Mavic 2 Pro fly away at the return home

[Yeo HongPoh]

I lost my 6 months old Mavic.on way flying returning home.
after DJIGO4 indicated RC strong interference.
next movement my phone blackout. so I activated RT on my RC. After regaining display. I saw drone stops in midway. estimated was about 300 ft. away from the TF point. maintaining good GPS with 15 satellite on.
then I lost control again. My RC cannot maneuver the drone. I also lost the location of my drone and had no sight at all in the sky. I tried to relink with my drone from DJIgo4 also failed.
I made many attempts to restart DJIgo4 and relink with Mavic.
DJIGO4 relink prompt me to press relink bottom on the drone. how can I press the drone when it was flying in the air? I pressed the buttons at the bottom of the RC. hopping it will reconnect but doesn't help.
Both the battery on drone and RC were fully charged before taking off.
I can't do anything but just to let my Mavic consume up the battery and crash landing.
I retrieve my flight record and locate the last location of the drone. but was unable to find.
I lost my drone now. Still under warranty. what shall I do next?

Every time I fly Mavic I was very uncertain. Only hope nothing will happen.
DJIGO4 displayed the notice or warning was too fast. Before you can read what warning message and what had happened. The display when off. So we need to do a lot of guesswork what had happen and decide what action to take immediately. As drone was flying and battery keep consuming.
After I’d build my confidence that DJI design was so good and safe to fly without worries of losing your drone. Yet it can happen to me.
DJI needs to look into my incident seriously. How can the drone lost connection in midair and unable to relink with it? Did DJI anticipate this can happen before?
I cannot find any write out about precaution of preventing drone being losing connection while flying. And how to relink the drone when it lost connection while flying in midair.

 

[Amckim2084]

Sorry to hear about that. I just got a Mavic 2 Pro recently and have had 2 flights so far. I'm still scared about flyaways even though I've never had one in the 5 years I've been flying. I had a crash once with P3S in return to home but it was pilot error because my return home height was not higher than a wooded hill. I was able to get it back with Marco Polo. I'm assuming you didn't have any kind of tracking on it? If you ever find it or if you get a new one, look into it. Hopefully DJI can help you out in some way.

 

[slup]

If you want help analyzing the data then you can either retrieve the logs and post them here directly, or upload them to PhantomHelp or AirData and post the link back here.
The log we need is the TXT log from the mobile device you flew with, below how to retrieve it.

Mobile device DJI TXT logs

The log naming convention, based on the date and time of the start of the flight, is: DJIFlightRecord_YYYY_MM_DD_[hr-min-sec].txt.

With iOS devices running DJI GO 4 the TXT logs are in Apps » DJI GO 4 » FlightRecords.

With Android devices with DJI GO 4 the TXT logs are in DJI » dji.go.v4 » FlightRecord.

 

[Yeo HongPoh]

hope I send this flight record to the correct link.

 

[slup]

Hate to be the one that break it to you ... but everything behaved by the book from your take off over to the disconnect with the initiation of failsafe RTH with it's initial flight path back track & rotation towards home.

But everything ends up with that you crash the drone into a building 104 meters above your HP ...

All good until the disconnect (blue graph) at 460sec when the M2P does exactly what's it design to do ... it initiated failsafe RTH (dark green area in chart). When signal returns the M2P have just finished it's back tracking & are preparing to continue to go home in a straight line. You write in you description that you pushed the RTH button ... this meant that you cancelled the RTH home (white area in between the dark green & light blue area), but you push again & the M2P start again up a RTH (light blue area) & the drone picks up heading speed (purple graph) ... but you push the RTH button again & cancel & the drone stands still & hoovering with 0 speed. Suddenly you starts to input different stick movements, first a short negative throttle input which descend the M2P to 104 meters (red graph) then followed by elevator & aileron inputs which makes the drone to steer out to the left & then later crash into the building.



