P4P Complete Loss of control, til crash

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Hi,
Would appreciate some experienced assistance. In the middle of a roof inspection (still photos only) my P4P indicated a compass error (I think) then attempted to land. As it was not safe to do so, the drone just hovered in place. I tried to cancel the landing but the response from the app was a " request time out". I tried to return to home; nothing. I restarted DJO Go4; nothing. I restarted the remote; nothing. I restarted my iPhone 7; nothing. In short I had no control of the drone but still had return vision and control of the gimbal. I could tilt up and down and see live vision, just not motor / servo control. Eventually the battery went flat, the drone tried to land on the sloping roof, and obviously tumbled to the gutter.
I'm wondering if anyone else has experienced the same. I have done at least 100 jobs like this in the past 9 months without issue. Flight records attached for anyone who can understand them.
Any clues to the issue would be appreciated...
Fausto
 

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  • DJIFlightRecord_2020-02-17_[08-26-20].txt
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Fly Dawg

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@Fausto .... There is no compass issue in this flight. The issue being that when you activated Go Home @~725 seconds, the aircraft was too close to the home point and immediately shifted to autoland. At ~781 seconds the status again changed to "Hover". The battery was fine and was not the issue.

1582040454336.png
 
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BigAl07

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@Fausto welcome to the forum. Sorry about your incident but hopefully some of our experienced Accident Log GuRus can help diagnose the cause and resolution.

How bad is the aircraft damaged if any?
 

RodPad

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Yes,
Welcome to the Forum!

Hate to see the first post, crashed or lost. :rolleyes: :(

Take a look at this.
This is the basic look see, and as far as my knowledge goes.

Add to what @Fly Dawg stated.

When you look at the simple log, you can see you tried RTH and the Phantom was to close to the home point.

I guess you kept trying to cancel RTH?
You hadn't seen the message 12m 5.6s which was displayed once?

Rod
 
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Hi Guys,
Thank you for the replies so far. Answering the question; no obvious damage, just some marks on the blades. I have not restarted the drone as I don't want to loose any data stored locally for DJI to retrieve.
I've looked at the link above to view the log (thanks Rod) and I think I need to explain a little further what happened. I know time can feel like it is slowed down, but I feel this went on for a lot longer then the log suggests, and I did things that I'm not seeing in the log, Particularly the RTH, I didn't initial that, not at the start at least.
When I lost control the drone appeared to go into RTH / landing as I believe it had lost connection with the RC. I wasn't aware of this initially and tried to trouble shoot. My first step was to quit and restart DJO Go4, nothing I then restarted my iPhone, and obviously Go4, nothing. Then i noticed the rear lights were rapidly flashing yellow (it looked white to me though) I believed this was an indication that the RC link had failed. I then restarted the remote, nothing. The entire time I had return vision and could control the gimbal. This is when I purposely pressed RTH, trying wake up the system. Every attempt to abort the auto landing was met with a time out error. The whole time the yellow lights flashed until the battery was exhausted. I guess it could be a malfunctioning RC but I'm nervous to power it up as I said earlier.
I am not confident to use this drone for work anymore (for the obvious reason) and talking to the local repairers, they believe it needs to go to DJI as they can access additional data to ascertain the issue.
Thanks,

Fausto
 
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RodPad

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@Fausto,
If you upload the data here, these guys will give you more info than DJI will. (It is free with your member ship)

So....

#1 Is this P4P under warranty?
#2 If yes, then upload a .dat file from your mobile device.
#3 If no, then do #2 then ask what what #4 is.

Instructions for what I'm asking.
Flight log retrieval and analysis guide

@Fly Dawg, @BigAl07, @sar104 and others will be waiting for your replies.

Its your turn, I need to call it a Knight nite night.


Rod
 
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@Fausto .... There is no compass issue in this flight. The issue being that when you activated Go Home @~725 seconds, the aircraft was too close to the home point and immediately shifted to autoland. At ~781 seconds the status again changed to "Hover". The battery was fine and was not the issue.

View attachment 117300
Thanks for the explanation. I may be misinterpreting this display, but it appears to end at battery approx. 42%. I was getting critical battery warnings until the drone finally just landed. I assume that was a lot less than 42%?
Fausto
 
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@Fausto,
If you upload the data here, these guys will give you more info than DJI will. (It is free with your member ship)

So....

