What it appens if immediately after landing, instead to pull down the trottle and stop the motors (as I usually do...), you release the sticks and let the propellers running?
In my case, after few seconds, the fan speed tends to increase and my P3 pro seems to try a take-off...
Very strange behaviour!! More: under these circumstances, if I do not stop immediately the motors, the P3 tends to spill and crash on the ground!

I have hexperienced this strange anomaly few days ago, fortunately without consequences.
Note: in the past, I never noticed this critical sability because my usual behaviour was to stop the motors immediately after landing...

My questions:
1) Is this normal?
2) Have any of you noticed the problem and found a solution?

Suggestions and comment are welcome!
Thanks a lot!

1) Is this normal? Somewhat...
2) Have any of you noticed the problem and found a solution? Perhaps...

See this identical thread: "Phantom 3 revving when idle on the ground, help?"
Your P3 barometer is in the roof of the battery compartment. Altered airflow within the battery compartment while on the ground may make the barometer sense that the P3 is descending and signal more power for stabilization. While the props are turning, the Main Controller (MC) is receiving sensor inputs that it may react to and take corrective action -> compass/gyros/accelerometers/barometer.

Also not sure if this comes into play but your ground sensors might be trying to tell you that your way to close to the ground.

Check out the specs...Hover accuracy +/- 0.1m when using VPS or +/- 0.5m without.  VPS only works above 0.5m so the best you can expect is a hovering accuracy of +/- 0.5m.  Your Phantom thinks it's hovering (it doesn't know you've landed) so will constantly adjust the motors to hold altitude & keep itself level.

The solution is to disarm the motors when you land.

As nigelw says, shut down the motors when you land. The aircraft does not know it is on the ground, and if your battery is low, it may go into automatic RTH mode, and try to ascend to RTH height.

Always shut down when you land.  If you want to idle on the ground, restart the motors and let them idle.  Landing and letting it sit without shutdown is dangerous, and appears to be normal behavior.

AG0N-Gary Posted at 2016-1-26 01:12
Always shut down when you land.  If you want to idle on the ground, restart the motors and let them  ...

This is what I usually do immediately after landing!

Anyway we cannot deny the fact that the critical and fast drag of the bird near ground level represents an issue!

Thanks a lot for your suggestions!

Geebax Posted at 2016-1-25 23:07
As nigelw says, shut down the motors when you land. The aircraft does not know it is on the ground,  ...

I agree with shutting down the motors as soon as you're on the deck, but if I'm reading your post correctly, the aircraft won't attempt to RTH if battery is critical.

If you're within 20 meters of home point, the P3 will never try to execute the standard RTH, it will always just land in place. So assuming you've landed back near your home point and your battery is also critical,, in this instance it "should" just stay where it is (I.e. stationery on the ground) and probably will turn the motors off automatically.

Anderjon Posted at 2016-1-26 18:17
I agree with shutting down the motors as soon as you're on the deck, but if I'm reading your post  ...

I agree with your summation, but there are cases reported here where people landed, possibly not where their home point was set, and left the aircraft motors running in order to run down the battery. As the battery ran down, the aircraft took off again to execute an RTH.

And also it has occurred that people have let it sit there with the motors running then decided to lift off again, and the aircraft has tipped over when doing so.