I lost my DJI Air 2 in a lake

[Ciobi]

Last year I made a regular flight on the shore of a lake while I was fishing. Everything went normally until a moment when I suddenly lost the signal. I waited quietly for the drone to return home, but that did not happen. After about 5 minutes I got in the car and went closer to the place where the drone should have been still flying, but I could not find it.
I do not understand how it lost the signal so suddenly? There was no obstacle between me and the drone and there were no more than 950m. I am attaching a link with the flight data. Please help me someone who can better interpret this data.

Thank you.

 

[Meta4]

I do not understand how it lost the signal so suddenly?

The only logical explanation is that your drone had a sudden loss of power.
No power = instant loss of signal and the drone falls from the sky.

 

[msinger]

I do not understand how it lost the signal so suddenly?

The signal was pretty consistent near the end of the flight. As noted above, it likely dropped out due to a loss of power.

 

[Capt KO]

Sorry for your loss. Too late now but the A2 might have been salvageable shortly after the dunking. Fresh water doesn't usually destroy these drones immediately and if dried thoroughly and quickly can fly again. Of course someone has to go swimming at last know location.

 

[Ciobi]

The water was 2.5 m deep. I tried to find it by swimming but I had no chance. It probably lost power when it was moving at 40 km/h. and it fell further than the last point that appears recorded on "Find my drone", especially since the height at that moment was 40 m.
I also thought that the only explanation is that it suddenly lost power. Now I bought an Air 3, but, honestly, I don't trust it to fly anymore.
Thanks for the answers!

 

[Capt KO]

Please don't give up.. Most pilots suffer a loss eventually but it leads to becoming an even better pilot. Fear is the biggest obstacle to flying drones, learn to overcome it and you'll thrive. Send us some pics n vids when you can.. and don't be afraid of the water, nearly all my flights are over water.

 

[EJs Mini down under.]

Please don't give up.. Most pilots suffer a loss eventually but it leads to becoming an even better pilot. Fear is the biggest obstacle to flying drones, learn to overcome it and you'll thrive. Send us some pics n vids when you can.. and don't be afraid of the water, nearly all my flights are over water.

same here, as i live on an island

 

[Bad Santa]

Could have broken a prop or had one come off.

 

[Meta4]

Could have broken a prop or had one come off.

The data makes it clear that this didn't happen.
If it did the data would have shown he drone spiraling downwards and the OP would have been well aware of the issue.
But the data shows the data suddenly ending with the drone is steady, straight, level flight .

 

[msinger]

Could have broken a prop or had one come off

That's unlikely since the flight log shows no signs of a broken or lost prop.

 

[kpjamro]

There was also a loss of signal at 5:20 but it recovered by itself. That was a hint.
I note that you last descended from 650 to 140 feet where your radio coverage would have been reduced quite a bit. But it was rather sudden. However, it looks like still had RC signal at that point, even though video was lost. Hitting RTH or simply ascending might have saved the day.

 

[Meta4]

I have heard of a phenomena where a drone sensor's can mistakenly read a body of water reflection as
the sky. The drone is then instructed by god DJI to adjust its altitude and dives in to land....
As this makes sense to me

This isn't true and none of it makes any sense.

(my standard habit) always be ready to switch to Sport Mode and completely take over control of the drone in case I observe something I do not understand. This last point is my advice to all :
Unless I am mistaken, Sport Mode cuts off GPS and sensors.

You are mistaken.
Sport Mode does not "cut off GPS".
It simply makes allows the drone to tilt further and fly faster.
Obstacle avoidance can't work with the greater tilt angle.

Practice switching to this mode in a panic mode in an emergency.

Switching to Sport Mode isn't going to help in an emergency.

For those interested I came up with this last point after having experienced the famous toilet bowl effect a long time ago. This was when we had to build our drones ourselves.... In summary the toilet bowl effect could happen if the GPS Compass antenna was not properly positioned on the drone taking into account the true magnetic north at the drone's precise location. The drone could start going into a wide circular motion like if caught in a toilet bowl flushing as it would overcompensate the GPS Compass false reading. It would go faster and faster and would turn sharper and sharper until it drops from the sky... unless you turned off the GPS when it started happening.

This is confused and misleading and completely irrelevant to flying modern DJI drones.
.
What you experienced had nothing to do with positioning the GPS Compass (there's no such thing) antenna,taking into account the true magnetic north at the drone's precise location, even if such a thing was possible.
It was due to not having calibrated your compass to account for the magnetic fields that were part of the drone itself.

 

[Meta4]

Hitting RTH or simply ascending might have saved the day.

No.
His drone's Failsafe Action was set to RTH on loss of signal.
There were no obstacles between to drone and controller and the drone was making good speed towards home when the data ends.
If the issue was simply losing signal (it wasn't), the drone would have initiated RTH and come home.
The issue was that the drone lost power, which explains the loss of signal, and the drone fell from the sky.

 

[Meta4]

I do not pretend to know everything and would not comment categorically I know the truth but:
Very common issue reported a multitude of times about sensors and water reflections

Yes .. it's a complete myth which gets repeated a lot, just like you are doing here.
It had nothing at all to do with the OP's incident.

