The servo screw was not missing, the photo was taken part way through dissasembly and removal of the servos for Andreas to inspect the whole stab assembly.

The servo arms are OEM heavy duty rigid glass filled nylon as supplied with these high torque digitals and are more than up to the job. They are impossible to bend by hand and stronger than the dual phenolic control surface horns and 3mm brass reinforced pushrods via which they move the respective control surfaces.

Hope that helps explain the picture more clearly.

Rob.