A few seconds before takeoff and landing, the flight attendants ask to raise the window blinds. What is it for ? It's not to admire the landscape...
During instructions given by crew members before and during the flight, it is common to receive instructions on how aircraft blinds should be positioned. Airliner windows perform several essential functions beyond simply providing a panoramic view to passengers. One of these functions, and arguably the most crucial, is the ability to quickly identify a technical problem near the device. Whether it's smoke, an engine fire, a breakage, or any other potential incident, the windows allow the crew and passengers to identify these emergency situations.
According to 2022 statistics, 26% of accidents occurred between ground departure and aircraft climb, while 36.5% occurred between descent and landing. In-flight emergencies represent only 33.9% of total accidents. This means that the take-off and landing moments are the most risky. These phases typically only last 30-45 seconds, meaning pilots need to make quick decisions in the event of an engine failure or other technical issue.
Hence the importance that everyone inside the plane can quickly identify an external problem, without it being hidden behind a lowered blind. For example, if a fire breaks out near one of the plane's exits, it cannot be opened, and all passengers on board will have to go to another door. In the event of ditching (i.e. landing on water), it is important to check that the water does not exceed the level of the door sill. This is why all the companies give this instruction on take-off and landing.
With this question of visibility, it may seem preferable to leave the blinds always open, but this is not necessarily the case. The choice varies from airline to airline and depending on the aircraft model. In fact, keeping the windows closed helps control the climate inside the plane. Lowered curtains can reduce the interior temperature of the aircraft by 1.5°C to 2°C in the hottest regions of the planet, as this reduces the incidence of the sun and improves the efficiency of the air conditioning.
Finally, closing the blinds also makes it possible to plunge the cabin into darkness and allow passengers to sleep even if the aircraft is located at that time in an area where it is daytime. Acclimatization to the time change is thus made easier for passengers.