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Airplane Landing Video - How to land an airplane

Landing is the last part of a flight, where a flying animal, aircraft, or spacecraft returns to the ground. When the flying object returns to water, the process is called alighting, although it is commonly called "landing" and "touchdown" as well. A normal aircraft flight would include several parts of flight including taxi, takeoff, climb, cruise, descent and landing. This article describes the last portion of flight as the plane, bird, or rocket touches the ground.

Landing occurs after descent. While inflight, the four major forces acting on the object are; lift, thrust, gravity and drag. Flying is accomplished by generating enough lift to offset gravity to stay in the air. See the picture of the wing describing the four forces. To land, the airspeed and the rate of descent are reduced to where the object descends at a slow enough rate to allow for a gentle touch down.

Each different type of flying object generates lift in a different manner. Airplanes, birds and flying insects use a wing. A bird generates thrust and lift by flapping its wings, and aircraft generate thrust with some form of an engine. The air passing over the wing of an aircraft generates lift. A helicopter uses rotary wings to generate lift and changes the angle of the rotor to generate thrust. Rockets or Vertical Jet engines are also commonly used on speciality aircraft to generate Lift. Air balloons use a lighter than air gas to generate buoyancy or lift.

The term landing is also applied to people or objects descending to the ground using a parachute. These objects are considered to be in a controlled descent instead of actually flying. A parachute works by capturing air inducing enough drag that the object that is falling hits the ground at a relatively slow speed. There are many examples of parachutes in nature including the seeds of a dandelion. People who intentionally land using a parachute are called parachutists.

Sometimes, a safe landing is accomplished by using multiple forms of lift, thrust and dampening systems. The lunar lander used a rocket, landing gear and the legs of the astronauts to land on the moon. Several Soviet rockets including the Soyuz have used parachutes and airbag landing systems to dampen the landing on earth.

Aircraft usually land at an airport on a firm runway or helicopter landing pad, generally constructed of asphalt concrete, concrete, gravel or grass. Aircraft equipped with pontoons are able to land on water. Aircraft also sometimes use skis to land on snow or ice.

For aircraft, landing is accomplished by slowing down and descending to the runway. This speed reduction is accomplished by reducing thrust and/or inducing a greater amount of drag using flaps, landing gear or speed brakes. As the plane approaches the ground, the pilot will execute a flare to induce a gentle landing.

A flare is performed by rotating the wings where the rate of descent will be reduced often by adopting a nose-up attitude. The attitude is held until the undercarriage touches the ground, and the controls are either held until all wheels touch the ground or gently adjusted (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 airspeed to remain aloft. The stall warning is often heard just before landing indicating that this speed and altitude have been reached. The effect causes a very light touch down for the pilot and passengers.

In large transport category (airliner), aircraft pilots land the aircraft by "flying the airplane on to the runway." The airspeed and attitude of the plane are adjusted for landing. The airspeed is kept well above stall speed and at a constant rate of descent. A flare is performed just before landing and the descent rate is significantly reduced causing a light touch down. Upon touchdown, spoilers (sometimes called "lift dumpers") are deployed to dramatically reduce the lift and transfer the aircraft's weight to its wheels, where mechanical braking, such as an autobrake system, can take effect. Reverse thrust is used by many jet aircraft to help slow down just after touch-down, redirecting engine exhaust forward instead of back. Some propeller planes also have this feature, where the blades of the propeller are re-angled to push air forward instead of back.

Factors such as crosswind where the pilot will use a crab landing or a slip landing will cause pilots to land slightly faster and sometimes with different attitudes to ensure proper handling and safety of the plane. Other factors affecting a particular landing might include some or all of the following partial list; the plane size, wind, weight, runway length, obstacles, ground effects, weather, runway altitude, air temperature, air pressure, air traffic control, visibility, avionics, and the overall situation, et cetera.

For example landing, a multi-engine turboprop military (C-130 Hercules) under fire in a grass field in a war zone, requires different skills and precautions than landing a single engine plane (Cessna 150) on a paved runway in uncontrolled airspace, which is different from landing an airliner (Airbus A380) at a major airport with the support of air traffic control.

Pilots follow a course of training to develop the experience to routinely land in each situation. Professional pilots have extensive training, experience, and certification on the types of planes they are flying.

Emergency landing

An emergency landing is an unplanned landing made by an aircraft in response to a crisis which either interferes with the operation of the aircraft or involves sudden medical emergencies necessitating diversion to the nearest airport.

