Landing, along with takeoff, is one of the most delicate phases of flight. Essentially, it is a maneuver that allows an aircraft to dissipate all its energy until it comes to a complete stop on the ground.Depending on the aircraft's weight, weather conditions, and the state of the runway (dry, wet, snowy, etc.), more or less space will be required.
Naturally, airports served by commercial airlines have runways suitable for landings in almost all conditions. However, during the descent, pilots must verify—using specific tables or software—that the assigned runway has the appropriate length and characteristics for the expected arrival conditions.
The Approach
From cruise altitude to the final stages of the landing, the aircraft is "guided" by instructions from Air Traffic Controllers. During the descent, pilots gradually slow the plane down. To fly at lower speeds, it is necessary to change the shape and size of the wings; this is achieved through mechanisms called "flaps" and "slats". (see here).
The landing gear is then extended, and final checks are performed to ensure everything is ready. Once near the runway, except in rare cases where a "visual approach" is necessary, the maneuver continues using high-precision procedures
The Instrument Landing System (ILS)
Most airports are equipped with a system called the ILS (Instrument Landing System).
It emits two "fans" of radio waves—one vertical and one horizontal—which overlap to trace an "invisible path" for the plane to follow.
Pilots see indications on their instruments that allow them to stay exactly on this path right until touchdown, even if weather conditions prevent them from seeing the runway until the very last moment. In fact, onboard systems can perform the entire maneuver automatically (an Autoland), which is common during very limited visibility (like in fog). See this post.
In fact, these automated systems are able to pick up these "fans" and adjust the controls so that the aircraft stays perfectly centered between them. Once very close to the ground, other onboard sensors "perceive" the distance from the deck and maneuver the plane so that contact with the runway is "gentle."
A landing is only completed if all parameters are met and the control tower explicitly provides radio authorization. At any time, if something "doesn't look right," the maneuver can be interrupted by performing a "Go Around".
Touchdown and Braking
As soon as the wheels touch the runway, several things happen in quick succession:
- An automatic braking system engages, equipped with a type of "ABS" to prevent the wheels from locking.
- Panels on the wings called "spoilers" (or speed brakes) rise to help slow the plane down.
- The "reversers" are deployed—devices that redirect engine thrust forward to help the plane decelerate.
- Valves open to equalize the pressure between the cabin and the outside.
Once at a safe speed, the aircraft taxies to its assigned parking area.
Why was that landing so "bumpy"?
During your "career" as a passenger, you won't always experience a buttery-smooth landing. Sometimes, you might feel what seems more like a "controlled crash"!
This is normal and remains perfectly safe. Several factors influence how "firm" a landing is:
- Runway length and conditions: On a short runway, a firm landing is desirable to dissipate energy immediately upon contact. Similarly, on a wet or slippery runway, a "heavier" touchdown ensures the tires grip the ground instantly.
- Aircraft type: Every model has a different landing gear system; generally, the larger the plane, the smoother the contact feels.
- Weather: Wind gusts can make the landing maneuver quite laborious—so show your pilots some' understanding!
DontWorryFlyHappy!