Editing Taxiing

{{short description|Movement of an aircraft on the ground, under its own power}}
{{Use American English|date=March 2020}}

[[File:Airbus airliners lined up at Chengdu.jpg|thumb|[[Airbus]] [[jet airliner]]s taxiing at [[Chengdu Shuangliu International Airport]]]]
[[File:Taxiing SeaVixen aircraft.jpg|thumb|A privately owned [[Sea Vixen]] taxis back from an [[air show]] flight, with wings folding as it moves.]]

'''Taxiing''' (rarely spelled '''taxying''')<ref>{{Cite book|url=https://books.google.com/books?id=CDYp9BX3GwwC&pg=PA515|title=United States Air Force Dictionary|last=Dept|first=United States Air Force|date=1956|pages=515|language=en}}</ref> is the movement of an [[aircraft]] on the ground, under its own power, in contrast to [[towing]] or [[pushback (aviation)|pushback]] where the aircraft is moved by a tug. The aircraft usually moves on wheels, but the term also includes aircraft with skis or [[Buoyancy|floats]] (for water-based travel).

An airplane uses [[taxiway]]s to taxi from one place on an [[airport]] to another; for example, when moving from a [[hangar]] to the [[runway]].  The term "taxiing" is not used for the accelerating run along a runway prior to [[takeoff]], or the decelerating run immediately after [[landing]], which are called the takeoff roll and landing rollout, respectively; however, aircraft are considered to be taxiing when they leave the runway after landing to travel to a [[gate (airport)|gate]] or remote stand for disembarkment.

== Etymology ==

{{Main|Taxi#Etymology}}
[[File:British Airways Airbus A319-131 G-DBCG taxiing on the apron at Heathrow, 31 January 2024.jpg|thumb|An [[Airbus A319-131]] operated by [[British Airways]], taxiing on the apron at [[Heathrow Airport]]. This photograph was taken from a [[Boeing 787 Dreamliner#787-10|Boeing 787-10 Dreamliner]], which was in the process of taxiing on a [[taxiway]].]]
As early as 1909 aviation journalists envisioned aeroplanes to replace the [[taxicab]] in traffic-congested cities.<ref>''Flight'', Volume 1, 1909-12-11, page 804.</ref> 

Some aviators and some linguists report that around the year 1911 the [[slang]] word "taxi" was in use for an "airplane". They suggest that the way aircraft move under power before they take off or after they land reminded someone of the way [[taxicab]]s slowly drove around the block when looking for passengers.<ref>{{cite web | url=https://www.quora.com/Why-is-taxiing-as-done-by-airplanes-etc-called-that | title=Why is taxiing (As done by airplanes, etc) called that? }}</ref><ref>{{cite web | url=https://www.etymonline.com/word/taxi | title=Taxi &#124; Etymology, origin and meaning of taxi by etymonline }}</ref>

Also by 1909, French aviation pioneers like [[Louis Blériot|Blériot]], [[Henri Farman|Farman]] and [[Gabriel Voisin|Voisin]] used the term "taxi" for a [[trainer aircraft]], that was so constructed that a pupil would not accidentally get airborne.{{Citation needed|date=November 2022}}

Usage of the word for an airplane quickly disappeared again, but the verb "to taxi" stuck, and words like the "[[taxiway]]" were derived from it.

== Propulsion ==

The thrust to propel the aircraft forward comes from its [[Propeller (aircraft)|propeller]]s or [[jet engine]]s. Reverse thrust for backing up can be generated by [[Thrust reversal|thrust reversers]] such as on the [[Boeing C-17 Globemaster III]], or reversible pitch propellers such as on the [[Lockheed C-130 Hercules]], a rare procedure known as [[powerback]]. Most aircraft, however, are not designed to back up on their own and must be pushed back either by hand or by using an [[Pushback (aviation)|aircraft tug]].

