Editing Landing (section)

== Aircraft ==
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 ([[floatplane]]) or with a boat hull-shaped fuselage (a [[flying boat]]) are able to land on water. Aircraft also sometimes use skis to land on snow or ice.

To land, the airspeed and the rate of descent are reduced such that the object descends at a low enough rate to allow for a gentle touch down. 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 [[Air brake (aircraft)|speed brakes]]. When a fixed-wing aircraft approaches the ground, the pilot will move the control column back to execute a [[Landing flare|flare]] or round-out. This increases the [[angle of attack]]. Progressive movement of the control column back will allow the aircraft to settle onto the runway at minimum speed, landing on its main wheels first in the case of a [[tricycle gear]] aircraft or on all three wheels simultaneously in the case of a [[conventional landing gear]]-equipped aircraft, commonly referred to as a "taildragger".<ref name="AviationGlossary">{{cite web|url = http://aviationglossary.com/icao-definition/flare-icao-definition/|title = Flare (ICAO Definition)|access-date = 26 January 2011|last = Aviation Glossary|year = 2011}}</ref><ref name="Phase">{{cite web|url = http://www.intlaviationstandards.org/Documents/PhaseofFlightDefinitions.pdf|title = Phase of Flight Definitions and Usage Notes|access-date = 26 January 2011|last = International Civil Aviation Organization|author-link = International Civil Aviation Organization|date=June 2010|archive-url = https://web.archive.org/web/20070612214654/http://www.intlaviationstandards.org/Documents/PhaseofFlightDefinitions.pdf|archive-date = 12 June 2007|url-status = dead}}</ref><ref name="CraneFlare">Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 217. Aviation Supplies & Academics, 1997. {{ISBN|1-56027-287-2}}</ref><ref name="TC">[[Transport Canada]]: ''Aeroplane Flight Training Manual, 4th Edition'', pages 104-115. Gage Educational Publishing Company, 1994. {{ISBN|0-7715-5115-0}}</ref>

=== Light aircraft ===
[[File:PiperPA28CherokeeLanding.jpg|thumb|[[Piper Cherokee]] landing sequence from approach to flare]]
In a [[light aircraft]], power is adjusted to control the descent rate, and pitch attitude is adjusted to control airspeed,<ref name="RASA">{{cite book |title=Aircraft |date=1984 |series=Volume 64 |page=50 |url=https://books.google.com/books?id=AkspAQAAIAAJ |access-date=28 February 2023 |publisher=Royal Aeronautical Society Australian Division. |language=en}}</ref> although theoretically they must be adjusted together.<ref name="Bjork">{{cite book |last1=Bjork |first1=Lewis |title=Piloting for Maximum Performance |date=1996 |publisher=McGraw-Hill |isbn=978-0-07-005699-2 |page=229 |url=https://books.google.com/books?id=IHFTAAAAMAAJ |language=en}}</ref>

In a light aircraft, with little [[crosswind]], the ideal landing is 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 (flight)|stall]] warning is often heard just before landing, indicating that this speed and altitude have been reached. The result is very light touch down.<ref name="TC" />

Light aircraft landing situations, and the pilot skills required, can be divided into four types:
* Normal landings<ref name="TC" />
* [[Crosswind landing]]s - where a significant wind not aligned with the landing area is a factor<ref name="TC" />
* Short field landings - where the length of the landing area is a limiting factor<ref name="TC" />
* Soft and unprepared field landings - where the landing area is wet, soft or has ground obstacles such as furrows or ruts to contend with<ref name="TC" />

=== Large aircraft ===
[[File:Delta Air Lines Boeing 767-400ER N834MH FRA 2011-11-26.png|thumb|A landing [[Delta Air Lines]] [[Boeing 767-400ER]]. The smoke emanating from the left main [[Landing gear|undercarriage]] wheels shows that it touched down on that main landing gear first, which is normal procedure in a left cross wind.]]
In large [[transport category]] (airliner) aircraft, pilots land the aircraft by "flying the airplane on to the runway."{{citation needed|date=February 2023}} The airspeed and attitude (pitch angle)<!-- The correct term is "attitude" here, not altitude, please do not change this without discussion on the talk page first --> of the plane are adjusted for landing. Thrust and pitch must be adjusted together,<ref name="Roy">{{cite journal |last1=Jeffrey A. |first1=Roy |title=The Stabilized Approach |journal=FAA Aviation News |date=May–June 1990 |page=4 |url=https://books.google.com/books?id=bIgsnbWISb8C&pg=RA8-PA4 |access-date=28 February 2023 |publisher=Flight Standards' Accident Prevention Program Branch, Federal Aviation Administration, Department of Transportation |language=en}}</ref> however the technique is reversed compared to light aircraft.<ref name="NASA Technical Paper">{{cite book |title=NASA Technical Paper |date=1981 |publisher=National Aeronautics and Space Administration, Scientific and Technical Information Office |page=6 |url=https://books.google.com/books?id=vAMDAAAAIAAJ |access-date=28 February 2023 |language=en}}</ref> In large aircraft, thrust is used to control airspeed and pitch is used to control rate of descent.<ref name="NTSB">{{cite book |title=Aircraft Accident Report, United Airlines Flight 232, 19 July 1989 |publisher=National Transportation Safety Board |location=Appendix D |page=123 |url=https://books.google.com/books?id=2QU6AQAAMAAJ |language=en}}</ref> The airspeed is kept well above stall speed and at a constant rate of descent. A [[Landing flare|flare]] is performed just before landing, and the descent rate is significantly reduced, causing a light touch down. Upon touchdown, [[lift dumper|spoiler]]s (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 (aircraft)|propeller]]-driven airplanes also have this feature, where the blades of the propeller are re-angled to push air forward instead of back using the 'beta range'.

=== Environmental factors ===
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 aircraft attitude to ensure a safe landing.

Other factors affecting a particular landing might include: the plane size, [[wind]], [[weight]], runway length, obstacles, [[ground effect in aircraft|ground effects]], [[weather]], runway altitude, [[air temperature]], [[atmospheric pressure|air pressure]], [[air traffic control]], [[visibility]], [[avionics]] and the overall situation.

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

[[Required Navigation Performance]] (RNP) is being used more and more. Rather than using radio beacons, the airplane uses GPS-navigation for landing using this technique. This translates into a much more fluid ascent, which results in decreased noise, and decreased fuel consumption.<ref>{{cite web |url=http://www.geaviation.com/systems/products-and-services/performance-based-navigation/learning-rnp.html |title=Required Navigation Performance &#124; GE Aviation Systems |publisher=GE Aviation |access-date=2012-07-16 |url-status=dead |archive-url=https://web.archive.org/web/20120729132651/http://www.geaviation.com/systems/products-and-services/performance-based-navigation/learning-rnp.html |archive-date=2012-07-29 }}</ref>