When is the ELS operated electrically by the flight crew?

The correct choice indicates that the Engine Lowering System (ELS) is operated electrically by the flight crew prior to departure. This process is essential as it ensures the system is configured correctly before the aircraft begins its flight. Operating the ELS prior to departure helps in preparing the aircraft systems and ensuring all configurations are stable and ready for takeoff.

The operation of the ELS is particularly important for safety and performance reasons, as it allows the crew to adjust certain aircraft settings while on the ground. This proactive approach can prevent potential issues during the flight and ensures that the aircraft is operating optimally right from the start. Hence, focusing on the preparations before takeoff, like operating the ELS, is a key part of the flight crew's responsibilities.