{{Short description|Principal directions in aviation}} {{redirect|Yaw, pitch, and roll|the mechanics concept|Moment of inertia#Principal axes|Euler angles with the same names|Euler angles#Tait–Bryan angles|aircraft design coordinates|Lofting coordinates}} [[Image:Yaw Axis Corrected.svg|thumb|The position of all three axes, with the [[right-hand rule]] for describing the angle of its rotations]]
An [[aircraft]] in flight is free to [[Rotation|rotate]] in three dimensions: '''''yaw''''', nose left or right about an axis running up and down; '''''pitch''''', nose up or down about an axis running from wing to wing; and '''''roll''''', rotation about an axis running from nose to tail. The yaw, pitch, and roll axes are alternatively designated as ''vertical'', ''lateral'' (or ''transverse''), and ''longitudinal'' respectively. These axes [[Moving frame|move with the vehicle]] and rotate relative to the Earth along with the craft. These definitions were analogously applied to [[spacecraft]] when the first crewed spacecraft were designed in the late 1950s.
These rotations are produced by [[torque]]s (or [[Moment (physics)|moment]]s) about the principal axes. On an aircraft, these are intentionally produced by means of moving control surfaces, which vary the distribution of the net [[Aerodynamics|aerodynamic]] force about the vehicle's [[center of gravity]]. [[Elevator (aeronautics)|Elevator]]s (moving flaps on the horizontal tail) produce pitch, a [[rudder]] on the vertical tail produces yaw, and [[aileron]]s (flaps on the wings that move in opposing directions) produce roll. On a spacecraft, the movements are usually produced by a [[reaction control system]] consisting of small rocket thrusters used to apply asymmetrical thrust on the vehicle.
==Principal axes== {{See also|Ship motions}} <gallery mode="packed"> File:Aileron yaw.gif|alt=Yaw animation of a plane|Yaw File:Aileron pitch.gif|alt=Pitch animation of a plane|Pitch File:Aileron roll.gif|alt=Roll animation of a plane|Roll </gallery> *[[Flight control surfaces#Vertical axis|Vertical axis]] or yaw axis — an axis drawn from top to bottom and perpendicular to the other two axes. *[[Flight control surfaces#Transverse axis|Transverse axis]], lateral axis, or pitch axis — an axis running from the pilot's left to right in piloted aircraft, and parallel to the wings of a winged aircraft, parallel to the [[buttock line]]. *[[Flight control surfaces#Longitudinal axis|Longitudinal axis]], or roll axis — an axis drawn through the body of the vehicle from tail to nose in the normal direction of flight, or the direction the pilot faces, similar to a ship's [[waterline]].
Normally, these axes are represented by the letters X, Y and Z in order to compare them with some reference frame, usually named x, y, z. Normally, this is made in such a way that the X is used for the longitudinal axis, but there are [[axes conventions|other possibilities]] to do it.
=== {{Anchor|Yaw}}Vertical axis (yaw) ===<!-- Other articles link here. --> <!--- the image in the following line has been moved up to replace the image with the wrong orientation of the roll angle ---> <!--- [[Image:Yaw Axis Corrected.svg|thumb|250px|The position of all three axes, with the [[right-hand rule]] for describing the angle of its rotations]] ---> The '''yaw axis''' has its origin at the center of gravity and is directed towards the bottom of the aircraft, [[perpendicular]] to the wings and to the fuselage reference line. Motion about this axis is called '''yaw'''. A positive yawing motion moves the nose of the aircraft to the right.<ref>{{Cite web |title=The American Heritage Dictionary entry: yaw |url=https://www.ahdictionary.com/word/search.html?q=yaw |access-date=2026-04-09 |website=www.ahdictionary.com}}</ref> The [[Rudder#Aircraft rudders|rudder]] is the primary control of yaw.<ref name=Clancy_16.6 />
The term ''yaw'' was originally applied in sailing, and referred to the motion of an unsteady ship rotating about its vertical axis. Its [[etymology]] is uncertain.{{cn|date=April 2026}}
