Why you put up window shades on airplanes during takeoff and landing?

Answer 1

The reason why they want all shades up is because, airlines rely on passenger's vision of the whole outer aircraft. The only people who can see the engines and what happens in the surroundings, are their passengers. Crew who are seated at their crew seats, will not be able to see a whole lot of the plane's exterior. And obviously, planes do not have rear view or side view mirrors.

Thinking from a passenger's point of view, if you see something wrong going on outside, you would panic and call for the flight attendant immediately. Right? So that is how, flight crew would be alerted if anything goes wrong: by the passengers.

As for closing them at night, it differs with airlines. Most major airlines (SIA, MAS, Cathay pacific, Qantas) would still ask you to have it remain open, but they will turn off the cabin lights. (I actually don't know which airlines would ask you to close the shade as it is a safety procedure) Same thing, when you turn off the lights, you would be able to see the outside of the plane and report for anything that goes wrong.

Also, in any case of emergency, you will know not to go to the side with fire, or submerged into water by looking out the nearest window.