More anxious airline passengers will certainly have noticed it already—with each takeoff and landing of the plane, the staff watch closely to ensure the windows are left uncovered by shades. But why is such a rule in place when many passengers don’t like these particular stages of the flight? For simple security reasons, explains Peter Frenz, computer scientist and engineer at the airline company Lufthansa. According to his explanations to Sputnik, the shades need to stay up simply because in the case of an emergency landing the pilots and onboard staff need to keep an eye on everything that happens outside. In the case of the aircraft landing in an extreme situation, the rescue team also need to be able to see everything that happens inside the plane before they intervene. Finally, as Peter Frenz explains, this measure also allows the more stressed passengers to witness the moment of landing, which is always a great relief for them.