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Mavic air 2 lost signal above water and fog

ba2usa

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Hello,
I've flown drones for couple years now and never had an incident, until now.
I flew my mavic air 2 in Alaska in town of Whittier, over Prince Williams sound, i was flying it towards the glacier around 10am in the morning with a little bit of fog right above the lake, drone didn't have strong gps signal so it would only let me go to altitude of 30 meters(looking from my spot it was still above the fog). I flew almost 1.5 miles out with no problems, then once i headed back towards myself drone lost signal to the rc less then 1/4 mile away from me, at the moment it lost signal it was still at 40% battery, for next 20 seconds signal kept going in and out and for some reason it kept wanting to land automatically, i kept pushing cancel(X) button and not sure if it worked because signal never came back after 20ish seconds. I kept holding forward stick even after lost signal hoping it would make it to land instead of water.
RTH wouldn't work because it didn't have gps signal, so i'm thinking it most likely landed in the water. Is there ayone that can look at my logs?(for some reason it created 2)
Can anyone explain what hapened and possible gps coordinates where it was recorded last?
Thanks
 

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Phantomrain.org

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I cannot help with the logs but heavy Fog and heavy snow both can make the drone want to land because the sensor seems to get confused.

Recently one of our clients sent this picture in describing similar behavior in the fog.
I also have a video of it snowing so hard where the drone kept wanting to land also.

So wanting to land itself is normal but loosing signal is not.
At the end of the video I show the drone and what happened to it.


Neither of the two created a signal loss though , that may be something else.

Phantomrain.org
Gear to fly in the Rain and land on the Water.

Thanks to Beth for sharing he adventure in the myst.


DJI_0142 fog.jpg
 
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slup

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...drone didn't have strong gps signal so it would only let me go to altitude of 30 meters
...once i headed back towards myself drone lost signal to the rc...for some reason it kept wanting to land automatically
...i kept pushing cancel(X) button and not sure if it worked because signal never came back after 20ish seconds
The first log shows that you during the whole log duration didn't have any satellites locked at all ... it's equal in the second log from the same flight. Meaning no HP recorded & a flight in ATTI mode the whole way... no horizontal hold & no breaking when releasing the sticks at all.

So when you lost the connection your craft had no place to go home to ... in fact it didn't know where on earth it was. With no horizontal hold the craft would simply just drift away with the winds. The DJI software doesn't let this happen ... if in ATTI mode & losing the connection, the failsafe action will be landing.
...possible gps coordinates where it was recorded last?
No coordinates exists in neither of the 2 logs as explained above ...

Here a chart that shows the clear facts in the second log ...

The white background stripes is where it's no connection ... the pink says ATTI mode ... the grey is auto landing in progress.

The red graph is the height ... the green is #satellites (which is 0) ... the blue is the GPS level (which is 0)

(Click on the chart to make it larger)
1631355249542.png

...heavy Fog and heavy snow both can make the drone want to land because the sensor seems to get confused.
Fog had nothing to do with this incident.
 

tlswift58

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I don't understand why with poor visibility like that you would even attempt to fly?
And go 1.5 miles out. Guess they have awesome eyesight to see a gray drone in fog and other such conditions with NO GPS or RTH set.

We seem to be seeing a lot of this and end result is drone lost. Expensive education.

Also does OP have their "TRUST" cert?
 
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ba2usa

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Hello,
I knew the risks and what I'm getting into, I've done it before, weather was acceptable to me, drone was insured so I'm getting a new one for free.
My confusion is what would make it loose signal to the RC within 500 feet distance after 15 min flight when it was fine a mile away on first 5 minutes of flight.
Photo attached is how it looked like when I took off, weather was fine, no strong wind. Just the area was a little remote so gps couldn't stabilize the drone.
Don't understand what caused drone to disconnect from rc, there is a difference with losing video transmission for a bit but still having control of drone.
 

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ba2usa

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There's nowhere too remote for GPS to work.
Your lack of GPS was due to a hardware problem.
Maybe, as drone was just out of 1 year warranty so DJI doesn't really care what happened...
I was flying the same drone 3 days earlier in different part of Alaska, and still had gps problem, i always blamed it on "remote location" but it could very well be drone hardware.
Gps aside, i still don't understand why would it disconnect from RC, as it was still in the air and not damaged by anything before disconnected 🤔 I'm just trying to get better understanding so it doesn't happen to my replacement drone as i lost confidence in flying if random disconnect could happen anytime...
 

