Mavic 2 Pro.. 1 Min crash... :(

[gberry]

New user, my first post:

I have a Mavic 2 Pro that I launched and had an incident. I launched the drone and I may have had an issue with the phone dislodging from the remote or the USB cable may have dislodged, I'm not sure which because my eyes are focused on the drone. At about 100 feet after takeoff, drone above my head, I discovered I had no control over the drone and it hovered for about five seconds then drifted to the right (6 pm, no wind) and started a slow descent, from my position (an elevated platform) I could not get under it fast enough, it clipped some leaves and fell about 12 feet onto my lawn. The gimble was damaged and the IMU could not be calibrated. I submitted the drone to DJI for data analysis and warranty repair. DJI denied the claim as user error, stating that RTH was set under a tree. I rebutted this with screenshots from my DJI GO 4 App, but then they countered by saying a faulty USB cable was used, "Use better cable next time".

It looks like my bad luck extends further as the flight data on the phone is either corrupt or missing or incomplete, but I don't know if there should be flight data on the drone itself as this is also corrupt or missing or incomplete. Can someone confirm if flight data should be on a drone, please?
All of the above does not explain why I did not have control over the drone within seconds of launch, and I have many other flight logs launching from that very spot with no issues. I replayed the flight on my phone in the DJI app and the warning message that came up was about downward obstacle avoidance, ambient lighting. The IMU situation bothers me as well because I don't know if it was damaged because of the crash or if it was faulty in the first place and contributed to the crash. It was actually a refurbished unit from Amazon and I had it for only 2 days.

(1) Total loss of control shortly after launch.
(2) Drones slowly descending to an incorrect return to home point.
(3) IMU cannot be calibrated even though the actual fall distance was 12 feet
(4) Flight data missing from drone and/or phone.

 

[4wd]

If you trigger Return to Home but it's already very close it will just descend.
That could happen accidentally due to loss of contact.
Losing the phone connection shouldn't really do anything, you don't even need to have a device connected, but obviously various things are made more difficult.

 

[gberry]

DJI would have me belive that the phone is very necessary, Because when I asked about use of the phone, they stress on the point that the phone should be used In order to capture flight data. But I still don't know definitively if flight data is stored on a Drone.

 

[Meta4]

DJI would have me belive that the phone is very necessary, Because when I asked about use of the phone, they stress on the point that the phone should be used In order to capture flight data. But I still don't know definitively if flight data is stored on a Drone.

DJI's people aren't always very good with their communications.
You can unplug the phone in flight and it makes no difference to your ability to control the drone or it's ability to hold position or RTH.
If you disconnect the phone in flight, your data recording to the phone stops.
Your flight data suggests that's what happened as the data just stops with the drone132 feet up.

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

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You still had full control but we have no information to show what control inputs you might have made after that point.

The drone has an internal data recorder as well and DJI will have been able to read what it showed.

You always should have a good clear area around your launch point.
It's never a good idea to launch from close to a tree.

 

[gberry]

All the DJI representatives I spoke to would rather die then make that statement about maintaining flight control even if the phone is disconnected, believe me, I tried very hard and they refuse to say this, and they do not want to mention anything about the flight data that is stored on the drone. They keep asking me for the data on my phone or in my app. In fact, this is part of the reason they deny the claim stating that data loss is not covered under warranty. I could understand if it was user a data like video or images that are stored on the phone, but I don't think this applies to the flight data that is stored on the drone itself. Can someone correct me if I'm wrong?
With regards to the tree, there was one but not very close proximity and I do not use the automatic RTH feature, but if it was triggered, I did not enable it nor was I able to cancel it because the remote had no effect on the drone.

 

[MAvic_South_Oz]

because the remote had no effect on the drone

If that is really the case, then it sounds like it was an occusync issue, which is normally very reliable normally, especially this close.
WIll be watching for the flight analysis, which should reveal what happened I hope.

Strange with the drone logs missing, refurb and all, hope it works out and whatever steps to replace or repair aren't too painful.

 

[gberry]

Where will I get this flight analysis?

 

[Meta4]

Where will I get this flight analysis?

I gave you as much as anyone can back in post #4 above.

 

[sar104]

This is a difficult case to diagnose because there are so few data in the log. When you say that it attempted to land away from the home point - how far away?

 

[new2mavic]

It seems that the control signal to the drone was lost for some reason and the drone initiated RTH. This mechanism is turned on by default and I wonder if anyone will turn it off.

 

[bonmot]

If you trigger Return to Home but it's already very close it will just descend.
That could happen accidentally due to loss of contact.
Losing the phone connection shouldn't really do anything, you don't even need to have a device connected, but obviously various things are made more difficult.

In my very first time test flight on my Mavic 2 Zoom. My iPhone battery dead in 2 minutes in cold. I was able to fly the drone back and land no problem.

