Lost Mavic after a mile out.

[WCFields]

** Follow up from DJI **

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Hello all,
After a new firmware upgrade, I took out the mavic last Sunday and lost all connection with it after a while.
Pressed return home but it didn't come back.
Anyway...the log is with DJI but I was wondering what anyone here thought of it.
Thanks

I've uploaded the txt file.

 

[Gary cato]

after u did the upgrade did you re set everything, RTH heights and check all your settings were the same as pre updating

maybe @msinger can help with the file

 

[WCFields]

after u did the upgrade did you re set everything, RTH heights and check all your settings were the same as pre updating

maybe @msinger can help with the file

I probably should have but never did before and it looks like it may have caught up with me.
What I don't get is the last location and the speed and height it was at when it went off the radar.
Thanks and I will contact msinger.

 

[Cyberpower678]

Hello all,
After a new firmware upgrade, I took out the mavic last Sunday and lost all connection with it after a while.
Pressed return home but it didn't come back.
Anyway...the log is with DJI but I was wondering what anyone here thought of it.
Thanks

I've uploaded the txt file.

I can do a limited analysis of the log, but I'll see what I can do.

 

[Gary cato]

see the experts are here. ask and ye shall receive you just may not like what they have to say

 

[Cyberpower678]

I've got some unfortunate news. Your drone initiated RTH, but the IMU failed mid-flight, which resulted in a switch to ATTI mode. The drone got carried away by the wind. The good news, it landed on land somewhere. I'm working on figuring out a potential landing zone the drone may have landed.

The drift away seems to be caused by a technical fault, but unfortunately this is still pilot error. The drone was flown beyond the signal range and the wind was gusty up to 34 kph.

 

[WCFields]

I've got some unfortunate news. Your drone initiated RTH, but the IMU failed mid-flight, which resulted in a switch to ATTI mode. The drone got carried away by the wind. The good news, it landed on land somewhere. I'm working on figuring out a potential landing zone the drone may have landed.

The drift away seems to be caused by a technical fault, but unfortunately this is still pilot error. The drone was flown beyond the signal range and the wind was gusty up to 34 kph.

Thanks for that....how can you figure out where it may have landed by the log.....amazing.

 

[msinger]

Assuming the wind remained consistent for the remainder of the flight, the Mavic would have drifted about 190 meters before it made it to the ground when it auto landed. That means it would have landed at about the end of the red line in the image below.

 

[WCFields]

Assuming the wind remained consistent for the remainder of the flight, the Mavic would have drifted about 190 meters before it made it to the ground when it auto landed. That means it would have landed at about the end of the red line in the image below.

View attachment 10293

So....probably in the water then?

 

[Cyberpower678]

Assuming the wind remained consistent for the remainder of the flight, the Mavic would have drifted about 190 meters before it made it to the ground when it auto landed. That means it would have landed at about the end of the red line in the image below.

View attachment 10293

How did you get 190 meters? I got something significantly larger.

 

[msinger]

The flight log is showing it would have taken Mavic about 34 seconds to land. If the Mavic had flown at 5.6 m/s for 34 seconds, it would have traveled 190 meters (per this calculator).

How did you arrive at your significantly larger number?

 

[Cyberpower678]

I got something much larger, and places it over land.


The log shows the drone was drifting at an average speed of 5.8 m/s and that the drone had roughly 750 seconds of flight left including the time it takes to descend down when it hits 10%. Going off of that, the drone may have drifted over land pretty far. The wind was pretty intense at times. Now it's reasonable to assume that it probably wasn't drifting that fast for the last 12 minutes, but it's feasible to assume it went over land at some point. I'm assuming that it probably ended up in the yellow marked region somewhere.

BTW, the pin coordinates on the picture are 44°18'16.52"N and 76°20'4.73"W. I don't think it made it that far out. I would try looking for it around the shore first and move back.

 

[Cyberpower678]

The flight log is showing it would have taken Mavic about 34 seconds to land. If the Mavic had flown at 5.6 m/s for 34 seconds, it would have traveled 190 meters (per this calculator).

How did you arrive at your significantly larger number?

The Mavic didn't auto land immediately, so I assumed it hovered until it hit 10%, in which I also got roughly 26 seconds for it to land based on a descent rate of 3 m/s. See post above.

