Sad my first thread  is crash thread but such is life. I am in the process of submitting a ticket to support. Gimble broke off and the case is cracked .

Was doing a flight at work in a built up space covering the building work being done on the site. I lost signal about 80 meters away and it switched in to return to home mode .I hit cancel straight away as i did not want it to return .I was going to relocate myself  closer to the drone to it to get a better signal . But what happened is in the 5 seconds it took me to hit cancel it began its return journey and travelled 40 metre's and hit in to the side of a apartment block.

My question is this . My understand  is  i should expect the obstacle avoidance to halt the aircraft once its at  this point of sensing the hugh apartment block in front of it ? . Why did it fly straight in to a a block of apartments and why did the obstacle avoidance not work?. Part of the reason i got the Phantom 4 and not the 3 was this built in feature as i knew i would be flying in close proximity to buildings and wanted this supporting feature .  Once the drone in in return to home mode the aircraft obstacle avoidance should still work ? . checked my settings after the crash and it was set to on .

I am just looking for clarification that the Obstacle avoidance should  stop the aircraft from flying in to the building ?

Thanks

Youtube clip of its last seconds and the building it hit

https://www.youtube.com/edit?o=U&video_id=NYI3w4qMdrg

That Youtube link does not work for me.

Geebax Posted at 2017-4-13 15:20
That Youtube link does not work for me.

Soorry selected the wrong link

Drone2621 Posted at 2017-4-13 15:26
Soorry selected the wrong link

https://youtu.be/NYI3w4qMdrg

Don't see a crash on it.

ibuyufo Posted at 2017-4-13 15:33
Don't see a crash on it.

Lol  yes thats because the footage is not from the SD card , Its cache from the Ipad and signal cut out soon as it crashed .

If there is insufficient light it may fail or if flying in S-Mode. Not sure what happens in a RTH in S-Mode.

Drone2621 Posted at 2017-4-13 15:26
Soorry selected the wrong link

https://youtu.be/NYI3w4qMdrg

Based on the video, there could have been a potential lighting issue and that the building seems very monochromatic, which does not help when the OA cameras are also monochromatic in nature. Just to clarify, were you in Sport mode? Did you ensure that OA was enabled to begin with?

In RTH mode it should stop, then gain height and fly over the top, assuming the relevant options are not disabled.

Looking at the video, it does seem a bit dark for the obstacle avoidance, they are only tiny cameras so need decent light, there have been a few incidents around sunset when people have trusted them to work and they haven't due to low light...

But on the video, it does appear to stop?   Maybe it did stop but then hit an overhang when it tried to fly up and over?  Might be sensible to disable the up and over bit while you are on a building site...

DJI-Jamie Posted at 2017-4-13 16:38
Based on the video, there could have been a potential lighting issue and that the building seems very monochromatic, which does not help when the OA cameras are also monochromatic in nature. Just to clarify, were you in Sport mode? Did you ensure that OA was enabled to begin with?

Hi to the people who have posted observations

The light was good to me .I was not in sports mode  was in P mode. and i did have OA enabled . And it was not set to auto avoid are fly around so in that case it should have just stopped is my understanding .

I could understand a tree are a crane causeing the camera problems but this is a large flat faced apartment block .  Last image i seen was it heading towards the windows. I found the drone directly below  the windows of the apartment block last seen in the video.

Drone was just 80 feet away from me when it lost signal i hit cancell RTH soon as it showed. Not sure why there is such a delay on the RTH warning that a drone can fly 40 meters before you even get a optiont to cancell RTH. All it had to do was stay where it was

Drone2621 Posted at 2017-4-13 16:54
Hi to the people who have posted observations  

The light was good to me .I was not in sports mode  was in P mode. and i did have OA enabled . And it was not set to auto avoid are fly around so in that case it should have just stopped is my understanding .

It did RTH because there was no signal, you could not have cancelled RTH until you got the signal back so it may have had a lot of time to travel the 40m.

You might be better off setting it to hover on lost signal in that location.

What time of day was it?    Near sunset it can get quite dark before our eyes notice.

Nigel_ Posted at 2017-4-13 17:42
It did RTH because there was no signal, you could not have cancelled RTH until you got the signal back so it may have had a lot of time to travel the 40m.

You might be better off setting it to hover on lost signal in that location.

