If an aircraft is responding to a TCAS RA, which action would be incorrect?

• A. issue control instructions contrary to that advisory
• B. issue control instructions
• C. transfer the aircraft to another controller
• D. clear the aircraft to land while RA is active

Answer: (A)

When a TCAS Resolution Advisory is active, the maneuver it prescribes must be followed because it has priority over any ATC instructions. The pilots rely on the RA to maintain safe separation, even if that means deviating from ATC guidance. Issuing control instructions that contradict the advisory would pull the aircraft away from the safe avoidance path and could create a collision risk, which is why that action is not allowed.

Other actions that don’t conflict with the RA are appropriate: giving instructions that align with the RA or are neutral to it, transferring control to another controller for coordination, or clearing to land only when the RA no longer requires an avoidance maneuver.