 

[msinger]

Why would it hover until 10%? RTH is initiated 3 seconds after the remote controller disconnects.

 

[Cyberpower678]

Why would it hover until 10%? RTH is initiated 3 seconds after the remote controller disconnects.

The Mavic cancelled RTH on it's own because of an IMU error. The RC was disconnected several times after than, some longer than 3 seconds, but the altitude never dropped in between, hence my assumption of hovering until it died.

 

[msinger]

The RC was disconnected several times after than, some longer than 3 seconds, but the altitude never dropped in between, hence my assumption of hovering until it died.

That's a good thought. I've never seen a log where that happened though.

Maybe it was set to hover on RC signal lost too. Unfortunately, the logs do not show that.

FYI, the log only shows the downlink disconnecting. It's not possible to tell if the remote controller disconnected. I'm assuming it didn't since RTH was not initiated.

 

[WCFields]

That's a good thought. I've never seen a log where that happened though.

Maybe it was set to hover on RC signal lost too. Unfortunately, the logs do not show that.

FYI, the log only shows the downlink disconnecting. It's not possible to tell if the remote controller disconnected. I'm assuming it didn't since RTH was not initiated.

Once I started losing video connection and giving errors (imu) I pressed the RTH. Went out looking for it but no luck. The next day 3 of us went looking in fields and brush along the path like cyber power said....again no luck. I didn't go as far as middle road though. The following day, I went out looking again in adjacent fields and brush 1/2 way to middle road and yesterday, went around the shorline near the area and the corn field. Very frustrating but it really is like trying to find a needle in a haystack. Thank-you guys for trying to help me find it. Cheers.

 

[msinger]

Once I started losing video connection and giving errors (imu) I pressed the RTH.

Your flight log shows where you initiated RTH. It auto cancelled after the Mavic switched to ATTI mode. After that point, the downlink continued to drop. However, I think your remote controller was still connected until the end of the flight log. At that point, it probably dropped and RTH was auto initiated. Since your Mavic was still in ATTI mode, RTH would have caused it to auto land at its current location. That's why I'm assuming it landed in the water.

 

[Gary cato]

I've got some unfortunate news. Your drone initiated RTH, but the IMU failed mid-flight, which resulted in a switch to ATTI mode. The drone got carried away by the wind. The good news, it landed on land somewhere. I'm working on figuring out a potential landing zone the drone may have landed.

The drift away seems to be caused by a technical fault, but unfortunately this is still pilot error. The drone was flown beyond the signal range and the wind was gusty up to 34 kph.

can i ask how this would be pilot error? just curious. i would think if the IMU failed and there was video loss meaning he had no way of knowing where he was and RTH cancelled itself upon the IMU failure how it would be pilot error. One mile out is 2000 meters approx i guess which is not too far according to Mavic specs. (yes i know it can lose signal at 100 meters). Yet the drone is made to be flown and has the failsafes for this kind of situation.

There are many occasions (on IOS) where i have had full signal then bang gone in an instant, complete loss, lucky for me RTH has always initialised and worked.

Just feel its harsh to put this to pilot error so wondering where i am wrong in my thinking?

 

[Cyberpower678]

can i ask how this would be pilot error? just curious. i would think if the IMU failed and there was video loss meaning he had no way of knowing where he was and RTH cancelled itself upon the IMU failure how it would be pilot error. One mile out is 2000 meters approx i guess which is not too far according to Mavic specs. (yes i know it can lose signal at 100 meters). Yet the drone is made to be flown and has the failsafes for this kind of situation.

There are many occasions (on IOS) where i have had full signal then bang gone in an instant, complete loss, lucky for me RTH has always initialised and worked.

Just feel its harsh to put this to pilot error so wondering where i am wrong in my thinking?

The pilot error is that the drone was flown beyond the signal range of the RC. Looking at the log, the signal showed a steady decline in strength as it was being flown further away. It's the pilot's responsibility to maintain control of the drone while flying. It's true the IMU failed which is an issue on DJI's end, but this was avoidable if the drone was simply piloted back closer to the RC to maintain a signal link. If the drone was piloted back manually, the drone could have been sent in for a warranty service. I do note that the pilot had multiple opportunities to steer the drone for the brief moments when it reconnected allowing for the drone to be steered back. I don't mean to sound harsh, I'm just being honest, and realistic. Reality can be harsh sometimes, I know from first hand experience.