My mavic tried to land in the Ocean!!! NO downward control to land?

[Michael Fox]

I took my Mavic to Guatemala for a Sail Fishing trip. I tried to fly it the night before at the Resort and there was to much interference. They have Wi-Fi. I moved 20 feet farther away and it received GPS Signal and I flew it with NO issues. The next mourning we took a 35 ft chartered Fishing boat 40 Miles SW of the Mariana. (Just my guess of the location.) I had an Asus S 8.0 already connected to the controller. I did a Flight inspection on the Drone and had the arms extended and the blades out. I was on the fly bridge with the Captain and the drone. The ship had NO Sonar only a hand held GPS. My daughter hooked a Sailfish. I placed the Drone on the front of the ship. The tablet was already turned on. I powered up the Drone and then the controller. After the Drone was connected to the Controller I waited for a GPS Signal. I then flew the Drone up Hovered and tapped the Tablet screen to Focus and flew it around behind the Boat. I was hovering around above the hooked Sailfish trying to get it on Video. I was behind the boat Hovering so I looked down at the Tablet screen to see what the image of the ship looked like. My daughter started yelling Dad look at the Drone. I looked up and it was just above the water trying to land IN THE OCEAN!!! I pushed the up stick and nothing. I let off and pushed it up again and it started to slowly rise. I looked down at the Controller and it showed Connected but the Controller and said Landing. I looked back at the Drone and it was Landing again!!! I thought I could just fly it to the front of the boat but I could not control the Drone to go down so I had to land back on the front of the ship using the controller and let it move down by it self. I NEVER had any control to move the Drone down to land it. It ALWAYS showed it was connected and said Landing on the Controler all the time.There was NO other Boat in the area. I was LUCKY to save it. I have not turned it on since. I am SO disappointed. As I had purchased it for this trip.

 

[Strafe1]

I don't know the cause of your issue, but just as a side note, the recommended sequence for powering up is: First your controller, then the AC, then the app.
As for the landing, it sounds like you hit the auto land function. Save your disappointment for now, it could be pilot error!

 

[No1much]

Whenever you fly your Mavic over water, disable the VPS before it's above the water itself- otherwise it does something to confuse the aircraft and cause it to descend into the water. With VPS off, this seems to solve the issue for my Mavic at least.

It seems there may be a known problem with Mavics as well as Phantoms taking a swim if they're using VPS over enough liquid water.

 

[mchristepher]

I don't know the cause of your issue, but just as a side note, the recommended sequence for powering up is: First your controller, then the AC, then the app.
As for the landing, it sounds like you hit the auto land function. Save your disappointment for now, it could be pilot error!

Also, put your tablet/Phone in airplane mode.

 

[Michael Fox]

If the auto land function was hit by accident the controller will not allow an override? Why was I unable to move the drone down after i moved it back up in the air? I could move it every direction except down?

 

[Michael Fox]

I will also add I flew the Drone the night before and hovered 5 ft above the pool a couple of times and it had NO issues. When the issue over the Ocean happened it was 50ft in the air when it started landing.

 

[mminardi]

I will also add I flew the Drone the night before and hovered 5 ft above the pool a couple of times and it had NO issues. When the issue over the Ocean happened it was 50ft in the air when it started landing.

A few thoughts,

1) the sensors on the bottom bounce waves off the water, this results ( in some cases ) in an automatic RTH. I wonder if it's a safety mechanism for a failed sensor or in this case the water bouncing the waves off in a pattern it cannot compute.

So like mentioned above always turn of the sensors when flying over water.

2) if you had initiated RTH accidentally you are able to cancel on screen, you said you had noticed the warning, did you try to cancel? General speaking you have the ability to assist the drone during RTH to make adjustments. I have aborted many times with no issues as practice to see the response of the commands and never really had any issues.

All this being said when you are dealing with the situation you are trying to avoid losing the bird and not really thinking about what happen. You could always upload your logs and have the plethora of knowledgeable pilots here take a look at the data.

Just my thoughts.

