Phantom 4 flipped over, flew powered into ground from 200 feet!

[DanMan32]

My P3A hit a wire on ascent at about 20', tipped, looked like it tried to right itself but fell to the ground, ended upside-down grinding the hubs flat on the props. Wouldn't respond to CSC to shut motors.
Broken gimbal yaw arm, bent yaw motor shaft, cover plate for the yaw motor, pitch arm/motor, bent landing legs, one antenna popped out of its mount, broken compass wire, shell seams deformed, cracks in screw wells behind the motors. Camera body scratched up bad but camera itself looked OK. Not sure of UV filter lens.
Got new gimbal assembly though they quoted a repair, new shell, landing gears/compass.
I think one CW motor was slightly damaged but that didn't show up until 1 week later getting it back. It was slightly noisy sending it in but after a week it got somewhat worse. I think the other CW motor might also be developing an issue but very slight right now.
Wish I could rebuild the bad motor with new bearings, then I'd have a good spare. The 2312a just aren't easy to get apart. Even the brass ring is press fit.

Sent from my HTC 10 using PhantomPilots mobile app

 

[wa5tef]

Jim, honestly I'd let this go and stop getting wound up over it. I can tell it's not money you are worried about, you just want to know why it crashed, but at this point you won't get an answer. 100,000s of P4s are flying and not falling out of the sky, I hope your replacement never does and you just have fun with it

Thanks Alec. You and my wife so wish but it has become a monster with its on life cycle. I believe, as most of you do, that there was a flaw in my Phantom. The fact that DJI "could not find any data logs" proves my point from DGI's point of view and throwing a like new drone at me was to shut me up. I like David Crockett's philosophy when he said ?Be sure you are right, then go ahead". I have tried to live like that for 72 years and it has served me well, both in military and civilian life. When I feel that I am right about an issue, I don't tend to drop it unless the other party can prove me wrong. So far, everything they have done from falsifying the repair progress to show the different stages my drone went through for repair, down to the shipping date, when the serial number suddenly changed. I was told that the drone had been repaired and was being shipped back to me and that the data logs had been sent for analysis and I would be notified of the cause of the crash. I waited and waited while this was supposedly being done, only to find out that my drone was not repairable!! And they told me this after they already showed my serial number'd drone repaired and shipped. Now that is not right in anyone's view. DJI has a negative reputation for its service and I nearly did not buy one because of all the bad reviews but I did so, hoping I might get a good one. Now that all this has happened, and I have just submitted to DJI Support a very detailed email which in my view proves my point. I am going to give them a few days to respond and if they do not respond, I will post it here and two other forums for all to see. It might be interesting reading.


Anyway thanks for the input. It would have been a lot easier to just drop it and forget what DJI has done but had I done so, I would have gone against my core beliefs.

I really appreciate your input, watch for my final posting in case of DJI's negative response.

Thanks,
Jim
WA5TEF

 

[Steve Bynum]

I flipped my P4 while flying in the living room because I used the CSC to power it down. The aircraft suddenly scooted across the floor, flipped and went to a high power setting while upside down. While flying this afternoon, I landed on the edge of the grass by the driveway and powered down using left stick down. I used a CSC to restart the motors as I was low on battery and was going to show someone the low battery RTH operation. I decided to power down and used the CSC command while on the ground. The AC skittered across the grass and almost flipped and I was able to send the correct commands to regain control and land safely. Lesson learned, DO NOT CSC TO SHUT DOWN THE AC! Use left stick down!


Sent from my iPad using PhantomPilots

 

[AlecW]

I flipped my P4 while flying in the living room because I used the CSC to power it down. The aircraft suddenly scooted across the floor, flipped and went to a high power setting while upside down. While flying this afternoon, I landed on the edge of the grass by the driveway and powered down using left stick down. I used a CSC to restart the motors as I was low on battery and was going to show someone the low battery RTH operation. I decided to power down and used the CSC command while on the ground. The AC skittered across the grass and almost flipped and I was able to send the correct commands to regain control and land safely. Lesson learned, DO NOT CSC TO SHUT DOWN THE AC! Use left stick down!

What controls did you apply for CSC and do you have a P4 with newish firmware? In any event CSC (emergency motor shut off is a better name) is not needed to land at all. If you perform the old P3 and early P4 firmware CSC on the ground it's gonna do weird stuff.

 

[sar104]

Hey SAR104, thanks for posting. Perhaps you could explain to DJI then how this could happen. DJI says that there are no flight records available ant to me that says "Warranty issue". I hope you have read enough of my posts outlining what happened so I won't post it again for the 40th time. I see you are an experienced flyer (since 2014) so you should know what you are talking about. Please review these posts and comments and let me know what you think. I have had many suggestions as to what might have happened but I have found none of them match the actual conditions. Some fresh ideas would really be helpful!

