P3A Lost Connection (twice) At Hover / 15 Feet AGL, Couldn't Reconnect

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So at VERY Low altitude, my P3A lost connection with my remote... twice...

The first time I launched I had a good connection and plenty of satellites. I used the Go App to launch (like I usually do). It hovered at the pre-designated heght (like 3 feet or so, whatever it is). Then it just hovered there. I tried to ascend and rotate and nothing. Just stood there hovering about three feet off the ground.

I walked over and caught it and turned the battery on the AC off.

No pre-flight warnings, no radio interference warning, nothing like that.

So I turned off the RC, (having already turned off the AC), turned and restarted my phone, and tried to launch again, using the Go App to launch.

This time it made it up to about 15 feet and then the RC lost connection. It just hovered there pretty much in place, 15 feet off the ground.

I kept turning off and turning on the RC and it never regained connection.

So I stood there like an idiot in the middle of the street for about 20 minutes or so for the battery to wear down and for it to come down. I caught it as it slowly descended. No damage or anything this time.

This bird has seen a few spills. This is the first time I tried to fly it after doing an IMU calibration.

As it was hovering, the front lights were blinking red and the rear lights were blinking yellow constantly. Not in a pattern, just continuously blinking yellow.

Here are the DAT files taken from the aircraft:

Shorter one (about 30MB) of take and hovering about three feet off the ground:

Dropbox - FLY259.DAT

Longer One (about 100 MB) that was about a 15 minute flight hovering about 15 feet off the ground:

Dropbox - FLY260.DAT

And here are the text files from the DJI Go app. They are very small because the connection was lost so quickly.

Dropbox - DJIFlightRecord_2018-05-21_[15-09-58].txt

Dropbox - DJIFlightRecord_2018-05-21_[15-11-55].txt

Note: On both of those txt files it says there was a warning to unlock an authorization zone, but I never gone a screen on the app to unlock the authorization zone. Was there a TFR that I didn't know about??? Where I was flying was class G airspace.


Any thoughts?
 
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Sorry, I have nothing. But it’s weird that you had to wait for the battery to run down before the drone landed. It should implement and RTH in the case of a lost signal from the RC. Sounds like it did - but based on battery power not signal. Be interesting to hear what others have to say. I’ve noticed my P3A losing signal intermittently recently - if only briefly.
 
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Sorry to forum bomb again - but I can’t get passed thinking it must be some environmental factor. You mention you were in the street - were there a lot of houses of other buildings near by? High voltage power lines, HIRTA, hell I don’t know, solar flare?
 
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Sorry, I have nothing. But it’s weird that you had to wait for the battery to run down before the drone landed. It should implement and RTH in the case of a lost signal from the RC. Sounds like it did - but based on battery power not signal. Be interesting to hear what others have to say. I’ve noticed my P3A losing signal intermittently recently - if only briefly.
Thanks for the response.

Yeah, I am pretty sure the RTH height is set to 200 feet or something.

But it didn't go anywhere. It just hovered there. Then eventually just slowly descended.
 
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Sorry to forum bomb again - but I can’t get passed thinking it must be some environmental factor. You mention you were in the street - were there a lot of houses of other buildings near by? High voltage power lines, HIRTA, hell I don’t know, solar flare?
Well, there were houses near by, but since it was kind of windy, I picked a launch area where the houses had fairly large lawns in front since I wanted to give myself plenty of room in case there was a gust. So I would say the walls of the houses were about thirty to forty feet from the drone. No wrought iron gates or anything like that near by. And no warnings.

No cars were parked that close, either.
 
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Well, there were houses near by, but since it was kind of windy, I picked a launch area where the houses had fairly large lawns in front since I wanted to give myself plenty of room in case there was a gust. So I would say the walls of the houses were about thirty to forty feet from the drone. No wrought iron gates or anything like that near by. And no warnings.

No cars were parked that close, either.
Hmm, weird. Hopefully others more knowledgeable than I will add to the replies.
 
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Does anyone know if there is a file I can upload that would "explain" why it disconnected and didn't automatically activate RTH???
 
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Either the .txt of the flight from your Apple or android device. Or better the .dat from the aircraft.

You need DJI assistant 2 to get the .dat and it’s downloaded from the main DJI.com site.

There is a sticky on this site on how to pull the .txt and up load it so others can view it. If you can’t find it just search this forum for instructions to upload a flight record.

The .dat you will need to put in a location others can pull it down like google drive.

Pail Caldwell
 
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Well, I donwloaded DJI Assistnat 2 and it is not letting me do anything. It is just on the screen at the start that vaguley shows a graphic of plugging a USB cable into a laptop.

I have logged into my DJI account and that hasn't changed anything.
 
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Here are the DAT files taken from the aircraft:

Shorter one (about 30MB) of take and hovering about three feet off the ground:

Dropbox - FLY259.DAT

Longer One (about 100 MB) that was about a 15 minute flight hovering about 15 feet off the ground:

Dropbox - FLY260.DAT

And here are the text files from the DJI Go app. They are very small because the connection was lost so quickly.

Dropbox - DJIFlightRecord_2018-05-21_[15-09-58].txt

Dropbox - DJIFlightRecord_2018-05-21_[15-11-55].txt

Note: On both of those txt files it says there was a warning to unlock an authorization zone, but I never gone a screen on the app to unlock the authorization zone. Was there a TFR that I didn't know about??? Where I was flying was class G airspace.
 
