Looking for the some feedback on my drone flying itself into the ocean yesturday. I am still in shock a little, all happened so fast.

Yesturday I was flying out over the ocean filming a friend surfing and I dediced to test out Active Tracking mode. Hovering at about 9 meters above the water and locked onto my friend the drone decended down into the ocean.
All sensors were enabled, all pre flight checks were completed.
Thoughts . . . . is there a case here?

log file

Looking forward to some feedback, don't wanna make the same mistake again when I replace my drone.

unfortunately your log doesn't show why your aircraft was descending , but it looks like thats what happened, one thing i find strange is it descended pretty slowly all you needed to stop it was cancel AT or press pause button.
i think this will be a decision for dji to determine the cause. i wish you good luck.

hallmark007 Posted at 2018-6-10 11:15
unfortunately your log doesn't show why your aircraft was descending , but it looks like thats what happened, one thing i find strange is it descended pretty slowly all you needed to stop it was cancel AT or press pause button.
i think this will be a decision for dji to determine the cause. i wish you good luck.

Granted my reaction time to the drone descending was on the slow side it would be nice to know why the drone wants to fly down so close to the water/ground level when in active tracking.

DouganatorNZ Posted at 2018-6-10 11:19
Granted my reaction time to the drone descending was on the slow side it would be nice to know why the drone wants to fly down so close to the water/ground level when in active tracking.

that is certainly unexplained in the log, and dpi may be able to pull something else from your flight log, but it doesn't any input from operator that would cause it to lower altitude.

DouganatorNZ Posted at 2018-6-10 11:19
Granted my reaction time to the drone descending was on the slow side it would be nice to know why the drone wants to fly down so close to the water/ground level when in active tracking.

Perhaps it is another case of Attack Tracking, instead of Active Tracking.  

There has been several pilots report problems where their drone in Active Tracking decides to go on the Attack.   Few videos have been posted showing the Attacks or attempted Attacks.

Do I need to submit my log file to DJI or will it be picked up from here?

I understand your drone was at height of 9m before it descended into the water, were you moving the controls manually at any point to have the Mavic Air circle or change direction?

davidmartingraf Posted at 2018-6-10 12:05
I understand your drone was at height of 9m before it descended into the water, were you moving the controls manually at any point to have the Mavic Air circle or change direction?

No movement by myself at all, it was hovering in Active Tracking mode with a fix on my subject.

What I find a bit strange from the flightrecord is that the VPS sensors apparently have registered nothing at all when it was back to low altitude before dumping into the sea. It is well known that water surface is irritating the sensors, but no altitude value at all is a surprise for me. But as hallmark007 has explained already, this is clearly for DJI to analyse. I wish you well for your support case: https://www.dji.com/support
In any case you should check if the waves might have carried it back onto the beach.

My thoughts about it is the same as HedgeTrimmer in post #5
There has been a few cases the drone would all of a sudden dive toward the subject in Active Track.
Do you have any video?

DouganatorNZ Posted at 2018-6-10 12:05
Do I need to submit my log file to DJI or will it be picked up from here?

You should open a formal support case with DJI: https://www.dji.com/support

B1houdini Posted at 2018-6-10 12:31
My thoughts about it is the same as HedgeTrimmer in post #5
There has been a few cases the drone would all of a sudden dive toward the subject in Active Track.
Do you have any video?

Sorry no video, I was hovering and waiting for my subject to catch a wave

I don't think active track is GPS positioned.  Instead it uses the image to try to hold position.  As long as the image looked good and was tracking the subject, decending into the ocean isn't a problem.  I wonder if ground proximity sensors don't work over clear water.

B1houdini Posted at 2018-6-10 12:31
My thoughts about it is the same as HedgeTrimmer in post #5
There has been a few cases the drone would all of a sudden dive toward the subject in Active Track.
Do you have any video?

this is nothing like what happened in other active track situations not even close, this was a controlled decent of aircraft this can be clearly seen in the flight log.

This is why I would never ever do active track over water period.  The sensors seem to act up according to a few cases I have seen here.  Sorry for your loss hopefully it will work out well for you.  As mentioned by Wachtberger make sure to get a case started here https://www.dji.com/support/product

hallmark007 Posted at 2018-6-10 12:55
this is nothing like what happened in other active track situations not even close, this was a controlled decent of aircraft this can be clearly seen in the flight log.

The one video I saw showed the drone tracking and then slowly descend toward the subject. Looked controlled to me. Never saw any flight data so I can't say what was the cause.

Very sorry for your loss! It sucks for sure. This is why I firmly believe the best practice is to learn any and all features by manually doing them. I do not trust most of the Tracking and Waypoint features provided in these drones and the Go4 App, I never use OAS or VPS, have them all shut down on the P4P,MP and MA (you would be surprised at how much smoother the drones fly when Expo, Gain & Braking is set manually without interference from internal algorythems).
I do use the quickshot Asteroid feature  in the MA though as I can't accomplish that manually. As for POI's, Boomerangs and Dronies they can all be done manually and the more practice the better they get.