=== {{Anchor|Pitch}}Lateral axis (pitch) ===<!-- Other articles link here. --> The '''pitch axis''' (also called '''transverse''' or '''lateral axis''')<ref name=MISB>{{cite web|title=MISB Standard 0601|url=http://www.gwg.nga.mil/misb//docs/standards/ST0601.8.pdf|publisher=Motion Imagery Standards Board (MISB)|access-date=1 May 2015|archive-date=24 March 2017|archive-url=https://web.archive.org/web/20170324002900/http://www.gwg.nga.mil/misb//docs/standards/ST0601.8.pdf|url-status=dead}} Also at [[:File:MISB Standard 0601.pdf]].</ref> passes through an aircraft from wingtip to wingtip. Rotation about this axis is called '''pitch'''. Pitch changes the vertical direction that the aircraft's nose is pointing (a positive pitching motion raises the nose of the aircraft and lowers the tail). The [[Elevator (aeronautics)|elevators]] are the primary control surfaces for pitch.<ref name=Clancy_16.6 />
=== {{Anchor|Roll}}Longitudinal axis (roll) ===<!-- Other articles link here. --> The '''roll axis''' (or '''longitudinal axis'''<ref name=MISB/>) has its origin at the center of gravity and is directed forward, parallel to the fuselage reference line. Motion about this axis is called '''roll'''. An angular displacement about this axis is called '''bank'''.<ref name=Clancy_16.6>Clancy, L.J. (1975) ''Aerodynamics'' Pitman Publishing Limited, London {{ISBN|0-273-01120-0}}, Section 16.6</ref> A positive rolling motion lifts the left wing and lowers the right wing. The pilot rolls by increasing the lift on one wing and decreasing it on the other. This changes the bank angle.<ref>{{cite book |title=A Dictionary of Aviation |first=David W. |last=Wragg |isbn=9780850451634 |edition=first |publisher=Osprey |year=1972–73|page=224}}</ref> The [[aileron]]s are the primary control of roll. The rudder also has a secondary effect on roll.<ref>FAA (2004). ''Airplane Flying Handbook''. Washington D.C.:U.S. Department of Transportation, Federal Aviation Administration, ch 4, p 2, FAA-8083-3A.</ref>
==Relationship with other systems of axes== [[File:MISB ST 0601.8 - Yaw, Pitch & Roll.png|thumb|upright=1.75|Yaw/heading, pitch and roll [[angle]]s and associated vertical (down), transverse and longitudinal axes]]
These axes are related to the [[Moment of inertia#Principal axes|principal axes of inertia]], but are not the same. They are geometrical symmetry axes, regardless of the mass distribution of the aircraft.{{Citation needed|date=November 2011}}
In aeronautical and aerospace engineering intrinsic rotations around these axes are often called [[Euler angles]], but this conflicts with existing usage elsewhere. The calculus behind them is similar to the [[Frenet–Serret formulas]]. Performing a rotation in an intrinsic reference frame is equivalent to right-multiplying its characteristic matrix (the matrix that has the vectors of the reference frame as columns) by the matrix of the rotation.{{Citation needed|date=November 2011}}
==History== The first aircraft to demonstrate active control about all three axes was the [[Wright brothers]]' [[Wright_Glider#1902_glider|1902 glider]].<ref>{{cite web|url=http://www.grc.nasa.gov/WWW/K-12/airplane/rotations.html|title=Aircraft rotations|access-date=2008-08-04| archive-url= https://web.archive.org/web/20080704135659/http://www.grc.nasa.gov/WWW/K-12/airplane/rotations.html| archive-date= 4 July 2008 | url-status= live}}</ref>
==See also== *[[Aerodynamics]] *[[Aircraft flight control system]] *[[Euler angles]] *[[Fixed-wing aircraft]] *[[Flight control surfaces]] *[[Flight dynamics]] *[[Moving frame]] *[[Panning (camera)]] *[[Six degrees of freedom]] *[[Screw theory]] *[[Triad method]]
==References== {{Reflist}}
==External links== *[https://www.flyaeroguard.com/learning-center/pitch-roll-yaw/ Pitch, Roll, Yaw] *[https://web.archive.org/web/20110717062743/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0749489 Yaw Axis Control as a Means of Improving V/STOL Aircraft Performance.] *[https://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/9091/28850/01297903.pdf?temp=x 3D fast walking simulation of biped robot by yaw axis moment compensation] *[https://web.archive.org/web/20110612204855/http://www.patentstorm.us/patents/6478262/claims.html Flight control system for a hybrid aircraft in the yaw axis] *[https://gwg.nga.mil/gwg/focus-groups/misb/ Motion Imagery Standards Board (MISB)] {{Webarchive|url=https://web.archive.org/web/20220823155115/https://gwg.nga.mil/gwg/focus-groups/misb/ |date=2022-08-23 }}
[[Category:Aerodynamics]] [[Category:Attitude control]] [[Category:Line (geometry)]]