The master caution is part of the warning system used on Airbus airliners, where illuminated caution lights and an aural chime alert the flight crew to a system abnormality that is not an immediate emergency. Clips of cockpit alerts spread through flight simulator communities, aviation videos and soundboards, where the recognisable chime became shorthand for a technical fault. Online, creators detached it from real flying and now use it whenever a machine, game or person signals that something needs attention before it gets worse.