mavic zoom crash data interpretation help

[SkyDogII]

hi there, well I finally figured out how to retrieve the dat files...

I need some help with this please. I have no idea of how to read it like you guys do.
at the very end of the flight one of the propellers came apart and the AC crashed and burned.
I was hoping you might be able to tell exactly what happened.

after this incident it went down in the water. I guess I was too close to a metal bridge, ac disconnected and instead
of returning home or stopping to regain signal, it decided to land in the LA river channel... I cant seem to locate the dat for that one.

thanks for your help. here's the one with the blades that came apart.

 

[Meta4]

I need some help with this please. I have no idea of how to read it like you guys do.
at the very end of the flight one of the propellers came apart and the AC crashed and burned.
I was hoping you might be able to tell exactly what happened.

Maybe another flight?
This one ends with a safe landing: DJI Flight Log Viewer - PhantomHelp.com

 

[Elude]

Sorry to hear it landed on the river

 

[DanMan32]

Am I missing something or did you answer your own question: prop failure?

 

[SkyDogII]

thanks for the help meta4. I said I was lame.. anyway, I think this is the correct file for the flight i was talking about.

and yes, I did see the prop come apart, but was just curious if anything happened prior to that... I did remember seeing a motor error come across the RC but don't know much about that. That's what I was interested in. Anyway, thanks again for your help.

 

[PhantomFandom]

thanks for the help meta4. I said I was lame.. anyway, I think this is the correct file for the flight i was talking about.

and yes, I did see the prop come apart, but was just curious if anything happened prior to that... I did remember seeing a motor error come across the RC but don't know much about that. That's what I was interested in. Anyway, thanks again for your help.

Well I haven't looked at the log but a prop failure pretty much answers the question and leads to a very bad day of flying. When the prop fails, that motor will overspeed and you will get some sort of motor speed or ESC error. That error is a symptom of the prop failure and not the cause. I can't think of any type of other failure that could cause a prop to fail.

Were these original DJI props? Did you check the props immediately before the flight for any scratches, nicks, gauges, etc? Any chance that something hit the prop during flight?

 

[SkyDogII]

HI,
Yes i did check them before and the appeared to be fine. they were non-oem props... The whole blade came off completely, where it attaches to the push on connector. Like the plastic just disintegrated around the screw hole. so i was wondering if the motor speed up before the failure or after...It's no big deal. cya

 

[PhantomFandom]

I don't see how even a sudden motor acceleration could possibly rip a prop apart. Seems more likely a defect. Personally I only buy and use DJI props.

 

[DanMan32]

Whose prop was it if not DJI (OEM)?

 

[Meta4]

Yes i did check them before and the appeared to be fine. they were non-oem props... The whole blade came off completely, where it attaches to the push on connector. Like the plastic just disintegrated around the screw hole. so i was wondering if the motor speed up before the failure or after..

Here's what that data looks like: DJI Flight Log Viewer - PhantomHelp.com

The flight appears to have gone normally until 11:35.7.
You were in Sport Mode and had been flying all over the sky at 100 feet.
You released the sticks and the drone was slowing, you gave it a little rudder for half a second and the drone rotated clockwise about 35 degrees.
It had been tilted back from braking two seconds earlier and suddenly tilted forward again, without picking up speed.
Its rotation changed from clockwise to anti-clockwise and it began to lose altitude without tumbling.
It's hit the ground at 11:41.1 and the motor current error you saw came soon after, while the drone was on the ground.
Other error messages after that are a result of the crash, not indicating a cause.

 

[SkyDogII]

Meta4 thank you for reading the crystal ball for me. I appreciate it. PhantonFandom. That’s probably the question. I should have asked at the beginning of the thread. That was exactly what I was wondering Had a hard time spitting that out. Thank you.

I can’t recall the name brand. amazon special for $11 fora set of 4.
Believe me. I won’t be buying those again and I won’t be flying close to any metal bridges either. What a horrible weekend.
Thanks again for helping this old man out guys.

 

[DanMan32]

That's just too cheap.
I got suckered with cheap P3 props with seller claiming they were genuine. Clearly they were not genuine. Seller refunded my money including shipping and didn't ask for them back.

I would have bought the P3 directly from DJI which was almost cheapest, but their shipping fee was more than the props. I ended up ordering them from BestBuy. Price from them was only a few $ more than DJI but with ship to store being free.

 

[sar104]

HI,
Yes i did check them before and the appeared to be fine. they were non-oem props... The whole blade came off completely, where it attaches to the push on connector. Like the plastic just disintegrated around the screw hole. so i was wondering if the motor speed up before the failure or after...It's no big deal. cya

Are you sure that the entire prop came off in flight? The data don't support that scenario - the complete loss of a prop leads to a very different result, with rapid pitch roll and yaw oscillations (~ 3 Hz) and much faster descent. The maximum descent speed here was only around 5 m/s.







The motor speed data are in the mobile device DAT file (FLY076.DAT).

How to retrieve a mobile device DAT file: How to retrieve a V3.DAT from the tablet

 

[SkyDogII]

sar Thanks for looking. When I retrieved the m2z one of the two blades was gone on that one side.
I thought the motor error happened first, accelerated speed on that one engine, blade comes off and crash. But it looks like it happened so fast that the error I saw was when it was already on the ground in a pile.
Thank you everyone for your help. I really appreciate he time you guys spend dealing with clowns like me. It’s a great forum. Thank you

 

[RayOZ]

Sorry to hear abt your crash. Sometimes, when trying to save a few bucks, we forgot that it’s the props that keep our $1000 drone in the air. When I first started, I got a Spark, and I thought I’d save a few bucks buying a 3rd party prop. It soon started to behave strangely. It didn’t crash, but as soon as I swap to the original DJI prop, it was fine. From then on, I won’t risk buying cheap knockoffs.

 

[PhantomFandom]

Sorry to hear abt your crash. Sometimes, when trying to save a few bucks, we forgot that it’s the props that keep our $1000 drone in the air. When I first started, I got a Spark, and I thought I’d save a few bucks buying a 3rd party prop. It soon started to behave strangely. It didn’t crash, but as soon as I swap to the original DJI prop, it was fine. From then on, I won’t risk buying cheap knockoffs.

Just my opinion but I would extend that beyond cheap third-party knock-off props. DJI puts a lot of engineering research into the entire craft, INCLUDING the props. So why would I even think about using third party props? To save a few dollars? Nope. To supposedly get slightly better performance? Nope. To change the sound profile? Nope. I'll stick with DJI and not risk having issues.

The same exact thing applies to batteries. Sure the savings can be considerable on a battery, but it's just not worth the risk.

 

[RayOZ]

I think it's just conditioning, if something original was $15, and you could get a cheap knock-off for $10, that's 33% savings. It's fine when you are talking about a stand-alone object. It's a problem when forgetting the bigger picture: the cheap prop is connected to an expensive drone that keeps it airborne. It's just changing of mindset. Cheap parts for a RC car is not as big a problem as cheap parts for a drone.