Types of emergency landings

There are several different types of emergency landings for powered aircraft: planned landing or unplanned landing

-Forced landing, the aircraft is forced to make a landing due to technical problems, medical problems or weather conditions. Landing as soon as possible is a priority, no matter where. A forced landing may be necessary even if the aircraft is still flyable. This can arise to either facilitate emergency medical or police assistance or get the aircraft on the ground before a major system failure occurs which would force a crash landing or ditch situation.

-Precautionary landing, may result from a planned landing at a location about which information is limited, from unanticipated changes during the flight, or from abnormal or even emergency situations. The sooner a pilot locates and inspects a potential landing site, the less the chance of additional limitations being imposed by worsening aircraft conditions, deteriorating weather, or other factors.

-Crash landing, is caused by the failure of or damage to vital systems such as engines, hydraulics, or landing gear, and so a landing must be attempted where a runway is needed but none is available. The pilot is essentially trying to get the aircraft on the ground in a way which minimizes the possibility of injury or death to the people aboard.

-Ditching, is the same as a crash landing, only on water. After the disabled aircraft makes contact with the surface of the water, the aircraft will typically sink if it is not designed to float.

Procedures

If there is no engine power available during a forced landing, fixed-wing aircraft glide, while a rotary winged aircraft (helicopter) autorotates to the ground by trading altitude for airspeed to maintain control. Pilots often practice "simulated forced landings", in which an engine failure is simulated and the pilot has to get the aircraft on the ground safely, by selecting a landing area and then gliding the aircraft at its best gliding speed.

If there is a suitable landing spot within the aircraft's gliding or autorotation distance, an unplanned landing will often result in no injuries or significant damage to the aircraft, since powered aircraft generally use little or no power when they are landing. Light aircraft can often land safely on fields, roads, or gravel river banks (or on the water, if they are float-equipped); but medium and heavy aircraft generally require long, prepared runway surfaces because of their heavier weight and higher landing speeds. Glider pilots routinely land away from their base and so most cross-country pilots are in current practice.

UAV forced landing research

Since 2003, research has been conducted on enabling UAVs to perform a forced landing autonomously.

Notable examples of emergency landings

Large airliners have multiple engines and redundant systems, so forced landings are extremely rare for them, but some notable ones have occurred. The most famous example is the Gimli Glider, an Air Canada Boeing 767 that ran out of fuel and glided to a safe landing in Gimli, Manitoba, Canada on July 23, 1983. On June 1982, British Airways Flight 9, a Boeing 747 en route from Kuala Lumpur to Perth lost power in all four engines, three of which subsequently recovered, eventually diverting to Jakarta. On April 28, 1988, Aloha Airlines Flight 243 experienced an explosive decompression mid-flight, forcing an emergency landing at the Kahului Airport with only one casualty, flight attendant Clarabell "C.B." Lansing. More recently, Air Transat Flight 236 ran out of fuel over the Atlantic Ocean on August 24, 2001 and made a successful forced landing in the Azores.

A less successful crash landing involved Southern Airways Flight 242 on April 4, 1977. The DC-9 lost both of its engines due to hail and heavy rain in a thunderstorm and, unable to glide to an airport, made a forced landing on a highway near New Hope, Georgia, United States. The plane made a hard landing and was still carrying a large amount of fuel, so it burst into flames, killing the majority of the passengers and several people on the ground.

Airliners frequently make emergency landings, and almost all of them are uneventful. However because of their inherent uncertain nature, they can quickly become crash landings or worse. Some notable instances include Swissair Flight 111, which crashed near Halifax, Nova Scotia, Canada on September 2, 1998 while dumping fuel in preparation for a precautionary landing due to fire; United Airlines Flight 232, which broke up while landing at Sioux City, Iowa, U.S.A. on July 19, 1989; and Air Canada Flight 797, which burned after landing at Cincinnati/Northern Kentucky International Airport on June 2, 1983 after a fire started in the cabin.

On January 17, 2008, British Airways Flight 38, a Boeing 777 crashed while attempting to land at London Heathrow Airport, England. The plane came down too early and passed just a few hundred feet over the houses before the runway. The plane crash landed and skidded, eventually stopping just on the runway, creating a large, visible skid mark for some 400m before the runway. Thirteen people sustained minor injuries as the plane collapsed after the front landing gear came off.

