Rc calibration failed

Hardware Pixhawk family
1

pre arm check RC calibration failed.?

2

What type of TX?
Sometimes a spectrum will have exact 1100,1500,1900 outputs and you need to set trims to 99%

3

I am using raspberry pi and pixhwak 2.4.8 and need to fly using dronekit without remote control

4

what are your params like? Also, what is the error message you get in the messages tab in mission planner?