What signal typically indicates a call from the lavatory?

In the context of aircraft operations, lavatory calls are primarily signaled through an ACP (Audio Control Panel) indicator. When an occupant uses the lavatory call button, it initiates a visual and auditory alert that is communicated to the flight crew. The ACP indicator specifically serves as a way for the crew to recognize that there is a call from the lavatory, allowing them to respond promptly.

While there may be other alerting systems within the aircraft, such as a flashing red light or sound alerts, these do not specifically indicate a lavatory call; instead, they may serve broader purposes or indicate different systems within the aircraft. Similarly, a galley announcement would not pertain to lavatory calls directly. The use of the ACP indicator provides a reliable and clear signal exclusively for this type of communication, emphasizing its significance in maintaining cabin crew responsiveness and overall passenger service.