I KNEW that eventually something would happen....  On the 32nd flight of my little over 1 month aquisition I was shooting video along a local river bank when the controller flashed across the top. "Aircraft Disconnected"...  At the time it was only 2200 ft away, line of sight, approx 15 to 18 ft above the water surface.
This has happened before, usually recoonects within a few seconds and we press on...  This time it stayed offline....  So I waited for the  RTH to bring the bird back.....  Still waiting and that's been over an hour ago.

Flight log from the Go 4.0 showed no warnings, 62% a/c battery, 5:22 seconds into the flight.  last data showed the aircraft increasing in alt at 1.1 mph, 11 mph horizontal speed, was actually turned around and returning to my location up river.  Prior to flight I had calibrated (always do) and it set the home pointnto justwhere I took off from.

Now the only thing I can think of is it could have clipped the water somehow but I don't think it was anywhere near low enough, unless the barometer handling the altimeter was not working right..  I was only 3.3 ft below my takeoff point which was approx 20 to 25 ft above the river surface (at a public boat ramp).

Going to call/email DJI this afternoon and see if they casn check the logs and see if there were any internal failure that can be identified.

Any constructive words of wisdom from the maters on this forum?

Roger

You said it was line of sight, so what did the Aircraft do? Did you watch it splash down into the river?Also, was it just the app that disconnected or did you lose the green light on the controller as well?

Did not physically see it hit the water as a concrete piling for the bridge was obstructing my view at that time....    The app showed disconnection, did not look down at the controller itself as I was looking for the drone to come back into view.  It was at least 500ft away from the bridge so it should not have hit the bridge structure.

Oldmaninwva Posted at 2017-1-22 08:38
Did not physically see it hit the water as a concrete piling for the bridge was obstructing my view at that time....    The app showed disconnection, did not look down at the controller itself as I was looking for the drone to come back into view.  It was at least 500ft away from the bridge so it should not have hit the bridge structure.

It was near the bridge it wasn't near the bridge......I don't understand

Sorry, but It looks like your connection was lost because of going behind the bridge (metal, concrete, obstructing) .
If you did not set the height high enough for the RTH it might have hit the bridge.

Download the log and DJI or the guys on the forum will check it out.


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ePetLicensing.c Posted at 2017-1-22 09:04
Sorry, but It looks like your connection was lost because of going behind the bridge (metal, concrete, obstructing) .
If you did not set the height high enough for the RTH it might have hit the bridge.

This seems to be an accurate diagnosis. Sorry for your loss, but concrete and steel structures are rough on signals.

Yes the connection was lost for sure, I was more than 500 ft past the bridge and my RTH altitude was set to 120m  (set that on initial setup and left it) so depending on how long it takes for the RTH to take over on a lost connection it's "Possible" that if the P4 was still moving horizontal (back towards me) at the last recorded speed then it "Could" have went into the bridge...  I was watching the area the whole time and did not see the P4 after signal was lost, so it (to me anyways right now) seems to have lost power and dropped into the water.

I have had a couple lost connections before, they always came right back.  Only on a forced lost connection where I shut off the controller and verified the RTH feature, the bird went to failsafe rth in under 5 seconds and came right back to my take off point so I know that feature worked (at least then)

After first getting the P4 I did set the RTH alt right then and left it.

Now I just need to figure out how to download the flight data from the Go 4 app.

Thanks for the help guys

Oldmaninwva Posted at 2017-1-22 11:15
Yes the connection was lost for sure, I was more than 500 ft past the bridge and my RTH altitude was set to 120m  (set that on initial setup and left it) so depending on how long it takes for the RTH to take over on a lost connection it's "Possible" that if the P4 was still moving horizontal (back towards me) at the last recorded speed then it "Could" have went into the bridge...  I was watching the area the whole time and did not see the P4 after signal was lost, so it (to me anyways right now) seems to have lost power and dropped into the water.

I have had a couple lost connections before, they always came right back.  Only on a forced lost connection where I shut off the controller and verified the RTH feature, the bird went to failsafe rth in under 5 seconds and came right back to my take off point so I know that feature worked (at least then)

Have a look at the instructions on Phantom Help , there may be enough information to help understand what might have gone wrong.

