Control Test Procedure from the BCX Manual (Page 12 - 14)

If when you do the control test, the controls do not respond properly, then you would

double-check the location of the servo connections on the 4-in-1 unit.
These should be positioned as follows (when viewing the helicopter from behind):

Channel 1 (Lower Port) – Forward aileron servo
Channel 2 (Upper Port) – Rear elevator servo

Once you have confirmed that the servo connection locations are correct, all controls should be functioning
properly.

If this is not the case, then let us know because we'll be really curious.

Per the manufactuere, ff you do encounter any problems with your Blade CX responding properly to the transmitter, do not fly.
Contact Horizon Hobby’s Product Support staff at 1-877-504-0233.