They were asking (and so am I) how they RESTART the drone AFTER stopping the motors during the free-fall.
Some people have said that the motors WILL restart in freefall, and indeed that is presumably with the normal CSC motor start. It's how I restarted my Phantom 3 in mid air.
I am not out to argue with those saying the motor will restart in freefall but I wish to pass on the experiences I have had with a Mavic Mini and an
Mavic 2 Pro/Zoom.
I was, and am, reluctant to try this in real life with those drones so I simulated it, as best I can, by holding the drone in my hand an wobbling it significantly, to simulate presumed wobble in freefall. I found that occasionally the motors would restart but more often they would NOT restart.
I realise that it is not an entirely accurate simulation and maybe the drones are 'clever enough' to recognise the difference between freefall and being held in the hand but...........
If in real life the drone IS in freefall you have nothing to lose by trying for a restart and everything to gain.
With regards to what happens after a successful restart, with my Phantom 3Adv it continued to fall and at near terminal velocity. It took me a moment to realise the motors start at idle and I then gave it full throttle to halt the fall.
However, stemming from being able to launch my Mavics from my hand, simply by moving the hand holding the drone up and down, I have a suspicion the Mavics are 'cleverer' than the Phantom 3 and might realise they were falling and throttle up themselves. But erring on the side of caution and throttling up will/would not be a bad idea.
That thinking also raises one other possiblilty, with the Phantom at least, restart the motors ASAP after stopping them and allow the drone to fall with the motors at idle. I suspect the descent speed would still far exceed the normal flight maximums.
Obviously if a Mavic is clever enough to realise it is in freefall and automatically throttle up that idea is not irrelevant.
In connection with the midair motor stop and button pushes, I seem to remember mention of a button push requirement being added to the
Phantom 4's.