Hey all!! I am going to talk a little bit about flight, and why are landing and takeoff the most important moments during a flight.
Like when we drive a car, when we accelerate, our speed increase and when we brake, our speed decrease. We use these accelerate/brake to keep moving forward with more/less speed. In an airplane, it is the same with one simple complication: when you speed up forward you also gain altitude and when you speed down you lose altitude. One flight is divided into three main phases: takeoff, cruise and landing.
Takeoff
In this phase, the airplane must speed up as much as it can, therefore our acceleration forward must also be the maximum, for that the engines must operate at full power. The airplane will accelerate until it reaches the take-off velocity (when the airplane leaves the ground). An interesting fact is that the airplanes usually take off against wind, that’s because the take-off velocity is measure relative to the wind, and if the wind have the opposite direction, the take-off velocity relative to the ground is smaller. Theoretically, if the wind has enough speed it can lift an airplane by itself. After takeoff, the airplane will basically keep its velocity to climb until it reaches the cruise altitude. Some days ago, a cargo plane did not reach its take-off velocity in time and crashed:
https://www.youtube.com/watch?v=YTwk9sRnHa0
Cruise
This is the simplest phase. Here, the airplane only needs to keep the cruise velocity, which is smaller than a climb velocity. At the cruise velocity, the wings will generate an upwards force that has the same magnitude as the airplane total weight, therefore, the airplane will not gain/lose altitude. The engines will operate only enough to keep the airplane velocity constant.
Landing
When the airplane approaches to the airport, it starts to lose altitude long time before the landing, this is because the airplanes do not have brakes like cars do, but it will lose velocity slowly, and therefore, will lose altitude.
When the airplane is almost landing, the pilot must align the airplane with the landing way. Sometimes, this is not easy and the pilot have to try sometimes until he is able to land. Some days ago, in Madeira island, Portugal, the pilot only managed to land properly at its fourth attempt:
https://www.youtube.com/watch?v=ofH-_K-lsqc
If you want to learn more, here is a good video that explains way better and detailed how the airplanes fly:
https://www.youtube.com/watch?v=YyeX6ArxCYI
I hope you enjoyed this post and if you did not know how airplanes fly, now you do.
Have a nice flights and Merry Christmas!!