Today I was out doing touch and go's in ATTI mode, in an empty soccer field with very light winds.  All was going well until I noticed that someone was approaching me from the right.  For safety conecerrns I decided to land and kill the power.  The landing was perfect, but when I went to cut the power, the P4 tilted forward and turned upside down in the grass and began to shoot around the field, first going this way and then that way as well as cutting a fair amount of grass.  Mean while, I was trying to cut the power, but no method seemed to work.  It finaly stop in some deeper grass and I shut the battery off manually.

Lessons Learned: 1) If distracted while flying in ATTI mode, switch to P mode. 2) A healthy P4 sure covers a lot of ground when it is upside down. 3) Although the P4 does cut grass very short, it wears the tips of the props off very quickly.

Changed the blades, check all the controls, inspected the P4 for damage, there was none.  All is well. Back to the big blue !

Hi,

My I ask how you kill the power to the blades ?

Mr.buGSy Posted at 2016-6-24 17:16
Hi,

My I ask how you kill the power to the blades ?

I tried both the two stick method and the single stick method with RTH, but they take a second or so to work, and I was in a panic and probably did not hold them long enough.  The P4 caught up in high grass, stopping 3 of the blades, so I was able to power off the battery.

j5255@yahoo.com Posted at 2016-6-24 14:41
I tried both the two stick method and the single stick method with RTH, but they take a second or  ...

RE: "... with RTH"?

BTW: Motor stop can be practiced without takeoff and can be practiced without propellers.

Best way to shut down the motors after landing is just lower the throttle all the way.

I was going to say what Ken said. That's the actually the best way. But I understand your reaction — not easy when panic kicks in. Important thing is that it was unharmed.

Using the CSC command to shut off the motors can be tricky, especially when the ground might not be flat. If you don't choose to use the autoland feature, throttle down will always be the best choice. It's good to hear there was no harm or foul.

This has happened before, and it seems that once a Phantom is upside down, the CSC does not work. DJI might like to look into this, as it has been reported many times.

Airspace Explor Posted at 2016-6-24 17:50
RE: "... with RTH"?

BTW: Motor stop can be practiced without takeoff and can be practiced without  ...

Left Stick at 4 o'clock and hold, press RTH
I had actually practiced this many times, however, in a panic and watching in horor as the P4 skipped around the field, I suspect I was not holding them long enough.  It takes about 1.5 to 2 seconds for the P4 to react.

j5255@yahoo.com Posted at 2016-6-24 16:33
Left Stack at 4 o'clock and hold, press RTH
I had actually practiced this many times, however, in a ...

Is this combination what is recommended for Phantom 4?

For a Phantom 3, it's throttle stick down for 3 seconds (when aircraft is not descending). Down + Left, Center, Right, it doesn't matter. Down is down. It can be done with one finger while you're holding the aircraft with spinning propellers out of harm's way.

j5255@yahoo.com Posted at 2016-6-25 09:33
Left Stack at 4 o'clock and hold, press RTH
I had actually practiced this many times, however, in a ...

There should not be a delay, the CSC manouvre should be instantaneous. It is the engine stop manouvre, left stick down and hold that takes some time to actuate. But peop0le have reported before that once the aircraft is upside down, the only way to stop it is to removed the battery.

Airspace Explor Posted at 2016-6-25 09:51
Is this combination what is recommended for Phantom 4?

For a Phantom 3, it's throttle stick down  ...

The P4 has an alternative method, as described. Left stick down and in, while pressing RTH button.

The CSC shutdown will cause that, especially if there is a breeze. Doing the CSC will cause the rotors to be biased toward one direction. As Ken states, just do a throttle back once you land. Your Phantom will shut down without any tipping.

DJI-Ken Posted at 2016-6-24 18:07
Best way to shut down the motors after landing is just lower the throttle all the way.

Tried that as the first option but it tipped forward. The best I can figure is that I may have had some forward momentum in ATTI mode and the P4 was coasting forward on touch-down.  In any case,  no more ATTI landings for me for while.  Very thankful the P4 is a tough machine.  I was back in the air early this evening on two more missions with no issues.

I should also add that none of the blades split or broke.  The leading edges outer corners were rounded and there were a considerable number of pits in the leading edges.  The blades have now been retired.  I also made a fine (magnified with hand lens) inspection of the prop mounts and they appear to be perfectly square with no twists, breaks or distortion.  

j5255@yahoo.com Posted at 2016-6-25 10:34
Tried that as the first option but it tipped forward. The best I can figure is that I may have had  ...

That's good you changed props, use the old ones as paint sticks
You always need to land with no lateral movement at all or it will tip over.
Glad all is good and no aircraft damage.

As said when upside down shutdown don't work. Happened with my old P3 and after it was  dancing aroud on the pavement for a while i yanked the battery out. Therewas a ton of grit everywhere in the bird after that haha

Swedrone Posted at 2016-6-25 17:57
As said when upside down shutdown don't work. Happened with my old P3 and after it was  dancing arou ...

You better buy few tyre for your P3.You know,Just in case