Editing Thrust reversal (section)

==Effectiveness==
[[File:American Airlines N928AN wet landing at Tampa International Airport.jpg|thumb|An [[American Airlines]] [[Boeing 737 Next Generation|Boeing 737-800]] thrust-reversing on a wet runway.]]
The amount of thrust and [[Power (physics)|power]] generated are proportional to the speed of the aircraft, making reverse thrust more effective at high speeds.<ref name="Croucher2004 JAR">{{cite book|author=Phil Croucher|title=JAR Professional Pilot Studies|url=https://books.google.com/books?id=KY-MBUeQoZEC&pg=SA3-PA23|access-date =11 July 2013|date=1 March 2004|publisher=Lulu.com|isbn=978-0-9681928-2-5|pages=3–23}}{{self-published source|date=June 2022}}</ref>{{self-published inline|date=February 2020}} For maximum effectiveness, it should be applied quickly after touchdown.<ref name="Airplane handbook2011" /> If activated at low speeds, [[foreign object damage]] is possible. There is some danger of an aircraft with thrust reversers applied momentarily leaving the ground again due to both the effect of the reverse thrust and the nose-up pitch effect from the [[Air brake (aircraft)|spoilers]]. For aircraft susceptible to such an occurrence, pilots must take care to achieve a firm position on the ground before applying reverse thrust.<ref name="Croucher2004 JAR" /> If applied before the nose-wheel is in contact with the ground, there is a chance of asymmetric deployment causing an uncontrollable [[Aircraft principal axes#Vertical axis (yaw)|yaw]] towards the side of higher thrust, as steering the aircraft with the nose wheel is the only way to maintain control of the direction of travel in this situation.<ref name="Airplane handbook2011" />

Reverse thrust mode is used only for a fraction of aircraft operating time but affects it greatly in terms of [[Aircraft designer|design]], weight, [[Aircraft maintenance|maintenance]], performance, and cost. Penalties are significant but necessary since it provides stopping force for added safety margins, directional control during landing rolls, and aids in rejected take-offs and ground operations on contaminated runways where normal braking effectiveness is diminished. Airlines consider thrust reverser systems a vital part of reaching a maximum level of [[Airplane safety|aircraft operating safety]].<ref name="AsburyYetter2000 NASA">{{cite book|author1=Scott C. Asbury|author2=Jeffrey A. Yetter|title=Static Performance of Six Innovative Thrust Reverser Concepts for Subsonic Transport Applications: Summary of the NASA Langley Innovative Thrust Reverser Test Program|url=https://books.google.com/books?id=5znGWg08V7oC|access-date=10 July 2013|year=2000|publisher=Diane Publishing|isbn=978-1-4289-9643-4|pages=1–2}}</ref>