Plain English Meaning
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.
Full 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.
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.