#1 Is this P4P under warranty?
#2 If yes, then upload a .dat file from your mobile device.
#3 If no, then do #2 then ask what what #4 is.

Instructions for what I'm asking.
Flight log retrieval and analysis guide

@Fly Dawg, @BigAl07, @sar104 and others will be waiting for your replies.

Its your turn, I need to call it a Knight nite night.


Rod
Hi Rod,
Thanks,
#1 No
#2 Isn't that the file I already uploaded
#3 What's #4?
Fausto
@Fausto .... There is no compass issue in this flight. The issue being that when you activated Go Home @~725 seconds, the aircraft was too close to the home point and immediately shifted to autoland. At ~781 seconds the status again changed to "Hover". The battery was fine and was not the issue.

View attachment 117300
Hi Again,
It appears I can answer my own question. There are two other files that were created (I assume after my two reboots of Go4). These are attached.
I am so appreciative of your help!
Fausto
 

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  • DJIFlightRecord_2020-02-17_[08-42-00].txt
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  • DJIFlightRecord_2020-02-17_[08-45-27].txt
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Meta4

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Thank you for the replies so far. Answering the question; no obvious damage, just some marks on the blades. I have not restarted the drone as I don't want to loose any data stored locally for DJI to retrieve.
The internal data recorder holds the data from several flights, you would not lose any data if you try a test flight

You can view your data in these three files:

You got the drone into a bind when you initiated RTH too close to home and started it autolanding.
But Obstacle Avoidance detected an unsafe landing surface and prevented landing.
You needed to cancel the autolanding to get control back .
Flicking the flight control switch to Sport and back usually cancels any automated flight mode.

I'm nervous to power it up as I said earlier.
I am not confident to use this drone for work anymore (for the obvious reason) and talking to the local repairers, they believe it needs to go to DJI as they can access additional data to ascertain the issue.
Take the drone outside and try a test flight in a clear, open area.
If there's no damage, it should fly perfectly.
There is no chance that you'll overwrite any stored flight data by doing this.
 
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RodPad

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"It appears I can answer my own question. There are two other files that were created (I assume after my two reboots of Go4). "

Yes, every time you restart go and your flying, it starts a new log, also in the past I used to get a new log file on a P3S, if I lost signal and the signal came back.

I didn't understand this statement: "The whole time the yellow lights flashed until the battery was exhausted." Seeing the other two files it makes sense.

Everybody says fly your bird!

Couple of past threads on RTH, both have comments of the Phantom being to close to home.
Addition of low battery and RTH. Not really related to your low battery. But unexpected things that really happen. :rolleyes: ;)

Lesson learned from crash by RTH because flying with a low battery
DISABLE "Smart go home."

Rod
 
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The internal data recorder holds the data from several flights, you would not lose any data if you try a test flight

You can view your data in these three files:

You got the drone into a bind when you initiated RTH too close to home and started it autolanding.
But Obstacle Avoidance detected an unsafe landing surface and prevented landing.
You needed to cancel the autolanding to get control back .
Flicking the flight control switch to Sport and back usually cancels any automated flight mode.


Take the drone outside and try a test flight in a clear, open area.
If there's no damage, it should fly perfectly.
There is no chance that you'll overwrite any stored flight data by doing this.
Thanks for the feedback. I need to stress I did not initiate a RTH. The drone was 5 meters away from me in plain sight, just above a garage I was inspecting. The RTH was initiated some other way, I believe due to a loss of connection with the RC. I didn't mention it in my post, but yes I tried to go into sport mode and ATTI mode many times. The only control / response of the drone was the gimbal and return vision. Every time out that is seen on the log is me trying to cancel the auto landing.

Cheers, Fausto
 

RodPad

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OK,
I have never seen a P4.

Post #1 "I tried to return to home; nothing. "
Post #5 "Particularly the RTH, I didn't initial that, not at the start at least."
Post #11 "The RTH was initiated some other way, I believe due to a loss of connection with the RC. "

Until post #11, I wasn't paying much attention to your RTH statements.

The first log.
11m 58.9s Obstacle Avoided. Revise Flight Route

12m 0.3s
12m 5.0s
5 seconds pass.

Phantom shows no speed and home position change of .3 ft. While you were attempting to move it.
Could this have prompted you to use RTH?
Would it not have been moving because of Obstacle Avoidance?

Then you couldn't cancel it because it had switched to Auto Landing?
If it is Auto Landing does it ignore RTH commands?
The log shows no signal loss until 13m 13s. RTH had already been activated before this.