Emergency water landings

Eight intentional passenger (cargo) airliner ditchings have been documented. These figures are for intentional water ditchings, usually as a result of in-flight fuel depletion, rather than an accidental overshoot of landing runway into a body of water. The following figures show survival rates for passengers and crew:

-US Airways Flight 1549, Airbus A320, New York City to Charlotte/Douglas International Airport, 15 January 2009, made a controlled safe water ditch into the Hudson River after losing thrust in both engines due to birdstrike at about 3000 feet altitude three minutes into the flight after a normal takeoff from LaGuardia Airport; 155 passengers and crew made an orderly evacuation as a NYC fireboat towed the floating aircraft with passengers standing on the wing, 100% survival rate

-Tuninter Flight 1153 , August 6, 2005, off the coast of Sicily, 39 occupants, 23 survivors, 59% survival rate

-Miami Air Lease Convair CV-340, December 4, 2004, Mall lake, Florida, 2 occupants, 2 survivors, 100% survival rate

-Ethiopian Airlines Flight 961, November 23, 1996, off the Comoros Islands, 175 occupants, 45 survivors, 26% survival rate

-ALM DC9, May 2, 1970, the Caribbean, 63 occupants, 40 survivors, 63% survival rate

-Aeroflot Tupolev 124 ditching in Neva river, October, 1963, narrowly missed a tugboat which sped to plane, cast a line and towed it to shallow waters, where the occupants were deboarded onto tug, 52 occupants, 52 survivors, 100% survival rate

-Pan Am Flight 6 Boeing Stratocruiser "Sovereign of the Skies", October 16, 1956, in the Pacific between Honolulu and San Francisco, 30 passengers and crew, 30 survivors, 100% survival rate

-Northwest Orient Airlines Flight 2, Boeing Stratocruiser, April 2, 1956, ditched in the 430 feet Puget Sound, 38 passengers, all survived the ditching but 5 could not recover from the freezing waters, 87% survival rate.

-Sept. 28, 1962, Flying Tiger's Super H Constellation passenger aircraft with a crew of 8 and 68 U.S. military (paratrooper) passengers ditched in the North Atlantic about 500 miles west of Shannon, Ireland after losing three engines on a flight to Frankfurt, Germany. 45 of the passengers and 3 crew were rescued, with 23 passengers and 5 crew members being lost in the storm-swept seas. All passengers successfully evacuated the airplane. Those who were lost succumbed in the rough seas. 100% survival rate for landing and evacuation.

Though not a passenger plane, still relevant - Colombian AF C 130 Hercules, October 1982, en route between the Azores and Bermuda stayed afloat for two days.

Water landing

A water landing is, in the broadest sense, any landing on a body of water. All waterfowl, those seabirds capable of flight, and some human-built vehicles are capable of landing in water as a matter of course.

The phrase "water landing" is also used as a euphemism for crash-landing into water in an aircraft not designed for the purpose. The National Transportation Safety Board of the United States government defines "ditching" in its aviation accident coding manual as "a planned event in which a flight crew knowingly makes a controlled emergency landing in water. (Excludes float plane landings in normal water landing areas.)" Such water landings are extremely rare for commercial passenger airlines.

By design

Seaplanes, flying boats, and amphibious aircraft are designed to take off and land on water. Landing can be supported by a hull-shaped fuselage and/or pontoons. The availability of a long effective runway was historically important on lifting size restrictions on aircraft, and their freedom from constructed strips remains useful for transportation to lakes and other remote areas. The ability to loiter on water is also important for marine rescue operations and fire fighting. One disadvantage of water landing is that it is dangerous in the presence of waves. Furthermore, the necessary equipment compromises the craft's aerodynamic efficiency and speed.

Early manned spacecraft launched by the United States were designed to land in water by the splashdown method. The craft would parachute into the water, which acted as a cushion to bring the craft to a stop; the impacts were violent but survivable. Landing over water rather than land made braking rockets unnecessary, but its disadvantages included difficult retrieval and the danger of drowning. The NASA Space Shuttle design was intended to land on a runway instead.

In distress

Although extremely uncommon in commercial passenger travel, small aircraft ditchings are common occurrences. According to the United States Coast Guard, including helicopters and fixed-wing aircraft, between military, air carrier, corporate, and general aviation, there is, on average, one ditching every day in U.S. waters alone.

Source: Wikipedia