View source for Jettison (aviation)

{{short description|Aviation procedure}}
[[File:BA0025 G-CIVX Fuel Jettison 2.JPG|thumb|Fuel being dumped (jettisoned) from the left wing tank of [[Boeing 747-400]]]]
In aviation, to '''jettison''' is to discard fuel, external stores or other expendable items.<ref name="gunston">{{cite book|last=Gunston|first=Bill|title=Jane's Aerospace Dictionary|publisher=Jane's Publishing|location=London|date=1986|isbn=0 7106 0365 7}}</ref><ref name="Crane">Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 292. Aviation Supplies & Academics, 1997. {{ISBN|1-56027-287-2}}</ref> The item is usually jettisoned by operating a switch or handle; external stores may be separated from the aircraft by use of [[explosive bolts]] or a mechanism.

== Fuel jettison ==
{{Main|Fuel dumping}}
:Fuel jettisoning or fuel dumping is an emergency procedure used by crews to reduce the weight of an aircraft in an emergency when the aircraft has reached its maximum landing weight.<ref name="Crane" />

== External stores jettison ==
:Some military aircraft can carry weapons (for example bombs or rockets) and [[drop tank|fuel tanks]] on external [[hardpoint]]s. The pilot can jettison them if necessary, so they do not inhibit actions during [[Air combat manoeuvring|combat]] or in an emergency. Airports may establish specific safe areas for the jettison of external stores, when required.<ref name="FAA">{{cite web|url= https://www.faa.gov/air_traffic/publications/atpubs/atc_html/chap9_section_5.html|title= Jettisoning of External Stores|access-date= 15 July 2022|author = Federal Aviation Administration|author-link = Federal Aviation Administration |work= faa.gov|archive-url= https://web.archive.org/web/20220120195822/https://www.faa.gov/air_traffic/publications/atpubs/atc_html/chap9_section_5.html|archive-date= 20 January 2022|url-status= live}}</ref><ref name="AV">{{cite web|url= https://theaviationist.com/2019/06/29/watch-the-moment-an-indian-jaguar-has-a-bird-strike-jettisons-weapons/|title= Watch the Moment an Indian Air Force Jaguar Jet Has a Bird Strike, Jettisons External Loads.|access-date= 15 July 2022|last= Demerly|first= Tom|work=theaviationist.com |date= 29 June 2019|archive-url= https://web.archive.org/web/20210724051126/https://theaviationist.com/2019/06/29/watch-the-moment-an-indian-jaguar-has-a-bird-strike-jettisons-weapons/|archive-date= 24 July 2021|url-status= live}}</ref>
<gallery widths="220" heights="165">
File:Drop tank.jpg|A {{convert|330|USgal|L|-capacity|lk=on|adj=mid}} [[Sargent Fletcher]] drop tank being moved across the flight deck of an aircraft carrier
File:JDAM GBU30 MER.jpg|Three GBU-31 [[JDAM]] precision guided bombs on a triple-ejector rack, under the wing of a [[Boeing B-52 Stratofortress|B-52]]
</gallery>{{clear}}

== Other ==
:Some aircraft may jettison components for various other reasons, for example slip-wing aircraft such as the Hillson F.H.40 that discards the upper wing after take off.<ref>https://militarymatters.online/forgotten-aircraft/the-hillson-fh-40-slip-wing-hurricane/</ref><ref>https://planehistoria.com/hillson-fh-40-hurricane/</ref>
<gallery widths="220" heights="165">
File:Hillson Bi-mono 3view.svg|[[Hillson Bi-mono]] with slip-wing. The aircraft could take off as a biplane, [[Jettison (aviation)|jettison]] the upper, disposable wing, and continue flying as a monoplane. A single example was built, which successfully demonstrated jettisoning of the slip wing in flight
</gallery>{{clear}}

==See also==
*[[Fuel dumping]]

==References==
{{Reflist}}

[[Category:Emergency aircraft operations]]
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