After the drone is assembled, it must be ESC calibrated.

The purpose of the calibration is for the ESC to record the maximum and minimum values of the transmitter's throttle and to ensure that all 4 motors have the same output.

ESC calibration is no longer required after that, unless any motor, ESC or transmitter is replaced.

1. Push throttle to top & turn on transmitter

2. Plug in drone battery and wait for Pixhawk to reboot

3. Unplug battery, then plug in battery and wait for Pixhawk to reboot

4. Press the safety switch for 2 seconds

5. Motors make 1 piece of music, after that pull throttle to bottom

6. Motors make another piece of music

7. Now the ESC calibration is complete

8. Check all motors rotate in the same speed

After the ESC is calibrated, Pixhawk does not work and the drone is not ready to fly at this time.

If you need to fly, you must restart the Pixhawk.