 

[Robbyg]

I am going to throw out a theory on this.
The downward ultrasonic sensor is almost useless on water but I suspect that if you get low enough it picks up some signal bounce. Since it is calibrated on land the signal at 20ft up might bounce back in a very odd pattern due to the absorption and the oceans wave action. Maybe the signal from one pulse is picked up right after the next pulse and the Mavic thinks that it is much lower than it really is. Maybe this is what initiates an auto landing?

 

[Paul Dawson]

Can I chime in and ask - is it then preferable to disconnect the FVS (Forward and Downward vision system) when flying over any body of water, no matter the size? Reason I ask is, the last time I flew I took the MP over a small section of Creek water (about 1 metre above) and the water was still and I experienced no ill effects. Just wondering if any water crossing no matter how insignificant, poses any risk at all of a unplanned drowning?
Paul.

Sent from my SM-G900I using MavicPilots mobile app

 

[gregw]

I have flown my Mavic over the sea many times, and have had the VPS on during all flights. So far, I have not had any problems with VPS over the sea. The accuracy on the VPS indicator in the app seems to be quite accurate for my Mavic. This includes fast low flights in Sports mode as well as hovering around 3 - 4 meters height over the sea taking videos of boats. The only time I turn off VPS is when I am just about hand catch the Mavic, so the Mavic doesn't spin up the rotor when it senses my hand.

From your symptoms, it may indicate a problem with your VPS sensor... There are quite a few threads over the DJI Forum about the Mavic indicating that it is landing when it is a few hundred feet in the air, and the only way to solve this problem was to turn off the VPS sensors. I suggest you contact DJI and send them your log to see if there was any error.

BTW, how many flights have you had on your Mavic? If you've only had a few flights, this may indicate a hardware problem and you may have to send it back to DJI for warranty repair.

I'm one of the lucky ones who's received a good Mavic without problems. So far, over 9+ flight hours and 66KM flight distance without issues..

 

[Andrew F]

Whenever you fly your Mavic over water, disable the VPS before it's above the water itself- otherwise it does something to confuse the aircraft and cause it to descend into the water. With VPS off, this seems to solve the issue for my Mavic at least.

It seems there may be a known problem with Mavics as well as Phantoms taking a swim if they're using VPS over enough liquid water.

I fly over the ocean all the time and have never experienced a VPS or sonar problem - other than braking for a large wave that was clearly below the Mavic (but only by 6 feet.) They say its the "nap" of the water that causes problems. I've been there much and still never had a problem. I think he accidentally hit the auto land button.

 

[Andrew F]

I have flown my Mavic over the sea many times, and have had the VPS on during all flights. So far, I have not had any problems with VPS over the sea. The accuracy on the VPS indicator in the app seems to be quite accurate for my Mavic. This includes fast low flights in Sports mode as well as hovering around 3 - 4 meters height over the sea taking videos of boats. The only time I turn off VPS is when I am just about hand catch the Mavic, so the Mavic doesn't spin up the rotor when it senses my hand.

From your symptoms, it may indicate a problem with your VPS sensor... There are quite a few threads over the DJI Forum about the Mavic indicating that it is landing when it is a few hundred feet in the air, and the only way to solve this problem was to turn off the VPS sensors. I suggest you contact DJI and send them your log to see if there was any error.

BTW, how many flights have you had on your Mavic? If you've only had a few flights, this may indicate a hardware problem and you may have to send it back to DJI for warranty repair.

I'm one of the lucky ones who's received a good Mavic without problems. So far, over 9+ flight hours and 66KM flight distance without issues..

Hmm. I'm pretty skeptical about VPS causing a forced landing at elevation. That makes no programmatic sense. What message from VPS could possibly cause an emergency landing? Because it thinks the ground is right there? I suppose that's possible. But even when I fly at 1 foot and keep it there, my Mavic doesn't force land.

