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Crashed my Mavic air in cave water

UAV forecast won't be much help in identifying magnetic interference - if only it could!
Didn’t say that either, just another problem we have to deal with and not just blaming DJI as quickly something strange happens to the drones.
 
Have you ever seen satellite-TV when heavy rain falling? It’s like snowing on the screen and the receiption disappears. You seems to be that old (like me) that you were born before cable-tv.?
That is not positioning... completely different signal.
 
Have you ever seen satellite-TV when heavy rain falling? It’s like snowing on the screen and the receiption disappears. You seems to be that old (like me) that you were born before cable-tv.
I've been using GPS for 20 years in all weather and haven't ever had a problem in the worst weather.
 
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The only thing that will block your GPS signal on your drone is:

-Terrain ( rocks, concrete, trees and so on)
- The military when they do testing.

That’s it.

Again weather, wind, or atmosphere has nothing to do with it!!! (Actually it’s even funny when mentioned)
 
The only thing that will block your GPS signal on your drone is:

-Terrain ( rocks, concrete, trees and so on)
- The military when they do testing.

That’s it.

Again weather, wind, or atmosphere has nothing to do with it!!! (Actually it’s even funny when mentioned)
Maybe also include metal bridge trusses.
Also consider standard road bridges if VLOS is lost even at very close range.
These things will also block controller signal. RTH is a disaster if your under a bridge and RTH kicks in.
 
...1. Could this “maximum altitude reached” while flying just 3 metres above the ground be a production faillure? And could this help me to get a new drone if it is the case?
2. Do you have any recommendations on what I can do more with my drone which is currently surrounded by dry rice?...
Regarding your questions:
1) No, as @Meta4 mentions in post #8.
2) Normally, you would first rinse it with distilled or de-ionized water to flush out any solids from the dunking but the cave water may have been clean enough (providing no sediment was stirred up in the recovery) to skip this step. That would be followed by another rinse with 99% (or as high as you can get) isopropyl alcohol to displace the water. Don't forget to flush the motors and gimbal. Then a gentle blow dry and placement in a sealed container with some silica gel packets.
 
Two threads???
DJI will not fix a water damaged drone full stop.
If you had refresh, and could return it, you would get a new/refurb one.
No refresh, buy a new one.
 
So today I’m going to test if the drone is still working. However, I’m affraid some rice is still inside the drone. Could this damage th drone when I start it up again later today?
 
So today I’m going to test if the drone is still working. However, I’m affraid some rice is still inside the drone. Could this damage th drone when I start it up again later today?
Some gentle hits with your palm and some canned air may dislodge if inside. I suppose a finer grain could get stuck in the cooling fan. Confirm that the fan is running before you fly. Don't forget to carefully inspect the motors and insure that they spin freely. Too late now, but you should wrap first with cheesecloth to keep the rice out and to keep it from sticking or leaving residue (better yet to use silica gel packets). Good Luck!
 
Sorry to hear about, but it’s the same stupidity as to fly under bridges close to water just for a good movieclip. The gps satellites are all over the sky in all directions and most of the time the drone can see 12-20 of those, if you then cover the receiving by flying under something (bridges, threes, rock, caves) for a few seconds there might not be enough with just 6-9 satellites and the drone goes in to atti-mode wich means manually flying, and then you must know how to solve it. A expensive learning money for the future.
I prefere an app called ”UAV Forecast” wich show me how many sats that is receivable right now depending on weather and wind and atmosphere.

Not sure you need to be as abrupt as this! It was more 'naivety' / lack of knowledge that caused this

Yes, I am also sorry OP lost his new drone, but he is guilty of several stupid mistakes:

1. He has obviously not read the manual, that explains the operation of a very complex device.
2: He did not read, understand, or interpret the data given from the instrumentation, nor the terminology.
3. He never practiced flying in ATTI mode, that would have helped him recognize the ACs erratic behavior, and either fly with caution, or abandon the idea about flying in a cave.
4. He was overcome and "was so thrilled about the beautiful nature and instantly grabbed my new Mavic Air. Due to impatience, OP neglected pre-flight checks and procedures, and took off with 0 satellites in view.
5. Experienced pilots know 80%+ of AC mishaps occur due to pilot error, and not claim-worthy DJI hardware failures.

