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What Spoilers Do The 747-400 Use In Flight?  
User currently offlineSAAFlight202 From , joined Dec 1969, posts, RR:
Posted (12 years 3 months 1 week 5 days ago) and read 3955 times:

What spoilers do the Boeing 747-400 use to slow it down on descent?

Gian

8 replies: All unread, jump to last
 
User currently offlineFanoftristars From United States of America, joined Jul 2000, 1573 posts, RR: 5
Reply 1, posted (12 years 3 months 1 week 4 days 22 hours ago) and read 3922 times:

the ones on the wings.


"FLY DELTA JETS"
User currently offlineStarship From South Africa, joined Nov 1999, 1098 posts, RR: 16
Reply 2, posted (12 years 3 months 1 week 4 days 22 hours ago) and read 3916 times:

Between the two engines above the wing are a row of outboard spoilers, which are used as air brakes, when they are extended upwards.

The inner set of spoilers between the fuselage and the first engine location are the ground spoilers and are used as lift dumpers.

In addition to the above the 747-400 is equipped with

Inboard Krueger flap segments
Intermediate Krueger flap segments
Outboard Krueger flap segments
Inboard triple-slotted flap segments
Outboard tripple-slotted flap segments
Inboard high speed ailerons
Low-speed ailerons



Behind every "no" is a "yes"
User currently offlineJETPILOT From United States of America, joined May 1999, 3130 posts, RR: 32
Reply 3, posted (12 years 3 months 1 week 4 days 22 hours ago) and read 3895 times:

The 747 has both flight spoilers and ground spoilers.

Flight spoilers are used to increase descent rate without increasing airspeed and also to slow a plane down quickly while maintaining a given altitude. the flight spoiler are the outer spoiler panels. These flight spoilers also serve as ground spoilers when the plane is on the ground

Ground spoilers deploy to spoil lift allowing the full weight of the aircraft to sit on the gear increasing effective braking. The inboard spoilers are the dedicated ground spoilers, and will never deploy in flight.

The outer spoilers work in different combinations and are not dedicated to a single duty.

When the control wheel is moved past a certain point the flight spoilers move asymetrically in proportion with the ailerons through a spoiler mixer in order to increase roll rate.

The same spoilers are deployed symetrically in proportion to the movement of the speed brake handle. in order to slow the plane, or expedite descent.

The outboard flight spoilers can act as flight spoilers while augmenting roll rate by assymetric deplyment while being deployed to slow or increase descent rate. They can do both at once.

One important point. You can either go down or slow down. You can't do both at the same time.

JET



User currently offlineQantasA330 From Iraq, joined Dec 2000, 306 posts, RR: 0
Reply 4, posted (12 years 3 months 1 week 4 days 16 hours ago) and read 3865 times:

These guys answered it pretty well... at UAL we require that the 'air brakes' are only used when absolutely necessary. Due to the fact that using them puts TREMENDOUS pressure (because they are usually used at high speed) on the hydrolics system under the spoilers.

*-422Driver*

User currently offlineJETPILOT From United States of America, joined May 1999, 3130 posts, RR: 32
Reply 5, posted (12 years 3 months 1 week 4 days 16 hours ago) and read 3855 times:

Are you really a UAL -422 Driver?????

JET

User currently offlineQantasA330 From Iraq, joined Dec 2000, 306 posts, RR: 0
Reply 6, posted (12 years 3 months 1 week 4 days 16 hours ago) and read 3848 times:

KIDDING........ but I know a friend whos dad is....

I was just thinking of a screen name for him! Smile
He is gonna join a.net soon if not already which is great!

:::QantasA330:::

User currently offlineQantasA330 From Iraq, joined Dec 2000, 306 posts, RR: 0
Reply 7, posted (12 years 3 months 1 week 4 days 16 hours ago) and read 3846 times:

Let me put that another way SadCause I don't think that I made much sense before)

I am at my friends house (whos dad signed up for a.net about 2 weeks ago-and is a -422 pilot with UAL) - I was teaching him how to use this forum.... my screename was signed in - and he posted the responce under my name, not his by accident  Sad sorry.... but at least we will have a -422 driver on these forums soon (he's not that good with the net yet.... Smile)

Sorry again...
:::QantasA330:::

User currently offlineSAAFlight202 From , joined Dec 1969, posts, RR:
Reply 8, posted (12 years 3 months 1 week 4 days 11 hours ago) and read 3830 times:

Thanks for the great explainations.

Regards

Gian
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