Thanks,
Jim
WA5TEF

Unfortunately, while I think that VRS (vortex ring state, or descending through prop wash) can be ruled out, I don't have any idea what might have caused the crash that you described. Single motor failure typically doesn't lead to stable descent, either upright or inverted. Double motor failure might lead to that, but is highly improbable. A CSC shutdown could flip a quad but, as noted by others, the P4 has no CSC for shutdown. Are you completely certain that it flipped, and that the motors were still running? I'm also surprised that even a free fall from that height, let alone the power dive that you described, could result in anything other than complete destruction unless it landed in something very soft - can you comment on the impact location?

FC is flight controller - it refers to the onboard computer that monitors the sensors (compass, GPS, inertial and barometer), and controls the motors to execute the intention of the stick inputs.

 

[Steve Bynum]

What controls did you apply for CSC and do you have a P4 with newish firmware? In any event CSC (emergency motor shut off is a better name) is not needed to land at all. If you perform the old P3 and early P4 firmware CSC on the ground it's gonna do weird stuff.

I have the P4 with current software. My stick inputs were left stick down right and right stick down left.
Definitely a self taught lesson on what NOT to do.

 

[chris digata]

Ive see all this happen before, the guy Im talking about took it up and tried to do what he had seen others do!
It was the CSC flip fall and restart while it falls inverted, it then corrects itself into a hover before it hits the ground.
Thats if all goes well and your quick enough.. COUGH! logs logs and logs

 

[kirk2579]

Ive see all this happen before, the guy Im talking about took it up and tried to do what he had seen others do!
It was the CSC flip fall and restart while it falls inverted, it then corrects itself into a hover before it hits the ground.
Thats if all goes well and your quick enough.. COUGH! logs logs and logs

I read a lot but did not see if he posted the device flight logs fro Phantomhelp.com
lots to be learned if we have that..

no way would the logs disappear from BOTH the quad and The device at once....

 

[AlecW]

I read a lot but did not see if he posted the device flight logs fro Phantomhelp.com
lots to be learned if we have that..

no way would the logs disappear from BOTH the quad and The device at once....

That's the mystery here, I don't think anyone has seen the log other than DJI.

 

[kirk2579]

That's the mystery here, I don't think anyone has seen the log other than DJI.

that's what I thought. and why I asked
now the question to OP is this.
WHY NOT?

all this posting and only the OP has the possible answer yet has not shared it!
many, many, un answered questions !

about every month or so we get similar postings it seems.
big issue , lots of posts, never a log file.

 

[techstud]

I believe this is caused by something called "retreating blade stall". It's a tendency for fixed rotor aircraft and can be catastrophic in helicopters and the like. Other phantom pilots have experienced it and call it "the flip of death". Look these things up to get a better idea of what might have happened.

This shouldn't occur under normal circumstances, especially in a steady descent. In my mind, it has to be a failure of the phantom to right itself. The processing units in DJI drones are supposed to be able to compensate for this by adjusting rotation speeds in stalling blades. I would think DJI has to recognize this as a failure of their systems and thus not something you should pay for.

 

[sar104]

I believe this is caused by something called "retreating blade stall". It's a tendency for fixed rotor aircraft and can be catastrophic in helicopters and the like. Other phantom pilots have experienced it and call it "the flip of death". Look these things up to get a better idea of what might have happened.

This shouldn't occur under normal circumstances, especially in a steady descent. In my mind, it has to be a failure of the phantom to right itself. The processing units in DJI drones are supposed to be able to compensate for this by adjusting rotation speeds in stalling blades. I would think DJI has to recognize this as a failure of their systems and thus not something you should pay for.

I don't see any way that could happen in a pure descent since there isn't, by definition, a retreating blade in that situation. Even with wind producing a lateral velocity component the Phantom prop speeds must be far too high for the (effectively) retreating blade to stall. And even if it did, surely the quad rotor configuration would result in lift symmetry being maintained.

 

[dwallersv]

I have a very simple question: The OP claims to have taken pictures/video of the AC where it crashed; why hasn't this been posted and shared?

The cached video from the flight is sitting there on the iPad... why hasn't this been shared? We could all see for ourselves the inverted flight.

I don't have facts to challenge the OPs veracity in all this. What I will say, however, is that I am suspicious. My reasons for being so are the lack of data, the agressive, defensive tone of the OP, his willingness to draw very negative conclusions about DJI simply because they don't call him back fast enough, and on and on.

Glaring inconsistencies regarding whether or not this was a warranty service repair.

