Hello folks,

I'm hoping for help in working out what went wrong here.
I had a flight recently where I initiated the Return To Home command twice. The reason I did so was while it was returning I had a look aroun and wasnt sure the RTH was still good so hit it again. The secnd time I hit it, the aircraft immediately started to tumble. And from 400m height, the resut was pretty much as you would expect. It gave me a live feed of the fall and then it went blank on impact.
After a lot of searching I managed to retreive the aircraft (less the camera which I just couldnt locate) and have just worked out how to get these flight data recordings off the machine (which by the way came off the remote actually, not the actual aircraft). At least I retreived my photos and footage off the microsd, so finding it was good.

I am returning to the place of purchase tomorrow but wanted to get the data off first. They will liase with DJI to see if there is any warranty due.

Still I am perflexed as to what exactly happened. GPS lock was good. I calibrated the compas immediately before the flight. Everything was working fine until disaster struck.
I already bought a replacement, but naturally until I know what happened here I am somewhat concerned it may happen again. Was it pilot error, equipment malfunction? I'm looking for some help thanks.

Basic info - Phanto 3 Pro. Battery was at >60% when retreived from the crash.



Cheers,
Todka

By the look of the video you got a weak GPS Signal and upon pressing RTH it went bonkers...did you try to turn off GPS mode and take control over it ? You where quite high so you got time to try it. Of course if it was spinning out of control ATTI mode might not have done you any good.

Interesting to hear what DJI says..

Im really confused here, you said "while it was returning" you hit it again. I also notice you have your max height set to 444.8 M, current australia law states you can't fly above 123 M. It appears that there may be a glitch in the system but if it was on its way home why didn't you just let it come home? Also I don't ever use RTH unless its an emergency.

What about a video showing your stick movements?
And yea, 444M is pretty high...
What did you do to stop RTH the first time?

once you hit the rth the second time, you in fact cancelled RTH!! as far as why it went bonkers? not enough info to give an educated guess. at 400+m , i doubt you had any man made electromagnetic interference.not having gps or having compass errors should not make p3 upside aown and tumble. maybe there was a motor or prop problem. in the photo i cant tell if props are whole or broken!! if broken, maybe it broke mid flight!!

Gabe R Posted at 2015-9-1 01:21
Im really confused here, you said "while it was returning" you hit it again. I also notice you have  ...

Hello Gabe. While it was returning from my initial RTH command, I used the panning control on the right stick to see if it would return to home in a side on orientation aimed at the hills I was filming. That seemed to cancel the return to home instead, in any case I was unsure if RTH was still working, so I pressed it again. I don't see anything wrong with using the RTH function. Is there? How you use yours is up to you and unless there is an issue I am unaware of, whats the problem?
I don't claim to know exactly what is and isn't allowed for control input and am here to learn. The P3 comes out the box with a quick start manual and that's it. Plus an FAA height warning which is not relevant for my country. No instructions for the DJI Pilot app either. It would be nice to have some more detailed resources so a new operator can skill up a bit more before flying. I have no previous UAV experience except for a Parrot bebop which is not really transferable knowledge.

My location was remote outback. The nearest town with a mobile phone transmitter capable of internet use was at least 500k's away. So no internet resources to referance. Just work it out myself as best I could.

Regarding height, you are quoting regs for controlled airspace.  This was not. There were no birds or aircraft withing sight or hearing either and the phantom was in line of sight. It should be able to fly 500m height without issues, and the object I was filming required the height. I'm impressed with how quickly it climbs. Very cool when it is all working properly. Still trying to work out what went wrong.

toddyplex Posted at 2015-8-31 19:51
Hello Gabe. While it was returning from my initial RTH command, I used the panning control on the  ...

the only way u cancel rth on rc is by hitting it again. moving the stick now with the Smart Go Home does not cancel rth. when u pressed it a second time that is when u cancelled rth.
without flight log and stick controls, its a guessing game. maybe u did a CSC by mistake?

paullindqvist Posted at 2015-8-31 23:35
By the look of the video you got a weak GPS Signal and upon pressing RTH it went bonkers...did you t ...

Hi Paul. Thanks for the suggestion. I didn't think to try that. Maybe that would have been worth a shot.  The tumble was immediate and quite severe. My live feed was pretty much a blur of colour. It did take a while to fall, but I was lost for ideas. I considered trying the starting command but I also was trying to keep an eye on the aircraft so I could know where to search for it.

aparis99.gmail Posted at 2015-9-1 04:57
What about a video showing your stick movements?
And yea, 444M is pretty high...
What did you do to ...

Hi. Thanks for the reply. I'd love to see that too. Any links for how I can get that information off it? That would be most useful to see.

toddyplex Posted at 2015-8-31 19:56
Hi. Thanks for the reply. I'd love to see that too. Any links for how I can get that information o ...

on your flight log at the bottom left u will see an icon of the controls, hit that and ur stick movements will show uo

rayrokni Posted at 2015-9-1 05:06
once you hit the rth the second time, you in fact cancelled RTH!! as far as why it went bonkers? not ...