QuadKid Posted at 2018-6-10 13:22
Very sorry for your loss! It sucks for sure. This is why I firmly believe the best practice is to learn any and all features by manually doing them. I do not trust most of the Tracking and Waypoint features provided in these drones and the Go4 App, I never use OAS or VPS, have them all shut down on the P4P,MP and MA (you would be surprised at how much smoother the drones fly when Expo, Gain & Braking is set manually without interference from internal algorythems).
I do use the quickshot Asteroid feature  in the MA though as I can't accomplish that manually. As for POI's, Boomerangs and Dronies they can all be done manually and the more practice the better they get.

I am the same way just feels smoother with OAS/VPS turned off which I never fly with.  Plus you get better battery life and faster speed.  I never fly close enough to anything to have to worry about a collision.  I am with you just do not really trust most of the features which is why I prefer to do manual flying like you said.  

27.2 feet in 4.8 seconds.  With Active Track trying to adapt to changes in height of target due to waves?

I echo everyone's sentiments that it will be up to DJI Support to review and determine the outcome of what went wrong. Good luck with everything and try to ask DJI what options you have for receiving a replacement drone so that you can get back up flying again quickly.

Was it going straight towards the tracking subject or some other point?

SeanGalbraith Posted at 2018-6-10 18:37
Was it going straight towards the tracking subject or some other point?

Straight towards the subject but crashed maybe 30 from the subject.

We do apologize for the inconvenience and I am sorry to know that your Mavic Air crashed. The best thing we can do in this situation is for you to create an online repair request on this link https://repair.dji.com/repair/index so that we will be able to check what really happened to the drone. You need to sync the flight records from the DJI Go 4 app as well for analysis.

DouganatorNZ Posted at 2018-6-10 19:38
Straight towards the subject but crashed maybe 30 from the subject.

Certainly couldn't say for sure, but that sounds like a DJI drone attack that other people have reported.

maybe you hit water from a 9 foot wave.

Thank you for all the feedback.
I can confirm today that DJI have accepted my claim and a replacement is going to be with me on Monday.
Very good result from DJI.

Would still be nice to know why the drone decided to attack its subject but I guess there will be no more Active Tracking for me over water.

Back in air soon in a few days

DouganatorNZ Posted at 2018-6-14 01:35
Thank you for all the feedback.
I can confirm today that DJI have accepted my claim and a replacement is going to be with me on Monday.
Very good result from DJI.

Great job wish you luck with the new one. Fly Safe.

Great news about you get new replacement!! Have safe flights!! Remember calibrate everything before first take off!!

Fly safe mate and enjoy your Mavic Air

Hello,

I am posting here because I need some help from you guys to help me understand DJI’s support respond after my drone crashed in the ocean.

As mentioned my drone crashed last March. I was flying above the ocean and I lost track of it and it crashed in the ocean. Luckily I found it on the beach the next day and I could recover the SD card and all photos and videos.

I must mention that the Mavic Air was my fist drone and I bought it for its performance but specialty for collision and obstacle avoidance sensors.

What I asked DJI support is why didn’t the bottom sensors intervene in order to avoid it crashing into the ocean I got several explanations.
-        “The drone flies to the sides and the obstacle avoidance on both sides will not work in the GPS. There will be no prompts and it has mentioned in the user manual, please see the screenshot below:
The Lateral Vision Systems are only active in ActiveTrack 2.0 and Tripod Mode, as well as QuickShots sub-modes of Circle, Helix, and Boomerang (when using firmware v01.00.01.00 or above). The angular speed is limited to 24°/s and the lateral flight speed is limited to 18 mph (29 mph).”
My question: The argument talks about Lateral Vision Systems. I am talking about bottom sensors. The video shows that the drone did not crash on the side but straight down. Is DJI’s argument valid?

-        A snapshot of the Flight Environment Requirements saying “3. Avoid obstacles, crowds, high voltage power lines, trees, and bodies of water”.
My question: Ok, I agree but “avoid” does not mean that it’s strictly prohibited. If I take the case of trees, a lot of tutorials can be found on Youtube showing how the collision avoidance works on the DJI Mavic Air, and guess what, the avoided obstacles are trees! Is DJI’s argument valid?

-        The conclusion of the analysis was : “ According to the conclusion of data analysis,
it was caused by the surface of the water which cannot be visually positioned. We kindly suggest that please read your user manual for the part of the manual visual positioning conditions.”
At least they are honest enough to recognize that the drone could not identify that the water was an impact object.
My question: In what cases is the collision avoidance system, that is a feature that is very much publicized, can be useful if you have to avoid trees, water etc when flying? Is the drone supposed to fly only in the desert, in open fields etc?  