The of the incident in the video you posted would probably be seen in the recorded flight data for that flight.
Without seeing the data, the video proves nothing at all.

You are right about Sport Mode by default still having GPS.
But you can set your Sport Mode to ATTI which is without GPS, Compass and sensors.
It has to be done via DJI Assistant.

You would have to hack your drone to do that.
It isn't available without hacking teh drone and isn't possible with some models.
But switching to Atti Mode wouldn't have done anything to help the OP.
His drone lost power and fell into a river.

Toilet bowl effect, a very well-known issue when building a drone, as an illustration to why it is important to know how to fly a drone without all its technologies such as GPS, Compass and Sensors.

I know what toilet bowl effect is and it had nothing to do with the OP's incident and gave an explanation of its cause in my previous post.
It also has nothing to do with placing of the "GPS compass" and the other stuff you mentioned.

If "modern drones"do not have the same issues as the "old drone" forums are still full of stories of mishaps...

His incident had nothing to do with the things you misunderstand and suggested here.
Yes, there are still mishaps, most of which are due to operator confusion and error.

 

[Meta4]

Sensors and water reflections : No proof maybe but you have no proof either it is really a loss of power in the case we are looking at.

It was a loss of power because none of the other alternative causes for the loss of the drone fit what the data shows.
As for the myth of water reflections, I have 12000 miles of flying over the sea and have analysed the data from hundreds of flight incidents including many that occurred over the water.
You: have heard tales about the drone sensor's being confused.

ATTI : no need to hack your drone just use the correct DJI Assistant version.

For the Mavic 3 pro ??

I repeat. I gave the toilet bowl incident as an illustration.
Could it be that what you think I misunderstand a misunderstanding on your part of what I am saying?

More likely that you think I misunderstood what I understood very well.

If mishaps were mostly operator confusion (!) and error where does a sudden loss of power fits in?

Data analysis has shown most mishaps to be operator error.
That's most but not all.
A small proportion are things like power loss due to batteries becoming dislodged, probably due to swelling and genuine rare hardware errors.

My point really is drones are great machines but operator "confusion" and errors aside they are still subject to unpredictable behaviors in particular situations (interference, KP index, reflections, etc...).

You've been taken in by myths.
Interference doesn't cause unpredictable behaviour, it just blanks out the control signal if it's strong enough and reduces your range.
Kp index ?? There has never been a single drone incident that could be attributed to flying in high KP conditions.
If you want to challenge me on that, show me the recorded flight data from a flight you believe was affected.
And if it was a real thing, wouldn't hundreds of drones be affected on the same day?
Kp index is going to Kp 7 in about 3-6 hours if you want to see how it affects your flying.
Also high again on April 5, 8 & 9.
Water reflections? Bah humbug!

Drones are very predictable and perceptions of unpredictable behaviour are most likely due to operator confusion or disorientation.

 

[Meta4]

Having a plan B ready like turning off quickly GPS, sensors and vision is in my opinion a good idea.
Take care.

Turning off your GPS and OA sensors is unlikely to help you if you encounter any "unpredictable behaviours".

 

[Sushi Wasabi]

You are right 110% and some more if you'd like.
Take care. Fly safe.

 

[Ciobi]

There was also a loss of signal at 5:20 but it recovered by itself. That was a hint.
I note that you last descended from 650 to 140 feet where your radio coverage would have been reduced quite a bit. But it was rather sudden. However, it looks like still had RC signal at that point, even though video was lost. Hitting RTH or simply ascending might have saved the day.

I tried all possible options in a very short time. First I tried to get up, then I activated RTH. All this, even though the screen was frozen. I drove pretty quickly to the place where I last saw the drone on the screen, but it was gone even though it had 50% battery left .During this time someone was permanently at the Home point, thus ruling out the possibility that the drone returned while I was away and then was stolen. The drone was flying at a height of 43 m, so I don't think the water reflection could have influenced any sensors. I've been flying drones for six years. I don't think I did anything wrong... I strongly believe that the drone suddenly lost power.

Thank you all for your opinions and support.

 

[Ciobi]

Please don't give up.. Most pilots suffer a loss eventually but it leads to becoming an even better pilot. Fear is the biggest obstacle to flying drones, learn to overcome it and you'll thrive. Send us some pics n vids when you can.. and don't be afraid of the water, nearly all my flights are over water.

That's right, but I'm annoyed that I don't know the truth. It's probably normal to have a loss at six years of flying , but at least I know why? That's why I feel insecure now.

Thanks for the thoughts!

 

[MS Coast]

That's right, but I'm annoyed that I don't know the truth. It's probably normal to have a loss at six years of flying , but at least I know why? That's why I feel insecure now.

Thanks for the thoughts!

The flight log clearly shows a sudden loss of power during normal flight. There's no control input you could have made to cause that.

The fact that the drone was over water is immaterial.

A failure of some component in the drone is a likely cause. Other possibilities are the battery disconnecting due to swelling and the battery not being installed securely. That last one is the only way I can see that you might have been responsible.

Get back on the horse. Continue flying responsibly and have fun.