Hey guys

So, this has NEARLY happened quite a few times now, but finally today it's happened - frequently when the aircraft is stationary and on the ground after landing, when both control sticks are moved to the bottom corners to stop the motors the drone will instead momentarily behave as though you had only moved the right stick fully to the side, causing it to jump a little to one side before adhering to the actual input of the sticks and stopping the motors.

Well this afternoon it fully flipped itself, driving one side into the grass, resulting in one of the motors being obstructed by something while seemingly at full power, making a VERY LOUD high pitched squealing sound and putting off a strong odour of burning metal. Second attempt to shut motors off seemingly worked as far as my memory serves, only one of the motors was still making the high pitched sound which would suggest it was still running, or trying to at least. Resorted to pulling the battery. This was all over maybe 5-7 seconds.

So far as I can tell, the flight replay reflects this exactly - the last 2 inputs on the sticks clealy show both sticks fully in the outside-bottom corners. First 'motor off' command, followed by another emergency attempt when the thing flipped. Understandably I'm not very happy at all.

The outside casing of the motor was VERY hot to touch. The motor spins freely with no obstruction, and I it doesn't appear as though anything had gotten inside of it. It either wound some grass around the shaft or I have no idea.


Likelihood that the affected motor is f'd and burnt out? The only other source of the smell I could think of is if the shaft itself was spinning on whatever's holding it still, which obviously isn't supposed to happen either.

Happy to provide the flight log file to show aircraft was landed, stationary, and stick input at the time it flipped (will need to refresh myself on how to get it though).


Thanks all!

Hi Trozzle
Sorry to hear that's happened to you too. A few people have mentioned this and it has happened to me too.
My advice is to not use the CSC except to start the drone.  When you land, simply keep the left altitude stick down for 3 seconds on its own and the drone will switch off. There is no need to do a CSC to shut it down on landing.
With regards to the state of your drone now; hard to say. ideally you'd get it checked out and maybe the motor replaced. But equally if the bird seems to fly right on a few low level open ground test flights, you may have got off lightly and be okay.
Good luck fella
Ian

wellsi Posted at 2016-3-17 16:23
Hi Trozzle
Sorry to hear that's happened to you too. A few people have mentioned this and it has hap ...

^^^^^^^^^
What he said

Thanks for the responses guys.

I haven't touched the drone since the incident. I'm unsure of performance or integrity of the affected motor as I merely spun it with my hand to check for jams and it spun freely. It was significantly hotter than the 3 other motors for some time so I simply left it.

I will be using the altitude stick method to kill the motors from now on, however if my drone has damaged the motor in question from this event I strongly believe this should not in any way be my financial responsibility to cover. Following the pilot instructions provided by DJI and (confirmed by the last few seconds of flight playback: aircraft height at 0.0m > both sticks to outside CSC potision > height jumps up to 0.9m and back to 0.0m over a few moments > sticks to CSC position again > end), I will be very disappointed if the motor has been damaged it should be covered by warranty or similar.

I'm not specifically pissed off this has happened, as I understand these things aren't going to be absolutely perfect or fool-proof; I'm concerned that this kind of thing could potentially not be covered by a guarantee when it's undeniably entirely the fault of the device itself.

You are lucky, if it only damaged a prop or two... And not an internally fried motor.
With the props removed, start the drone and see how it reacts to various stick movements.
Push the sticks in a direction that help speed up that hardest hit corner motor and see how it sounds.

Hopefully, it will all be running fine and you will forever heed the warning of not using CSC while landing.
That is an option for cutting the motors in an emergency use only.

RedHotPoker

From the smell and temperature of the motor, I'm not confident. The squealing sound however is of GREAT concern. It seems as though something was rotating on the body of the drone in lieu of the prop's ability to turn.

The props seem to be perfectly fine. I don't believe it was prop obstruction causing the motor to jam; I believe it was a thick piece of grass wound around the prop shaft, which fell off upon me pulling the battery and the motors losing power.
Sorry to sound blunt, but again - don't really care what the 'purpose' of CSC is - if it's detailed in documentation as a way to stop the motors, it should do just that and nothing more. For it to have flipped my drone, which is verifiable by flight data, any damage caused by that behaviour should not be my financial burden. Herein lies why I'm unhappy.

