. Because others who have landed in the water have determined that it was the VPS misreading the height over water. In your experience, it reads the water surface fine and actually keeps you above it.

 

[Egika]

same here - I've also been flying over water with VPS on. So far it has shown the correct height.
Just you cannot trust it to always do that!

 

[Andrew F]

This is what makes me wonder if this really has anything to do with the water, or if it's just the general faulty VPS issue that has been so common in the past. The OP states the Mavic ascended to 150'. I find it hard to believe that the water's surface is able to throw the sonar sensors off so badly from 150' way, enough to cause the sensors to think there's something just inches away. It doesn't quite make sense to me.

That's exactly right. It's more than VPS confusion. It's a hardware bug / flaw with a poor software reaction.

 

[Egika]

and yo

That's exactly right. It's more than VPS confusion. It's a hardware bug / flaw with a poor software reaction.

and you know that without even having looked at the full flight log. wow!
It just is a hardware limitation.

Similar to the Tesla not being able to detect white trucks against the sky. Which is the reason to not let the steering wheel go!

 

[Glen e]

Correct me if I am wrong, but VPS only tries to work when your AC is what, 15 meters above the water?

So wouldn't it be safe to fly over water if you fly your AC more than 15 meters above water with your VPS on?

Totally correct. I fly over a lake two times a week. But never at less than 100 feet off the lake surface usually much more than that, 150-200. I leave the VPS on and I've never had a problem or even any type of aberrant behavior from the Mavic.

 

[JJM]

So lesson of the day is to disable landing protection! You'll be ok if you turn it off!

 

[Dspace]

ChasiTail, sorry about the incident but awesome recovery save. Just curious what size/style of boat you were flying from? Were you hand launching and planning on hand catching or something else? Bow or stern? How flat was the water on the flight day, or put another way, how much wind that day? Nice looking lake BTW, do you live on it?

I assume you had RTH set to a fixed location rather than following the controller, or am I mistaken? What was the plan if signal lost? Stay reasonably close to the home point while flying (which would make sense)?

I live on the water and plan on doing a bunch of boat flying, but haven't quite gotten there yet. Trying to plan the routine in my head, thus the questions. I see plenty of YouTube examples of pilots, testing RTH on Terra firma, and hand catching the Mavic on dry non-drifting land, not so much on a drifting/rolling boat with rigging/obstacles everywhere and limited deck space.

 

[ThisIsCusel]

Funny that turning off landing protection actually protects it from landing.

So you practice, practice, practice. Then get confident in your ability to control the craft in the various modes, and understand how it responds in cretain situations. You perform a firmware update with vague description of changes. Then the craft behaves much differently during the most dire of situations. Sorry about your bird.

 

[ChasiTail]

ChasiTail, sorry about the incident but awesome recovery save. Just curious what size/style of boat you were flying from? Were you hand launching and planning on hand catching or something else? Bow or stern? How flat was the water on the flight day, or put another way, how much wind that day? Nice looking lake BTW, do you live on it?

I assume you had RTH set to a fixed location rather than following the controller, or am I mistaken? What was the plan if signal lost? Stay reasonably close to the home point while flying (which would make sense)?

I live on the water and plan on doing a bunch of boat flying, but haven't quite gotten there yet. Trying to plan the routine in my head, thus the questions. I see plenty of YouTube examples of pilots, testing RTH on Terra firma, and hand catching the Mavic on dry non-drifting land, not so much on a drifting/rolling boat with rigging/obstacles everywhere and limited deck space.

I have a 29' long pilothouse boat. The cockpit floor is a wide open 11' x 7 1/2' space.
Wind was 0-5 mph. Water was very calm.
I've practiced hand launching/catching several dozen times as well as landing on the boats deck while sitting on land. So with the conditions I was confident I could land. The first couple min of flight I flew just beyond arms reach to make sure catching could work. The backup plan was to fly to the boat launch & land on the parking lot if I couldn't land on the boat. I wasn't planning on flying more than a couple hundred feet away from the controller so didn't think losing signal would be a problem. I have RTH set to hover.

 

[Blucenturion]

I have a 29' long pilothouse boat. The cockpit is a wide open 11' x 7 1/2' space.
Wind was 0-5 mph. Water was very calm.
I've practiced hand launching/catching several dozen times as well as landing on the boats deck while sitting on land. So with the conditions I was confident I could land. The first couple min of flight I flew just beyond arms reach to make sure catching could work. The backup plan was to fly to the boat launch & land on the parking lot if I couldn't land on the boat. I wasn't planning on flying more than a couple hundred feet away from the controller so didn't think losing signal would be a problem. I have RTH set to hover.

That boat looks like it would be a piece a cake for hand catching Or the shanga langa, for that matter.

 

[Blucenturion]

That boat looks like it would be a piece a cake for hand catching Or the shanga langa, for that matter.

Panamian dance, that is.

 

[Robbyg]

I actually sent it in to DJI. I put in a bag of rice and silica for past 2 + days after the water landing. It apparently didn't like the bath it got and wouldn't work. Even if it had come back from the dead, I would always be afraid of a failure when flying and I don't think that would be very safe flying with questionable reliability.. So I started a case with DJI and mailed it off just before I made my original post. I have the DJI Refresh, as I'm new to flying and thought it would be good to cover myself if I hit a tree or something.. Never thought it would happen over a wide open lake. Still cant believe we hooked it before it sunk. So it'll be interesting to see how it goes with DJI.

I just hope others who read this do it before they encounter something similar, as its a very expensive lesson learned if you cant retrieve your downed drone.

The good news is that DJI cannot possibly renig on an exchange.
The bad news is there lousy turn around time!
I have to admit that I was really looking forward to seeing the cascade of system failures when these things have when they wet. Oh well the main thing is your on your way to getting a replacement. Maybe a DAT file like this will come around again at some point.


Good luck and keep us informed
Rob

 

[Robbyg]

This is what makes me wonder if this really has anything to do with the water, or if it's just the general faulty VPS issue that has been so common in the past. The OP states the Mavic ascended to 150'. I find it hard to believe that the water's surface is able to throw the sonar sensors off so badly from 150' way, enough to cause the sensors to think there's something just inches away. It doesn't quite make sense to me.

I have thought about it and the only possible explanation I can see is that the water may delay the pulse long enough that the previous pulse is just bouncing Back when the next pulse is being sent. So it sends out the sonar signal and instantly gets a return which translates that your just a tiny bit above the surface.

Rob