{{Short description|Aircraft control}} {{Redirect|Side stick||Rimshot (disambiguation)}} [[File:Airbus A380 cockpit.jpg|thumb|Airbus A380 flight deck with black side-sticks on the left side of the left seat and on the right side of the right seat. The throttle controls in the central console are black, labeled 1–4.]] [[File:F-16D cockpit at EFKA.jpg|thumb|F-16 cockpit showing side-stick]]
A '''side-stick''' or '''sidestick controller''' is an aircraft control stick that is located on the side console of the pilot, usually on the righthand side, or outboard on a two-seat flightdeck. Typically this is found in aircraft that are equipped with fly-by-wire control systems.<ref name="Crane">Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 463. Aviation Supplies & Academics, 1997. {{ISBN|1-56027-287-2}}</ref>
The throttle controls are typically located to the left of a single pilot or centrally on a two-seat flightdeck. Only one hand is required to operate them; two-handed operation is neither possible nor necessary.
== Prevalence == The side-stick is used in many modern aircraft, such as the:
* Fighter aircraft: ** F-16 Fighting Falcon (1974) ** Dassault Rafale (1986) ** AIDC F-CK 1 Ching-Kuo (1989) ** Mitsubishi F-2 (1995) ** F-22 Raptor (1996) ** F-35 Lightning 2 (2006) ** Chengdu J-20 (2009) ** Shenyang FC-31 (2012) ** KAI KF-21 Boramae (2022) * Jet trainers and light attack ** KAI T-50 Golden Eagle (2001) ** Boeing–Saab T-7 Red Hawk (2016) ** TAI Hürjet (2023) * Civil aircraft ** Airbus A320 (1984) and all subsequent Airbus aircraft,<ref name="fbw_sidestick">{{cite web |url = http://www.airbus.com/innovation/proven-concepts/in-design/fly-by-wire/ |title = Fly-by-wire - A CIVIL AVIATION FIRST |work = Airbus / Innovation / Proven concepts / In design / Fly-by-wire |publisher = Airbus | access-date = 6 July 2012 |url-status = dead |archive-url = https://web.archive.org/web/20120708070059/http://www.airbus.com/innovation/proven-concepts/in-design/fly-by-wire/ |archive-date = 8 July 2012}}</ref> including the largest passenger jet in service, the Airbus A380 ** Sukhoi Superjet 100 (2007) ** Gulfstream G400/G500/G600 (2014) * Helicopters ** Bell 525.
== Compared to centre sticks == A side-stick arrangement contrasts with the more conventional design where the stick is located in the centre of the cockpit between the pilot's legs, called a "centre stick". A side-stick arrangement increases ejection seat safety for the pilot as there is less interference amongst flight controls.{{Citation needed|date=August 2023}}
== Handling of dual input situations == In Airbus's implementation, input values of both side-sticks are normally added up,<ref>{{cite web | work = Airbus Safety First #03 December 2006 p. 5/5 | series = Airbus Safety First Magazine | title = Dual Side Stick Inputs | date = 2024-11-23 | url = https://safetyfirst.airbus.com/app/themes/mh_newsdesk/documents/archives/dual-side-stick-inputs.pdf | quote = "The two sidesticks are not mechanically linked as they are on older types of aircraft. This means that both sticks may be operated independently one of the other. When one sidestick is operated it sends an electrical signal to the Fly By Wire computers. When both sticks are moved simultaneously, the system adds the signals of both pilots algebraically."}}</ref> except when the "priority takeover button" is held down, causing any inputs on the other side-stick to be ignored.<ref>{{cite web | work = Airbus Safety First #03 December 2006 p. 5/5 | series = Airbus Safety First Magazine | title = Dual Side Stick Inputs | date = 2024-11-23 | url = https://safetyfirst.airbus.com/app/themes/mh_newsdesk/documents/archives/dual-side-stick-inputs.pdf | quote = "To avoid both signals being added by the system, a priority P/B is provided on each stick. By pressing this button, a pilot may cancel the inputs of the other pilot. An audio signal will indicate which sidestick has priority."}}</ref> Holding this button down for a minimum of 40 seconds will disable the other side-stick, which can be reversed by pressing the button on either side-stick again. If one stick is disabled a red light will show on it, and a green light on the active one.<ref>{{cite web | work = Airbus Safety First #03 December 2006 p. 5/5 | series = Airbus Safety First Magazine | title = Dual Side Stick Inputs | date = 2024-11-23 | quote = "A green light will come on in front of the pilot who has taken control if the other stick is not in neutral popsition, and a red light comes on in front of the pilot whose stick is deactivated." | url = https://safetyfirst.airbus.com/app/themes/mh_newsdesk/documents/archives/dual-side-stick-inputs.pdf}}</ref>
While the inputs are added up, the sum is clamped to the value of the maximum possible deflection a single side-stick;<ref>{{cite web | work = Airbus Safety First #03 December 2006 p. 5/5 | series = Airbus Safety First Magazine | title = Dual Side Stick Inputs | date = 2024-11-23 | url = https://safetyfirst.airbus.com/app/themes/mh_newsdesk/documents/archives/dual-side-stick-inputs.pdf | quote = "The total is limited to the signal that would result from the maximum deflection of a single sidestick."}}</ref> but this still means that when both side-sticks are deflected 50% in the same direction, the resulting effective input will be that of a fully deflected side-stick. Also, because the inputs are added, any deflection of the other side-stick in the opposite direction will in effect be subtracted, resulting in the inputs partially cancelling each other out. For example, if two inputs have opposite directions but equal magnitudes, the sum will be zero, and the flight control surfaces will not move.
