I have not flown my Phantom 3 in a few years.  I took it out to test fly it a couple days ago and everything seems to be working fine, except when I have landed and try to turn off the motors with the CSC command, they will not stop, in fact the motors actually increase speed.  
I can safely shut the motors off by holding the throttle down, so that works.  
I saw on a video an option to disable the CSC procedure on some DJI drones, but that option does not show up in my DJI GO control App.  Was this option ever available with the Phantom 3 Adv, or was there a software download that was available to disable this?  I have a vague recollection that I may have actually disabled the CSC engine stop option some years ago.

According to the P3A manual:
Starting the motors.
A combination stick command (CSC) is used to start the motors. Push both sticks down and either to the inwards or outwards corners to start the motors. Once the motors start relkease the sticks.

There are two methods to stop the motors.
Method 1: When Phantom 3 Advanced has landed, push the throttle down , then conduct the same
CSC that was used to start the motors, as described above . Motors will stop immediately. Release both
sticks once motors stop.
Method 2: When the aircraft has landed, push and hold the throttle down. The motors will stop after three
seconds.
Takeoff/Landing Procedures

1. Place the aircraft in an open, flat area with the battery level indicators facing towards you.

2. Turn on the remote controller and your mobile device, then the Intelligent Flight Battery.

3. Launch the DJI Pilot app and enter the Camera page.

4. Wait until the Aircraft Indicators blink green. This means the Home Point is recorded and it is now safe

to fly. If they flash yellow, the Home Point has not been recorded.

5. Push the throttle up slowly to take off or use Auto Takeoff.

6. Shoot photos and videos using the DJI Pilot app.

7. To land, hover over a level surface and gently pull down on the throttle descend.

8. After landing, execute the CSC command or hold the throttle at its lowest position until the motors stop.

9. Turn off the Intelligent Flight Battery first, then the Remote Controller

I'll fire mine up tomorrow and try them both. I know the "throttle back" works but there is a delay....

Hello there SpecialProjects. I am sorry for the trouble this has caused and thank you for reaching out. As cheddar-man posted above on post #2 a combination stick command ( CSC ) is used to start and stop the DJI Phantom 3 Advanced motors. Kindly please refer to the image below. Thank you.

Please read the problem encountered in post #1 DJI.Stephen!@!
When the OP pulls the sticks back and in or out, the motors DO NOT STOP.
I am going to try this a bit later to see if my P3A does or doesn't and will report here.

Have you tried both CSC positions, i.e. both sticks down and inwards, and both sticks down and outwards?   Are the sticks travelling all the way to the outside?  Perhaps it has a loose controller pot at the base of one of the sticks (I'm betting the right one as the left stick-down-and-hold works)?  It might only be getting to say 99% deflection which means the motors will be spinning quite fast.  You might want to check the EXPO values under settings and see if they are reporting a full deflection.  Failing that, you might need to upload a flight log here so we can see what values are being recorded.

You might try calibrating your controller.  Good luck.  

RIGHT! I have just fired up my P3A and it behaves in the same manner.
I calibrated the stickS, making sure both had 100% movement then started the motors by pulling both sticks back and inwards. No problem.

Pulling both sticks back and inwards again actually speeded up the motors, but did not stop them.
Pulling just the left stick fully back did stop the motors after momentarily speeding them up.

SO CSC DOES NOT WORK AS AN EMERGENCY MOTOR STOP!!

Interesting.  I have a few mins, so I took one of my P3Ps and controller outside and fired it up.  I didn't even bother with the mobile device.  I waited for the little light on the controller to change from red to green.  Did the CSC in the inner corners.  P3P motors started up.  Did it again.  Motors stopped.  Then I tried the outside corners.  Started normally.  Stopped normally.  Then I tried the inner and outer at the same time.  Same deal  Then I tried the outer and inner.  Same deal.  That's four different combinations.  All of them start and all of them stop.  Bottom line:  on my P3P, CSC works perfectly as illustrated in post #3 except the CSC also works inner/outer and also outer/inner which is not illustrated.  Disclaimer:  I haven't updated the FW since I bought this thing.  