Ok, well, to come to a complete stop, do you jam on the emergency brakes of your personal car/truck at every stop sign and traffic lights intersection?
Then put it in park, & shut it off. ;-)
You do, I can tell. You want to make sure it stops.

RedHotPoker

RedHotPoker Posted at 2016-3-18 08:21
Ok, well, to come to a complete stop, do you jam on the emergency brakes of your personal car/truck  ...

Taken directly from the P3A quick start guide, distributed by DJI. It is not advertised as an emergency method. It is advertised as THE method. You didn't need to be a smart ass.

You posted this thread, & I mistakenly thought you were seeking advise. So, Sorry for my commenting bud.
If you chose to do a CSC while landing your drone, and it went hay wire, that's on you.

As stated, left stick straight down, hold it for three seconds after landing, to shut down.
Ass is as ass does, and you pulled a boner. All further comments or other deviations in RC stick actions, are futile. Hahaha
Sometimes manuals aren't updated properly, and that CSC upon landing is a holdover from previous model instructions.
It should have been corrected & or omitted from current PDF. Sadly it wasn't brought up to today's standards.
But @DJI also want your drone/s sent in for expensive repairs. It's business at the speed of light. ;-)
Live and learn, I heard you say: "I won't do that again!" Hehe

RedHotPoker

No no - I appreciate the advice and enlightenment to the "hold altitude stick down 3 seconds" function. I may have misjudged the 'tone' you posted in though.
EDIT: on second thought, maybe you are being a dick unecessarily. Pulling a boner would be using CSC when the instructions said to hold the altitude stick down for 3 seconds. Given this isn't mentioned in the quick start guide (as per my screenshot), you're just being a dick. Please tell me I'm wrong.

From here on in, I will be using that method. That however shouldn't take away from the fact the current revision of the quick start guide provided here on DJI's website advises you to use CSC with no mention of holding the altitude stick down to kill the motors, and it was the (mal)function of this advised feature that has potentially caused damage to my drone. I interpreted your comments to suggest 'too bad so sad, you were doing it wrong' and that it's not DJI's problem, which I take massive issue with. I'll now presume that was not what you were getting at.

This is a live and learn situation, but any costs to repair this thing will not be on me. If the most appropriate instructions for shutting down the motors are to use the altitude stick solely, then DJI need to update their PDFs ASAP to avoid any further  ups from their poor programming of the CSC feature.

I would like input from a DJI rep on this, though I sense that will require me emailing the support team directly.

How does the phantom know not to kill the motors during decent if you holding the throttle completely to bottom ?  

Does it sense the attitude is not changing, and therefore ok to cut the motors ?

I wanted to help you, but you are dead set On @DJI being in your debt.
If you were to scan and speed read all my posts and threads on this and several other forums and blogs,
I rarely if ever, request advise or helpful knowledge from others, whom are far more knowledgable than I, in this arena.
Many here only frequent these fine forums to attempt in helping others become more proficient, and enjoy the hobby to its fullest, as far as your/their own capacity can thrust them.
Unfortunately, there have been a rash of drones that had minor or infrequently major malfunctioning gear and had to be sent in to @DJI for in house, physical assessment and repair.
But many several threads, on the other hand, have had only a minor pilot-malfunction.  Those concerns can often be alleviated through question and answer time on the forums. Show and Tell.
You show us a problem, and we will attempt to tell you how to fix and or repair it. At no cost to you. ;-) As you just need an Internet access point for relief of migraines and shoulder-neck cramps..

RedHotPoker

Yeah now I have literally no idea what you're getting at other than: a manufacturer (DJI) has no liability for damage caused by a malfunction of a feature the instruction manual advised me to use.

You have helped me in that you have advised me of a more reliable and appropriate function of the controls to shut down the engine which would avoid this in future. For that, I am thankful.

I don't appreciate suggestions DJI have no liability for incidents such as this. The aircraft was fully stationary before the malfunction of the advised feature caused it to lift off and flip. That's not pilot error. DJI's advice does not mention the more appropriate shut-down method you have; this incident was caused by poor programming and malfunction.

The aim of this thread was mostly to gauge opinions on whether the heat and burning smell should be of concern.

Same exact thing happened to me. Extremely frustrating. Joke. Just use the auto land now.

Sent before I could finish.... Check the motors visually if you have black all over the coil its probably a fried motor.