Hi Nigel

I understand what your saying about the RTH . The time was 19.40 and the lighting was fine .  Your right it would be best of just being set to hover once signal lost .

But the whole reason i payed the extra £500 for the phantom 4 over the phantom 3 was the advertised OA system.

I was sure the drone was capable of seeing a 100 foot wide building and stop its self flying in to it. The RTH feature and OA feature are ment to aid in flight .

But in my case the drone was in no danger what so ever and these systems kicked in and turned it in to a suicide drone that flyed straight in to the face of a large building .

Drone2621 Posted at 2017-4-13 19:22
Hi Nigel

I understand what your saying about the RTH . The time was 19.40 and the lighting was fine .  Your right it would be best of just being set to hover once signal lost .

The obstacle avoidance system is not magic.
It doesn't work anywhere, anytime.
It's good but there are a number of limitations that you have to be aware of.
Look at P22-23 of your manual to see a list of situations that can give the OA system trouble.

Labroides Posted at 2017-4-13 19:38
The obstacle avoidance system is not magic.
It doesn't work anywhere, anytime.
It's good but there are a number of limitations that you have to be aware of.

Its not Magic you trying to wind me up  ? Really a £1000 bit of kit not picking up a 100 foot building in daylight and your saying its not magic.  Make sure you tell DJI that next time they do a advertising campaign on the OA system.

There was nothing else close to the sensor range that could have confused it. I can pick up a parking sensor for £50  could have done a  better job. I must have faulty sensors are DJI has been selling a feature than does not work.  

Drone2621 Posted at 2017-4-13 20:05
Its not Magic you trying to wind me up  ? Really a £1000 bit of kit not picking up a 100 foot building in daylight and your saying its not magic.  Make sure you tell DJI that next time they do a advertising campaign on the OA system.

There was nothing else close to the sensor range that could have confused it. I can pick up a parking sensor for £50  could have done a  better job. I must have faulty sensors are DJI has been selling a feature than does not work.

No, it isn't magic.
Have you read the limitations in the manual yet?

Labroides Posted at 2017-4-13 20:11
No, it isn't magic.
Have you read the limitations in the manual yet?

Can i block people in this forum ?

It might help in understanding the situation if you post the footage from the aircraft rather than the one from your device. It might show the collision a bit clearer.

Drone2621 Posted at 2017-4-13 19:22
Hi Nigel

I understand what your saying about the RTH . The time was 19.40 and the lighting was fine .  Your right it would be best of just being set to hover once signal lost .

"The time was 19.40 and the lighting was fine "

This will have been the problem.  Even if your eyes told you that the lighting was fine, you were only 15 minutes to sunset London time, and it also looks like it was overcast not actually sunny.

You may have had a warning that the vision system was off if you look in the logs/flight replay?  Even if it hadn't declared it too dark, the cameras would have been struggling to see clearly.

The obstacle avoidance works great during the day, it doesn't work at all at night, close to sunset you need to be careful because it can drop out unexpectedly when you fly into shadow.  

You should also be careful flying close to structures and landing at that time of day because when you loose the downwards visual positioning sensors it will switch to using GPS for holding position which means it can drift several meters, or even more around buildings that can block the GPS reception - don't hover below head height when it starts to get dark because it can unexpectedly fly into people when using only GPS positioning.

Geebax Posted at 2017-4-13 22:18
It might help in understanding the situation if you post the footage from the aircraft rather than the one from your device. It might show the collision a bit clearer.

Hi ,  The footage is corrupt from the crash  i am in the process of trying to recover the MP4 footage .  I found the drone at the bottom of the apartment block under the winodws.

Its apparent it flew its self in to the wall of the block . The little clip i posted even shows it did at first  stop before it hit the wall but then it just went straight back at the same wall . I gave no user input to direct this it was automatic

I am just going to push on with my ticket and seek a refund and get a P3 . As i said at the start i JUST  wanted to confirm that the P4 drone should not be flying its self it to hugh walls in daylight . Lets not forgot the advertised product .

Could you upload the log here, see if it shows anything outside of the suggestions already? I too am surprised OA didn't stop it if was set to be active in RTH mode.

Nigel_ Posted at 2017-4-13 22:42
"The time was 19.40 and the lighting was fine "

This will have been the problem.  Even if your eyes told you that the lighting was fine, you were only 15 minutes to sunset London time, and it also looks like it was overcast not actually sunny.