Note: You can see your stick movements by clicking on each log entry.


Oops,
I didn't see these answers, I thought it was just part of the reply.

"Hi Rod,
Thanks,
#1 No
#2 Isn't that the file I already uploaded

#3 What's #4?"

What you uploaded is the .txt file.
On P4's there is also .dat file on your moble with more information that may help in your questions.

Number #4
You seemed to be concerned not to fly-it it, tell it was look by DJI, etc. Also them accessing the data.
"I am not confident to use this drone for work anymore (for the obvious reason) and talking to the local repairers, they believe it needs to go to DJI as they can access additional data to ascertain the issue.
Thanks, "
I was thinking it was under warranty.

This is another .dat file on the SD card glued to the main board inside the Phantom.
The Black Box like in a car.
Every time you turn the Phantom it starts saving to this card, and erases older data when the card is full.
It holds maybe the last 20-50 flights, etc anytime the Phantom is powered on.

This statement from @Meta4 is what he was referring to.
"The internal data recorder holds the data from several flights, you would not lose any data if you try a test flight"


Also this statement explains why it didn't land when it said it was auto landing.
"You got the drone into a bind when you initiated RTH too close to home and started it autolanding.
But Obstacle Avoidance detected an unsafe landing surface and prevented landing.
"
Wish I was a better reader, this summed up a lot of my theory and questions.

To retrieve these .dat files, the instructions are here.
Flight log retrieval and analysis guide
I'm not the one to read these files.

I now completely agree that is what happened and learned a lot about Obstacle Avoidance.
Rod
 
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OK,
I have never seen a P4.

Post #1 "I tried to return to home; nothing. "
Post #5 "Particularly the RTH, I didn't initial that, not at the start at least."
Post #11 "The RTH was initiated some other way, I believe due to a loss of connection with the RC. "

Until post #11, I wasn't paying much attention to your RTH statements.

The first log.
11m 58.9s Obstacle Avoided. Revise Flight Route

12m 0.3s
12m 5.0s
5 seconds pass.

Phantom shows no speed and home position change of .3 ft. While you were attempting to move it.
Could this have prompted you to use RTH?
Would it not have been moving because of Obstacle Avoidance?

Then you couldn't cancel it because it had switched to Auto Landing?
If it is Auto Landing does it ignore RTH commands?
The log shows no signal loss until 13m 13s. RTH had already been activated before this.

Note: You can see your stick movements by clicking on each log entry.


Oops,
I didn't see these answers, I thought it was just part of the reply.

"Hi Rod,
Thanks,
#1 No
#2 Isn't that the file I already uploaded

#3 What's #4?"

What you uploaded is the .txt file.
On P4's there is also .dat file on your moble with more information that may help in your questions.

Number #4
You seemed to be concerned not to fly-it it, tell it was look by DJI, etc. Also them accessing the data.
"I am not confident to use this drone for work anymore (for the obvious reason) and talking to the local repairers, they believe it needs to go to DJI as they can access additional data to ascertain the issue.
Thanks, "
I was thinking it was under warranty.

This is another .dat file on the SD card glued to the main board inside the Phantom.
The Black Box like in a car.
Every time you turn the Phantom it starts saving to this card, and erases older data when the card is full.
It holds maybe the last 20-50 flights, etc anytime the Phantom is powered on.

This statement from @Meta4 is what he was referring to.
"The internal data recorder holds the data from several flights, you would not lose any data if you try a test flight"


Also this statement explains why it didn't land when it said it was auto landing.
"You got the drone into a bind when you initiated RTH too close to home and started it autolanding.
But Obstacle Avoidance detected an unsafe landing surface and prevented landing.
"
Wish I was a better reader, this summed up a lot of my theory and questions.

To retrieve these .dat files, the instructions are here.
Flight log retrieval and analysis guide
I'm not the one to read these files.

