What is the correct initial radio call when an RA is in effect?

• A. Initial: "TCAS RA"
• B. Initial: "TCAS TA"
• C. RA in effect: "Retuning to assigned clearance"
• D. Unable to comply, TCAS RA

Answer: (A)

When a TCAS Resolution Advisory is active, you immediately communicate to ATC that you are following the advisory. The standard initial radio call is simply “TCAS RA.” This alerts ATC that you are responding to a TCAS RA and will be prioritizing the RA-provided maneuvers, which helps avoid conflicting instructions and maintains safe separation with other traffic.

Saying “TCAS TA” would only indicate a Traffic Advisory, not the active Resolution Advisory, so it doesn’t convey the urgent nature of the RA. The phrase about returning to an assigned clearance isn’t appropriate while an RA is in effect, since you follow the RA rather than revert to a prior clearance. The “unable to comply” option is reserved for scenarios where you truly cannot comply with the RA; it isn’t the standard initial call when RA is in effect.