Why do planes dim the lights before landing at night? It's not what you think

If you've ever taken a flight at night, you might have noticed the cabin lights being dimmed as the plane gets ready for the landing. While it might seem like a simple gesture to create a calming atmosphere for the passengers, there's a far more critical reason behind this practice — one that could be the difference between life and death in an emergency.


Sounds intriguing? Read on to know more.


The science of night vision:

Our eyes take approximately 10 to 30 minutes to fully adjust to darkness. This process, which is known as dark adaptation, is essential for seeing in low-light conditions. If you're suddenly thrust into darkness — say, during an emergency evacuation — your eyes need time to adjust. Dimming the cabin lights before landing allows passengers and crew to begin this adjustment process, ensuring that if the lights go out, they can still navigate safely.


Enhancing the visibility of emergency features:

Airplanes are designed and equipped with illuminated floor path lighting and exit signs to guide passengers for safe evacuations. However, these features are most visible when the cabin is dimly lit. Bright cabin lights can cause glare, making it difficult to see these crucial indicators. By dimming the lights, the contrast between the illuminated signs and the surrounding darkness is increased, enhancing visibility and aiding in a quicker, safer evacuation.


Preparing for external hazards:

Keeping window shades open during takeoff and landing isn't just a suggestion — it's a safety protocol. Open shades allow flight attendants to assess external conditions, such as fires or debris, that might affect evacuation routes. Similarly, dimming the cabin lights helps both passengers and crew see outside, providing a clearer understanding of the situation and aiding in decision-making during emergencies.



Reducing electrical load:

During critical phases like takeoff and landing, aircraft require maximum power to ensure optimal performance. Dimming the cabin lights reduces the electrical load, allowing more power to be directed towards essential systems. This practice ensures that in the event of a go-around or aborted landing, the aircraft has sufficient power reserves to perform necessary maneuvers.


Aligning internal and external lighting:

The human eye adjusts more effectively when the interior lighting of the aircraft matches the external lighting conditions. Dimming the cabin lights at night helps align the interior with the darkness outside, reducing the risk of disorientation during an evacuation. This alignment ensures that passengers and crew are better prepared to respond swiftly and safely to any emergency.



In simple words…

The practice of dimming cabin lights before landing at night is a multifaceted safety measure designed to enhance visibility, reduce disorientation, and ensure a swift evacuation if necessary. It's a small adjustment that plays a significant role in passenger safety during the most critical phases of flight. So, the next time the lights dim, remember — it's not about setting the mood, although it appears to be so; it's about preparing for the unexpected.