In addition to visual indications,<ref>{{cite web | work = Airbus Safety First #03 December 2006 p. 5/5 | series = Airbus Safety First Magazine | title = Dual Side Stick Inputs | date = 2024-11-23 | url = https://safetyfirst.airbus.com/app/themes/mh_newsdesk/documents/archives/dual-side-stick-inputs.pdf | quote = "When a dual input situation is detected, the two green priority lights located on the cockpit front panel flash simultaneously. The visual indication is an ADVISORY of a dual input situation"}}</ref> detection of more than a single side-stick deflection greater than 2°<ref>{{cite web | work = Airbus Safety First #03 December 2006 p. 5/5 | series = Airbus Safety First Magazine | title = Dual Side Stick Inputs | date = 2024-11-23 | url = https://safetyfirst.airbus.com/app/themes/mh_newsdesk/documents/archives/dual-side-stick-inputs.pdf | quote = "In order to warn the crew in case of dual sidestick operations, Airbus has designed a package of dual input indicators and audio warning. These operate when both side sticks are deflected simultaneously by more than 2°."}}</ref> from neutral without the priority takeover button being held down results in an aural "DUAL INPUT" warning repeated every five seconds.<ref>{{cite web | work = Airbus Safety First #03 December 2006 p. 5/5 | series = Airbus Safety First Magazine | title = Dual Side Stick Inputs | date = 2024-11-23 | url = https://safetyfirst.airbus.com/app/themes/mh_newsdesk/documents/archives/dual-side-stick-inputs.pdf | quote = "After the visual indication has been triggered, a synthetic voice “DUAL INPUT” comes up every 5 sec, as long as the dual input condition persists. The synthetic voice is a WARNING of a dual input situation."}}</ref> This aural warning has the lowest priority, and is overridden by a warning of higher priority, such as from the EGPWS,<ref>{{cite web | work = Airbus Safety First #03 December 2006 p. 5/5 | series = Airbus Safety First Magazine | title = Dual Side Stick Inputs | date = 2024-11-23 | url = https://safetyfirst.airbus.com/app/themes/mh_newsdesk/documents/archives/dual-side-stick-inputs.pdf | quote = "Note: This audio has the lowest priority among the synthetic voice audio alerts."}}</ref> posing a potential risk. Examples of this occurring include the 2009 crash of Air France Flight 447 (an Airbus A330 flying from Rio de Janeiro to Paris), the 2010 crash of Afriqiyah Airways Flight 771 an Airbus A330 from flying Johannesburg to Tripoli<ref>{{Cite web|url=https://aviation-safety.net/database/record.php?id=20100512-0|title=ASN Aircraft accident Airbus A330-202 5A-ONG Tripoli International Airport (TIP)|first=Harro|last=Ranter|website=aviation-safety.net}}</ref><ref>Page 81 "Conclusions" [https://reports.aviation-safety.net/2010/20100512-0_A332_5A-ONG.pdf Final Report of AFRIQIYAH Airways Aircraft, Airbus A330-202, 5A-ONG Crash], Occurred at Tripoli (LIBYA)on 12/05/2010 Published February 2013.</ref> and the 2014 crash of Indonesia AirAsia Flight 8501 (an Airbus A320 flying from Surabaya to Singapore).<ref>{{cite web|url=https://www.foxnews.com/story/is-flight-447s-fly-by-wire-aircraft-technology-safe/|title=Is Flight 447's 'Fly-by-Wire' Aircraft Technology Safe?|date=2009-06-12|publisher=Fox News|access-date=2013-05-29}}</ref><ref name="Ross">{{Citation|last=Ross|first=Nick|title=Air France Flight 447: 'Damn it, we're going to crash'|date=2012-04-28 |url=https://www.telegraph.co.uk/technology/9231855/Air-France-Flight-447-Damn-it-were-going-to-crash.html|quote=It seems surprising that Airbus has conceived a system preventing one pilot from easily assessing the actions of the colleague beside him. And yet that is how their latest generations of aircraft are designed. The reason is that, for the vast majority of the time, side-sticks are superb.|type=article|newspaper=The Daily Telegraph}}</ref>.
