Whazzat #7

When seated where you have a good view of the wing you will see little flapper things that come up from the top of the wing. These are generally called “spoilers”. They are intended to spoil the lift from part of the wing.  They also increase drag and help to slow the airplane down.  In the air only some of them are used and they don’t move all the way up.

When the ailerons are deflected  (a turn is started) the spoiler on the “low” wing will come up a little. This increases the roll rate of the airplane and makes it more sensitive to control input.  Since big airplanes handle a lot like a U-Haul truck  this is a good thing.

When descending you may occasionally notice the spoilers are extended for a period of time. This generally  indicates that the pilot is trying to get down more quickly than originally planned.  Getting down is something pilots always do.

Even a good plan needs to be flexible and sometimes we even forget to start down when we should. An unexpected tailwind can also put the airplane closer to an altitude restriction point than planned. When this happens the spoilers or “speed brakes” help a little to catch up but  Boeing airplanes (especially the 737)  are notorious for  just rumbling a little and not slowing down much.

Just after touchdown all of the spoilers extend fully. This helps to spoil most of the lift and puts weight on the wheels to make the brakes effective. Effective brakes are a good thing on a short wet runway.

Reverse thrust from the engines also helps to slow and stop the airplane but takes a while to become effective, that’s another story.

Happy Landings

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2 Responses to “Whazzat #7”

  1. Oh 🙂 you made me remember when I was a child in Ushuaia (Argentina) and returned from vacation, the 737-200 plane would as soon as she touched land deploy immediately all of their plates full open and the engines dismantled in two halves in what seemed a desperate attempt at slowing down before running out of runway. Our faces were stomped to the forward seats and when the scary thing ended we released our breath and explode in applause :). Those were the times!!

    The airport was SAWO and the runway is about 1650 meters with sea at both ends, I think it was just enough to handle the 737-200. 🙂

    Dani.

  2. The 737 is a great airplane for “short field” operations. The older versions like the -200 had noisier engines than the current “next generation” airplanes and they would shake a lot when stopping. The brakes work great though.

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