Your stick inputs ... red elevator (forward/backward horizontal movement), blue aileron (left/right horizontal movement) ... in the end only negative aileron which makes the M2P to move left into the building.



The 2D & below the 3D flight path





If it's like you say that the screen was black that were most probably due to that you by accident got your cable disconnected from your mobile device... you had RC connection with the M2P all the way from 483 sec until the flight ends at 566 sec. That were probably shown on the RC screen according to below from the user manual.

 

[new2mavic]

Sorry about your loss.

While the reason behind the screen black out is uncertain, I can see two things learnt here :

(1) the RTH height is set to just 60m but some of the buildings in this area is more than 100m tall so the craft may be unable to avoid the obstacles on it's way back.

(2) the RTH action has been cancelled twice during the recorded duration of the flight. Once RTH is initiated, it is not advisable to touch any button until the craft is in sight and you have good confidence to take control over it.

 

[Randy the locator]

slup
Its amazing what you do with the data and that you take the time to analyze and publish this ...VERY helpful THANKS !!!!!

Randy

 

[OurAngryBadger]

Sorry about your loss.

While the reason behind the screen black out is uncertain, I can see two things learnt here :

(1) the RTH height is set to just 60m but some of the buildings in this area is more than 100m tall so the craft may be unable to avoid the obstacles on it's way back.

So when in RTH, the m2P doesn't use its vision sensors to avoid obstacles?

Seems like it should still sense if it's going to crash into something during RTH and stop.

 

[new2mavic]

So when in RTH, the m2P doesn't use its vision sensors to avoid obstacles?

Seems like it should still sense if it's going to crash into something during RTH and stop.

Yes. It will stop in front of the obstacle but that will make little difference because it will finally crash after the battery is depleted.

 

[sar104]

So when in RTH, the m2P doesn't use its vision sensors to avoid obstacles?

Seems like it should still sense if it's going to crash into something during RTH and stop.

RTH and regular OA was disabled for this flight.

 

[sar104]

Yes. It will stop in front of the obstacle but that will make little difference because it will finally crash after the battery is depleted.

But that's not what happened - the pilot simply flew it into the building in P-GPS mode.

 

[OurAngryBadger]

RTH and regular OA was disabled for this flight.

Did he disable OA intentionally or was he in sport mode? Thats the part that is confusing me here. In P-GPS shouldnt obstacles avoidance be enabled by default

 

[sar104]

Did he disable OA intentionally or was he in sport mode? Thats the part that is confusing me here. In P-GPS shouldnt obstacles avoidance be enabled by default

He was in P-GPS mode, not Sport, as I stated above - flycState = 6.

 

[slup]

Did he disable OA intentionally or was he in sport mode? Thats the part that is confusing me here. In P-GPS shouldnt obstacles avoidance be enabled by default

No obstacle detection was activated according to the log ... neither ordinary or RTH OD. The flight mode after the last cancel of RTH was P-GPS ... Sport wasn't used during this flight.

To types of RTH was activated ... OutOfControlRTH (failsafe RTH) and RC_OnekeyGoHome (RTH on RC was pushed).
Green marks = RTH activated
Red marks = RTH deactivated

 

[charliej]

Hate to be the one that break it to you ... but everything behaved by the book from your take off over to the disconnect with the initiation of failsafe RTH with it's initial flight path back track & rotation towards home.

But everything ends up with that you crash the drone into a building 104 meters above your HP ...

All good until the disconnect (blue graph) at 460sec when the M2P does exactly what's it design to do ... it initiated failsafe RTH (dark green area in chart). When signal returns the M2P have just finished it's back tracking & are preparing to continue to go home in a straight line. You write in you description that you pushed the RTH button ... this meant that you cancelled the RTH home (white area in between the dark green & light blue area), but you push again & the M2P start again up a RTH (light blue area) & the drone picks up heading speed (purple graph) ... but you push the RTH button again & cancel & the drone stands still & hoovering with 0 speed. Suddenly you starts to input different stick movements, first a short negative throttle input which descend the M2P to 104 meters (red graph) then followed by elevator & aileron inputs which makes the drone to steer out to the left & then later crash into the building.

