Final answer:
When normal electrical power is lost in the flight deck, there are several backup lighting options available such as the Emergency Lighting System (ELS), flashlights with red filters, and the use of self-illuminating paint called Undark.
Step-by-step explanation:
If normal electrical power is lost in the flight deck, there are several backup lighting options available to ensure visibility and safety. One of the most common backup lighting systems is called the Emergency Lighting System (ELS). It provides illumination for critical flight instruments and controls, emergency exits, and escape paths. Another option is the flashlight, which pilots and crew members carry for immediate lighting needs in case of power failure. The flashlight is often equipped with a red filter to preserve night vision. Lastly, if all else fails, pilots can use the Undark system, which is a self-illuminating paint that was used in the past to mark instrument dials and switches.