Return to home only goes straight up!

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I am an experienced P3 pilot and picked up a P4 Standard in what looks to be like new condition. Before any flights I calibrated the IMU and Compass and started a series of small and short tests from my front yard with a maximum distance of about 300' from home. The max altitude was set to 120 meters and the RTH altitude to 60 meters. This would be the first time that I ever try to cancel a RTH while in near panic. I made a mistake in pressing "Cancel" instead of "OK" thinking that Cancel was stop returning. All flights were with DJI Go 4.

Here is what happened:
  • The P4 flew well in several small & short test flights and then I set the AC in a hover about 300ft from my house to do an accuracy test of the RTH.
  • At 4:12 I initiated a RTH with the RC button.
  • The flight log shows the distance from home to be 0ft. which is incorrect as it was at the corner about 300'away. This error started when the flight commenced and does not end until 6:34.
  • The AC rotated to face the home direction and then started climbing.
  • 4:22 AC reaches an altitude of 195' and reports "RTH: Backing up to avoid obstacle". There was no obstacle.
  • 4:53 Exceeds the maximum allowed altitude of 120 meters.
  • 6:01 AT an altitude of 763' the data log shows that it is pre-ascending and backing up to avoid an obstacle.
  • 6:34 The distance from home changes from 0 to 286ft after a brief loss of signal. Altitude was 970ft.
  • Mild panic set in and I invited my wife to come say goodbye to my new toy and was resigned to see it fall from the sky when the battery failed.
  • 9:00 At an altitude of 1,640' the connection was restored and this time I hit the "OK" when I cancelled the RTH.
  • From there I was able to bring it back down to a safe landing.
A few hours later after searching the internet and not finding a definite solution I set out for more testing. I set the RTH altitude to 40m and flew 100' away and at 160' altutude I pressed the RTH on the RC. Same result - immediate ascension until the RTH was cancelled. I thied the RTH button with the Android phone and had the same result. Next I tried Litchi app and the RTH behaved the same.

Not being a hardware of software expert I am stumped.

Here is the link to the Flight log viewer. DJI Flight Log Viewer - PhantomHelp.com
If the DAT file is needed please let me know and I will retrieve that.

Any and all help is greatly appreciated.
Dave
 
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That is extremely confusing, you say it thinks it needs to avoid an obstacle. Have you tried a RTH with obstacle avoidance of?

Good luck
 

PhantomWetSuits

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I love the part where you invited your wife to say good bye, I have been there on a fly away. lol

So the GPS signal was not to strong but held up , and Im wondering is it possible the Sun was affecting the front sensors which could cause the Sensor problem.

The other thing I would do is Flash the firmware on the Assistant 2 and check to see if your batteries have been updated.

If you fly in sport mode that will shut down the sensors and get you out of sensor problems really quick.

Attacking this problems from all angles is best:
Firmware, Sport mode and watching the sun flares.

NOTE: Once the sun gets to the sensors , they are whacked , confused so always get into sport mode when you suspect that.

Phantomrain.org
Gear to fly your Phantom 4 in the Rain and Float on Water.
 
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Oso

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I am an experienced P3 pilot and picked up a P4 Standard in what looks to be like new condition. Before any flights I calibrated the IMU and Compass and started a series of small and short tests from my front yard with a maximum distance of about 300' from home. The max altitude was set to 120 meters and the RTH altitude to 60 meters. This would be the first time that I ever try to cancel a RTH while in near panic. I made a mistake in pressing "Cancel" instead of "OK" thinking that Cancel was stop returning. All flights were with DJI Go 4.

Here is what happened:
  • The P4 flew well in several small & short test flights and then I set the AC in a hover about 300ft from my house to do an accuracy test of the RTH.
  • At 4:12 I initiated a RTH with the RC button.
  • The flight log shows the distance from home to be 0ft. which is incorrect as it was at the corner about 300'away. This error started when the flight commenced and does not end until 6:34.
  • The AC rotated to face the home direction and then started climbing.
  • 4:22 AC reaches an altitude of 195' and reports "RTH: Backing up to avoid obstacle". There was no obstacle.
  • 4:53 Exceeds the maximum allowed altitude of 120 meters.
  • 6:01 AT an altitude of 763' the data log shows that it is pre-ascending and backing up to avoid an obstacle.
  • 6:34 The distance from home changes from 0 to 286ft after a brief loss of signal. Altitude was 970ft.
  • Mild panic set in and I invited my wife to come say goodbye to my new toy and was resigned to see it fall from the sky when the battery failed.
  • 9:00 At an altitude of 1,640' the connection was restored and this time I hit the "OK" when I cancelled the RTH.
  • From there I was able to bring it back down to a safe landing.
A few hours later after searching the internet and not finding a definite solution I set out for more testing. I set the RTH altitude to 40m and flew 100' away and at 160' altutude I pressed the RTH on the RC. Same result - immediate ascension until the RTH was cancelled. I thied the RTH button with the Android phone and had the same result. Next I tried Litchi app and the RTH behaved the same.

Not being a hardware of software expert I am stumped.

Here is the link to the Flight log viewer. DJI Flight Log Viewer - PhantomHelp.com
If the DAT file is needed please let me know and I will retrieve that.

Any and all help is greatly appreciated.
Dave
We have seen this reported several times. Perhaps 10-12 times if I had to guess. There have been a few suggestions in those threads such as not facing the sun, turning off OA, turning off VPS, removing a gimbal guard, etc.

One other has been to downgrade FW which seemed to help numerous people.

Which FW versions are you using?

Does anything in this thread sound familiar to you and to your symptoms?

Note: I don’t have a P4, so I am only relaying what I have seen several times here on the forum.
 
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Thank you to Andyflac and PhantomWetsuits. I will re-do the tests with the sensors deactivated, and try sport mode.
Oso - that thread hit on the nose! The bird has firmware 02.00.0810 and exhibits 100% of the sysmptoms that Eaglecroft55 explains, right down to flying way too slow when going forward. Now I 'm in the process of downgrading.
 
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Question. Prior to calibrating the imu, did you look via the app to see if the imu needed to be calibrated? Or the compass?

I bought this used from a pawn shop that thought it was broken. One of the first things I did before the first flight was do a recalibrate on everything.
 

Oso

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Oso - A big thank you for leading me to the right thread. Reverting to the previous firmware 2.00.0700 solved ALL of the problems. RTH works perfectly and forward speed is not limited.
You're welcome. I'm so glad to hear it.
 

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