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Old 20th May 2007, 10:59
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PantLoad
 
Join Date: Jul 2006
Location: USA
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Not really...

Telstar,

Next couple of times this happens to you, try to experiement. I think you'll find that the first few increments of flaps/slats add very little drag, and the only thing you're accomplishing is beating up the flaps/slats and the passengers.

This is mainly why Boeing states this is not recommended. You're not really helping yourself. (What you want and need is drag...and you're not getting it with low flap settings.) Boeing has a publication somewhere (I remember reading it years ago.) about energy management in descents. If you can get your hands on this, it'll explain a lot.

The best way to 'slam-dunk' is with gear and speedbrake....keep your speed up a bit. It'll drop like a rock. The other alternative is to grit your teeth, slow up and work out your flaps, then gear, then more flaps (extend flaps on the normal schedule), until you get to approach speed plus a bit. Once you have full flaps, gear, idle thrust, you'll find the thing will come down nicely. (The trick is to be patient while you get to this configuration.) Of course, you must be careful to arrest the sink rate and be spooled at the proper time.

The idea of not using flaps/slats as a speedbrake applies to most airplanes. Again, it's drag you want and need, but flaps/slats don't give you what you need...unless you have everything hanging out.


Fly safe...


PantLoad
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