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Old 27th Jan 2013, 08:22
  #21 (permalink)  
PantLoad
 
Join Date: Jul 2006
Location: USA
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Not really....

Many years ago, specifically with regard to the 737 but applicable to all aircraft, really, Boeing published a document....I can't find it in my library, but I know I had it, I have it somewhere....where it showed that extending flaps/slats to slow the aircraft is not really productive. As I remember, they illustrated a case where the aircraft was high and fast....and three scenarios:

First, the pilots used the normal flap/extension regime, gear down right after Flaps 5.

Second, the pilots extended flaps/slats at Vfe, gear down at Flaps 5.

Third, the pilots used the speed brake and gear for getting where they wanted to be, extending the flaps/slats at the proper speed schedule.

The result showed the third scenario was the most effective.

Unless you go beyond about Flaps 15, you're really getting little additional drag. In fact, you're getting a lot of lift vs. the small increase in drag with the lower flap settings.

So, when you need it, use the gear / speed brakes as applicable. The flaps/slats will be happier. You'll get back to where you want to be on the approach much easier, quicker, with less nail biting.

Fly safe,

PantLoad
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