Definition
An incident in which two aircraft pass within 500 feet of each other in flight, or in which a pilot or flight crewmember reports that a collision hazard existed between two or more aircraft. NMACs are formally reportable events, and reports are filed with the FAA for investigation and safety analysis.
Plain English
A close call in the air — two aircraft came dangerously close to hitting each other, but didn't actually collide. If they got within 500 feet, or a pilot felt a real risk of collision, it counts as one and gets reported.
Context Anchor
Seen in safety reporting, traffic-avoidance discussions, and reports involving aircraft that passed too close to one another in flight.
Why Pilots Care
Reporting NMACs helps identify risky airspace and improves overall traffic separation practices.
Intuition Check
Do not read “near mid-air collision” as meaning the aircraft actually collided. In this term, it means they came close enough that a collision hazard existed.
Example Sentence 1
After the traffic passed less than 300 feet below us, the captain filed an NMAC report with the FAA.
Example Sentence 2
NMAC data is reviewed to find patterns in high-traffic terminal areas.