My DJI Air 2s plunged into the pacific ocean - not sure what happened

[PascalFL]

Good evening,

I'm currently spending my vacation in Costa Rica. I brought my Air 2s with me and was taking some arial shots. Before landing, I decided to do a 'fly-away' shot of myself. While the drone was flying backwards towards the ocean, out of nowhere the drone lost control and crashed into the ocean. This happened within seconds and I did not receive any warnings or anything. Unfortunately, I was not able to retrieve the drone due to strong currents.
I have no idea what happened. I downloaded the logs and it's saying that I had a weak GPS signal. I was connected to 23 satellites and obviously out in the open without any obstructions.
I'm attaching the log files. I hope someone can give me more insights. It sucks, it was the second day of the vacation and now I'm without a drone.

Logs

Is it worth asking DJI for a replacement?
Thank you in advance
~ Pascal

 

[Deleted member 170519]

Good evening,

I'm currently spending my vacation in Costa Rica. I brought my Air 2s with me and was taking some arial shots. Before landing, I decided to do a 'fly-away' shot of myself. While the drone was flying backwards towards the ocean, out of nowhere the drone lost control and crashed into the ocean. This happened within seconds and I did not receive any warnings or anything. Unfortunately, I was not able to retrieve the drone due to strong currents.
I have no idea what happened. I downloaded the logs and it's saying that I had a weak GPS signal. I was connected to 23 satellites and obviously out in the open without any obstructions.
I'm attaching the log files. I hope someone can give me more insights. It sucks, it was the second day of the vacation and now I'm without a drone.

Is it worth asking DJI for a replacement?
Thank you in advance
~ Pascal

The air 2s is always worth asking for a replacement. Haven't seen your log files, but seems something went amiss with the flyaway shot.

 

[TonyPHX]

There sure seem to be a lot of Air 2S reports lately when the drone is doing something other than manual flight. Not scientific I know, but I just cannot help but notice this.

 

[PascalFL]

Just to clarify. I did not use the inbuilt 'fly-away' feature. I did this manually.

 

[Yorkshire_Pud]

I suspect the weak GPS stems from the excessive tilts.
I suspect you lost a prop or motor but you really need @slup @Meta4 or @sar104 to have a look.
My take is that every thing was OK until 9:38.9 - 9:39.0.
Looking at the Phantomhelp csv the drone's pitch and roll, OSD.pitch & OSD.roll, were fairly stable until then but after that the pitch starts going screwy, followed shortly thereafter by roll.
It's a pity you weren't shooting video, CAMERA.isVideo = False

 

[Meta4]

I have no idea what happened. I downloaded the logs and it's saying that I had a weak GPS signal. I was connected to 23 satellites and obviously out in the open without any obstructions.

Towards the end of your flight you were flying backwards at full speed in Sport Mode and started to climb as well.
At 9:39.2 the data shows the start of the problem when your drone is no longer in smooth, stable flight.
It's losing height and violently tumbling and spinning.
The messages about weak GPS and Atti Mode come 1.5 sec later and are not causes of the problem.
They are a result of the problem and appear because the drone is upside down as it tumbles.

If the drone did not collide with a tree or bird, the problem was that the drone lost the front right propeller or motor.

 

[slup]

...I hope someone can give me more insights.

Your incident is a pretty straight forward loss of thrust in one corner... in your case from the front right corner. The reason for loss of thrust is usually either due to a prop or motor failure... which of them can't be determined without a readable .DAT log which contain the motor data... try to share the .DAT log ending with ...FLY051.DAT if you want to know, it's stored in the mobile device you flew with, it's in the same place as the .TXT log you already have shared but in a sub-folder there called MCDatFlightRecords (if I'm remembering correctly it's not encrypted & can be read by us).

Just before the incident you were commanding the AC to fly backwards in Sport mode with a full negative Elevator stick command + a full Throttle command for ascend (both dashed graphs below)... at 579sec into the flight the AC suddenly pitch front down & roll over to the right, both these changes in attitude indicate a thrust loss in the front right. At the same time the AC starts to rotate CCW... which again points to the front right as that corner should generate a CW rotational torque, but as that corner fail the prop-generated rotational torque becomes unbalanced... 2 corners torque CCW & only one that torques CW ... = AC starts to rotate CCW.

Might also add that the ATTI mode & message about "GPS signal weak" in the end, comes after the incident have started & aren't the cause of this.

The chart marker is placed where the incident starts at 579sec... values from there is depicted in the legend below the chart.

(Click on the chart to make it larger)

 

[slup]

...the drone lost the rear right propeller or motor.

Look again, the drone was travelling backwards ...

 

[Meta4]

Look again, the drone was travelling backwards ...

