Hey guys, been loving my Spark for about 18 months with zero crashes and very calm 100% normal mode flights.
Couple of days ago I was flying over a beach in Fiji when it suddenly started descending rapidly, not falling but dropping fast.
I tried to fly towards land and upwards but the spark landed into the waves a couple of meter ahead of me.
It was under the water for maybe 10 seconds before I grabbed it and disconnected the battery.

Im now trying to figure out what happened and if the drone can be saved.

1. Can someone help me go through the log and see if anything looks abnormal? I have no idea why the drone descended. I got no messages or warnings in DJI 4.
https://www.phantomhelp.com/logviewer/TBY0P46LOMRQOUQC9JF4/

2. I have disassembled the drone and found the heat sink (?) to be very eroded? Please check photos. Maybe the drone got overheated - Can I get this from sensor logs or similar?

Hello and good day dejv. I am sorry to know that you are having issues with your new DJI Spark. Since this issue is happening to your Drone. The best thing you need to do is to contact DJI Support at https://www.dji.com/support for us to help you further with this matter. Thank you.

Ow. Electricity and salt water do not mix. I expect your poor spark is a goner.

ok after reviewing your log i suspect you where flying wifi and no rc , you lost your vision sensor over the sea maybe it got wet maybe a wave, so it depended on gps for altitude ,I think your drone suffered from a faulty sensor due to prolonged use in a marine environment

I would agree, seems DJI's choice of metal composition is highly corrosive in salt water environment! That's some pretty bad PR for DJI I think right there, unless that aircraft which flies very high and could do some serous personal and property damage.

Scary! thanks for sharing

That's some serious corrosion!  Me thinks that is probably not the 1st time it has taken on a little sea water?

HI guys and thanks for your answers.
I was flying Wifi, yes. I do not own the RC - never have. So wifi is the only way I've ever been flying.
This was a clear day and on a beach so I had perfect line of sight to the drone. - Interesting not with the loss of vision sensors.

I have never used the drone in rainy weather, It has never crashed before and has definetly never touch sea water. I do not usually fly over water, this was on my vacation. It has always been kept inside the box it came with.
This was the first time it came into contact with water. I am not an expert, but it seems that corrosion like this should need quite some time to be able to go through the metal like this?

dejv Posted at 2-10 23:43
HI guys and thanks for your answers.
I was flying Wifi, yes. I do not own the RC - never have. So wifi is the only way I've ever been flying.
This was a clear day and on a beach so I had perfect line of sight to the drone. - Interesting not with the loss of vision sensors.

hi,

Wow, what a corrosion !!
How many days between his 'swim' and dismantling the drone?

Salt water can do great damage to metal parts, so if this was really the first time ever getting soaked (i do believe you) than it does say something about the salt water resistance of the Spark. Guess time for another one ; MA?

BTW, had a look at your flight too. Cannot see/find a reason why it went down.

cheers
JJB

dejv Posted at 2-10 23:43
HI guys and thanks for your answers.
I was flying Wifi, yes. I do not own the RC - never have. So wifi is the only way I've ever been flying.
This was a clear day and on a beach so I had perfect line of sight to the drone. - Interesting not with the loss of vision sensors.

salt air is strongest around coastal areas. ... Salt air will cause metals to oxidize and corrode.

Your vision sensors are located below the drone , you should make shure they are clean and spotless before flight , in you case the may have become faulty due to corrosion

JJB* Posted at 2-11 04:26
hi,

Wow, what a corrosion !!

Hi JJB*. It was about 4 days between.

Procedure was something like this:

0s. Crash
0-15s. Salt water and sand, submerged.
15s.  Battery separation.
2m. Rinse off with fresh water.
2m - 15m Drying with paper, shaking etc to get water out.
15m - 3days put into bag of rice, no tools avaliable at this time.
4 days. Disassembly.

Proteous Posted at 2-11 04:30
salt air is strongest around coastal areas. ... Salt air will cause metals to oxidize and corrode.

Your vision sensors are located below the drone , you should make shure they are clean and spotless before flight , in you case the may have become faulty due to corrosion [view_image]

I do live in a coastal area, so most of my flights have been within a few km of the sea.
- I have friends though in the same area with Sparks and theirs look brand new inside.

