fans8a1d5757 Posted at 2017-9-27 16:43
Look at the flight record Google maps does not show an obstacle anywhere The tree that  may have taken down my p3s is over 100m away on the point.  This entire sequence happened 63' above water after loss of signal. There was no obstacle involved before the RTH initiation.

It does not matter whether there was a tree there or not, the P3S does not have any form of obstacle avoidance anyway. It is a bogue message, and has most probably got nothing to do with what happened. My view is that the 40 Metre RTH altitude is too low for most conditions other than a flat desert.

fans8a1d5757 Posted at 2017-9-27 05:20
would love to do this but the drone is gone. the flight record just ends with the drone heading home @ 16 mph in open water in the middle of the channel. No obstructions anywhere.

Sorry to hear this. Wish you have a good luck to find the drone. If you have more questions, please feel free to contact the Support: http://www.dji.com/support.

fans8a1d5757 Posted at 2017-9-27 10:02
That would make sense. I will check with the owner of the house on the point tomorrow when I am back in Maine. Thanks for all your help on this!

I think it would have hit the tree on the near side to the home point rather than the far side, the far side and house don't look tall enough:

Sorry, you will have to cut and paste the link, this forum doesn't like it!  It should have flown straight towards the viewing point from the marker at it's last position:
"https://www.google.co.uk/maps/place/43%C2%B007'44.7%22N+70%C2%B038'30.4%22W/@43.1301591,-70.6454992,72a,35y,105.79h,79.23t/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d43.129077!4d-70.6417874"

Labroides Posted at 2017-9-27 06:05
Are you referring AG Column to this section  If yes it appears I back off the throttle when the RTH starts.
Yes, column AG is throttle data
No, it doesn' show you backing off until well after RTH has initiated.  (1024 is the centre stick position - 1684 is full forward)

I studied the CSV detailed report: The sensor false alarms appear to cancel the RTH since they do mention RTH during this period. Here is my evaluation. The P3S clearly did not respond to my throttle up command for almost three seconds before the RTH Go home sequence begins. the RTH begins but it appears to end with obstacle messages. Only after I throttle down @ 10m 48.5s does RTH begin again at 10m 49.8s

1. 10m 43s - 10m 45.9s   
Left Stick Command to Ascend: Altitude remains at 63' for entire 3 second sequence -P3S fails to respond to left stick throttle command
2. 10m 46s
" braking to avoid obstacle" RTH - this is an error since my P3S does not have sensors
3. 10m 46.1s
"braking to Signal Lost- Aircraft returning to home point" - Altitude still at 63' - Sensor error P3S does not climb to 40m RTH Altitude
4. 10m 46.2s -46.9s  
"Braking to avoid obstacle" another sensor error not associated w P3S- Altitude still at 64'. Missing RTH - sequence appears to end
5. 10m 47s -49.7s
RTH Aborted "Backing up to avoid obstacle" another sensor error not associated w P3S- Altitude still at 64' - Missing RTH - sequence appears to end
6. 10m 48.5s
Left Stick Command to Ascend Ends - throttle back to center
7. 10m 49.8s
"Cruise RTH"  RTH Mode re-initiates after three seconds of sensor error messages  Altitude still at 64' P3S fails to climb to set 40m RTH altitude
8. 10m 53.6s
Last frame  Altitude still at 64' P3S fails to climb to set 40m RTH altitude

Nigel_ Posted at 2017-9-28 03:13
I think it would have hit the tree on the near side to the home point rather than the far side, the far side and house don't look tall enough:

Sorry, you will have to cut and paste the link, this forum doesn't like it!  It should have flown straight towards the viewing point from the marker at it's last position:

Thanks but I tried many times & it won't load in google maps here on this side of the pond!

fans8a1d5757 Posted at 2017-9-28 04:14
Thanks but I tried many times & it won't load in google maps here on this side of the pond!

Still works here, don't include the "".

It is just the google maps 3D view of the house and trees, gives a better idea of where to look and the heights of the trees/buildings/etc. than the 2D views, you can find it yourself on google maps.

fans8a1d5757 Posted at 2017-9-27 16:43
Look at the flight record Google maps does not show an obstacle anywhere The tree that  may have taken down my p3s is over 100m away on the point.  This entire sequence happened 63' above water after loss of signal. There was no obstacle involved before the RTH initiation.

We don't have full information so have to join the dots to find the solution that best solves the puzzle.
This is further complicated by the Phantom losing signal so further flight data is not recorded by the app after signal is lost.
Another complication is that after signal is lost around 10:46 and RTh is initiated, signal is briefly restored to record another 8 seconds of data before the record ends.
Looking for why the Phantom did not climb, the only thing we know of that does this is, moving the left stick when the Phantom is at or above 20 metres.
This appears to be the most likely explanation in this case.

