TRUE/FALSE: Operating the HF radio in high power may result in disengagement of the AFCS yaw channel.

• A. True
• B. False
• C. Not applicable
• D. Yaw disengagement cannot occur

Answer: (A)

High-power HF transmissions can create electromagnetic interference and power-supply disturbances that affect avionics and control channels. The AFCS yaw channel depends on clean sensor signals and stable power to maintain stable yaw control. When the HF radio is operated at high power, RF energy can couple into avionics circuits or power lines, generating spurious signals or momentary loss of reference. The system’s fault-detection logic will disengage a control channel if it detects a fault or degraded data, to prevent unsafe control input. So, operating the HF radio at high power can cause the AFCS yaw channel to disengage, making this statement true.

The other options imply no disengagement or no applicability, which is not consistent with the protective behavior of the AFCS in the presence of RF-induced disturbances.