Thanks for the adivce Nigel  

Regarding the light i have to disagree i could see for miles and no need for lights any where . I did consider this before the flight .  Have a look at the clip from the flight i think the light should not be a problem . I checked my logs and got no warning  for lighting

calls4u2 Posted at 2017-4-13 23:20
Could you upload the log here, see if it shows anything outside of the suggestions already? I too am surprised OA didn't stop it if was set to be active in RTH mode.

Hello , i dont have access to the log at the moment and not sure if i am allowed to share have to check.
I made  a simple path from the flight log . Seems the OA started to work and took the drone back a few meters then to the left for aboiut 20 meters then straight back in to  the building.

Drone2621 Posted at 2017-4-14 00:14
Thanks for the adivce Nigel  

Regarding the light i have to disagree i could see for miles and no need for lights any where . I did consider this before the flight .  Have a look at the clip from the flight i think the light should not be a problem . I checked my logs and got no warning  for lighting

There is no exposure information in that video so I can't tell what the light level actually was.  From the lack of colour and contrast I guessed in my first response that it was around sunset, that is still what I see and you have confirmed that you were within 15 minutes of a London sunset.  (Was that the start of the flight or the time of the accident?)

Note that the obstacle avoidance cameras are the little ones on the legs, not the big one that this video is from, they are not as sensitive and need more light to operate well.  Even if there is enough light, they are monochrome cameras that need good contrast to detect distance to objects and this video does not have much contrast.  It does appear that it initially did see the building and put the brakes on, but then maybe couldn't visualise the distance to the wall when it was close up and could only see a bit of plain wall in front of it.

As I said earlier, you would not be the first person to have an avoidance failure near sunset.


There is no harm in following a warrantee claim.  With the aircraft log DJI will be able to see what was happening with the obstacle avoidance sensors and give the correct analysis.  Maybe there was a fault, but I am expecting that they will diagnose low light level and it will turn into an insurance claim instead of a warrantee claim.  Ultimately, they are obstacle avoidance sensors, not guaranteed crash prevention sensors, they have saved many aircraft and it only takes one successful avoidance for them to pay for themselves.  Flying around a building site I would definitely want them, and the vision positioning sensors that you wouldn't have on a P3, but you need to understand that their vision isn't perfect and just like humans they will sometimes make mistakes in poor viewing conditions and will not be able to see at all at night.  There was a thread a few weeks ago where someone was complaining about them not working and it turned out to be completely dark!

Drone2621 Posted at 2017-4-14 01:19
Hello , i dont have access to the log at the moment and not sure if i am allowed to share have to check.
I made  a simple path from the flight log . Seems the OA started to work and took the drone back a few meters then to the left for aboiut 20 meters then straight back in to  the building.

"Hello , i dont have access to the log at the moment and not sure if i am allowed to share have to check."

Of course you're allowed to share, it's easy to upload the information, instructions are on web page:-

http://www.phantomhelp.com/LogViewer/Upload/

You have some lovely footage of Newcastle there overlooking the Tyne, when you lost signal then there's no way it would be able to receive your instruction to cancel RTH. Had RTH altitude been set at an appropriate height then it would not have crashed into anything.

Drone2621 Posted at 2017-4-14 01:19
Hello , i dont have access to the log at the moment and not sure if i am allowed to share have to check.
I made  a simple path from the flight log . Seems the OA started to work and took the drone back a few meters then to the left for aboiut 20 meters then straight back in to  the building.

Just to reiterate, you will need to sync your Go app flight records when proceeding with a warranty claim with Support. Once they have reviewed them, they'll be able to tell you what happened. Everything at this point is speculation until then.

Based on what you've provided thus far, the OA was trying to do its job. Even with your diagram, one can't really tell whether the aircraft actually was in the correct angle in order to pick up the rest of the building prior to impact. With what little that could be seen from the video, the drone could have gone sideways into the building too agree that could have hindered function. Page 21 of the P4 manual does depict the vision angle limitations of the P4's forward sensors:

https://dl.djicdn.com/downloads/ ... ser+Manual+v1.4.pdf

Again, it's speculative until the fight records are able to be analyzed, but that is a possibility.

