What should be done if the emergency lights remain on after the aircraft is powered down?

When the emergency lights remain on after the aircraft is powered down, the correct procedure involves ensuring that the master battery is ON, turning OFF the emergency lights, and then switching the master battery OFF. This method is essential for several reasons.

First, ensuring the master battery is ON allows you to control the emergency lights properly. If the battery is turned off, you won't be able to manipulate the emergency lights or confirm their status. By turning the emergency lights OFF while the master battery is ON, you effectively ensure that they will not drain the battery unnecessarily, especially if the aircraft is in a situation where power conservation is critical.

Finally, switching the master battery OFF after turning off the emergency lights ensures that all systems are appropriately powered down without issues. This sequence helps maintain the integrity of the aircraft's electrical systems and prevents possible malfunctions or complications upon the next power-up.

Other options suggest either inaction or incomplete procedures that do not address the need to manage the power state of the emergency lights effectively and ensure overall aircraft readiness for future operations.