Oldmaninwva Posted at 2017-1-22 11:15
Yes the connection was lost for sure, I was more than 500 ft past the bridge and my RTH altitude was set to 120m  (set that on initial setup and left it) so depending on how long it takes for the RTH to take over on a lost connection it's "Possible" that if the P4 was still moving horizontal (back towards me) at the last recorded speed then it "Could" have went into the bridge...  I was watching the area the whole time and did not see the P4 after signal was lost, so it (to me anyways right now) seems to have lost power and dropped into the water.

I have had a couple lost connections before, they always came right back.  Only on a forced lost connection where I shut off the controller and verified the RTH feature, the bird went to failsafe rth in under 5 seconds and came right back to my take off point so I know that feature worked (at least then)

I just checked the advanced settings section on my DJI Go app, it had reset at some point to 50M, so still at 160+ ft it should clear any obstacle in the location it was at.

Oldmaninwva Posted at 2017-1-22 11:15
Yes the connection was lost for sure, I was more than 500 ft past the bridge and my RTH altitude was set to 120m  (set that on initial setup and left it) so depending on how long it takes for the RTH to take over on a lost connection it's "Possible" that if the P4 was still moving horizontal (back towards me) at the last recorded speed then it "Could" have went into the bridge...  I was watching the area the whole time and did not see the P4 after signal was lost, so it (to me anyways right now) seems to have lost power and dropped into the water.

I have had a couple lost connections before, they always came right back.  Only on a forced lost connection where I shut off the controller and verified the RTH feature, the bird went to failsafe rth in under 5 seconds and came right back to my take off point so I know that feature worked (at least then)

You should always check the RTH setting before every flight. DJI Go has ben known to reset some settings occasionally. Also, if it never actually lost connection with the remote, it wouldn't have returned to home. I am guessing that you just lost your App video feed, and not actually the connection to the remote. This means that you do not see what is happening, but the inputs that you give to the stick, will still control the aircraft. You could have inadvertently flown it blindly right into the bridge.

Oldmaninwva Posted at 2017-1-22 11:15
Yes the connection was lost for sure, I was more than 500 ft past the bridge and my RTH altitude was set to 120m  (set that on initial setup and left it) so depending on how long it takes for the RTH to take over on a lost connection it's "Possible" that if the P4 was still moving horizontal (back towards me) at the last recorded speed then it "Could" have went into the bridge...  I was watching the area the whole time and did not see the P4 after signal was lost, so it (to me anyways right now) seems to have lost power and dropped into the water.

I have had a couple lost connections before, they always came right back.  Only on a forced lost connection where I shut off the controller and verified the RTH feature, the bird went to failsafe rth in under 5 seconds and came right back to my take off point so I know that feature worked (at least then)

You say you were flying a few feet above the water, it is possible that your altitude was not reading correctly, I have had a few times where I would come down from a higher altitude and when it is just a few feet above the ground it would say it was at 20 ft or so

That's definitely a possibility... I've noticed that a few times in the past when I've had the drone up in higher altitudes and transitioned several times up and down..  This morning as I flew mine out over the river from the takeoff point I also walked down to the dock at the edge of teh river, brought the P4 down to approx 15 ft above me and the alt on the app showed a "negative 3.3 ft) and it stayed at that reading throughout the flight up to the disconnect.

Did you take into account that rivers are never flat and horizontal?  If they where then they wouldn't flow!

Over your 2200 ft distance, a 1 in 100 drop in the water level would put the drone 22 ft closer to the water and you say that it was only 15 ft above on the display?

Oldmaninwva Posted at 2017-1-22 12:01
That's definitely a possibility... I've noticed that a few times in the past when I've had the drone up in higher altitudes and transitioned several times up and down..  This morning as I flew mine out over the river from the takeoff point I also walked down to the dock at the edge of teh river, brought the P4 down to approx 15 ft above me and the alt on the app showed a "negative 3.3 ft) and it stayed at that reading throughout the flight up to the disconnect.

Another factor could have been if you had the VPS on. I was flying low over water last month and it would start sinking or rising, this was because I did not know to turn off VPS.

