Definition
Resolution Advisories are alerts issued by an airborne collision avoidance system (such as TCAS II) that direct the pilot to take a specific vertical maneuver — climb, descend, or maintain vertical speed — to resolve a predicted conflict with another aircraft. RAs are the second and more urgent stage of TCAS alerting, following Traffic Advisories (TAs), and are issued when the system calculates that a collision risk requires immediate action.
Plain English
RAs are cockpit warnings that don't just point out nearby traffic — they tell the pilot exactly what to do, vertically, to avoid a collision. They're the system saying 'climb now' or 'descend now,' not just 'watch out.'
Context Anchor
Seen in instrument flying and traffic avoidance system discussions, especially when learning how aircraft warn pilots about nearby traffic conflicts.
Derivation
From 'resolution' (Latin resolutio, meaning to settle or resolve) plus 'advisory.' The name reflects what the alert does: it resolves the conflict by giving a definite instruction, rather than just advising the pilot that traffic is present.
Why Pilots Care
Prompt compliance maintains safe separation and prevents mid-air collisions; delayed or incorrect response can result in loss of separation.
Intuition Check
Do not read advisory as casual advice here. In this context, an RA is an urgent safety command from the traffic system that the pilot is expected to follow unless doing so would make the situation unsafe.
Example Sentence 1
When the TCAS issued an RA to descend, the captain disconnected the autopilot and followed the guidance immediately.
Example Sentence 2
Pilots must immediately follow RAs while continuing to scan for other aircraft.