M3 drops from sky

[RC_Powerz]

So it happened, haven't had a drone go down in over 5 years and 2500 hours of flying. Was crawling along at 11mph at 220 feet and 60% battery getting some cinematic beachy sunset shots, its 7th flight and it just dropped like a brick, lost all power from what I could tell, last recorded flight data is at 218ft, but the battery, drone and lights stayed on the entire time, no transmission after impact but stayed powered up even while getting soaked by waves. Only 11th time being powered on, 1 hour and 58 min of flight on it. Don't have a screen recording but I got a never before seen "Navigation error" message in red on the screen as it was falling; not listed in logs, got a few low light warnings prior but normal for that time of day, nothing else out of the ordinary.

I have my suspicions that its battery related, battery was malfunctioning after, wouldn't shut off and lights were flashing abnormally, never could get it to power off, stayed on for hours. I honestly don't know what else it could be outside of an internal nav component failure, I did just fly 2 batteries through it pretty hard but barley peeked into the 25amp range and only for a few brief moments according to my AirData uav info. DJIFLY doesnt even show the flight, it doesn't show any of my flights for the day, but airdata was able to pull them all I've attached it if anyone wants to take a peek, this is the original format as well as a Airdata sharable link.

Yes, I have refresh care but in all honestly this was clearly a device failure, no fault of mine, has anyone had luck getting their refresh care fee waved in a device failure instance? I am seeing no reports of anything like it happening, but the way the flight data just stops recording midflight at 218 ft with all reports normal is odd to say the least, never seen anything like it. Surprisingly little physical damage considering the height it dropped from, one small crack on shell by battery compartment and front nose piece popped out on one side, came to rest upside down on the beach in the surf, landed directly upside down.

 

[slup]

Hi there ...

Looking into the last seconds of the flight & depicting it in a chart with some relevant battery & telemetry data doesn't show anything critical ... besides that the log ends with the AC still airborne.

The chart further below cover the green hand drawn part of the flight path ...



And here the data ... values in the legend from where the chart marker is placed, just in the end.

Red=Relative height
Green=Heading speed
Blue=Vertical speed (negative value=ascent, positive=descent)
Then...
The 4 cell voltages + battery percent

Nothing ...

(Click on the chart to make it larger)


But here it gets interesting ...

May I ask how the Emergency propeller Stop was set under the Advanced Safety settings ... Emergency Only or Always/Anytime?

There in the end of the log you command a perfect CSC for shutting off the motors, from 751,7sec to 753,3sec... a total duration of 1,6sec.

If you had the setting on Always or Anytime that explains why your AC goes down & why the log ends ... this as the .TXT log only run as long as the motors are on.

Here you see the CSC command for shutting off the motors. If this is correct ... this is a pilot error I'm afraid.

Here all stick inputs ...

(Click on the chart to make it larger)

 

[Meta4]

Yes, I have refresh care but in all honestly this was clearly a device failure, no fault of mine

The cause of your incident is no mystery.
Here's a clue from p55 in the manual:

You can check your joystick inputs in the Airdata display you posted

 

[sar104]

Ooops. I've never really seen anyone give a good explanation for the purpose of that maneuver in flight.

Anyway - it explains the lights-on descent, which generally rules out a battery issue, and not a processor crash, like we saw with a couple of previous early releases.

 

[slup]

...I've never really seen anyone give a good explanation for the purpose of that maneuver in flight.

We had a similar case here just some days ago ... same kind of maneuver but in tripod mode not in Sport as in this thread & sticks down/out instead, . Didn't actually look too strange in low speed.

Video of that incident below ... & the thread here --> DJI Mini 2 drop out sky

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

 

[Mavic3RCPro]

"The default setting can be changed in DJI Fly."

Where in DJI Fly can you change the default setting? And do you have a recommendation for what to change it to?

 

[slup]

"The default setting can be changed in DJI Fly."

Where in DJI Fly can you change the default setting? And do you have a recommendation for what to change it to?

The setting regarding emergency propeller stop is in the Advanced Safety settings in the DJI Fly app ... the default is "Emergency Only" which means that the flight controller/firmware decides during which circumstances the motors actually should turn off if you do the CSC...