A lot of times I just hit return to home when I get close to landing spot, it gently lands the drone and shuts the motors off automatically when it touches ground.

Indeed - RTH will just land if it's where it took off from, then shut down the motors. As will telling it to just land via the app. I wasn't actually going for a flight when this happened, merely took off and hovered a bit, then manually landed it. Under a minute "flight" time.

I suspect (with no evidence to support) that the motor itself was not specifically the source of the heat, sound, and odour, but that the shaft (which is the fixed part of the motor/propeller configuration from what I can tell) may have been spinning freely in its mount. Imagine the shaft spinning very quickly against plastic or whatever's supposed to be holding it stationary. Maybe. Just a guess.

Otherwise on initial inspection of the motor, it looked fine. Nothing inside/around the coils. No black sooty shit to suggest frying itself. Just the smell, heat, and sound it initially put off.

For what it's worth, I've had just as much of an odour come from the motor on an electric RC buggy I had years ago....though slightly less like the smell of welding lol

Aussie Maverick Posted at 2016-3-18 12:14
How does the phantom know not to kill the motors during decent if you holding the throttle completel ...

Yep exactly- through the barometric sensor

trozzle Posted at 2016-3-18 04:36
Indeed - RTH will just land if it's where it took off from, then shut down the motors. As will telli ...

Hi again Trozzle
The problem with a CSC for stopping the motors is if you move the right stick a fraction of a second before the left stick, the drone will initially think you're telling it to swoop sideways or backwards as fast as it can. It achieves that by diving into the direction of travel. Hence your bird dives into the ground.

It can easily be argued by us that DJI should have a better, more fail safe way of stopping the motors.  And hey presto, the update for the Phantom 4 now allows you to shut down the motors by down throttle and pressing RTH; this method avoids the scenario I've just outlined above.

So maybe you should simply ask DJI through a support / returns ticket and see what they say. BUt you'll also lose your drone for a month or more.
Try flying the bird in an open field, no higher than 3-4 metres. See how it goes.

If you believe the whining and blockage was caused by some thick grass, then perhaps it was the grass itself making the noise and burning up.  Get flying again and see what happens.

Cheers
Ian

wellsi Posted at 2016-3-18 17:33
Hi again Trozzle
The problem with a CSC for stopping the motors is if you move the right stick a f ...

I agree with what you say, and just to add to that, the screaming noise can come from a motor that is forcibly held from rotating.

I do think DJI should re-visit their Quick Start guide, as mine is the same, it does not mention the left stick down method. And while they are about it, the main manual should also stress that left stick down is the correct way to stop motors, except in an emergency. Not as a normal method of shutting the motors down when landing.

Geebax Posted at 2016-3-18 19:15
I agree with what you say, and just to add to that, the screaming noise can come from a motor that ...

Finally, we can agree on something ;)

There are more topics about this 'problem'.

I did some tests yesterday and these are the results:
- The drone lands and the motors lower down the gain which points the drone recognize it has landed, it's safe now to use the CSC method to shut down the props.
- The drone lands and the motors keep turning at a high speed, DON'T use the CSC method in this case, it will result in a tip over most of the time, only use the left throttle stick!

The problem is, a landing will not always results in the first description.
I'm also in contact with DJI about this.
I've sended more then 10 flight logs to DJI so they could investigate why the drone flips over at a CSC shut down when it's standing on the ground.
I'll let you know when i received a respond on this.

Maybe anyone who is in this same sittuation can check if you see the diffrence in landing, and agrees this works to avoid a tip over?

Fair play to the op. the quick start guide does say to use the csc to shut off the motor once landed. I also tried this once and saw the drone was about to tip and stopped and then pulled the throttle down until the motor stopped. My ability to respond fast enough is due to years of flying 6 ch helis. Without that and if I was a newbie my drone would have tipped also.

The OP seems to have a perfectly reasonable position that since DJI instructed people to land this way and not using the left stick straight down and hold method, that they should have responsibility for the results.  I get that the left stick straight down and hold is the better solution, but the OP posted the instructions DJI provided him and and that's clear not what they told users to do -- they encouraged them to use the CSC  method.  Word-for-word from the quick start guide:

"To land, gently pull the left stick (throttle stick) down to lower the aircraft until it touches the ground.  Then pull both sticks to the bottom inside corners to stop the motors."

