Not sure that CSC has to be done perfectly to avoid a tip over.
As far as CSC goes and being carried out "perfectly" - if the action of pulling down and in with the sticks is not 100% synchronized the Phantom will do exactly what it is designed to do! If you have landed on a level surface or not and the CSC is employed there is a very good chance the Phantom will react to the first stick "down and in command" - resulting in an "off angular" situation and she will then intentionally react to correct it via the IMU............
Have flown it since and all seems fine but was just wondering what happened
The Phantom will immediately detect the angle she is on (not level), CSC not carried out at exactly the same time (both sticks) and will react to correcting itself back to a level position via the IMU (Inertia Measurement Unit). Opposite motors will rev up and slow down in order to "level" out the Phantom - when on the ground this action very often will cause the "tip" over - which in fact is the IMU doing what it is supposed to do when it detects problems with the angular velocity and linear acceleration. Happens pretty fast with the IMU sending data to the main processor which carries out the correction via increasing and/or decreasing opposite prop speeds.
I experienced more than one "tip over" a year or so ago and rather than just accept these things happen - I wanted to know more of the "why this happens" - hence some research on it and finally understanding it. If you have ever tried to hand catch the Phantom you will notice right away the intentional action of the IMU by seeing, feeling and hearing the revs of the motors and props as she tries to level herself out and you will detect just how quickly she reacts to this situation. I have played around with mine by hand catching and holding/tipping it on purpose just to see/feel this reaction generated via the IMU and processor - - it is amazing, really.
She is a pretty amazing bird with all these components aboard, and having a brain like she does to do all that is required to safely take off, fly, maneuver and land. For the most part "tip" overs and a lot of other issues that result in damage are "operator error" Vs faulty equipment. and realizing the IMU is more than just something that needs calibration to correct a "tilted" horizon on a photo or video!
Knowing the "do's and dont's" with Phantoms is important to say the least - understanding "why and how" gives a much clearer appreciation of the technology and hopefully help with avoiding issues.