One thing is nagging at me, you say you flew behind a bridge pile, and it did not appear again, is that correct? It occurs to me that if it was an intact bridge, it may have gone into RTH, and tried to climb to RTH altitude and, in doing so, collide with the underside of the bridge.

"Any constructive words of wisdom from the maters on this forum?"

Yes ... without actual data, people can only make guesses and most are likely to be quite wrong.

Go to http://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.
Come back and post a link to the report it provides and someone here might be able to analyse it and give you an understanding of the cause of the incident.

Labroides Posted at 2017-1-22 14:24
"Any constructive words of wisdom from the maters on this forum?"

Yes ... without actual data, people can only make guesses and most are likely to be quite wrong.

Labroides

"Any constructive words of wisdom from the masters on this forum?"

    So many come to the forum not willing to take responsibility.
  Refreshing to see someone ask for help rather blast Dji for being at fault!
      I hope you can help Roger find the cause.
                    Thank You

Nigel_ Posted at 2017-1-22 12:36
Did you take into account that rivers are never flat and horizontal?  If they where then they wouldn't flow!

Over your 2200 ft distance, a 1 in 100 drop in the water level would put the drone 22 ft closer to the water and you say that it was only 15 ft above on the display?

Going down river would increase the distance between the water and the bird....  If I had gone upstream that would be a viable concern however a 1 ft drop in 100 ft is a little extreme, it would be more like 1/2  foot per mile if I remember right.  Thanks for the input though.  

Geebax Posted at 2017-1-22 13:30
One thing is nagging at me, you say you flew behind a bridge pile, and it did not appear again, is that correct? It occurs to me that if it was an intact bridge, it may have gone into RTH, and tried to climb to RTH altitude and, in doing so, collide with the underside of the bridge.

When it disappeared and lost comm with the controller it was approx 500 feet past the bridge...  When it dropped connection it was both vid and bird control at the same instant...  Like flipping a switch.  It would have had plenty of time and height on the RTH 50m to clear the bridge.

Labroides Posted at 2017-1-22 14:24
"Any constructive words of wisdom from the maters on this forum?"

Yes ... without actual data, people can only make guesses and most are likely to be quite wrong.

Finally got the time to submit the log file to the viewr site...  Heres the link...

http://www.phantomhelp.com/LogViewer/S7PGP0Y1NIJ5OPIS9F6K/#

all data stops with no additional info being recorded...

fansb1fe1104 Posted at 2017-1-22 12:57
Another factor could have been if you had the VPS on. I was flying low over water last month and it would start sinking or rising, this was because I did not know to turn off VPS.

Now THERES a more viable possibility..  I TOO was not aware that the VPS should have been turned off...  I missed that in my reading and youtube video watching marathons.....

Thanks fansb1fe1104

Oldmaninwva Posted at 2017-1-22 15:43
Finally got the time to submit the log file to the viewr site...  Heres the link...

http://www.phantomhelp.com/LogViewer/S7PGP0Y1NIJ5OPIS9F6K/#

It looks like after 1.26s you start loosing alt and landed.

But also the big problem I think is from where you took off the concrete slab would had plenty of steel rebar so this might have screwed your compass big time and also from the map it is seems you went too close to the edge of the river and there were plenty of trees and last but NOT least your big bridge.

I leave it for DJI because it seems that it just landed in the river.



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ePetLicensing.c Posted at 2017-1-22 16:02
It looks like after 1.26s you start loosing alt and landed.

But also the big problem I think is from where you took off the concrete slab would had plenty of steel rebar so this might have screwed your compass big time and also from the map it is seems you went to close the edge of the river and there were plenty of trees and last but NOT least your big bridge.

It was an asphalt parking lot, and the initial compass calibration went off without a hitch..  I had taken off, got it in the air and then took it over the river bank and started lowering the altitude  for the video shot I was going for...  The boat docks along the south bank of the river before and after the bridge.

The altitude that this file is showing at the time it most likely went swimming was -4.3 ft ( less than my take off), taking into consideration the elevation drop from take off to river surface of almost 20 ft I would have been at LEAST  10 or more ft above the river surface.

I am going to view a log of a few of my successful flights and see how the log files end the flights.

