Mavic 4 Pro motor overload and crash - options?

[ddublu]

Here is my flight log from AirData. One of the most basic flights I've ever flown. Stopped at a train station to shoot an Amtrak train (while parked at the station). Saw my drone the entire time, but it got to a point a few minutes in that it wouldn't go down. Tried turning obstacle avoidance off with no luck (couldn't find it in the menu fast enough)....Tried landing on its own from 150 ft, which I cancelled. It veered in one direction and then started rolling over. What did I do wrong here, if anything, and if I did nothing wrong, what are my support options through DJI (I'm in the US)? I have hull coverage, so $300 to replace seems the easiest route, but just curious about more feedback.

 

[Cafguy]

There is a lot going on at a Train station Electronic and Wi-Fi wise! (is that a signal next to your home-point?) Interference of some kind perhaps.
After next month Your options for service here are few, and warranty in U.S. worthless.
I say REPLACE IT ....NOW and SOON.

 

[slup]

This had nothing to do with any kind of electronic interference...

Instead it was likely the weather conditions that first caused the "low vertical limit landings" due to iced up VPS sensors & then later the motor errors together with loss of thrust due to prop icing in the end.



The flight was conducted just below the freezing point very close to the dew point temp... perfect conditions for prop icing.



And below a chart that shows the icing of the VPS sensor (green graph)... up to 36sec into the flight the VPS height was working as it should, but after that the VPS height was reported to be between 1,6-2,3ft the rest of the flight. This means that a constant applied negative throttle (past a threshold level) will begin a landing.

(Click on the chart to make it larger)

 

[ddublu]

This had nothing to do with any kind of electronic interference...

Instead it was likely the weather conditions that first caused the "low vertical limit landings" due to iced up VPS sensors & then later the motor errors together with loss of thrust due to prop icing in the end.

View attachment 186872

The flight was conducted just below the freezing point very close to the dew point temp... perfect conditions for prop icing.

View attachment 186870

And below a chart that shows the icing of the VPS sensor (green graph)... up to 36sec into the flight the VPS height was working as it should, but after that the VPS height was reported to be between 1,6-2,3ft the rest of the flight. This means that a constant applied negative throttle (past a threshold level) will begin a landing.

(Click on the chart to make it larger)
View attachment 186871

Thanks! I cancelled auto landing a couple of times because I couldnt get it near my takeoff spot. I noticed early on that it showed downward obstacle avoidance of 1.4m (I believe) so I couldnt move down. Did it think there was a surface below it? I think if I could have gotten it down when I was trying to, I could have saved it.

 

[slup]

...Did it think there was a surface below it?

Yes...

 

[jaja6009]

This section of the forum is invaluable to safe drone flying. Every RPIC should read these posts for lessons learned into drone crashes. Too many pilots think that their drones are crash proof from limited flying experience. I have to always stress to our pilots at work that the drone is one part failure away from falling and that external factors only increase the risk of an accident.

OP, I am not criticizing you in any way, just speaking in general about this section of the forum and how there are so many factors in safe drone flights.

This thread helped to remind me to pay attention to conditions conducive to icing since we are at that time of the year again.

I have used this section numerous times to gain insight into crashes or other problems.
Thank you to our crash experts for taking their personal time to help us out.

 

[Femski]

Keep in mind that Static electric could have built up either in transit from your car, or bag or from something you were wearing, like a wool jumper. Just on option to note.

 

[Kilrah]

Keep in mind that Static electric could have built up either in transit from your car, or bag or from something you were wearing, like a wool jumper. Just on option to note.

No.

 

[Meta4]

Keep in mind that Static electric could have built up either in transit from your car, or bag or from something you were wearing, like a wool jumper. Just on option to note.

How are you suggesting that static electricity build up can cause or contribute to an incident like this?

If this was genuinely an issue for drone flyers, wouldn't we have heard of hundreds of incidents just like it?

 

[Cafguy]

I build my Drones on a static free mat and sure static electricity could raise havoc with the Drones Electronics BUT DJI Drones have a good amount of ESD protection built in to them and I don't think static would be a problem unless of coarse you are physically touching the component with your bare hands..An assembled Drone, not to likely.....The plastic body and the added ESD protection would make small static discharges pretty much harmless.

 

[slup]

Keep in mind that Static electric could have built up...

Yeah sure...

But without going into how a IMU (compass, accelerometer & gyro) can get affected by a EMI discharge... note that the moisture in the air is a natural conductor, earthing any potential static charge and thus dissolving static electricity. Relative humidity must be below 40% in order for a static charge to be produced. The relative humidity during this flight was 96% at ground level & likely 100% at the height the drone was when the problems occurred.

 

[ddublu]

This section of the forum is invaluable to safe drone flying. Every RPIC should read these posts for lessons learned into drone crashes. Too many pilots think that their drones are crash proof from limited flying experience. I have to always stress to our pilots at work that the drone is one part failure away from falling and that external factors only increase the risk of an accident.

OP, I am not criticizing you in any way, just speaking in general about this section of the forum and how there are so many factors in safe drone flights.

This thread helped to remind me to pay attention to conditions conducive to icing since we are at that time of the year again.

I have used this section numerous times to gain insight into crashes or other problems.
Thank you to our crash experts for taking their personal time to help us out.

Totally agree and thanks to all that contribute! I probably have 600+ hrs but that doesnt make me or anyone immune to incidents like this. I have flown in precip before but it didnt even think of frozen fog and what it could do. Fortunately, I have hull insurance through FNIC so will be replaced for $300.