== Comparison of passive and active side-sticks == === Passive side-sticks === In the centre stick design, like traditional airplane yokes, both the pilot flying, PF's, and pilot not flying, PNF's, controls are mechanically connected together so each pilot has a sense of the control inputs of the other.
In aircraft with passive side-sticks, on the other hand, they move independently from each other, and do not offer any haptic feedback on what the other pilot is inputting. This can lead to "dual input" situations, which should be avoided {{xref|(see: {{slink||Handling of dual input situations}})}}.
=== Active side-sticks === However a later, significant, development is the "active" side-stick,<ref>{{Cite web|url=https://www.baesystems.com/en/feature/an-active-role|title=Commercial Active Sticks - An Active Role|website=BAE Systems {{!}} International|language=en|access-date=2019-08-10}}</ref> used in the Gulfstream G500/G600 series business jet aircraft. In this system, movements in one side-stick produce the same actions in the other side-stick and therefore provide valuable feedback to the other pilot. This addresses the earlier criticisms of the "passive" side-stick. The active side-stick also provides tactile feedback<ref>{{Cite web|url=https://www.baesystems-ps.com/pdf/active_sticks.pdf|title=BAE Brochure}}</ref> to the pilot during manual flight. In 2015, the three largest avionics manufacturers{{snd}}Honeywell, Rockwell Collins and Thales<ref>{{cite web|url= https://skiesmag.com/news/cockpitsofthefuture/|title= Cockpits of the Future|access-date= 6 February 2021|last= Dubois|first= Thierry |work=Skies magazine |date= 29 June 2015 |archive-url= https://web.archive.org/web/20210206145322/https://skiesmag.com/news/cockpitsofthefuture/|archive-date= 6 February 2021|url-status= live}}</ref>{{snd}}were predicting this would become the standard for all new fly-by-wire aircraft. In 2015, Ratier-Figeac, a subsidiary of UTC Aerospace Systems and supplier of passive side-sticks to Airbus since the 1980s,<ref>https://www.youtube.com/watch?v=3sXXx8rgeeE, How Collins Active Control Sidesticks Work – Aviation International News Aug 13, 2019</ref> became the supplier of active side-sticks for the Irkut MC-21.<ref>https://www.flightglobal.com/mc-21-ushers-active-sidesticks-into-commercial-aircraft-cockpits/116609.article MC-21 ushers active sidesticks into commercial aircraft cockpits By Stephen Trimble 22 April 2015.</ref> This is the first airliner to use them.{{Update inline|date=March 2026|?=yes|reason=article says that parts suppliers were changed after Russian invasion of Ukraine}}
Such an active side-stick can also be used to increase adherence to a safe flight envelope by applying force feedback when the pilot makes a control input that would bring the aircraft closer to (or beyond) the borders of the safe flight envelope. This reduces the risk of pilots entering dangerous states of flight outside the operational borders while maintaining the pilots' final authority and increasing their situational awareness.<ref>{{cite journal |author1=Florian J. J. Schmidt-Skipiol |author2=Peter Hecker |name-list-style=amp |title= Tactile Feedback and Situation Awareness-Improving Adherence to an Envelope in Sidestick-Controlled Fly-by-Wire Aircrafts.[sic] |url=https://www.researchgate.net/publication/299644586 |journal=15th AIAA Aviation Technology, Integration, and Operations Conference|page=2905|year=2015|doi=10.2514/6.2015-2905|isbn=978-1-62410-369-8 }}</ref>
==See also== *Centre stick *Yoke (aeronautics) *Fly-by-wire *Dual control (aviation) *Rudder pedals
===Accidents=== *Air France Flight 447 *Afriqiyah Airways Flight 771 *Armavia Flight 967 *Indonesia AirAsia Flight 8501
==References== {{Reflist}}
==External links== *[http://www.popsci.com/archive-viewer?id=xiADAAAAMBAJ&pg=81 Formation stick] from Popular Science 1945.
{{Aircraft components}}
Category:Design Category:Aircraft controls