At low power settings, combustion aircraft engines operate at lower efficiency than at cruise power settings. A typical [[Airbus A320 family|A320]] spends an average of 3.5 hours a day taxiing, using {{convert|600|L|USgal|sp=us}} of fuel. Hybrid electrically driven nose gear are under development to allow high use aircraft to shut down the engines during taxi operations.<ref>{{cite web|title=Torque Test: The German Aerospace Center unveils a silent, emissions-free electric nose wheel drive system for the Airbus A320 |last=Majcher |first=Kristin |date=1 April 2011 |website=Aviation Week Network |publisher=Aviation Week |url=http://www.aviationweek.com/Article.aspx?id=/article-xml/OM_04_01_2011_p69-294342.xml|access-date=2011-04-22 |url-status=dead |archive-url=https://web.archive.org/web/20170518234428/http://aviationweek.com/awin/torque-test |archive-date=18 May 2017 |quote=The new, electric nose wheel can power the A320 both forward and backward without requiring power from the aircraft's main engine. In addition to the energy savings, the electric nose wheel completely eliminates engine noise during taxi maneuvers. }}</ref>

== Control ==
[[File:Rule taksi geçiş üstünlüğü.png|thumbnail|Aircraft on the right hand side has the right-of-way during taxiing.]]

Steering is achieved by turning a [[Nose gear|nose wheel]] or tail wheel/[[rudder]]; the [[aviator|pilot]] controls the direction travelled with their feet. Larger jet aircraft have a tiller wheel on the left side of the cockpit that acts as a steering wheel allowing the nosewheel to be turned hydraulically. Braking is controlled by differential toe or heel brakes. Not all aircraft have steerable wheels, and in some cases steering is solely by means of differential braking (all [[Van's aircraft]] for instance) or solely by means of the rudder (including all [[floatplane]]s).

== Hover taxi ==
[[File:Eurocopter EC-120B Colibri (VH-VCC) at Canberra Airport.jpg|thumb|A [[Eurocopter EC120]]B hover-taxis]]

Skid-equipped [[helicopters]] and other [[VTOL]] (Vertical Take-Off and Landing) aircraft conduct hover taxiing to move in [[Ground effect (aircraft)|ground effect]] in the same manner that wheel-equipped aircraft ground taxi. In general hover taxis are conducted at speeds up to {{convert|20|kn|km/h mph|0|abbr=on}}, or below [[translational lift]].<ref name="Crane">Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 263. Aviation Supplies & Academics, 1997. {{ISBN|1-56027-287-2}}</ref>

The [[Bell CH-135 Twin Huey]] is hover taxied in a manner typical for skid-equipped aircraft of that size:

{{quotation|This sequence is initiated from a stabilized 5 ft hover. Move the aircraft forward over the ground at a brisk walking pace. Maintain a constant height above ground, constant forward speed and ensure that the skids remain parallel to the direction of movement. Anticipate stopping so that large rearward cyclic applications are not required as this may result in the tail skids striking the ground. You are often required to taxi out of wind; be aware that when taxiing downwind in strong wind conditions there may be insufficient rearward cyclic to ensure adequate control and that the tail will be nearer the ground. Taxiing downwind is limited to 30 [[knot (unit)|kts]].<ref name="CFACM40-35">10 Tactical Air Group: ''CFACM 40-35 CH-135 Standard Maneuver Guide'', page 1-1, section 103 Taxiing (unclassified). Canadian Forces Air Command, 1984</ref>}}

== Safety ==

When taxiing, aircraft travel slowly. This ensures that they can be stopped quickly and do not risk wheel damage on larger aircraft if they accidentally turn off the paved surface. Taxi speeds are typically {{cvt|16|to|19|kn|km/h mph|abbr=on}}.<ref>{{cite web |url= http://apps.dtic.mil/dtic/tr/fulltext/u2/a533367.pdf |archive-url= https://web.archive.org/web/20140426233535/http://www.dtic.mil/dtic/tr/fulltext/u2/a533367.pdf |url-status= live |archive-date= April 26, 2014 |title= A Statistical Learning Approach to the Modeling of Aircraft Taxi-Time |work= MIT Lincoln Laboratory |publisher= Federal Aviation Administration |date= 10 Aug 2010 |page= 4}}</ref>

Rotor downwash limits helicopter hover-taxiing near parked light aircraft. The use of engine thrust near terminals is restricted due to the possibility of structural damage or injury to personnel caused by [[jet blast]].<ref>{{Cite web|url=https://www.boeing.com/commercial/aeromagazine/aero_06/textonly/s02txt.html|title=Engine Thrust Hazards in the Airport Environment|website=www.boeing.com}}</ref>

== References ==

{{Reflist}}

== External links ==

* {{Commons category inline|Taxiways}}aircraft
* {{Commons category inline|Taxiing in aviation}}


{{Flight phases}}

[[Category:Aircraft operations]]
[[Category:Flight phases]]