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BTW: The remote does connect to the AC in my house fine. I didn't start the motors or anything, but just had the AC at one end of the house and walked to the other end of the house and it appeared that it stayed connected.
 
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Sorry, I have nothing. But it’s weird that you had to wait for the battery to run down before the drone landed. It should implement and RTH in the case of a lost signal from the RC.
Now that you mention this, I am pretty sure that I have it set to "hover" on lost RC connection.
 
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Hopefully one of the local experts here can look into the files and let you have some more info.

I guess you were able to get the assistant to connect? It's not the most straight forward process for sure.

On my drones, on lost of connection I have them set to RTH, it's so easy to just stop the RTH process if you regain connection, but if you are 2000' out or even 1000' and have to fly against the wind to come home, I have always felt it's best to have the aircraft start on back.

Paul Caldwell
 
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Hopefully one of the local experts here can look into the files and let you have some more info.

I guess you were able to get the assistant to connect? It's not the most straight forward process for sure.

On my drones, on lost of connection I have them set to RTH, it's so easy to just stop the RTH process if you regain connection, but if you are 2000' out or even 1000' and have to fly against the wind to come home, I have always felt it's best to have the aircraft start on back.

Paul Caldwell
Actually, I couldn't figure out how to get the DJI Assistant to work.

There is a way to use the app to set the AC into file transfer mode (or something like that... can't remember the exact name). That works fine as long as the RC and AC will connect.

As for what the drone should do when it loses connection, I have heard that if it is within 60 feet of the home point, the drone will just land WHERE IT IS, and not actually fly back t the exact launch point. I almost always fly within 60 feet of my launch point, and that means there is a good chance it will land on someone's roof.
 
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Good point on RTH, and interesting to know about how to get the .dat off the drone without assistant 2.

If you are on PC sometimes a driver issue comes up with Assistant 2. What I do, is turn on the drone, and then lauch assistant 2. When I get to the screen where you have the USB plug and computer, then I plug the drone into the USB port on the computer. If I try to launch with the drone already attached most times assistant 2 will not connect.

On Mac, it's a bit more straightforward it seems. With win10 each time I plug in the drone, win10 goes through the "new" device install BS, like when you plug in a remote hard drive (I guess due to the micro SD card on the drone). But it seems to eventually connect.

That is one other point, make sure you have an micro SD card in the Drone when you try to connect to assistant. Again, not sure why it would matter, but it seems to help.

Paul C
 
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Good point on RTH, and interesting to know about how to get the .dat off the drone without assistant 2.

If you are on PC sometimes a driver issue comes up with Assistant 2. What I do, is turn on the drone, and then lauch assistant 2. When I get to the screen where you have the USB plug and computer, then I plug the drone into the USB port on the computer. If I try to launch with the drone already attached most times assistant 2 will not connect.

On Mac, it's a bit more straightforward it seems. With win10 each time I plug in the drone, win10 goes through the "new" device install BS, like when you plug in a remote hard drive (I guess due to the micro SD card on the drone). But it seems to eventually connect.

That is one other point, make sure you have an micro SD card in the Drone when you try to connect to assistant. Again, not sure why it would matter, but it seems to help.

Paul C
If I'm not mistaken DJI Assistant can't be used to retrieve .DAT files from a P3 or an Inspire 1. You have to use the procedure described by @Just Mark
 
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If I'm not mistaken DJI Assistant can't be used to retrieve .DAT files from a P3 or an Inspire 1. You have to use the procedure described by @Just Mark
Thanks for the input, BudWalker. Can you make heads or tails out of my dat files??? I tried the DatCon and CsvView apps and unfortunately it just opens up the files in Chinese.
 
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Actually, I couldn't figure out how to get the DJI Assistant to work.

There is a way to use the app to set the AC into file transfer mode (or something like that... can't remember the exact name). That works fine as long as the RC and AC will connect.

As for what the drone should do when it loses connection, I have heard that if it is within 60 feet of the home point, the drone will just land WHERE IT IS, and not actually fly back t the exact launch point. I almost always fly within 60 feet of my launch point, and that means there is a good chance it will land on someone's roof.
I didn't know that until I discovered it while playing around one day. I was just testing the RTH out about 40 feet from where I took off to see how accurate it could be and it just landed where it was. As far as the "hover" option goes, I would change that immediately. Just imagine if you were flying over water and lost connection. It'd be a mad dash to see if you can find a boat to borrow before the battery gets too low.
 
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Fly Dawg

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For what it is worth in the interim of looking for a cause of this. Note in the graph below taken from FLY260 the dramatic increase in battery current, right at the point of RC disconnect. If this were the transmitter shutting down, I would not expect the current to go up. There is an underlying cause. There appears to be an additional load on the battery at the time of disconnect which could indicate an intermittent short of some sort. Still looking at this. The graph only shows the first 38 seconds. Disconnect was at 27.9 seconds.

Voltage.png
 
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Thank you so much, FlyDawg.

Any thoughts on what might cause the short? (I am guessing there are probably a million things that can cause a short). It's never been exposed to water. But it has had a couple of crashes.

Seems that as long as it is on the ground, it is fine. I understand that taking off probably puts the most strain on the motors and the airframe (and probably all other components).

Thanks again.

Thanks in advance.
 

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