ArduPilot has not finished starting
What ArduPilot says:
- PreArm: System not initialised
Start-up is still running: the sensors, the parameters and the outputs are being set up, and nothing may arm before that ends. The end is marked by “ArduPilot Ready”. A normal start takes a few seconds; this test cannot be switched off.
What to do, most likely first
You tried to arm in the first seconds after power-on or a reboot.
FixWait for “ArduPilot Ready”, keeping the aircraft still, then arm.
Start-up has stopped on a fault and will never finish.
CheckLook at the lines before this one: “Config Error: …” repeating every 5 seconds means start-up stopped there on purpose. “Initialising ArduPilot” repeating for up to half a minute is only the gyro calibration waiting for the aircraft to be still.
FixFix what that message names and reboot; it has its own explanation here.
The code that sends it
PreArm: System not initialised
ArduCopter/AP_Arming.cpp AP_Arming_Copter::run_pre_arm_checks() · Open in ArduPilot Copter-4.6.3
ArduCopter/AP_Arming_Copter.cpp AP_Arming_Copter::run_pre_arm_checks() · Open in ArduPilot Copter-4.7.1
ArduPlane/AP_Arming.cpp AP_Arming_Plane::pre_arm_checks() · Open in ArduPilot Plane-4.6.3