Wind shear is a sudden change in wind speed or direction that can rob an aircraft of lift on takeoff or landing, so modern airliners like the Boeing 737 are fitted with predictive warning systems that call it out in the cockpit. Recordings and simulator recreations of that alert have circulated for years among aviation fans, flight simulator players and plane spotters. Online it became a shorthand sound for an approach going wrong, shared in simulator clips, aviation compilations and meme edits where an instant aviation emergency is needed.