#2, 3, and 5 could be called naiveté . It's tough to say the same about #1 and #4. I think that DJI, however, shares much of the blame, by marketing their ACs to make drone flight look totally automated, with no experience needed. Common sense is still required.

I'm not trying to be harsh.....it happens to everyone. 3 nights ago, my Mav Air was 15" (6cm) above water, auto landing. I had ASSUMED the HP was still set the same as the 1st flight. I couldn't see the AC, with all the water reflection....and ascended in the nick of time. I'll admit is was stupid to activate RTH, when the AC didn't know where home was located....the last 10 seconds shows the AC almost 6 feet below my location.


I hope OP's Mav dries out, he never crashes again, and captures wonderful video :)
 
Yes, I am also sorry OP lost his new drone, but he is guilty of several stupid mistakes:
We try not to pass judgment by using the word ‘stupid’, but we all agree & have given him plenty of advice of where he went wrong.

Speaking of observations & advice, your video was taken at night in a built up, populated area. I take it you’re either flying in a country that has VERY relaxed laws for drone operations, or you have a full commercial licence and all the necessary waivers?
 
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We try not to pass judgment by using the word ‘stupid’, but we all agree & have given him plenty of advice of where he went wrong.

Speaking of observations & advice, your video was taken at night in a built up, populated area. I take it you’re either flying in a country that has VERY relaxed laws for drone operations, or you have a full commercial like licence and all the necessary waivers?
And who want’s to have a drone hanging outside the bedroom window late nights? Same stupidity in My eyes.
 
Mavics will fly very well and stable without GPS if they can get a VPS lock. It's designed to be able to fly using just VPS.
However a cave tends to be dark so VPS in such a case will probably fail, in which case you're in ATTI mode, subject to wind drift.
I've successfully flew my M2 indoors in an expo hall, no GPS, recording my Club's model train layout. I was limited to around 10 ft altitude though, the reliable limit of VPS, so 3 meters sounds about right.

VPS altitude on Air and M2 is based on IR, so it could have been sensing the bottom of the water basin vs water surface. How deep was the water?

Even with a VPS lock, water currents would be seen as stationary surface so the AC would follow the water current. Think of tracking the surface of a treadmill or people mover.
 
3 nights ago, my Mav Air was 15" (6cm) above water, auto landing. I had ASSUMED the HP was still set the same as the 1st flight.
That's not a good assumption because your drone can never use a homepoint from a previous flight because the recorded homepoint is completely lost when you power down the drone.
When you power up again, it has no homepoint until it gets GPS reception again.

[QUOTE="Flystraight, post: 800848, member: 104271"] I'll admit is was stupid to activate RTH, when the AC didn't know where home was located [/QUOTE]
What makes you assume the drone did not know where home was?
It would be very, very unlikely that your drone had not recorded a home point when you powered it up and it got a good GPS location fix.
It might be a good idea to have someone look at your recorded flight data to find out what actually happened rather than working from assumptions that aren't correct.
 
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We try not to pass judgment by using the word ‘stupid’, but we all agree & have given him plenty of advice of where he went wrong.

Speaking of observations & advice, your video was taken at night in a built up, populated area. I take it you’re either flying in a country that has VERY relaxed laws for drone operations, or you have a full commercial licence and all the necessary waivers?

Yes to both of your assumptions & questions (at least until October 2019). I run a heavy lift aerial video firm, in Singapore, and have the appropriate tickets. I agree, it is never constructive to pass judgement on others' knowledge, experience, and skillset. OP was flying a UAV in a country that forbids civilian use, and most certainly not in Son Doong Cave. It is the world's largest cave, and carefully preserved by Vietnamese authorities. ~100 visitors are allowed per year. There are many other world class caves, but all are prohibited from UAV use, unless fully sanctioned by several Government agencies, both military & civilian.
 
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