Arming Error


I’ve installed px4 Pixhawk on an SBach 342 fixed wing aircraft with a quad frame for VTOL. I’m using two separate batteries to power the two systems - quad and aircraft. Is this acceptable or is it necessary to power both systems using a single battery during calibration? At the moment, even though QGroundControl displays ESC calibration as complete, while testing the setup after connecting the batteries, Pixhawk is flashing a blinking red light. Is this an arming error or something else? Kindly advise.