Drone2621 Posted at 2017-4-13 23:08
Hi ,  The footage is corrupt from the crash  i am in the process of trying to recover the MP4 footage .  I found the drone at the bottom of the apartment block under the winodws.

Its apparent it flew its self in to the wall of the block . The little clip i posted even shows it did at first  stop before it hit the wall but then it just went straight back at the same wall . I gave no user input to direct this it was automatic

'Hi ,  The footage is corrupt from the crash  i am in the process of trying to recover the MP4 footage .  I found the drone at the bottom of the apartment block under the winodws.'

The camera would have stopped recording at the time of the crash, so the file would not have been finalised. All you have to do is put the card back in any similar aircraft and switch it on for a short time and the system will fix the file for you.

Thanks for the feedback Nigel and Aardvark

The time in the video is about 3 min before the crash . The lighting was fine not what I consider low light at all . If this was the case then OA system would be more are less useless for any one who lives in a cloudy part of the world .

If I don't get a refund through DJI I will go through trading standards . Fact are this the the drone was in no danger . Lost its signal just  60 meters from home. The RTH height was set at 80 meters the building it crashed in to was less than 50 meters high .

The OA did not work as advertised  unless I got the phantom suicide drone . Maybe  I missed the part where it said . Yes the OA will stop JUST once when it detects a Hugh wall in front of it . But then it will go a bit to the left ON ITS OWN  and smash straight in to that wall . But hell its not MAGIC  its not CRASH PROOF  its just a OA system that can't tell the difference between a Hugh building and clear sky now thanks for your 1000 and close the door on your way out.

That is not the OA that was sold and advertised by Dji. I would have saved £500 and got the P3 if that's what I was wanting .  And yes I read the manual and its insulting to suggest its user error for a drone with a much advertised OA system not to detect a wall in day light with nothing else within 20 feet of it.

Understand some people have vested interests in DJI and the forum. But to defend a OA system that fly's straight in to a wall of its own accord tells me I am wasting my time here. Next time i sell a car and the air bag fails to activate  in a crash i will be sure to call upon this forum to help them understand its not magic and it does not prevent crashs. Regarding the flight log I have no intention of throwing that junk that is Itunes on to my Ipad , fact that you have to go through such a process to share your flight log says a lot. DJI can access it to confirm the flight details

All I wanted to know was should I expect a P4 OA sensors  to pick up a Hugh building with a flat surface and its OA system prevent it from crashing in to it .  Yet all I hear is reasons it  may not have the ability to do this and this is from experienced users. That tells me the P4 OA system is a a cheap gimmick that's not to be trusted in any operating environment and indeed should raise safety concerns about its usage and don't get me started on the way they advertised this system. Just want a refund and go back to the P3 . A extra 600 for a 4k camera a few min of battery life and AO system that does not work is a joke.

Again thanks for the feedback and taking the time and advice given even if I find it hard to swallow and a touch patronizing. I will just follow this through with DJI now . Happy flying and hopefully some one can learn from my mistakes with the P4 OA system .

Leave you with the crash i managed to recover along with DJI sales pitch

I am intrigued as to who Hugh is?

Drone2621 Posted at 2017-4-14 20:48
Thanks for the feedback Nigel and Aardvark

The time in the video is about 3 min before the crash . The lighting was fine not what I consider low light at all . If this was the case then OA system would be more are less useless for any one who lives in a cloudy part of the world .

Nice video,but the obstacle avoidance appears to work!

I assume that the crash was due to the wind...

To look at your claim that it returned at the wrong height and to confirm wind issues we would need to see the log...

Nigel_ Posted at 2017-4-14 23:29
Nice video,but the obstacle avoidance appears to work!

I assume that the crash was due to the wind...

Lol your winding me up wind ??  there was no wind , first you say its the light then wind . I do hope DJI is paying you people .

The OA works ???  if it worked it would have not flown back in to the building . Sorry its clear you dont know what your talking about , stroll on Nigel and spare me your pearls of wisdom . You be telling me Putin hacked in to my drone next .

