Arming quadcopter during free fall

Hello.

I am seeking advice for my current problem which is deploying quadcopter from fixed wing aircraft in flight. I would like to arm the quadcopter during free fall and then start pre-uploaded mission. I have GCS written by me which allows me to monitor progress of the flight and to send directly commands via MAVLink telemetry.

I think that the autopilot refuses force arm command during real free fall, becased during Gazebo simulation I received message “Preflight Fail Accel range hold still on arming” when I tried to arm the vehicle.

What is the correct approach for my problem?

Thank you for your replies.