I now completely agree that is what happened and learned a lot about Obstacle Avoidance.
Rod
Thanks Rod,
Yes I think my replies were a little hap hazard and that didn't help.
The one thing I would like to stress though, is that it is assumed I initiated a RTH. I did not, until quite a few minutes had passed when I was quite literally trying anything and everything to get control. I don't understand the correlation between obstacle avoidance and return to home. I do jobs like this daily, and even earlier ion the flight you can see where I get warnings from the OA. Some times I turn it off so I can manoeuvre the drone to a position I need, then turn it back on.
It seems to me that people are assuming that I initiated something, then panicked when it went wrong. That is not the case. From the three log files you can see this situation went for 12 or more minutes with no control of the flight control of the drone. Any attempt to cancel was met with time out errors. Also the entire time the drone's rear lights were rapidly flashing yellow which I believe means a loss of contact with the RC, which is clearly not correct.Maybe it was my iPhone I don't know.
I'm no where near as experienced as many pilots on this forum, but I am not a newbie. This is my second DJI drone and I have completed over 77 hours of flight time on them in 477 flights. The Go4 app says I have a "growth value" almost 766,000.
I'm not saying I was not to blame, maybe I didn't react in the correct way, I am prepared to accept that.
Thanks and sorry for the rant...
Fausto
PS DAT files attached
 

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  • 2020-02-17 08_26_26-07JDE6F00201GZ.dat
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  • 2020-02-17 08_39_42-07JDE6F00201GZ.dat
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  • 2020-02-17 08_42_07-07JDE6F00201GZ.dat
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  • 2020-02-17 08_45_38-07JDE6F00201GZ.dat
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RodPad

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You just got your facts wrong. :rolleyes: ;)
No Problem, I understand. :cool:

These .dat files must be from the mobile?

My limited skills is what you can see same as I on the browser.
I don't know if any of this data can actually confirm that the RTH button was pressed or what.
These guys go way beyond my abilities, maybe they will take another look at what you provided.

If you haven't, download the .dat files from the Phantom, I do that periodically (enough that I always have dups). They will get overwritten.

I sent a P3S under warranty for Remote Signal Problem after a successful Firmware update. :rolleyes:
When I got it back, I saved all the .dat files, there were two or three that were dated while DJI had it.
One of these days I will take time and figure out some of this stuff.

Rod

Added:
It takes a long time get those files, Phantom has to on maybe have a fan blowing on the camera?
 
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Hi Guys,
While in the process of downloading the DAT files from the drone I had a reoccurrence of the disconnection issue! Please view the attached video and you can clearly see the Aircraft Disconnected warning, yet I had complete control of the gimbal. Exactly as was the case on Monday...
 
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We've seen many times this misterious 'command timeout' massege with similar drone behaviour.
Really nice to know what is that?
 
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RodPad

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Hum, I really don't know anything about the P4 communications.
What Is interesting that you had live video from the Phantom and the data from the camera (ISO, SD card capacity, etc) and remote control controlling the camera (Still had a two way link).

But no aircraft data, which I assume should have been in the same signal as the camera data.
Does anybody know if the two data streams should be in the same signal?

@quaddamage,
I think your the P3A/P guy, on camera and communication from the gimbal. Could this happen on a P3, would you know about the P4?


"Aircraft Disconnected warning, yet I had complete control of the gimbal. Exactly as was the case on Monday... "

First problem it was a Monday.
The Disconnect message in the log, seemed to be after your problem started? When you were restating everything was my thought.

The disconnect message you have a video of, what does it show in your flight log?

I assume you can play your flight back in GO, have you done that?

This thread is getting twisted and turning in to a knot, I think we can get it untangled. ;):)


Rod
 

RodPad

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We've seen many times this misterious 'command timeout' massege with similar drone behaviour.
Really nice to know what is that?
Is this only on P4's?
You got any similar links?

Rod
 

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@sar104 have you seen any other incidents like this one?
 
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I think your the P3A/P guy, on camera and communication from the gimbal. Could this happen on a P3, would you know about the P4?

Never had a P4 of any kind.

Looking at the boards, here's sensor.
Then it goes to Ambarella.
So that part is the same as in P3P. But then the FPV video doesn't seem to go to DaVinci.. It goes probably there?
Not all chip markings are visible, so no idea which does the compression. But that board contains the whole Ligtbridge, so definitely this is where the signal goes through Lightbridge encoding and high frequency modulation (Artosyn chips do that, they were used in late versions of P3P as well).

So my conclusion is: this looks almost exactly like Ph3, only which-chip-is-on-which-board is different. The only real difference might be that DaVinci might've been replaced by another chip with the same function. Not sure if it was replaced as I can't see markings. If someone has better photos of the big board, I could tell which chip does that.

From the look of it, most of these would even work if flashed with Ph3 firmware. The circuit is identical, only on different board configuration.
 
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