Prep please have tried to help you here but you don't want to listen, indeed you even talked about blocking one of the most knowledgeable guys on here. The logs will show settings and real time environmental conditions which would let you know exactly what happened. As i did earlier, I'm surprised OA didn't kick in and all people are trying to do is figure out why it seems to have not saved your drone. Reading the posts might just help you learn about flying. Every other first flight I've heard of has been in an open safe environment yet you choose a building site.

calls4u2 Posted at 2017-4-15 01:04
Prep please have tried to help you here but you don't want to listen, indeed you even talked about blocking one of the most knowledgeable guys on here. The logs will show settings and real time environmental conditions which would let you know exactly what happened. As i did earlier, I'm surprised OA didn't kick in and all people are trying to do is figure out why it seems to have not saved your drone. Reading the posts might just help you learn about flying. Every other first flight I've heard of has been in an open safe environment yet you choose a building site.

Its not my first drone and  the reason it was a building site was because it was work but like others you cant be bothered to read  instead just more assumptions .

And yes i would have liked to blocked that clown who says patronizing  dribble like "its not magic" dont care how long he has sat at his computer posting for i dont come on the internet to make friends.

I asked one simple question about the OA system i never said i wanted to share my flight log with you. I never asked any one for a full explanation. I dont need some one to tell me how to fly .

My question was about a system that failed thats it . Can a mod please close this thread  before some sad sack tells me i broke regulation 293738/48829 during the course of my flight and I am part of the reasons drones will soon be banned .

Without seeing  logs I've had to assert to the only answer logically available from the information contained in your posts: Darwin and natural selection.

Drone2621 Posted at 2017-4-15 00:18
Lol your winding me up wind ??  there was no wind , first you say its the light then wind . I do hope DJI is paying you people .

The OA works ???  if it worked it would have not flown back in to the building . Sorry its clear you dont know what your talking about , stroll on Nigel and spare me your pearls of wisdom . You be telling me Putin hacked in to my drone next .

The only time I have seen a Phantom fly like that was when very close to the downwind side of something very large that was creating a lot of air turbulence.

You were on the downwind side of a tower block!

OA dose not fly sideways during RTH. The crash was not caused by OA.

Drone2621 Posted at 2017-4-15 02:00
Its not my first drone and  the reason it was a building site was because it was work but like others you cant be bothered to read  instead just more assumptions .

And yes i would have liked to blocked that clown who says patronizing  dribble like "its not magic" dont care how long he has sat at his computer posting for i dont come on the internet to make friends.

"My question is this . My understand  is  i should expect the obstacle avoidance to halt the aircraft once its at  this point of sensing the hugh apartment block in front of it ? "

There's more to consider here than the Obstacle Avoidance. DJI Recommend that you do not fly beside large structures, why ?

Because it may block your GPS signal, or perhaps reflect signals giving false information to aircraft, therefore it may not know exactly where it is and cause it to fly off in a different direction.

Similarly, these large structures usually contain lots of ferrous materials which will play havoc with the on-board compass' (plural), once again leaving the aircraft maybe not knowing which way it is pointing.

That is why the full flight record can be useful to ascertain exactly what 'may' have happened.

The Phantoms are complex machines relying on all these bits of information to work properly. That is why they are recommended for adults and not children.

Aardvark Posted at 2017-4-15 05:18
"My question is this . My understand  is  i should expect the obstacle avoidance to halt the aircraft once its at  this point of sensing the hugh apartment block in front of it ? "

There's more to consider here than the Obstacle Avoidance. DJI Recommend that you do not fly beside large structures, why ?

Another great reply your DJI Tshirt is in the post. Adults tend not to spend their time in internet forums are in open fields with other grown men talking about drones that's something children would do.

In the real world P4 get used every day in every line of business and yes many operate near large structures be it rocks,cliffs, buildings are search and rescue film production. Photogrammetry is what i do with the drone and the P4 is not my only drone . Again I suggest you revisits DJI advertisement on the P4 and its capabilities.

Next time some ones car loses a wheel and it hits a wall and the air bag does not go off. You be sure to tell them its not recommended you drive on a road near a wall that's why the air bag did not activate,its the same principle .

Try reading the question before you spout your DJI fan boy script. There is simple no excuse for this system to run its self in to a building in this manner RTH home height set at 80 meters building height 40 meters.

Next you be telling me DJI recommend we don't fly on a Friday and there for its user error . Like others your patronizing while  singing from a DJI  hymn sheet. I feel sorry for new pilots who are confornted by  some of the utter garbage that gets thrown at them by some of the forum dwellers.

