FAA Airline Transport Pilot (ATM)Navigation, Air Traffic Control and ProceduresMedium
During cruise flight, an airliner's TCAS issues a Resolution Advisory (RA) directing a climb, while ATC simultaneously instructs the crew to descend for traffic separation. What action should the flight crew take?
- AFollow the RA and notify ATC of the deviation as soon as practicable
- BFollow the ATC instruction, since ATC retains final authority for separation
- CQuery ATC for clarification before responding to either instruction
- DMaintain current altitude until ATC and TCAS guidance are reconciled
Show answer & explanationAnswer & explanation
Correct answer: A. Follow the RA and notify ATC of the deviation as soon as practicable
Per AIM guidance, when a TCAS RA conflicts with an ATC instruction, the flight crew should follow the RA, since it is based on the most current and localized traffic picture, and notify ATC of the deviation as soon as practicable.
Why the other options are wrong
- B. ATC does not have real-time knowledge of the exact conflicting traffic geometry that generated the RA; TCAS should be followed instead.
- C. Delaying response to query ATC wastes critical time needed to resolve the conflict.
- D. Maintaining altitude ignores the safety-critical RA guidance and increases collision risk.
TCAS Resolution Advisory Priority
When a TCAS RA and ATC instruction conflict, the RA takes priority because it reflects real-time, localized traffic conflict data.
- Follow the RA immediately
- Do not maneuver contrary to the RA
- Notify ATC of the deviation as soon as practicable
Memory trick: RA rules over ATC — 'Robot beats Radio' in a conflict.