 

[Andrew F]

I am going to throw out a theory on this.
The downward ultrasonic sensor is almost useless on water but I suspect that if you get low enough it picks up some signal bounce. Since it is calibrated on land the signal at 20ft up might bounce back in a very odd pattern due to the absorption and the oceans wave action. Maybe the signal from one pulse is picked up right after the next pulse and the Mavic thinks that it is much lower than it really is. Maybe this is what initiates an auto landing?

I fly over the ocean and waves all the time and never have any issues. I want the sensors on because I don't WANT to land accidentally in the water if I get too close.

 

[gregw]

Hmm. I'm pretty skeptical about VPS causing a forced landing at elevation. That makes no programmatic sense. What message from VPS could possibly cause an emergency landing? Because it thinks the ground is right there? I suppose that's possible. But even when I fly at 1 foot and keep it there, my Mavic doesn't force land.

No idea why this is the case, except some people have encountered this problem before.. I think most of the cases occur because the VPS thinks the Mavic is within landing distance from ground, and will automatically initiate landing whenever the pilot lowers the left stick to go into a descend...

 

[Andrew F]

No idea why this is the case, except some people have encountered this problem before.. I think most of the cases occur because the VPS thinks the Mavic is within landing distance from ground, and will automatically initiate landing whenever the pilot lowers the left stick to go into a descend...

Well, that makes sense I guess. Easy to test by simply putting it in sports mode. But sports mode seems to suck the life of my battery dry unacceptably fast so I stay away from it other than for short bursts and odd sensor states.

 

[Cyberpower678]

If the auto land function was hit by accident the controller will not allow an override? Why was I unable to move the drone down after i moved it back up in the air? I could move it every direction except down?

Landing mode is an intelligent flight mode. You have limited control until it is disabled. Think of it this way. The drone uses a virtual controller to maneuver. In landing mode, the left stick is down all the way. No when you add you controller onto that the differences are added together. So when it pushes down, and you push up, they cancel each other out. So hence no response. If you need to cancel landing fast, flip the sport mode switch back and forth. That disables any active IFM currently running on the drone.

 

[Cyberpower678]

I am going to throw out a theory on this.
The downward ultrasonic sensor is almost useless on water but I suspect that if you get low enough it picks up some signal bounce. Since it is calibrated on land the signal at 20ft up might bounce back in a very odd pattern due to the absorption and the oceans wave action. Maybe the signal from one pulse is picked up right after the next pulse and the Mavic thinks that it is much lower than it really is. Maybe this is what initiates an auto landing?

So fly higher. I've flown over the ocean with sensors on, and had no issues. ;-)

 

[Michael Fox]

I contacted Support and explained what happened. They requested the flight data I sent it in. The data shows height distances below 0, -17ft and -18ft at a couple points.I think the closest it ever got to the water was 4 or 5 ft? but only one time and that was the first time it tried to land from 50ft up. I made sure everything was updated and calibrated before I left. I turned everything on today and see a new update for the app and drone and updated them.

 

[Michael Fox]

I did not hear any warning. Of course the boat is running and their is loud diesel engine noise. The wave action was very mild. The day before had some 10-15mph wind and bigger waves and I didn't want to risk flying until it calmed down.

 

[Andrew F]

I contacted Support and explained what happened. They requested the flight data I sent it in. The data shows height distances below 0, -17ft and -18ft at a couple points.I think the closest it ever got to the water was 4 or 5 ft? but only one time and that was the first time it tried to land from 50ft up. I made sure everything was updated and calibrated before I left. I turned everything on today and see a new update for the app and drone and updated them.

Oh! Now we have some facts to deal with. I often get negative values on height while flying low over the ocean. I have just ignored those as I honestly don't care what they say. But it makes sense that automatic systems might get messed up by that. I'm sure it was frightening when it happened and I'm sorry you didn't get the shot of a lifetime. You need more flight time so that you are a little less amped up when something goes wrong. I have LOTS of hours of flight time and I can still get stressed out when something isn't exactly right. The next time I have the ability, I will test with and without sensors over the ocean and see what happens. But I think I'll put on my fancy floats when I have the sensors off. Haha.