If you set it to "Always" ... well then you might by accident put your stick in the CSC position & shut off the motors ... you should have the setting on "Emergency Only"

 

[Deleted member 103366]

Ooops. I've never really seen anyone give a good explanation for the purpose of that maneuver in flight.

It does look quite interesting when seen from below AFTER making sure the drone is in the breakdown / emergency only response mode.
I wanted to confirm what the breakdown/ emergency only response did.
Other than that, the video is like being on a descending roundabout.

 

[RC_Powerz]

Hi there ...

Looking into the last seconds of the flight & depicting it in a chart with some relevant battery & telemetry data doesn't show anything critical ... besides that the log ends with the AC still airborne.

The chart further below cover the green hand drawn part of the flight path ...

View attachment 138305

And here the data ... values in the legend from where the chart marker is placed, just in the end.

Red=Relative height
Green=Heading speed
Blue=Vertical speed (negative value=ascent, positive=descent)
Then...
The 4 cell voltages + battery percent

Nothing ...

(Click on the chart to make it larger)
View attachment 138306

But here it gets interesting ...

May I ask how the Emergency propeller Stop was set under the Advanced Safety settings ... Emergency Only or Always/Anytime?

There in the end of the log you command a perfect CSC for shutting off the motors, from 751,7sec to 753,3sec... a total duration of 1,6sec.

If you had the setting on Always or Anytime that explains why your AC goes down & why the log ends ... this as the .TXT log only run as long as the motors are on.

Here you see the CSC command for shutting off the motors. If this is correct ... this is a pilot error I'm afraid.

Here all stick inputs ...

(Click on the chart to make it larger)
View attachment 138307

it's on Emergency only, never changed the default, that was more of a old school late reaction, last ditch knee jerk reaction when I saw it start falling towards the surf and my camera view spinning out with the navigational error warning flashing on screen. it gave a red nav error on the screen after it was falling, one I have never seen. Im not saying it cant happen but I did have it set to emergency only and have been flying DJI since the flamwheels and never had that happen in flight, certainly would take my lumps if it was my fault and actually feel more confident about the hardware, that's what refresh care is for afterall. Does anyone know if the Emergency shut down feature is actually functioning or perhaps one that got left on the chalkboard for January and needs more work? because it sure felt like the drone decided to just shut its motors down on its own.

 

[slup]

it's on Emergency only...

In that case ... try to see if you can find the mobile device .DAT log from this flight, perhaps that can reveal more (if DJI let us read them for a Mavic 3).

You find it in the same folder as the .TXT logs but in a sub-folder there called MCDatFlightRecords, the one from this flight ends with FLY015.DAT

 

[Deleted member 103366]

ling, it was also still on and running while laying upside down, pretty sur

Do you mean the motors were still twitching or running?

 

[bkushner]

The setting regarding emergency propeller stop is in the Advanced Safety settings in the DJI Fly app ... the default is "Emergency Only" which means that the flight controller/firmware decides during which circumstances the motors actually should turn off if you do the CSC...

If you set it to "Always" ... well then you might by accident put your stick in the CSC position & shut off the motors ... you should have the setting on "Emergency Only"

View attachment 138328

When set to Emergency does the drone notify you to do the maneuver?

 

[slup]

When set to Emergency does the drone notify you to do the maneuver?

No ... the firmware only allow you to actually stop the motors when you do the CSC (when some kind of DJI defined emergency is ongoing).

 

[RC_Powerz]

Do you mean the motors were still twitching or running?

No, sorry, wasn't clear there, not spinning, just drone powered on, lights flashing , gimbal tight and trying to work, lost connection to controller when it hit ground, never regained it, but drone acted like it has just been powered up and set upside down when it was retrieved. Full loss of power is the only way I can explain it, but it was set to Emergency only for emergency propeller stop so that should take operator error being a possibility out of the equation for an E shutdown since the flight controller makes that call.