Hi. Thanks. 2 rotors were missing blades, but the break point has red dirt in them so I suspect it was from impact. Your comment made my remember I omitted another vital bit of information. Just before the loss of control, I got an overheat warning. I missed what the word preceding overhear warning was.  I really should have included that in the original post. It would also be great if I could get that data off the aircraft too. Hopefully DJI know how to retrieve this stuff. Appreciate the input.

toddyplex Posted at 2015-8-31 20:01
Hi. Thanks. 2 rotors were missing blades, but the break point has red dirt in them so I suspect it ...

i am going to guess that the prop broke off in mid air.
why? u may ask
if it had broken on impact u would be able to maybe find it nearby. the fact that it has red dirt, could be that it had broken off already and upon impact it got the red marks. and since the broken props were not nearby could mean my theory may hold water.

rayrokni Posted at 2015-9-1 10:00
on your flight log at the bottom left u will see an icon of the controls, hit that and ur stick mo ...

Excellent. Thanks man.. Ill try that.

rayrokni Posted at 2015-9-1 09:55
the only way u cancel rth on rc is by hitting it again. moving the stick now with the Smart Go Home ...

More good info thanks. So if I pan it, it should continue on the RTH path and allow panning? Will it hold the orientation? I like that.  Regarding CSC, I certainly hope not, but the stick commands should reveal.  Thanks again.

toddyplex Posted at 2015-8-31 20:41
More good info thanks. So if I pan it, it should continue on the RTH path and allow panning? Will  ...

yes, now u can have control of sticks while it flies back to u.

So you can play back the flight on the Pilot app without connecting to your controller. i didn't know that.  I have checked the control input immediately prior to and during the loss of control.
There is full left stick down (no sideways input, just descending) and partial right stick up (also no sideways input). So no CNC command. If it's useful beyond that description I can capture the screen video tonight when I am home and post that up.
Anyway, from what I can see, there is no control input reason for this failure. So I am starting to firm up my opinion that it is a fault with the aircraft or its controlling software.
I will repost any feedback I get from DJI once that happens, which may be with a fair delay.  Appreciate the helpful comments and thought.

I guess one possible reason is that you pressing RTH simply coincided with a mid air impact or a prop breaking off, maybe not very plausible but the sudden tumbling of the aircraft seems very odd.

birdstrike.....ufo......llws

Submit the logs to DJI, perhaps they give you a replacement. And please show us the video of your flight

Aircraft handed over to the selling store and bound for DJI.
I uploaded a new video that includes the stick input into the original post at the top.

Swedrone, there is a file on the SD card for that flight, but it doesn't play. Possibly due to the file end not being terminated correctly. I haven't worked out how to view it as yet.

Birdstrike unlikely due to the height and not being any birds in the sky, so the best explanation seems to be rotor breakage or a weird software/hardware issue.

Wow - 23m/s vertical drop velocity. Motors must have shut down I guess.... Question is why.....

After some forum searching I found out how to fix the corrupted .mov file.   Here it is.

http://forum.dji.com/thread-17147-1-1.html

toddyplex Posted at 2015-9-1 06:15
After some forum searching I found out how to fix the corrupted .mov file.   Here it is.

http://fo ...

Wow, not exactly sure what I am seeing and tried to play it frame by frame but it looks like front left motor might have went out and that initially pointed the front left arm down quite a bit (is that the arm we see in the video on the left?) and then the prop going around slowly about three times.  I think left front motor overheated and and slowed or stopped prop speed.  If that is indeed what happened the gimble did great job keeping horizon before it couldn't any more during the tumble.

toddyplex Posted at 2015-8-31 19:41
More good info thanks. So if I pan it, it should continue on the RTH path and allow panning? Will  ...

How hot out was it?... or just wondering if dust particles at takeoff may have become lodged in a motor causing overheating and perhaps seizing of the motor. If you fly in the area from time to time maybe there was a buildup of dust and not just from this flight.

Perhaps the combination of dust in a motor and the ambient heat caused motor problems leading to the disaster.

Butch

It was around 25 degrees C.   Takeoff was from a rock but i had flown from beaches previously. I hand turn the rotors when i put them on each time and there were no unusual feelings.  
As you can see from the video, the spin was sudden and quite severe.  

Gabe R Posted at 2015-8-31 11:21
Im really confused here, you said "while it was returning" you hit it again. I also notice you have  ...

So, Gabe R stated that you were far above your allowed altitude and you contradicted him?

I hate to be an asshat but, this is from CASA:
Civil/Hobby Use

For drone operators looking to do a bit of skylarking with their quadcopters, the rules from CASA aren’t anywhere near as serious. Private operators don’t need approval from CASA before taking flight with their drones, but there are some rules that need to be respected.

