What does the "DOOR" aural warning indicate when an engine is running?

The "DOOR" aural warning signifies that there is an unsafe condition related to the main cabin door when the engine is running. This warning alerts the flight crew to a potentially critical situation where the door may not be properly secured, which can compromise cabin pressurization and overall safety during flight.

In aviation operations, it is crucial to ensure doors are not only closed but also secured before takeoff and during flight. The sound alerts the crew immediately, prompting them to check the door status and take appropriate actions to secure it. Other doors may have their own specific indications, but the "DOOR" aural warning specifically pertains to the safety of the main cabin door in this context.