Drone2621 Posted at 2017-4-15 12:54
Another great reply your DJI Tshirt is in the post. Adults tend not to spend their time in internet forums are in open fields with other grown men talking about drones that's something children would do.

In the real world P4 get used every day in every line of business and yes many operate near large structures be it rocks,cliffs, buildings are search and rescue film production. Photogrammetry is what i do with the drone and the P4 is not my only drone . Again I suggest you revisits DJI advertisement on the P4 and its capabilities.

Given that you've provided no factual information other that some bits of video apparently showing a Phantom crashing into a building it is difficult to support your cause or otherwise. I can only try and give advice based on what experience I might have, to perhaps explain what caused the crash. Perhaps enabling you to avoid a repeat in the future.

Good luck with your claim, keep us updated as to how you get on.

p.s the bit that doesn't quite make sense to me (but it could be me just being stupid) is that you appear to have a good live stream signal (as your 1st video extract from iPad)  yet no control over the aircraft

Just to add to that, I would prefer you don't come back here at all. You are an arrogant twit, and it is abundantly clear you do not need any answers, help or advice from anyone on this forum. So, do us all a Hugh favour and rack off elsewhere. To anyone reading this, don't feed this fool any further.

Geebax Posted at 2017-4-15 15:13
Just to add to that, I would prefer you don't come back here at all. You are an arrogant twit, and it is abundantly clear you do not need any answers, help or advice from anyone on this forum. So, do us all a Hugh favour and rack off elsewhere. To anyone reading this, don't feed this fool any further.

Don't care what you think I never asked you to post in the thread did I  ?. I  know your used to new posters putting up with condescending and patronizing remarks . Forums the world over are the same a small handful of circle jerkers who spend there days on the forum  think they run it.

You going to come across with remarks like " its not crash proof"  "it's not magic "  "Must have been the wind" "why you fly on a building site"  Then don't spit your dummy when some one throws that crap back at you. You people even go so far as to make up the P4 rule book as you go along you literally make this crap up as you go.

Drone forums always had a  high percentage of basement dwellers who aligning them self with the company.They have been spouting there own crap for so long uninterrupted they start to believe it . I seen a number of threads with reported problems and its apparent you people are looking for every and any excuse to blame user error rather than machine., try to remove your headfrom the pocket of  DJI and looks at what's in front of you for a change.

Still waiting to be told the Russians hacked my drone

Drone2621 Posted at 2017-4-15 16:53
Don't care what you think I never asked you to post in the thread did I  ?. I  know your used to new posters putting up with condescending and patronizing remarks . Forums the world over are the same a small handful of circle jerkers who spend there days on the forum  think they run it.

You going to come across with remarks like " its not crash proof"  "it's not magic "  "Must have been the wind" "why you fly on a building site"  Then don't spit your dummy when some one throws that crap back at you. You people even go so far as to make up the P4 rule book as you go along you literally make this crap up as you go.

I fully realise you do not care what I think, it is plain for everyone to see you do not care for anything that anyone else says either. So the real puzzle was why you ccame here in the first place, as you have managed to insult just about everyone on the forum. Of course that is not hard from the safety of your computer. If you came here to garner some support for the fact that you OA did not work, you might have got some, but you burnt all bridges in your pathetic wake of insulting, badly spelt vitriol.

Aardvark Posted at 2017-4-15 14:41
Given that you've provided no factual information other that some bits of video apparently showing a Phantom crashing into a building it is difficult to support your cause or otherwise. I can only try and give advice based on what experience I might have, to perhaps explain what caused the crash. Perhaps enabling you to avoid a repeat in the future.

Good luck with your claim, keep us updated as to how you get on.

Because it was in RTH mode I had no user input at any point in the video. I managed to get the footage of the SD yesterday with  the djifix.live555 fix which saved all my footage will have to donate to that great free app. The stream was recorded in my Ipad DJI application  I did not see it live all i seen live was the RTH activated and the last second before it crashed.

Factual ?  Its a question of you not trusting what some one says i think  . I told you the facts no point in me not telling the truth .DJI will see it all anyway so what would be the point in me not telling the truth  ? .

RTH set at 80 meters height Buildings 40 meters height . RTH activated about 60 metes from home point. Drone was  out of my control after that it is what you see in the video it did not go to 80M height and its OA system failed  and the drone is good for nothing put parts as a result .