Ground proximity warning systems were introduced on airliners in the 1970s to reduce controlled flight into terrain accidents, and Boeing jets use their automated voice callouts during final approach. The system announces descending altitudes, with ten feet being one of the last callouts before touchdown. Recordings and simulator recreations of these callouts spread through flight simulation and aviation forums, then into short video edits. The ten callout in particular became a shorthand online for a landing that is about to happen, whether flown perfectly or badly.