When it is dark outside, or at the beginning and end of a flight, cabin lights are often turned off and passengers are asked to close the window shades. This process is done for the safety of both passengers and crew members. The dimming or turning off of cabin lights during takeoff and landing helps passengers adjust their vision to low light conditions, which is crucial in emergency situations.
The human eye takes time to fully adjust to darkness, and turning off the cabin lights allows passengers and crew to do so more effectively. This adjustment can make a significant difference in emergency evacuation scenarios. In addition to aiding vision adjustment, turning off the cabin lights makes emergency lights and illuminated aisles more visible, ensuring that passengers are fully prepared to evacuate quickly and safely if needed.
Another reason for turning off the cabin lights is to reduce the aircraft’s power consumption, optimizing engine performance during critical flight periods. In addition, pulling the window shades during the day floods the cabin with natural light, increasing visibility. Overall, the combination of turning off cabin lights and closing window shades helps ensure passenger safety and preparedness during flights.