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I see a lot of planes using thrust reversers and stopping in the middle of the runway in plane spotting videos, but I don't understand why they do it when they can obviously not use the reversers and still stop safely.

Also, doesn't it waste fuel? Don't airlines prioritize fuel savings over stopping faster? Why are reversers used even when they don't need to be used?

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    $\begingroup$ Welcome to aviation.SE! We already have a lot of questions about thrust reversers; this one in particular addresses fuel implications. Do they help? If you're new to the site you might also like to check out the tour. $\endgroup$ – Pondlife Apr 8 at 3:38
  • $\begingroup$ Can you point to some of the videos? Planes really should not stop in the middle of the runway, they should get off it as soon as possible (and safe). Stopping in the middle of the runway will severely screw up the sequencing of the following aircraft. $\endgroup$ – Jörg W Mittag Apr 8 at 7:20
  • $\begingroup$ @Pondlife I didn't mean a complete stop. I mean they came to like 20-30 knots or so $\endgroup$ – Air Canada 001 Apr 9 at 0:09
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There's a lengthy paper on the NASA web site that investigated this. There's a lot of detail covered in that paper so I'm not going to reproduce any of it here, but the main positive points that emerge are:

  • Improved safety margins on landing1
  • Reduced wear on brakes and tyres
  • Reduced brake temperature leading to faster aircraft turn around.

Even when setting this against additional engine maintenance and fuel consumption, the airlines surveyed overwhelmingly considered that the installation and use of thrust reversers gave a worthwhile return on investment.

1 Thrust reversers are not considered when assessing braking systems for certification.

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    $\begingroup$ Another reason, and I suspect the most important one (though I'm not an airline pilot) is that most terminal buildings are located roughly mid-field. Therefore, if you can use thrust reversers and slow down enough to exit the runway near mid-field, you have a short taxi to the gate, saving several minutes, which is good for on-time statistics. Basically the same reason I usually landed my Cherokee rather long when I was based at a commercial field - I could slow, exit, and be right on my FBO's ramp. $\endgroup$ – jamesqf Apr 8 at 4:38
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    $\begingroup$ @jamessqf The author of the paper covered that. See page 6, para. 2: 'The airlines do not promote the practice of a quick egress from the runway to meet scheduled arrival times.' $\endgroup$ – CatchAsCatchCan Apr 8 at 5:57
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    $\begingroup$ I imagine thrust reversers allow many more movements at busy airports. Reversers get airplanes off the runway much faster, allowing ATC to have shorter spacing between approaching airplanes. $\endgroup$ – GdD Apr 8 at 8:06
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    $\begingroup$ @CatchAsCatchCan: There's a difference between saying "airlines do not promote", and pilots doing it anyway. Sort of like police departments insisting that they don't have ticket quotas :-( $\endgroup$ – jamesqf Apr 8 at 16:42

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