Do you find DJI’s answers valid or am I the only one considering that the anti-collision system did not do its job?

Like always when it comes to support a manufacturer will find the perfect phrase lost in some kind of documentation in order not to repair or replace the device. Nevertheless, in some cases, like this topic, I saw that the devices crashed in the ocean have been replaced.

Thank you for giving me your opinion about this issue. I might be wrong when I am blaming DJI. But I also might be not…

Andrei

i wish you luck in solving your issue

AndyFR69 Posted at 1-7 08:03
Hello,

I am posting here because I need some help from you guys to help me understand DJI’s support respond after my drone crashed in the ocean.

What I asked DJI support is why didn’t the bottom sensors intervene in order to avoid it crashing into the ocean
The conclusion of the analysis was : “ According to the conclusion of data analysis,
it was caused by the surface of the water which cannot be visually positioned. We kindly suggest that please read your user manual for the part of the manual visual positioning conditions.”
Is DJI’s argument valid?

The downward facing sensors are not magic and have many limitations.It is important to understand these limitations and the circumstances where the sensors might not be reliable.
DJI explain this on p18 of the Mavic Air manual:
  

Operate the aircraft with great caution in the following situations:

    a. Flying at high speeds below 1.6 ft (0.5 m).

  b. Flying over monochrome surfaces (e.g. pure black, pure white, pure red, pure green).

  c. Flying over highly reflective surfaces.

  d. Flying over water or transparent surfaces.

  e. Flying over moving surfaces or objects.

  f.  Flying in an area where the lighting changes frequently or drastically.

  g. Flying over extremely dark (< 10 lux) or bright (> 100,000 lux) surfaces or towards bright sources of light (e.g. towards sunlight).

  h. Flying over surfaces without clear patterns or texture.

  i.  Flying over surfaces with identical repeating patterns or textures (e.g. tiling).

  j.  Flying over small and fine objects (e.g. tree branches or power lines).

  k. Flying at high speeds of over 11.2 mph (18 kph) at 3.3 ft (1 m)

  
At least they are honest enough to recognize that the drone could not identify that the water was an impact object.
My  question: In what cases is the collision avoidance system, that is a  feature that is very much publicized, can be useful if you have to avoid  trees, water etc when flying? Is the drone supposed to fly only in the  desert, in open fields etc?  
The drone is fine for flying in many different situations but the pilot has to be aware of the limitations and when he needs to exercise proper care appropriate to the flying situation.

Do you find DJI’s answers valid or am I the only one considering that the anti-collision system did not do its job?
I think their summary is probably valid.
I would have to examine the flight data to see if there was any other important information.

Like always when it comes to support a manufacturer will find the perfect phrase lost in some kind of documentation in order not to repair or replace the device.
Page 18 of the manual is not hidden.
It's also not to avoid warranty claims.
It's there to warn you of the limitations of the vision sensors and when they might not be reliable.

Nevertheless, in some cases, like this topic, I saw that the devices crashed in the ocean have been replaced.
It would all depend on what cause the crash.

I might be wrong when I am blaming DJI. But I also might be not…
No .. it really looks like you are wrong this time.

Labroides Posted at 1-7 19:44
What I asked DJI support is why didn’t the bottom sensors intervene in order to avoid it crashing into the ocean
The conclusion of the analysis was : “ According to the conclusion of data analysis,
it was caused by the surface of the water which cannot be visually positioned. We kindly suggest that please read your user manual for the part of the manual visual positioning conditions.”

Hi,

Thank you for your reply. So it seems that I was wrong! I bought the drone because as a beginner I taught the anti-collision system would help me in some situations. But the list of exceptions is really long. In that case it might be wiser for me to buy a cheaper drone like the Mavic Mini that does not offer the feature and therefore does not have a 3 pages long limitation list. At least with the Mini when you crash it you know that you are responsible.

Thanks again for the analysis.

AndyFR69 Posted at 1-9 01:37
Hi,

Thank you for your reply. So it seems that I was wrong! I bought the drone because as a beginner I taught the anti-collision system would help me in some situations. But the list of exceptions is really long. In that case it might be wiser for me to buy a cheaper drone like the Mavic Mini that does not offer the feature and therefore does not have a 3 pages long limitation list. At least with the Mini when you crash it you know that you are responsible.

In that case it might be wiser for me to buy a cheaper drone like the Mavic Mini that does not offer the feature and therefore does not have a 3 pages long limitation list. At least with the Mini when you crash it you know that you are responsible.

The simple solution is to avoid flying close to obstacles.

DouganatorNZ Posted at 2018-6-10 12:05
Do I need to submit my log file to DJI or will it be picked up from here?

yes, open a case file asap.

I had my case resolved and a replacement sent out as DJI took responsibilty of my MA disapearing.

Fingers crossed for you
you can see this on