Yeah .. I got the backwards angle mixed up and fixed it.

 

[Yaros]

Is it worth asking DJI for a replacement?

It's worth a try. Send them the log data as well. They might consider it an aircraft failure and not a pilot error, then they might replace it for free.

Looks like a propeller or motor failure, as pointed out by Meta4 and slup.

it's saying that I had a weak GPS signal. I was connected to 23 satellites and obviously out in the open without any obstructions.

These messages were recorded when the drone was already falling, that's why it had “bad signal”.

This might have happened because of a badly attached propeller, not fully locked in.

 

[Yaros]

There sure seem to be a lot of Air 2S reports lately when the drone is doing something other than manual flight.

Yes! It is strange, but even I experienced a strange situation with a Mavic Air 2S drone a couple of weeks ago.

 

[bmwbob]

If it's under warranty definitely contact DJI for replacement. If the log shows motor failure they should replace it!

 

[GFields]

Perhaps @Meta4 or @slup

Good evening,

I'm currently spending my vacation in Costa Rica. I brought my Air 2s with me and was taking some arial shots. Before landing, I decided to do a 'fly-away' shot of myself. While the drone was flying backwards towards the ocean, out of nowhere the drone lost control and crashed into the ocean. This happened within seconds and I did not receive any warnings or anything. Unfortunately, I was not able to retrieve the drone due to strong currents.
I have no idea what happened. I downloaded the logs and it's saying that I had a weak GPS signal. I was connected to 23 satellites and obviously out in the open without any obstructions.
I'm attaching the log files. I hope someone can give me more insights. It sucks, it was the second day of the vacation and now I'm without a drone.

Logs

Is it worth asking DJI for a replacement?
Thank you in advance
~ Pascal

Perhaps @Meta4 or @slup can shed some expertise on this

 

[slup]

Perhaps @Meta4 or @slup

Perhaps @Meta4 or @slup can shed some expertise on this

You have it out from what's supplied in post #7.

 

[GFields]

You have it out from what's supplied in post #7.

weird, I guess I should have refreshed my page as those posts where not there when I made the suggestion. But thanks for your reply.

 

[bikeboy74]

I'm always impressed to see you guys figure out what has happened to a lost drone. I also mostly fly an Air 2S and I worry that someday I'll be posting my data on here for help. Are there any data settings or mistakes in controller settings that could prevent my Log from being complete in the event of a flyaway/crash/etc.? Just want to be sure sure I get it right. Thanks.

 

[slup]

...Are there any data settings or mistakes in controller settings that could prevent my Log from being complete in the event of a flyaway/crash/etc.?

Nowadays & in general... no, besides see to that the internal memory in the mobile device you use to fly with isn't full & then deactivate the log auto sync in the DJI Fly app.

A DJI drone have 3 types of logs...

An aircraft stored .DAT log which have the most comprehensive data, recorded in rates up to 200Hz... unfortunately this log haven't been readable for others besides DJI since the DJI Mavic Pro 1. It records from power on to power off & it will make use of the AC internal memory which fills up & then the oldest logs will be overwritten on rolling bases.

An mobile device stored .DAT log, almost as comprehensive as the one in the AC, but only recorded in rates up to 10Hz. This log is also recorded from power on to power off. Unfortunately most of the crafts using the DJI Fly app, this log is encrypted & only readable by DJI (but think this log still can be read by us for the MA2s).

Lastly a mobile device stored .TXT log is created, it records from motors on to motors off. This log is in general readable for us, either directly or has to go through either Airdata or PhantomHelp to be decrypted. The data in a .TXT doesn't include the raw sensor or motor data, instead, roughly said, only the telemetry & camera data.

The 2 later log types are depending on that the mobile device is connected to the aircraft (via the usb cable-RC-AC), if the connection is broken the recording is stopped.

In case of an incident, the syncing to the DJI cloud service should be postponed (in the DJI Fly app the syncing is on by default, so if you have a readable mobile device .DAT log it's better to deactivate the auto sync) until you really want to deal with DJI staff. This as it's common that the mobile device .DAT log is deleted when syncing... this prevents us to have access to it.

If you want to read up more on logs, do it HERE

 

[Yorkshire_Pud]

I think @slup should have emphasised the 'switch off syncing' comment.

In addition you can copy or move both the .txt and the DAT from the screen device to computer etc.

 

[bikeboy74]

Thank you for this information. Very helpful. Does the video recording thru the FLY app provide any useful/helpful info?

 

[bikeboy74]

I think @slup should have emphasised the 'switch off syncing' comment.

In addition you cam copy or move both the .txt and the DAT from the screen device to computer etc.

Thank you!