Kilrah

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Since there is no GPS log it's impossible to know where you were, but if you went behind a hill/obstacle that could explain it.
You do have to always expect a drop, which is why you don't want to fly if you can't get a GPS lock and the safety of RTH.
 

ba2usa

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Since there is no GPS log it's impossible to know where you were, but if you went behind a hill/obstacle that could explain it.
You do have to always expect a drop, which is why you don't want to fly if you can't get a GPS lock and the safety of RTH.
The path was clear, no hills or any obstruction at all between drone and RC, see photo i attached above in one of my replies, it was a straight flight there and back, almost no turns
 

Agustine

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The path was clear, no hills or any obstruction at all between drone and RC, see photo i attached above in one of my replies, it was a straight flight there and back, almost no turns
Any chance there might have been a larger boat in the bay that has sonar or GPS navigation equipment running. This could cause problems with your connection. I have seen this on a couple of Autel drones in the past.
 

ba2usa

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Any chance there might have been a larger boat in the bay that has sonar or GPS navigation equipment running. This could cause problems with your connection. I have seen this on a couple of Autel drones in the past.
Possibly as there is ferry 2 miles away that is going all the way to Washington state weekly
 

Agustine

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Possibly as there is ferry 2 miles away that is going all the way to Washington state weekly
Well if its two miles away I don't think it would have caused you any problems. You would have had to been a lot closer for any interference. There were not any smaller chartered fishing boats around? They do run that type of equipment.
 

Meta4

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Any chance there might have been a larger boat in the bay that has sonar or GPS navigation equipment running. This could cause problems with your connection. I have seen this on a couple of Autel drones in the past.
There's no chance of that having any effect on his drone.
I've flown around boats and ships extensively for 5 years without a glitch.
 

Agustine

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There's no chance of that having any effect on his drone.
I've flown around boats and ships extensively for 5 years without a glitch.
Ya so have I but I know of one or two posts over at the Autel forums where the EVO I drone was flying near a ship and it flew a way. Autel chalked it up to interference with the ships electronics.
It was only a suggestion as to what might have happened. Been doing this since 2015 so I have seen a few things that might surprise you. ;)
 

Meta4

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I was flying the same drone 3 days earlier in different part of Alaska, and still had gps problem, i always blamed it on "remote location" but it could very well be drone hardware.
It wasn't the remote location.
The G in GPS stands for Global.
The system was created to provide global navigation, anywhere, any time and in any weather.
It had to be a faulty GPS receiver or connection.

Gps aside, i still don't understand why would it disconnect from RC, as it was still in the air and not damaged by anything before disconnected 🤔 I'm just trying to get better understanding so it doesn't happen to my replacement drone as i lost confidence in flying if random disconnect could happen anytime...
You said earlier:
>> I flew almost 1.5 miles out with no problems, then once i headed back towards myself drone lost signal to the rc less then 1/4 mile away from me, at the moment it lost signal
Since you had no GPS, you also had no indication of distance or direction to the drone.
You couldn't see the drone either.
So how do you know it was less than 1/4 mile away?
How did you know where it was to be able to point the controller to maintain a strong signal?

Here's what the last two minutes of your flight data looks like:
It's full of Lost Downlink warnings which suggests that your drone was out on the edge of signal reception and to push a little further would cause loss of control signal.

I'd worry more about the reliability of the operator than a replacement drone.
 

Meta4

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Been doing this since 2015 so I have seen a few things that might surprise you..
I doubt it.
I've logged >4000 miles at sea flying ships and boats, also since 2015.

A ship's GPS has no emissions and their sonar is directing an ultrasonic signal into the water.
Neither willl have any effect on a drone (even an Autel drone).
Perhaps you meant radar?
But most of my flying is close around ships with active radar and it has zero effect on DJI drones.
DJI_0634a-M.jpg
 
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ba2usa

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It wasn't the remote location.
The G in GPS stands for Global.
The system was created to provide global navigation, anywhere, any time and in any weather.
It had to be a faulty GPS receiver or connection.


You said earlier:
>> I flew almost 1.5 miles out with no problems, then once i headed back towards myself drone lost signal to the rc less then 1/4 mile away from me, at the moment it lost signal
Since you had no GPS, you also had no indication of distance or direction to the drone.
You couldn't see the drone either.
So how do you know it was less than 1/4 mile away?
How did you know where it was to be able to point the controller to maintain a strong signal?

Here's what the last two minutes of your flight data looks like:
It's full of Lost Downlink warnings which suggests that your drone was out on the edge of signal reception and to push a little further would cause loss of control signal.

I'd worry more about the reliability of the operator than a replacement drone.
No need to be a smartass... Noone likes that.
I know what gps stands for, even GPS on your cellphone will sometimes loose signal for short periods of times when travelling through remote area, it happened multiple times when I was driving through Canada to get to Alaska using Google maps...

I had video stream on my phone up until 13 minutes of flight so i know where the drone was at the moment of signal loss, attached is a photo of my last visual before i lost video stream as well. By my visual estimate that is within 1/4 mile away from me.
If you got a question regarding the situation ask nicely!
This is my 3rd DJI drone and first incident since i started flying in 2016.
 

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Meta4

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No need to be a smartass... Noone likes that.
I know what gps stands for, even GPS on your cellphone will sometimes loose signal for short periods of times when travelling through remote area, it happened multiple times when I was driving through Canada to get to Alaska using Google maps...
It's not smartassery to give factual advice.
Particularly when you don't seem to have a good understanding of what's involved.
As long as you have a clear unobstructed view of the sky, it's not at all normal to lose GPS signal when in a remote area at all.
The wilds of Alaska are no more remote than anywhere else since the satellites are 12000 miles away, orbiting the earth.
 
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