The rules are simple:

• Stay at least 30 metres away from people with your drone.
• Keep your drone under 400 feet (121.92m).
• You may not operate your drone above a large gathering of people (e.g.: at sporting events, over crowds at the beach or groups of protestors).
• You must keep your drone within sight while you’re operating it.
• You may not operate your drone within 5km of an airport and a place where planes take off or land from.

I'm not totally sure, but it seems the flight took place WAY out in the middle of nowhere.  Can't we cut some slack if that is the case?
Noone around to harm and no property to damage?

What is the white object that appeared in the lower left corner at 00:21 ???
Oh...Sir edward addresses that in post number 24

That seems to be your answer

Did a motor overheat, melt the plastic and come out of it's saddle?

What was the Height setting set to when in RTH?

Ok, after a bit of research, it is not unheard of that Phantom motors can overheat to such a degree that they do melt the plastic and cause a catastrophic inflight failure.

stvnvicbc Posted at 2015-9-2 07:53
So, Gabe R stated that you were far above your allowed altitude and you contradicted him?

I hate  ...

Yes, you are an asshat.  If you are going to act as the forum height police you should at least get your facts correct.

CASA rules

It was not controlled airspace. It was remote. No height restriction.

Back on topic thanks.

oksxen Posted at 2015-9-2 08:56
What was the Height setting set to when in RTH?

I usually have it set to 50 or 60M to avoid trees. Given it was pretty high I usually give it some down stick on the way home to reduce the battery burn from first coming over me then slowly lowering down for ages. The usual return path is flat to above, then vertically down which is fine at lower heights.  

Cessna172 Posted at 2015-9-2 08:11
I'm not totally sure, but it seems the flight took place WAY out in the middle of nowhere.  Can't we ...

Thanks man. Both for the input and the common sense.  
An overheat warning flashed up, but if was brief and I couldn't read it in time. It didn't show in the log play either. So I am hoping that DJI can work it out. The thing that was really suspicious was that the failure occurred exactly when I pressed RTH. Which could be coincidental as suggested, but is suspicious.

The engine casings showed no sigh of heat damage. It took me over an hour to locate it so no chance to feel the temperature.

I got a replacement P3pro sent out to me which arrived 4 days later at a town I drove out to.  I know its a different unit, but it also had some issues with overheating in the IMU. I had one flight where I calibrated the compass and took off in GPS mode, and after 5 minutes of flight it gave a compass error followed by GPS disengaging. Went into atti mode and started to fly off in the wind. That made me wonder is it possible it was the consequence of an IMU overheat?

toddyplex Posted at 2015-9-1 20:31
I usually have it set to 50 or 60M to avoid trees. Given it was pretty high I usually give it some ...

I see. I read a similar issue from another post here not so long ago. P3 started to spin on its way down and crashed.  

stvnvicbc Posted at 2015-9-2 05:53
So, Gabe R stated that you were far above your allowed altitude and you contradicted him?

I hate  ...

Definite Asshat.

looks like a system/motor error, I say this because it happened immediately after RTH was initiated.. I dont see any pilot error there, and I would not accept anything but a replacement unit from DJI, esp since you've already bought another.

atkinson500 Posted at 2015-9-2 18:44
looks like a system/motor error, I say this because it happened immediately after RTH was initiated. ...

im thinking along similar lines. The evidence from the log amd video seem supportive. I see you from Aust also. I bought through Paxtons and the importer is CR Kennedy. Paxtons have been supportive and went above and beyond the call getting me a second unit shipped express to Broome to meet me there. I'm optimistic of a fair outcome.

I think sending to DJI will be the best option. Only they can really give you an answer..

You say an overheat message appeared, was this just before you RTH ( and did you do this because of the error? ). Also if you had a new one and also had overheat issues then maybe its an issue you need to think of.

Have yuo posted the flight logs ( from App and MC? )

There are a few messages related to heat that can come up.. Listed below..

"Battery Overheated"
"Battery Critically Overheated"
"Overheating During Discharge"
"The system has overheated. Turn off the aircraft and allow the motors to cool for five minutes, then re-start the Advanced Calibration."
"Camera Overheated"
"Battery is overheated, please Return-to-Home as soon as possible"

Hi sploodge. The overheat warning was just before my first RTH command, and was the reason I started bringing her home after only 10 mins or so flight time. I was splitting my time between looking at the aircraft and looking at the FPV and I only caught a glimpse of the warning. Enough to say with reasonable confidence it was Warning ???????????? overheat (or overheated). Nothing more verbose than that.
I don't quite follow what you mean with the logs posting. I screen captured the playback from the app at the top. The aircraft is with the importer now who is apparently just back from China getting DJI training. I sent them the aircraft and the controller. Now I just have access to the app. Thanks for your input. Appreciated.
Cheers.

atkinson500 Posted at 2015-9-2 05:31
Definite Asshat.

Ubandictionary.com - noun
A person, of either gender, whose behavior displays such ignorance/obnoxiousness that you would like to make them wear their own ass as a hat.

Oxforddictionaries.com - noun
North American vulgar slang
A stupid or contemptible person.