Editing Thrust reversal (section)

===In-flight operation===
[[File:C17 Reverse Thrust.JPG|thumb|right|A [[vortex]] made visible as powerback is used on a [[Boeing C-17 Globemaster III]]]]
Some aircraft, notably some Russian and [[Soviet aircraft]], are able to safely use reverse thrust in flight, though the majority of these are propeller-driven. Many commercial aircraft, however, cannot. In-flight use of reverse thrust has several advantages. It allows for rapid deceleration, enabling quick changes of speed. It also prevents the speed build-up normally associated with steep dives, allowing for rapid loss of [[altitude]], which can be especially useful in hostile environments such as combat zones, and when making steep approaches to land.{{Citation needed|date=July 2013}}

The [[Douglas DC-8]] series of airliners has been certified for in-flight reverse thrust since service entry in 1959. Safe and effective for facilitating quick descents at acceptable speeds, it nonetheless produced significant aircraft buffeting, so actual use was less common on passenger flights and more common on cargo and ferry flights, where passenger comfort is not a concern.<ref>{{Cite web|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19950022395.pdf|title=NASA Technical Reports Server (NTRS)|date=June 1995|last1=Hamid|first1=Hedayat U.|last2=Margason|first2=Richard J.|last3=Hardy|first3=Gordon|access-date=2017-07-07|archive-date=2020-02-01|archive-url=https://web.archive.org/web/20200201022240/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19950022395.pdf|url-status=live}}</ref>

The [[Hawker Siddeley Trident]], a 120- to 180-seat airliner, was capable of descending at up to 10,000&nbsp;ft/min (3,050&nbsp;m/min) by use of reverse thrust, though this capability was rarely used.

The [[Concorde|Aerospatiale-BAC Concorde]] supersonic airliner could use reverse thrust in the air to increase the rate of descent.  Only the inboard engines were used, and the engines were placed in reverse idle only in [[subsonic flight]] and when the aircraft was below {{cvt|30,000|ft|m}} in altitude. This would increase the rate of descent to around {{cvt|10,000|ft/min|m/min}}.{{Citation needed|date=January 2010}}

The [[Boeing C-17 Globemaster III]] is one of the few modern aircraft that uses reverse thrust in flight. The Boeing-manufactured aircraft is capable of in-flight deployment of reverse thrust on all four engines to facilitate steep [[Tactical descent|tactical descents]] up to 15,000&nbsp;ft/min (4,600&nbsp;m/min) into combat environments (a descent rate of just over 170&nbsp;mph, or 274&nbsp;km/h). The [[Lockheed C-5 Galaxy]], introduced in 1969, also has in-flight reverse capability, although on the inboard engines only.<ref>{{cite web|url=http://foxtrotalpha.jalopnik.com/what-it-is-like-to-fly-the-americas-biggest-jet-the-ga-1727650088|title=What It's Like To Fly America's Biggest Jet, The Gargantuan C-5 Galaxy|first=Tyler|last=Rogoway|website=jalopnik.com|date=31 August 2015|access-date=3 April 2018|archive-date=1 February 2020|archive-url=https://web.archive.org/web/20200201013735/https://foxtrotalpha.jalopnik.com/what-it-is-like-to-fly-the-americas-biggest-jet-the-ga-1727650088|url-status=live}}</ref>

The [[Saab 37 Viggen]] (retired in November 2005) also had the ability to use reverse thrust both before landing, to shorten the needed runway, and taxiing after landing, allowing many Swedish roads to double as [[Highway strip|wartime runways]].

The [[Shuttle Training Aircraft]], a highly modified [[Grumman Gulfstream II]], used reverse thrust in flight to help simulate [[Space Shuttle]] aerodynamics so astronauts could practice landings. A similar technique was employed on a modified [[Tupolev Tu-154]] which simulated the Russian [[Buran (spacecraft)|Buran]] space shuttle.{{Citation needed|date=July 2013}}