View attachment 95959

Your stick inputs ... red elevator (forward/backward horizontal movement), blue aileron (left/right horizontal movement) ... in the end only negative aileron which makes the M2P to move left into the building.

View attachment 95960

The 2D & below the 3D flight path

View attachment 95961

View attachment 95962

If it's like you say that the screen was black that were most probably due to that you by accident got your cable disconnected from your mobile device... you had RC connection with the M2P all the way from 483 sec until the flight ends at 566 sec. That were probably shown on the RC screen according to below from the user manual.

View attachment 95963

Brilliant analysis. Really informative and very helpful for me who is still trying to understand the flight logs.

 

[GarthH]

Scary thought to imagine a M2P flying into a window that looks to be about 70 floors up. Could have hurt someone at the window and even worse, fell on someone at ground level.

 

[Yeo HongPoh]

Hate to be the one that break it to you ... but everything behaved by the book from your take off over to the disconnect with the initiation of failsafe RTH with it's initial flight path back track & rotation towards home.

But everything ends up with that you crash the drone into a building 104 meters above your HP ...

All good until the disconnect (blue graph) at 460sec when the M2P does exactly what's it design to do ... it initiated failsafe RTH (dark green area in chart). When signal returns the M2P have just finished it's back tracking & are preparing to continue to go home in a straight line. You write in you description that you pushed the RTH button ... this meant that you cancelled the RTH home (white area in between the dark green & light blue area), but you push again & the M2P start again up a RTH (light blue area) & the drone picks up heading speed (purple graph) ... but you push the RTH button again & cancel & the drone stands still & hoovering with 0 speed. Suddenly you starts to input different stick movements, first a short negative throttle input which descend the M2P to 104 meters (red graph) then followed by elevator & aileron inputs which makes the drone to steer out to the left & then later crash into the building.

View attachment 95959

Your stick inputs ... red elevator (forward/backward horizontal movement), blue aileron (left/right horizontal movement) ... in the end only negative aileron which makes the M2P to move left into the building.

View attachment 95960

The 2D & below the 3D flight path

View attachment 95961

View attachment 95962

If it's like you say that the screen was black that were most probably due to that you by accident got your cable disconnected from your mobile device... you had RC connection with the M2P all the way from 483 sec until the flight ends at 566 sec. That were probably shown on the RC screen according to below from the user manual.

View attachment 95963

any info indicating the last height of the drone? I was thereafter 2 hrs cannot find it. I need to confirm if it's still on the rooftop. or already drop on the floor. this photo was from find my drone from DJIGO4. Thanks

 

[BullDoggBoyz]

Wow....Amazing analysis of what happened! That's some skill right there. Speaking of skill, I'm sorry you crashed your drone Yeo, but you are lucky nobody got seriously injured from that mishap. Not to sound like the drone police, but it's situations like this that are causing our hobby/craft to be religiously scrutinized and laws being made to make it almost impossible to continue flying as a hobbyist anymore. You need to practice and have confidence in your equipment before you venture to try certain flights. The blackout of your device is unfortunate and apparently caused you to panic, rather than trust that your AC would return home upon losing connection.

 

[Yeo HongPoh]

This photo has shown the drone location from DJIGO4. dose it means the battery on the drone gives GPS position. If the drone was taken away by people. will GPS give a different position as long as the battery on the drone still alive? I went there after 2 hrs. could not find on the floor.

 

[sar104]

any info indicating the last height of the drone? I was thereafter 2 hrs cannot find it. I need to confirm if it's still on the rooftop. or already drop on the floor. this photo was from find my drone from DJIGO4. Thanks

There are no data after the collision with the building at 15 mph, so whether it ended up on the ground or higher up is impossible to determine. All you have is the collision point.