 

[MAvic_South_Oz]

It seems that the control signal to the drone was lost for some reason and the drone initiated RTH. This mechanism is turned on by default and I wonder if anyone will turn it off.

. . . or change the options, it can be changed in settings to RTH, hover, or land where it is.
RTH is / was default (30m / 120') on my M1P, pretty sure the M2 aircraft would be that also.

 

[RayOZ]

First flight should’ve been done on an open field in broad daylight. There’s an element of pilot error here. And since it’s refurbished from a 3rd party, and no flight logs, DJI might not be inclined to cover that under warranty. Bad for business. You need full proof that it was faulty. Your recollection of what happened is not proof.

 

[gberry]

This is a difficult case to diagnose because there are so few data in the log. When you say that it attempted to land away from the home point - how far away?

The horizontal distance from the launch point is about 18 ft. The lunch point was an elevated platform, good for all-around space and visibility. The drone hovered for a few seconds and then started to descend and drift at the same time, so it's final landing spot would've been even further.

 

[gberry]

It seems that the control signal to the drone was lost for some reason and the drone initiated RTH. This mechanism is turned on by default and I wonder if anyone will turn it off.

I have used RTH on this drone very seldom, and it is very accurate, but I do prefer to land manually, nothing to do with safety or anything, just like the feeling of being in control. Even launching the drone I prefer to use the sticks.

 

[gberry]

First flight should’ve been done on an open field in broad daylight. There’s an element of pilot error here. And since it’s refurbished from a 3rd party, and no flight logs, DJI might not be inclined to cover that under warranty. Bad for business. You need full proof that it was faulty. Your recollection of what happened is not proof.

I absolutely appreciate all input and I ensure that you have my utmost respect as well as all the other members of the forum. May I humbly ask what the effects of open field and better lighting would have on the loss of control ability of the drone?
I'm definitely seeking answers that we may all learn more as I have since joining the group, not necessarily trying to poke holes in the reliability of the drone (though there may be some) because even if DJ I were to replace the drone completely, we would still not know why I lost complete control of the drone seconds after takeoff. I hate the uncertainty and it may cause me to pack my running shoes on my next flight.

 

[gberry]

In my very first time test flight on my Mavic 2 Zoom. My iPhone battery dead in 2 minutes in cold. I was able to fly the drone back and land no problem.

Definitely, one would expect that external Influences such as a dead or disconnected phone would still allow you to maneuver the drone. But in my case, it's the loss of data that DJI is focusing on and stated that it was user error that caused the loss of data, They even said, "Use better cable next time", I kid you not, they actually said it in an email reply, even though this is the DJI cable that was provided with the drone.

 

[sar104]

The horizontal distance from the launch point is about 18 ft. The lunch point was an elevated platform, good for all-around space and visibility. The drone hovered for a few seconds and then started to descend and drift at the same time, so it's final landing spot would've been even further.

It's hard to deduce much from that either, unfortunately. With regard to DJI's comments on the USB cable - that might well account for the app disconnecting from the RC, but it's not going to have any effect on RTH accuracy.

 

[MAvic_South_Oz]

I wonder if the micro usb was damaged in some way, contributing to the device connection problem.
It's a know problem with the square controller input and people attempting to put them in reversed.

But of course this should not have affected flyability with controller and aircraft.

I'm not sure about how to solve this with DJI, if there is not enough data for the forum analysts to give feedback.

Maybe escalate it and have some brief bullet pointed facts to give, the most important how close the aircraft was to home / you, and how you didn't have any control.
Without logs though, one can see DJIs hesitation in accepting responsibility, anything could have happened after disconnection.

There is definitely no more useful info on the drone logs ?

Perhaps the experts can work on the best list to present to DJI, but it's looking a bit shaky for them to cover.

 

[gberry]

It's hard to deduce much from that either, unfortunately. With regard to DJI's comments on the USB cable - that might well account for the app disconnecting from the RC, but it's not going to have any effect on RTH accuracy.

Granted, I wasn't in an open field in the middle of the day, I was trying to get a sunset shot, but with such a comedy of errors, loss of control right after takeoff, inaccurate RTH, Flight data and IMU, we just cannot easily account for all these anomalies.

UPDATE: DJI has finally advised me that flight data is not stored on the drone itself. Their customer service department definitely misled me repeatedly and intentionally where this is concerned. Even when I asked them bluntly they refused to give a straight answer and were content with me ending our phone calls knowing that I had the wrong information, or maybe their customer service agents don't know the answer either. One person even said he's not authorized to give me that information.

So If during a flight the Occusync connection were to fail, there would be no adequate records of the flight and hence a resulting crash would be considered as not covered, due to lack or loss of data.
If the DJI Go app were to fail, or the cell phone become disconnected from the RC and a crash was to happen, even if it's not due to pilot error, it would be considered as not covered due to lack or loss of data also.
A clear Win-Win for DJI.