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

JLane · Apr 14, 2017

Saylor101 said:
One question I have, and apologize if answered earlier in this thread or else where, is the downward sensors are only active below 13m

It's not that they're inactive above 13m, but they're not effective or at least not used by the Flight Controller above that height.

and that there is no way to turn them OFF except by turning ON Sport mode?

Sport mode doesn't switch off the downward sensors (VPS), it only disables forward OA. You can disable the VPS via the setting in the app.

And you only turn off the forward sensors with the "vision symbol" on the RC?

Not sure exactly what you mean by this.

So I've read...turn off the VPS, turn off Landing Protection, try not to go full left stick down, stay above 13m...and if it does start to "auto land" go to sport mode asap? Yet some pilots do not do some, or all of that. Yes, the manual has the warnings about flying over water....but we all want to do it. A lot of conflicting information and opinions.

Turning off Landing Protection seems to be the most important thing, because it will prevent the Mavic from entering a forced auto-landing from any height. And as for the aborting of a forced auto-landing, that has now been fixed in firmware .0600 so applying throttle does work again.

Whether or not disabling the VPS helps or hinders seems to be more open to debate, but DJI does say that it may not perform optimally while flying over water. I personally haven't disabled VPS on the occasions when I've flown over water.

Mavicvagyok · Mar 21, 2018

ChasiTail said:
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.

Did your boat have the sonar/depth finder active at the time of the crash?

AFAIK most boats your size have the sonar on the rear of the boat, which the MP ultrasonic sensors may have picked up as cross-talk as the boat went underneath it. You wrote that the problems occurred only when you began to hover and the boat passed underneath, so the boat would be the independent variable here. (No idea what side scan sonar from a boat would do in this case.)

Was the water shallow or deep, clear or murky?

Also wonder if the radar you have on top may have interfered, but it doesn't look like a spherical unit (so it probably doesn't broadcast vertically).

dbyantis · Mar 21, 2018

Robbyg said:
It certainly looks like that it was the VPS system.
You are one lucky guy, that it is not sleeping with the fishes

I can see when battery system was under severe stress and it seems like a lot of systems started to crash. I have never seen a log of the systems getting flooded with water.

Can you please please upload the 400mb+ DAT file to a file sharing service so we can see in more detail what happened.
I am going to contact BudWalker because he is the Jedi Master of Log file analysis. I think he will want to personally look at this one. At the very least you will get a very good report of what happened and the community will gain some useful info.

Rob

Do you know why the OP link to the log now redirects to a page of general Phantom links?

HighlandsVideo · Mar 21, 2018

Congratulations on retrieving your bird after all that. I find it interesting that it wigged out right after exiting an autonomous flight mode.
Also, I'm wondering whether the water did any damage since it remained fired after getting wet.

I got some downward sensor errors over water for the first time yesterday, but the bird still flew as normal and I brought it back and set it down. I had launched with a partially charged battery (56%) and after I changed to a fully charged battery, the warnings didn't return even when I repeated the exact same flight.