Plain English Meaning
The ability of an aircraft (especially a drone) to spot other aircraft or obstacles and move out of the way in time to avoid a collision.
Full Definition
The capability of an aircraft, particularly an unmanned aircraft system (UAS), to detect potential conflicting traffic or hazards and take appropriate action to maintain safe separation, fulfilling the see-and-avoid responsibility required of manned aircraft under visual flight rules.
Context Anchor
Seen in unmanned aircraft operations, traffic avoidance discussions, and rules about keeping aircraft safely apart.
Derivation
A direct adaptation of the long-standing pilot rule 'see and avoid.' Because an unmanned aircraft has no onboard pilot to see, the word 'see' is replaced with 'sense' — meaning detection by cameras, radar, transponder receivers, or other equipment.
Why Pilots Care
Allows drones to share airspace with manned aircraft without requiring continuous visual monitoring by a ground operator.
Intuition Check
Do not read “sense” as just casually noticing something. In this term, it means detecting a hazard in time to take a clear avoidance action.
Example Sentence 1
The drone's sense-and-avoid system alerted the operator to a low-flying helicopter approaching from the east.
Example Sentence 2
During the test flight the aircraft used sense and avoid to climb and pass behind crossing traffic.