Facts of prior crash, then increasingly watered down to sound like nothing in subsequent posts.

Too much is wrong with this story for me to accept that it was simply an innocent situation where the AC just went crazy.

 

[jbrown630]

Proper Emergency Shutdown for up to date aircraft is left stick down and right and RTH button.

 

[George_Sav]

On January 21, my Phantom 4 was at 419 feet. I started a descent normally it seemed until at about 200 feet it flipped over and proceeded straight to the ground very fast. I reacted giving full throttle up to halt the fall but not knowing the drone was inverted, it flew faster. It hit the ground hard and bounced. Upon arriving at the crash site, I found the drone laying on its top, propellers all broken but all lights on, the battery showing 3 green LED's with one blinking, ready for the next flight command! I video'd the site for record then took the drone inside, cleaned the mud off the top and attached new propellers. Powered it up and all seemed to work except the gimbal. The drone had hit the ground so hard that the gimbal mount or camera had dented the housing just above it. The camera worked fine, only the gimbal was a little stiff. I carried it outside, grabbed my iPhone to video the event and powered it up at idle. It seemed normal so I flew it up to about 3 feet and tried the yaw commands, all normal, then to about 10 feet and tried the forward, left and right and back stick commands and again normal. SO, to have a Phantom do a power dive from 200 feet and basically survive is awesome! The toughness of this craft is amazing. The top shell was slightly damaged on two of the arms but since the drone hit flat on its propellers, it apparently was not damaged too bad.
SO, I know everyone is wondering why the drone flipped? I am too? I sent the drone to DJI for repair with a request to review the flight logs to determine what happened. No response. I called support, promised an email explaining same, no results. Emailed support, got same promise, same response. Got on DJI Forum and posted for about a week and no one has had a good idea why the drone flipped and DJI rep promised to get the flight logs and advise, but still waiting. Also, no one has been able to tell me how it is possible to make a Phantom fly upside down! I paid for the repairs and had the drone repaired and it is on its way back here, set to arrive Thursday but without knowing why it flipped, I am afraid to fly it again.

Can anyone, help. I need to know how it is possible to flip? No, no prop, no motor, no anything failure noted. No bird strike, no tree strike, no wind gust, etc. No external conditions that could have caused it.

Anyone please! Thanks,
Jim
WA5TEF

You may wish to renter the operational height of your drone as you are not allowed above 400ft AGL .... must have been a wind gust

 

[Wolffboy]

You mentioned you have video and pictures of the crash site. Where are they posted?
Please post any physical record (pictures or video) to lend some credence to your tale.
So many of these threads somehow are missing video or pictures when the OP states they exist.

 

[wa5tef]

OK, I do not have any video as I turned it off to make the single photograph from 400 feet. I did make a video of the crash site plus several photos of it. I also have a video later that night of the same crashed drone flying, with only new propellers. I'll locate them and post them here. I'll have to figure out how to do it as I'm still a fairly newby at this.
Thanks,
Jim
WA5TEF

 

[wa5tef]

OK, I have located all my video and photographs. I just need to know how to post them now. AND Thanks to that suggestion, I carefully reviewed my video of when I took the drone into the hamshack to check it out and I did find the photo evidence I was looking for. I told DJI that I had proof that the Drone crashed upside down but did not have video or photo evidence but I fouind it!!! The camera ring, was pointing mostly up during the crash and the impact drove the fing of the camera lens upward into the gray area around the bottom of the Phantom 4. It impacted so hard that the camera ring actually dented the plastic on the body of the drone! There is also a dent on the camera body. I believe that DJI saw the dent on it when they analyzed it for information but did not own up to it, now I have video proof of my claim! So, if someone can let me know how to post the video and stills here, I would really appreciate it.
Thanks,
Jim
WA5TEF

 

[wa5tef]

I just uploaded the first video I found to YouTube. It shows the dirt in the propeller hub and most important of all, it clearly shows the dent in the gray area caused by the camera and gimbal mount! Also, note that the battery was still operational, being over 75% capacity remaining. When I inserted the battery and powered it back on, you can hear the clicking noise that the radio (I think) emits when it is transmitting data back to the RC unit. I have not been able to send this to DJI yet because I did not know it existed but I do now.
Just go to YouTube and search exactly as this: Phantom 4crash damage. Note no space between 4 and crash.
Please post your comments here.
I'll post the others as soon as I locate them.
Thanks,
Jim
WA5TEF

 

[wa5tef]

Second video is at Phantom 4crash damage 2
Note still no space between 4 and crash. This one shows the Phantom from the top with grass and dirt and also the "limp" gimbal mount.
Thanks,
Jim
WA5TEF