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I was on a flight today and I noticed that as we were approaching to land, the plane drastically reduced its speed for few seconds and then regained its speed.

Can somebody tell me why?

Federico
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gucci
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    Speed is very difficult to observe from the passenger compartment. What makes you think you reduced speed and then regained it? Perhaps your question is answered here: If airplanes can't use reverse thrust in flight, what am I hearing? – DeltaLima Jun 19 '19 at 11:43
  • Possible duplicate of If airplanes can't use reverse thrust in flight, what am I hearing? – DeltaLima Jun 19 '19 at 11:48
  • You mean that G forces moved you forward, then back into your seat? – John K Jun 19 '19 at 11:53
  • Even a sim can create this perception when you are sitting inside a box bolted to the ground and connected to hydraulic actuators. – Juan Jimenez Jun 19 '19 at 12:19
  • Fun read: https://en.wikipedia.org/wiki/Sensory_illusions_in_aviation – Sanchises Jun 19 '19 at 13:35
  • Recently I was on an A320 that on final approach, not even 500’ AGL, suddenly pitched up sharply, sank, went to TO/GA power (you could hear the engines chainsawing), slammed the nose back down, and rolled back the engines. I knew about the extreme pitch-up because I was looking out the window and had a clear visual reference for pitch. But if I hadn't, and was only going by gee forces, I could have mistaken that for dramatically slowing down and speeding up. – Harper - Reinstate Monica Jun 19 '19 at 16:02
  • Wind shear? Have no experience of this in commercial aircraft, but in SEL it's not uncommon to encounter changing winds, and add throttle and/or pitch down to counter them. – jamesqf Jun 19 '19 at 17:03
  • Very interesting question:The inertia of the aircraft prevents the spoilers to reduce drastically in few seconds the speed of the aircraft, that’s typically a gust effect; the regain in speed is natural because the gust may change suddenly its direction, but the later speed increase could result too from the pilot who decided by precaution to increase the thrust suspecting a kind of slight wind shear. – – user40476 Jun 19 '19 at 20:21
  • Could be the tiltback from the landing flare – Koyovis Jun 19 '19 at 23:30
  • @user40476 Hi i am a actually new to the aviation world so do you all have any resources or any links where i can learn all the things related to aviation and aircrafts . I am very entgusiastic about aviation and i would appreciate it greatly if you all could help me out – gucci Jun 20 '19 at 14:35

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Your question uses the adverb "drastically". It's very unlikely that whatever happened was drastic. When an airliner does something drastic, it's a pretty memorable experience. In the absence of visual cues, some other sensations can be magnified in our experience, so it's quite possible that any change was less extreme than it seemed to be.

Sometimes, the plane is actually slowing down and speeding up. This could be in response to an air traffic control instruction, a not-quite-right adjustment that needs to be corrected, changes in local wind condition and so on.

It could also be that the plane needed a little adjustment after intercepting the glide-slope.

At this stage of its flight, the crew many need to respond to many different kinds of factors in its environment.

However, just because you had sensations of speeding up or slowing down doesn't mean that that is actually what happened. Changes in pitch can also produce these sensations, especially when combined with changes in engine sound.

In short, if that did actually happen, it could be for all kinds of reasons, but just as likely, it was an illusion.

Daniele Procida
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