Landing
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Landing is the last part of a flight, where a flying animal or aircraft returns to the ground. When the flying object returns to water, the process is called alighting, although it is commonly called "landing" as well. Hitting the ground too hard is prevented by wing to fly (including rotor wings), a parachute or rockets or a vertically directed jet engine; in the case of a balloon the buoyancy is slightly decreased for a soft landing. Aircraft usually land at an airport on a runway or helicopter landing pad.
For aircraft or birds, landing is generally accomplished by gradually tapering down airspeed and lift. The first phase is the flare, where the rate of descent will be reduced by adopting a nose-up attitude. After slowing down, the plane changes pitch into the landing attitude shortly before touching down. The attitude is held until the primary wheels touch the ground and the controls are either held until all wheels touch the ground or gently adjusted (often in the case of tail-draggers) to ensure the nose-wheel or tail-wheel lightly touches the runway.
In a small plane, with little crosswind, it is considered a "perfect" landing when contact with the ground occurs as the forward speed is reduced to the point where there is no longer sufficient lift to remain aloft. The stall warning is often heard just before landing indicating that this speed and attitude have been reached. The effect causes a very light touch down for the pilot and passengers.
Large transport category (airliner) aircraft land the aircraft by "flying the airplane on the runway." The airspeed and attitude of the plane are adjusted for landing. The airspeed is kept well above stall speed and a constant rate of descent. Just before landing the descent rate is reduced to a few feet per minute causing a light touch down. Usually spoilers (Sometimes called "Lift Dumpers") are immediately deployed to dramatically reduce the lift and transfer the aircraft's weight to its wheels, where mechanical braking can take effect. Reverse thrust is used by many jet aircraft to help slow down just after touch-down.
Factors such as crosswind where the pilot will use a crab landing or a slip landing will cause them to land slightly faster and sometimes with different attitudes to ensure proper handling and safety of the plane. Pilots must also be aware of ground effects to ensure a smooth landing.
To land on an aircraft carrier, a conventional aircraft (moving at, perhaps, 150 mph [240 km/h]) is equipped with tailhooks to engage one of up to four arresting cables stretched across the deck, stopping the aircraft within 320 feet (100 m) after engaging one of the cables. To assist safe landings, the carrier will usually steam directly into wind at full speed, thus reducing aircraft's speed relative to the carrier deck, and eliminating any crosswind.
