Definition
A display indication given to the pilot by the Traffic Alert and Collision Avoidance System (TCAS II) recommending a specific vertical maneuver, or in some cases a restriction of vertical maneuvers, to maintain safe separation from another aircraft equipped with an operating transponder.
Plain English
A direct instruction from the aircraft's collision avoidance system telling the pilot to climb, descend, or hold their vertical rate to avoid hitting another aircraft.
Context Anchor
You encounter this term when using or studying onboard traffic collision-avoidance equipment, especially in airline, turbine, and instrument flight operations.
Derivation
From Latin 'resolvere' (to loosen, settle) and 'advisare' (to consider, advise). 'Resolution' here means settling or resolving the conflict; 'advisory' suggests guidance — but in TCAS use, the advisory is treated as a command, not a suggestion.
Why Pilots Care
Following the instruction promptly restores safe vertical separation and prevents collision.
Grounding Statement
If another aircraft is closing in, a Resolution Advisory is the onboard system’s immediate instruction for avoiding the conflict vertically.
Intuition Check
Do not read “advisory” as a casual suggestion. In this FAA context, a Resolution Advisory is urgent collision-avoidance guidance that the flight crew must treat seriously.
Example Sentence 1
When TCAS issued a Resolution Advisory to climb, the crew immediately disconnected the autopilot and pitched up to comply.
Example Sentence 2
The resolution advisory called for a descent, so the crew reduced power and lowered the nose to increase separation from the traffic below.