If DJI doesn't want people using the CSC method to land and isn't condient that will not result in any poetntial for it flipping the drone over, why did they tell people to do it?

Check this out it may help

I think we all agree straight left stick down is better.  It's just baffling that it's not what DJI recommends and there are many people who won't read this forum or other sites or videos and just follow the DJI instructions.

I only had my P3P for a couple of weeks before my crash.  OPs incident seemed similar to mine in the description of the "loud squealing sound".  I was flying about 20 feet off the ground when I heard the loud screeching sound and the P3P flipped and went straight to the ground.  I remember having the right stick to the right and left stick full up at the time I heard the sound and the Phantom flipped.  I wonder if my crash and maybe yours could have been just a motor issue.

Thanks for the video Buzz Lightyear.  I was using the CSC for shutting down motors and hadn't had an issue, in the future I will use the down left stick method.

trozzle Posted at 2016-3-18 08:31
Taken directly from the P3A quick start guide, distributed by DJI. It is not advertised as an emer ...

Hey Trozzle,
I see exactly why you did the CSC after landing. The instructions were posted in DJI's latest Quick Start manual. Their full manual however, shows both methods and further explains the CSC method by saying "after landing, push the throttle down, then use the combined stick maneuver...)  And that is method one! It's very tricky and your P3 will easily tip over. They are crazy to show that method for normal shut off.

IMO  Method 2 from the full manual should be method one and the only method to stop the motors after a normal landing, and of course the only one shown in the quick start guide. The emergency shut off  method (IMO) should be  a real button under a red warning cover on the RC. Like you would see on a piece of dangerous equipment in a factory.
I'm sure they will fix your P3 if necessary. You really should change the props in case there was damage to their internal threads.
Below is from a page in the latest full manual:

Thanks for the responses everyone!

I'll be swapping the props for sure. Will be getting it out today and having a good look over everything before giving it a test without props, and then just hovering around as suggested. I'll also familiarise myself with the preferred method of shutdown by holding the left altitude stick down, though as everyone seems to agree here this would be a simpler method and should have been the one advised in the quick start guide while really it'd be smartest to go through the entire user manual before diving into these things, it isn't absolutely necessary and this is why we have quick start guides. Read that, then refer to the full user manual for specific functions.

I totally agree with a big red button too! That would be ideal.

Thank you again for all your input everyone. I'm not out here shaking my fist at DJI as though they should be at my service over this, not at all....but I do like to know that I'm not out in the cold in terms of coverage for something that as most agree wasn't my fault when following instructions.

Really, beyond the logistics cost of shipping, if anything has been damaged here it would likely be of negligible cost to DJI anyway. What's a single P3A motor worth?

trozzle Posted at 2016-3-18 16:07
Thanks for the responses everyone!

I'll be swapping the props for sure. Will be getting it out toda ...

Motors are about $20.  Labor in the open market is about $80 (US).  Ask me how I know....

Hopefully this will teach you an important lesson. Never read the instructions.

In the US, this would likely not be deemed DJI's fault since somewhere along the line you probably agreed to something that said DJI could use pi=3.0 and you have no recourse.  YMMV since you live in some other legal jurisdiction.

But, as has been suggested, turn it on without props first, if it does OK, try a short flight.  Make sure you do contact DJI and make them aware.  

Being in Australia (who knows why it says Switzerland below my avatar lol), our consumer rights and protections are pretty good, so much I'm very confident this wouldn't be a problem if I had to go down that avenue.

Haha to some degree I agree about not reading instruction. Generally I'll read a quick start guide to make sure I don't do/miss anything stupid, then I'll refer to the full manual on things I'm uncertain about.

What's the go with warranty when it comes to having a part such as the motor replaced? I'm absolutely confident in doing it myself, however I'd presume DJI would void warranties unless work was completed by a certified repairer?

trozzle Posted at 2016-3-19 11:52
Being in Australia (who knows why it says Switzerland below my avatar lol), our consumer rights and ...

There is one authorised service shop for DJI in Melbourne, you probably would have to send it to them.

I'm sorry for your crash, please contact DJI support @ http://www.dji.com/support
Also, please watch your language, I don't like having to go through and editing posts.

Thanks for the reply. Sorry for the language, I didn't mean any offence so anyone. Will keep it PG from here

I'll fill out a support form once I'm back on a PC.