I've read and seen in videos you always turn on the remote control before the Phantom.
When should you turn on your mobil device? Does it mater?

Don't think it matters.

You should always:

1. READ THE MANUAL!  http://www.dji.com/product/phantom-3/download

2. Yes..  Turn on the controller & launch the app first.

3.  Lastly turn on the P3.  

Use the reverse order to shut down. Basically you never want the P3 to be on without a control signal to lock onto.

Fulgerite Posted at 2015-5-12 07:48
You should always:

1. READ THE MANUAL!  http://www.dji.com/product/phantom-3/download

Correct.  The first thing the craft does is look for its Remote(TX) if it cant find it or is turned on later than the craft it could jumble up the pairing sequence.

Thank for that!

I turn on TX then power up the aircraft and wait for link up (green LED on TX). Then I launch the app. Never had any trouble.