Definition
A notification issued by air traffic control or a flight service station to inform a pilot of a known or suspected condition that requires attention, such as an aircraft in distress, a hazard in the vicinity, or a deviation from the expected flight path. An alert prompts heightened awareness and may require a specific response, but is not itself a clearance or instruction.
Plain English
A heads-up from ATC or flight service that something needs your attention right now.
Context Anchor
Pilots may see or hear alerts from cockpit equipment, air traffic control, or aviation procedures when a possible safety problem needs attention.
Derivation
From the Italian phrase 'all'erta', meaning 'on the watch' or 'on the lookout'. The aviation use keeps that original sense — be watchful, something needs your attention.
Why Pilots Care
Responding promptly to an alert prevents collisions, terrain encounters, and other incidents.
Intuition Check
Do not read alert as just a casual heads-up. In aviation, an alert points to a possible safety issue that should be checked promptly.
Example Sentence 1
The controller issued a traffic alert, advising the pilot of converging traffic at the same altitude two miles ahead.
Example Sentence 2
ATC radioed a traffic alert when another airplane crossed the final approach course.