Just tried again and using the CSC method, the motors do stop but after speeding up for about five seconds!! Not what you want in an emergency!

I remember a discussion about this many years ago.  The discussion might have been re the P2 series though - not sure.  Either way, it used to be the CSC would stop the motors instantly.  But at some point, DJI apparently made a FW change because people began reporting a 3-sec delay in the stop.  Others would argue there is no delay.  That's when we realized there had been a FW change.  As we see in the vid, there is a delay there.  For the record, there is no delay in either of my P3Ps.  It is instant stop.  So it does appear to be a FW change at some point.  I have early FW.  I kind of like the idea of putting in a short delay because it could keep a pilot from accidentally triggering the deadly motor stop during flight.  

cheddar-man Posted at 6-21 06:36
Just tried again and using the CSC method, the motors do stop but after speeding up for about five seconds!! Not what you want in an emergency!

Here it is.

That is what my drone does.  I did find that holding the left stick (throttle) down and then pressing the RETURN TO HOME button on the controller immediately stopped the motors

SpecialProjects Posted at 6-21 12:32
That is what my drone does.  I did find that holding the left stick (throttle) down and then pressing the RETURN TO HOME button on the controller immediately stopped the motors

I've read that also so I'll try it out tomorrow.

Mark The Droner Posted at 6-23 05:24
https://www.youtube.com/watch?v=y1mOrao0FTI

What version of firmware are you using?  My controller is Ver 1.9.2 and my drone is Ver. 1.11.20 and the App is Ver 3.1.68
As far as I know these are the latest versions for all of these.  

SpecialProjects Posted at 6-23 14:12
What version of firmware are you using?  My controller is Ver 1.9.2 and my drone is Ver. 1.11.20 and the App is Ver 3.1.68
As far as I know these are the latest versions for all of these.

My controller is 1.9.2, my P3P is Ver 1.5.30+, my app is 3.1.1.

Mark The Droner Posted at 6-21 10:25
I remember a discussion about this many years ago.  The discussion might have been re the P2 series though - not sure.  Either way, it used to be the CSC would stop the motors instantly.  But at some point, DJI apparently made a FW change because people began reporting a 3-sec delay in the stop.  Others would argue there is no delay.  That's when we realized there had been a FW change.  As we see in the vid, there is a delay there.  For the record, there is no delay in either of my P3Ps.  It is instant stop.  So it does appear to be a FW change at some point.  I have early FW.  I kind of like the idea of putting in a short delay because it could keep a pilot from accidentally triggering the deadly motor stop during flight.

According to the firmware release notes, the delay was added with firmware v1.10.90
"Slowed motor stopping time to three seconds during flight."

The firmware release notes for all revisions and the changes are available here.  It was introduced to appease fliers complaining that they might accidentally hit the CSC position in flight, immediately causing the aircraft to fall.  However in reality, there is little likelihood of deliberately flying that combination of moves (maximum descent while moving lateraly at top speed while moving to the rear at top speed while rotating at full speed) unless you were "swinging on the sticks like a monkey on crack"!  If you were doing that, there is just as much likelihood of executing the combination a second time, immediately restarting the motors.

SpecialProjects Posted at 6-21 12:32
That is what my drone does.  I did find that holding the left stick (throttle) down and then pressing the RETURN TO HOME button on the controller immediately stopped the motors

Pressing the RTH button on the Phantom 3 is not required to stop the motors.  You will find it is responding to the left-stick-down-fully-while not-changing-altitude input only.  As far as I know it may have been introduced as a CSC feature on the Phantom 4 (which I don't have).

Thanks for the info.  Yeah I was experimenting with the left stick down thing.  I found the motors will stop at full left stick down and also at about 3/4 left stick down.  Half left stick down didn't stop the motors.  I hope we all understand left-stick-down only works with the phantom on the ground or otherwise after having landed/crashed, etc.