Forget the obstacle warnings.
There is no sensor to detect obstacles - so no obstacle was detected.
You just have mysterious spurious messages.

The obstacle that does matter is Stage Neck which definitely blocked the signal from your controller to the Phantom when you flew behind it.
It is only 33 ft above sea level (plus whatever trees, lighthouses, powerlines etc which could be above ground height.
Since the Phantom didn't come home and signal was not regained, the most likely explanation is that your Phantom crashed into something there.

Labroides Posted at 2017-9-28 07:16
We don't have full information so have to join the dots to find the solution that best solves the puzzle.
This is further complicated by the Phantom losing signal so further flight data is not recorded by the app after signal is lost.
Another complication is that after signal is lost around 10:46 and RTh is initiated, signal is briefly restored to record another 8 seconds of data before the record ends.

So bottom line I need your advice for a future disconnect. What would you do if you were flying low behind and obstruction like the stage neck point, the I-phone screen goes black and you get the "disconnected" message on the top of the screen?  I know this probably won't happen to you but it most likely will happen to other lvl 1's...so what is the best course of action?
Do you wait for an RTH message (as I did not) and do nothing?
Or do you push the throttle and try to climb back to a signal without waiting for the RTH?

fans8a1d5757 Posted at 2017-9-28 14:17
So bottom line I need your advice for a future disconnect. What would you do if you were flying low behind and obstruction like the stage neck point, the I-phone screen goes black and you get the "disconnected" message on the top of the screen?  I know this probably won't happen to you but it most likely will happen to other lvl 1's...so what is the best course of action?
Do you wait for an RTH message (as I did not) and do nothing?
Or do you push the throttle and try to climb back to a signal without waiting for the RTH?

Once you have flown behind an obstacle and lost signal it's too late to do anything.
Because you have lost signal, whatever you do won't get through (unless you get signal back).
The key point is to prevent problems by being aware of where your Phantom is in relation to obstacles and not flying into positions where you will lose signal.

Labroides Posted at 2017-9-28 15:18
Once you have flown behind an obstacle and lost signal it's too late to do anything.
Because you have lost signal, whatever you do won't get through (unless you get signal back).
The key point is to prevent problems by being aware of where your Phantom is in relation to obstacles and not flying into positions where you will lose signal.

That's what I don't understand: the flight record shows that the P3S received my throttle up commands from the RC  for almost three seconds and did not respond by gaining altitude.

Why would it show it received the throttle up command and still remain at 63' for three seconds?

Setting your RTH to a level higher than any obstacle in the flight area , will solve signal loss and subsequent RTH. Ask me, I know I learned the hard way

fans8a1d5757 Posted at 2017-9-27 16:48
Thanks to all for your time and comments!  Hopefully this discussion adds more to the knowledge base!

Are you using the Phantom SE instead of the Phantom 3 Standard app?

WD9EON Posted at 2017-9-30 16:44
Are you using the Phantom SE instead of the Phantom 3 Standard app?

no...P3s app

stuka75 Posted at 2017-9-28 17:47
Setting your RTH to a level higher than any obstacle in the flight area , will solve signal loss and subsequent RTH. Ask me, I know I learned the hard way

Make sure you review those settings if you are flying in a different area. Sometimes a different altitude is required.

The throttle stick is as an emergency break what flight mode you ever set. I did a try to follow me. The copter got wrong GPS coordinates from my tab and was on a way to fly elsewhere but i pushed the left stick up and down and this mode was stopped. This can also stop climbing in RTH.

Nigel_ Posted at 2017-9-28 03:13
I think it would have hit the tree on the near side to the home point rather than the far side, the far side and house don't look tall enough:

Sorry, you will have to cut and paste the link, this forum doesn't like it!  It should have flown straight towards the viewing point from the marker at it's last position:

Thanks for your help!
Link to video:

fans8a1d5757 Posted at 2017-10-7 12:00
Thanks for your help!
Link to video: https://www.youtube.com/watch?v=gC31o3qpa4E

Thanks for posting the video, always interesting to see what really happened.

Strange that it turned 90 degrees, if it had been a P4 with obstacle detection then it would still have crashed!

Presumably it received a bit of control signal and you had your finger on the left stick.

In future, if you fly behind things, make sure you are high enough that 1. the radio signal has direct line of sight so that you don't loose control, and 2. it can RTH without hitting anything.

The other thing that can be useful - if you loose the video, be very careful with the controls not to either cancel an RTH climb or to cancel an RTH altogether by pressing the button to start an RTH.  The safe way to ensure an RTH is to turn the controller off for 10 seconds.

The Phantom looks OK, is there much damage?