Oldmaninwva Posted at 2017-1-22 16:17
It was an asphalt parking lot, and the initial compass calibration went off without a hitch..  I had taken off, got it in the air and then took it over the river bank and started lowering the altitude  for the video shot I was going for...  The boat docks along the south bank of the river before and after the bridge.

The altitude that this file is showing at the time it most likely went swimming was -4.3 ft ( less than my take off), taking into consideration the elevation drop from take off to river surface of almost 20 ft I would have been at LEAST  10 or more ft above the river surface.

That will be a good idea.

When I looked at the GOOGLE MAP, it looked like concrete slab. Sorry!



Protect animal population. Spayed or Neutered? and License your Pet!

After reviewing a random slice of my flights over the past month I have noticed one very disturbing issue...  With the Take-off and Landing locations being within only a few ft of each other, the take off altitude and the landing altitude were randomly all over the place  with variances being from a negative 26 ft (-26) to a positive 40 and sometimes 50 ft differeance...  Appears the longer I was in the air the greater the  take off to landing altitudes were....

Now...  How many others are getting variances like this??

I do want to thank ALL those helping me understand this,
I will definitely submit this info to DJI to see what they say....  I doubt very seriously that they will replace the bird under a electrical failure but its worth a shot..

Oldmaninwva Posted at 2017-1-22 12:01
That's definitely a possibility... I've noticed that a few times in the past when I've had the drone up in higher altitudes and transitioned several times up and down..  This morning as I flew mine out over the river from the takeoff point I also walked down to the dock at the edge of teh river, brought the P4 down to approx 15 ft above me and the alt on the app showed a "negative 3.3 ft) and it stayed at that reading throughout the flight up to the disconnect.

If VPS was on, part of the flight logic is to keep you above a surface. If it was off and you chose to fly over a river, you are trusting the barometer alone flying so low,  that is not smart.

Sorry to hear. I lost mine in a river today when it set a new return to home point and wouldn't let me cancel RTH!

Oldmaninwva Posted at 2017-1-22 16:34
After reviewing a random slice of my flights over the past month I have noticed one very disturbing issue...  With the Take-off and Landing locations being within only a few ft of each other, the take off altitude and the landing altitude were randomly all over the place  with variances being from a negative 26 ft (-26) to a positive 40 and sometimes 50 ft differeance...  Appears the longer I was in the air the greater the  take off to landing altitudes were....

Now...  How many others are getting variances like this??

Sorry but someone has to say this. If you MUST fly under a bridge, do it from close by. And with metal all around, you should keep line of sight.

Apart from the technical reasons, there are security ones. The more people do this, the more likely the whole hobby will be shut down. There are already a ton of haters out there. Why give them more ammunition?

Oldmaninwva Posted at 2017-1-22 16:34
After reviewing a random slice of my flights over the past month I have noticed one very disturbing issue...  With the Take-off and Landing locations being within only a few ft of each other, the take off altitude and the landing altitude were randomly all over the place  with variances being from a negative 26 ft (-26) to a positive 40 and sometimes 50 ft differeance...  Appears the longer I was in the air the greater the  take off to landing altitudes were....

Now...  How many others are getting variances like this??

Yes ... the possibility of indicated altitude drift is one thing that comes to mind.
Were you looking down at the water to have an idea of your clearance height?

The flight data doesn't give us a lot to go with.
The low battery level at the start (82%) may be a concern but voltage seems OK at the end of the flight record - 62% @15.1V.
You flew out 2200 feet along the river at low altitude and the record just stops with no error messages or other clues.
If it was due to signal being blocked by a narrow concrete bridge pylon, you would expect the Phantom to have quickly drifted past the dead zone on the course and speed it followed (cross river and 15 mph).

RTH height was sufficient to clear the bridge and signal should have been quickly reconnected if the Phantom started to climb to RTH height.

Here's a pic for anyone trying to visualise:

Labroides Posted at 2017-1-22 16:52
Yes ... the possibility of indicated altitude drift is one thing that comes to mind.
Were you looking down at the water to have an idea of your clearance height?

