When does the white Jet Pump Operating light turn on?

The white Jet Pump Operating light is designed to illuminate when the respective motive flow shutoff valve is in transit. This happens during the operation of the fuel system when the valve is moving to either open or close, indicating that it is not yet in its final position. The light serves as a visual cue to crew members that the system is actively adjusting and that attention should be paid to the fuel flow operational status.

Understanding the role of this light is crucial for pilots, as it helps them monitor the fuel system's performance and ensures that the valving system is functioning as required for optimal operation. If the light were to indicate maximum capacity, standby mode, or a fuel leak, it would mislead the crew regarding the actual state of the system, potentially leading to inappropriate responses or actions.