 

[sar104]

it's on Emergency only, never changed the default, that was more of a old school late reaction, last ditch knee jerk reaction when I saw it start falling towards the surf and my camera view spinning out with the navigational error warning flashing on screen. it gave a red nav error on the screen after it was falling, one I have never seen. Im not saying it cant happen but I did have it set to emergency only and have been flying DJI since the flamwheels and never had that happen in flight, certainly would take my lumps if it was my fault and actually feel more confident about the hardware, that's what refresh care is for afterall. Does anyone know if the Emergency shut down feature is actually functioning or perhaps one that got left on the chalkboard for January and needs more work? because it sure felt like the drone decided to just shut its motors down on its own.

Your recollection is incorrect though. The aircraft was perfectly stable (within the constraints of the rather extreme stick inputs that you started around 747 s) when you completed and held the CSC at 751.7 s. It was not falling or spinning out of control at that time. The CSC motor stop is recorded in the log at 753.3 s, and was a direct result of your stick inputs - this was not a hardware failure or loss of power.

The graph below shows the aircraft and gimbal attitudes, height, stick positions and motor status.

 

[jonatious]

No ... the firmware only allow you to actually stop the motors when you do the CSC (when some kind of DJI defined emergency is ongoing).

What does that mean? When does the drone know when I am moving to that position for emergency vs always?

 

[Meta4]

What does that mean? When does the drone know when I am moving to that position for emergency vs always?

No-one knows.
DJI hasn't explained what constitutes an emergency and it's difficult for anyone to test to find out.

If it is set to always, CSC will always cut the motors.
If set to emergency only ... it would only cut motors inwhat DJI considers an emergency (whatever that is).

 

[RC_Powerz]

Your recollection is incorrect though. The aircraft was perfectly stable (within the constraints of the rather extreme stick inputs that you started around 747 s) when you completed and held the CSC at 751.7 s. It was not falling or spinning out of control at that time. The CSC motor stop is recorded in the log at 753.3 s, and was a direct result of your stick inputs - this was not a hardware failure or loss of power.

The graph below shows the aircraft and gimbal attitudes, height, stick positions and motor status.

If true wouldn't that mean "emergency" mode for motor stop function on the M3 isn't functioning properly? I never have changed that default for any of my birds, it was on default of "emergency", never have I selected "always". My understanding is that "emergency" mode would need to see a few more abnormal variables to decide that "yes this is an emergency and not a input error, shut it down" I mean isn't that feature supposed to prevent such a situation as being described?

 

[sar104]

If true wouldn't that mean "emergency" mode for motor stop function on the M3 isn't functioning properly? I never have changed that default for any of my birds, it was on default of "emergency", never have I selected "always". My understanding is that "emergency" mode would need to see a few more abnormal variables to decide that "yes this is an emergency and not a input error, shut it down" I mean isn't that feature supposed to prevent such a situation as being described?

I can only tell you what happened as recorded by the log. It doesn't record CSC preferences.

 

[Deleted member 103366]

What does that mean? When does the drone know when I am moving to that position for emergency vs always?

Assuming the FLY app for the M3 works in the same way that it does for the Mavic Mini.
With the response set to "Emergency Only", it is the drone that decides whether or not it will comply with the instruction issued by the pilot, via the pilot putting the sticks in the CSC position, to stop the motors. In that situation the drone will only stop the motors if it considers itself to be in an emergency situation or that is has suffered an emergency.
If it thinks there is no emergency then it will not stop the motors.
I tested this with a Mavic Mini (MM), I sent it up to 107m, switched the speed mode to the slowest and put the sticks in the CSC position. I held them there for 41 seconds ( from the time stamps in the log ), the MM descended in a nice, controlled helix, until the MM was around 3ft off the ground.
It even slowed its descent as the ground came within the range of the downward looking sensors.
When I released the joysticks the MM hovered.
As Meta4 says, what constitues an emergency is unknown.

I also tried a similar experiment, AT LOW HEiGHT, with the response to the CSC position set to "Anytime", with the MM the motors stopped after the CSC had been held for around 1.7 seconds I think. I also recently hand held a Mavic 2 Zoom and tested the delay in its "Always" mode and the motors stopped after the CSC hand been held for 1.2 seconds, see Mavic 2 pro fly away?