Thanks for the better visual Labroides...  Before the bird got to the row of boat docks that stick out further, I was walking down to the ramp dock just to the left of the ramp..  I was standing 1 foot above the water level through out the rest of the flight.   It was at least 10 to 15 above the water at that time, that was a visual.

Altitude drift seems the most likely culprit based on all of this, but maybe DJI can figure something more out when I send in the info.

Again... Thanks for the help here.

Oldmaninwva Posted at 2017-1-22 17:37
Thanks for the better visual Labroides...  Before the bird got to the row of boat docks that stick out further, I was walking down to the ramp dock just to the left of the ramp..  I was standing 1 foot above the water level through out the rest of the flight.   It was at least 10 to 15 above the water at that time, that was a visual.

Altitude drift seems the most likely culprit based on all of this, but maybe DJI can figure something more out when I send in the info.

Sorry I couldn't be more help.
Often the flight data tells a more detailed story but sometimes the data just stops.
Usually that is because the Phantom was flown behind a mountain or tall building.
In this case that may be an ominous sign.

Oldmaninwva Posted at 2017-1-22 16:17
It was an asphalt parking lot, and the initial compass calibration went off without a hitch..  I had taken off, got it in the air and then took it over the river bank and started lowering the altitude  for the video shot I was going for...  The boat docks along the south bank of the river before and after the bridge.

The altitude that this file is showing at the time it most likely went swimming was -4.3 ft ( less than my take off), taking into consideration the elevation drop from take off to river surface of almost 20 ft I would have been at LEAST  10 or more ft above the river surface.

Just a FYI, it's also not recommended that you calibrate your compass every time. It's a common fallacy that has caused more than a few issues. It's probably not why you lost your drone and it certainly not going to get it back, but injecting it here so that others don't think it's what you're supposed to do.

Now that said, I fly abandoned railroad bridges frequently. It's never something you do when you can't see the bird. Bridges have 6 million and one things to wreak havoc with controls.

Mike-the-cat Posted at 2017-1-22 16:38
If VPS was on, part of the flight logic is to keep you above a surface. If it was off and you chose to fly over a river, you are trusting the barometer alone flying so low,  that is not smart.

But it's also well documented that VPS has issues over water because it's a reflective surface.

What's the height on that bridge?  at 50m RTH, just knee jerk in looking at that picture it could have potentially flown back toward home point and run right into it.  We're talking 164 feet here, that's not an insignificant bridge there.

CCrew Posted at 2017-1-22 20:41
But it's also well documented that VPS has issues over water because it's a reflective surface.

There have been adjustments made to the algorithm.

All said and done, the OP indulged in high risk behaviour. To then expect the company to compensate for this is RIDICULOUS. People should behave like adults here.

Mike-the-cat Posted at 2017-1-22 16:38
If VPS was on, part of the flight logic is to keep you above a surface. If it was off and you chose to fly over a river, you are trusting the barometer alone flying so low,  that is not smart.

VPS has a hard time with reflective surfaces and moving surfaces from what I have read, over a lake it may not have much of an issue but a running river or waterfall stream in my case definitely messes with the VPS.

If it only lost the telemetry feed but still had control signal perhaps you unknowingly flew it into the river simply by moving the sticks when you thought that it was out of range and returning home.

Sorry to learn about your loss. I can only empathize with you and hope it all gets straightened out.  Good luck.

I have faith in DJI, that they will look into this & fIx the anomaly.


RedHotPoker

Phantom-Paul 7 Posted at 2017-1-22 23:42
If it only lost the telemetry feed but still had control signal perhaps you unknowingly flew it into the river simply by moving the sticks when you thought that it was out of range and returning home.

Actually...  It lost both at the same time, which to me anyways indicates a total loss of battery power.  The aircraft status message at the top left of the screen immediately showed "Aircraft Disconnected" and at the same time the video was gone.

Well... Submitted a preliminary email to DJI support about the loss of the P4...  Will see what happens.  will keep the forum updated.
While I do have the loss of the drone insured through my homeowners, there still is a $500 deductible on it...  Next aircraft will have a no deductible policy purchased before flying

Once again, thanks to all the ones who provided input on this incident, very enlightening to say the least, learned a lot that's fer sher!