What additional line of the CAS 9-line is a mandatory readback when working with NATO forces?

The significance of Line 8 in the Close Air Support (CAS) 9-line brief when working with NATO forces lies in its specific requirement for communication and coordination within joint operations. Line 8 is crucial as it details the type of control required for the aircraft in the area of operation, including whether the mission should be in a "danger close" situation or controlling the aircraft with either positive or terminal guidance.

When coordinating with NATO allies, it is essential to confirm that all parties involved have a clear understanding of this line due to the potential impact on mission safety and effectiveness. Ensuring a mandatory readback of Line 8 helps establish a mutual understanding of the control measures in place and emphasizes the importance of clarity regarding the method of target engagement and the respective responsibilities of the ground troops and air support.

This requirement for mandatory readback enhances situational awareness and minimizes the risk of fratricide, ensuring that allied forces can effectively work together in complex operating environments.