Oh, also - there is sand inside the motors - is there any way to open the motors? I noticed there is a small locking ring on the motor axle - I did get that off but cant find a way to separate the rotating part from the fixed part? Just force?

dejv Posted at 2-11 05:05
Oh, also - there is sand inside the motors - is there any way to open the motors? I noticed there is a small locking ring on the motor axle - I did get that off but cant find a way to separate the rotating part from the fixed part? Just force?

to be honest with you with the amount of corrosion your drone has ,I would send that in to dji ,I would not risk trying to repair it myself , trying to fly that in its present condition would be another accident waiting to happen

dejv Posted at 2-11 04:59
Hi JJB*. It was about 4 days between.

Procedure was something like this:

Hi,

The correct procedure would have been:
0s. Crash
0-15s. Salt water and sand, submerged.
15s.  Battery separation.
1m Disassembly
2m. Rinse off with fresh water.
3m. Rinse off with pure alcohol
3days dry it with a hairdryer, then let it dry over a warm furnace
Then assemble it and try.

That rice bag thingy is an urban legend, it does not really help drying up humidity inside electronics.

Have you bought that Spark used? Because the amount of corrosion looks like it spent days or weeks in salt water...max be the previous owner lied to you.

Anyway, you need all new electronics boards and probably the ESCs. Basically this thing is toast.

Cheers,
Wolferl

Hi,

I think the only way to repair that drone would be to jack up the props and drive a new drone under them.

Living near the ocean is what got you. There is a lot of salt in the air near the coast line. It is amazing how quickly aluminum can corrode being near ocean air. I wonder if one could conformal coat the aluminum to prevent this kind of corrosion.

If you get sand in a motor the best way to remove it is to use compressed air. There are metal particles in sand and it will stick to the magnets in the motor. I cleaned several Phantom 3 motors for a guy using compressed air and they were fine.

The best things to do if you crash in salt water. Even fresh water is some cases.

1. Remove the battery ASAP. A MUST!!!
2. Place the entire drone (less battery) in a bucket of fresh water. DI (de-ionized) water is best, you can get DI water at most super markets. Start with fresh water ASAP if that is all that is available then transfer to DI water ASAP.  Leave it in the DI water until you are ready to disassemble it. I would not wait too long, disassemble ASAP. Disconnect all connectors to allow any trapped moisture to escape. The key is not allow fresh air to come in contact with the salt water inside the drone. Place it in a bucket of salt water if no fresh water is available but exchange for fresh or DI ASAP.
3. After disassembling, use compressed air to blow as much water from the components  as possible.
4. Give everything a a good scrubbing with some isopropyl alcohol or fresh DI water and a soft brush. Then blow dry again with some compressed air. If the compressor has a moisture filter (air dryer) that's even better but not necessary.
5. Place the disassembled drone (less plastic parts if possible)  on a sheet of wood or soft towel and place it in your oven. Set the oven to warm or as low as possible and leave the door slightly open to allow moisture to escape. Electric ovens are best as natural gas and propane contain moisture. Bake the drone for a minimum of 24 hours. The temperature must be kept low, you should be able to pick up and hold the drone without any discomfort. You do not want to re-flow any solder. Our bake-in room was kept at +40 degrees C  (100 degrees F). Anything much hotter may distort some of the plastic.
6. Reassemble the drone and hope for the best.

The battery should be replaced I would not recommend trying to save the battery.

Most electronic PCB  (printed circuit board) assemblies are soldered using either no clean flux or water clean flux. We have a DI wash station used to clean assemblies that used water clean flux. It's like a giant dish washer. Most electronic components are capable of water clean. Just not salt water.

I disagree with some of the comments made. Aluminium is fairly resistant to corrosion when exposed to salt. Boats and window frames are made of aluminium and Ive never heard of either falling apart. Especially when exposed to oxygen it develops an oxide layer which further protects it.

The problem is when aluminium is exposed to a different (less active) metal where it can get ugly and it gives up atoms and falls apart. That wont matter if you live on an island or the desert. So I suspect the design of this heatsink is a problem or something went bad during the manufacturing process where it hasn't been isolated correctly from other metals.

Id say push DJI to replace this under warranty.