Why Do Airplanes "Turn on the Air Conditioning" and Emit Fog During Takeoff and Landing?

Fog from the Ceiling Adjusts Air Pressure

The intriguing phenomena that occur on airplanes often amaze passengers. For those who frequently fly, the white fog that billows out during takeoff and landing is a familiar sight. Many are accustomed to it, but not all are aware of its purpose. Some jokingly speculate if it's clouds entering the aircraft cabin.

The answer is a resounding no. Experts explain that the fog originates from a humidifier that pressurizes the air in the passenger cabin during takeoff and landing.

As the aircraft changes altitude, the air pressure inside can fluctuate. The humidifier helps mitigate discomfort and create a more comfortable environment for passengers.

Window Shades Up for Visibility

Additionally, during takeoff and landing, passengers are required to keep window shades raised. This allows flight attendants to observe and identify aircraft positions in case of an emergency.

Furthermore, for daytime flights, having the window shades up and the cabin lights dimmed helps passengers adjust their eyes to the outdoor light intensity. In the event of an evacuation, this prevents temporary vision impairment caused by sudden light changes.

Summary

During takeoff and landing, airplanes emit fog to maintain cabin airflow and adjust air pressure. Passengers must also raise window shades to ensure unobstructed visibility for flight attendants. Moreover, adjusting to outdoor light conditions through window visibility and light dimming helps mitigate vision issues in the case of an evacuation.