AC_B777
Topic Author
Posts: 723
Joined: Sat Aug 19, 2000 5:15 am

744 Slat Configuration

Fri May 10, 2002 8:50 am

Hey all,

I was looking at the picture below and was wondering about the Kruger flap configuration set for landing.
This KLM 744 has landed with only the outboard Kruger slats deployed. Why would'nt the mid and in-board sections be deployed?
Obviously the a/c is still travelling fairly fast as shown by the spray, and too early to retract the flaps.
What kind of performance would the 744 have in this configuration? Is this a normal practice for KLM or any airlines? I ask because I have never seen a plane land or takeoff with only a partial flap/slat setting.
Thanks.

AC_B777


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In life, some days you are the bug..... some days you are the windshield!
 
hkniceguy
Posts: 128
Joined: Tue Jun 26, 2001 12:53 pm

RE: 744 Slat Configuration

Fri May 10, 2002 10:37 am

On 747-400, inboard Kruger slats will retract when applying reverse during landing, to avoid the structure damage to the slats. This information is from a book about 747-400.
 
hkniceguy
Posts: 128
Joined: Tue Jun 26, 2001 12:53 pm

RE: 744 Slat Configuration

Fri May 10, 2002 10:43 am


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CX Flyboy
Posts: 6007
Joined: Sun Dec 26, 1999 6:10 pm

RE: 744 Slat Configuration

Fri May 10, 2002 10:44 am

That is correct, this can be seen inside the cockpit as an indication. Normally the little flap indicator sign is marked 25 or 30 (As appropriate) and is in green, indicating the flaps are in position. Select reverse on the ground and the indication will turn magenta coloured, indicated not all flap groups are in the right position they should be. When reverse is deselected, the indication turns green again, as the leading edge extends again (Only for you to put them back in again!).
 
AC_B777
Topic Author
Posts: 723
Joined: Sat Aug 19, 2000 5:15 am

RE: 744 Slat Configuration

Fri May 10, 2002 10:54 am

Huh, I never noticed that before.
Thanks for the info guys.

AC_B777
In life, some days you are the bug..... some days you are the windshield!
 
Mr.BA
Posts: 3310
Joined: Sun Sep 24, 2000 12:26 pm

RE: 744 Slat Configuration

Fri May 10, 2002 2:56 pm

Cxflyboy:

Sorry I didn't really get you there. You mean it's normal for the middle slats and inboard slats not to extend and only to extend after retracting reverse thrust on the ground? (Flaps 25/30 both have slats extended?) Wonder why the slats don't extend? Thanks a lot for the further explanation.
Boeing747 万岁!
 
AJ
Posts: 2295
Joined: Wed Nov 03, 1999 3:54 pm

RE: 744 Slat Configuration

Fri May 10, 2002 7:29 pm

The aircraft has Flap 25 or 30 set for landing, including all leading edge flaps extended. The flight deck indication is a green line at 25 or 30. When the reverse thrust levers are raised to the interlock the inboard and midspan leading edge flaps retract whilst the engine reverser system is activated, giving a magenta line on the flap indicator (Boeing code for commanded but not yet reached). After the reversers are stowed the leading edge flaps redeploy giving a green indication.
 
Mr.BA
Posts: 3310
Joined: Sun Sep 24, 2000 12:26 pm

RE: 744 Slat Configuration

Fri May 10, 2002 11:49 pm

Thanks AJ... but any explanation to why the inboard and middle slats retract when the reverse is activated?

Cheers
Boeing747 万岁!
 
hkniceguy
Posts: 128
Joined: Tue Jun 26, 2001 12:53 pm

RE: 744 Slat Configuration

Sat May 11, 2002 12:56 am

Mr.BA: Is to avoid the structure damage to the slats when applying reverse. Becoz the oppsite thrust effect on the slats area very strong, the slats will damage if it's not retract
 
aerosol
Posts: 497
Joined: Mon Oct 23, 2000 10:31 pm

RE: 744 Slat Configuration

Sat May 11, 2002 1:09 am

I have flown on a Boeing 744 of LH (FRA-HKG); during approach the middle slats were retracted. No Idea why this was, never seen that before.
 
A388
Posts: 7157
Joined: Mon May 21, 2001 3:48 am

RE: 744 Slat Configuration

Sat May 11, 2002 1:27 am

I didn't even notice this, nice to know and thanks  Smile/happy/getting dizzy
 
AC_B777
Topic Author
Posts: 723
Joined: Sat Aug 19, 2000 5:15 am

RE: 744 Slat Configuration

Sat May 11, 2002 3:28 am

Hey guys,

Thanks for the info, but I was wondering is this feature only found on the 744 or is it on all series of the 747?
If it is only on the 744, then what would the difference be from all other series? Does the 744 engines have different characteristics than the 741, 742 and 743 when it comes to reverse thrust?
Here is a picture of a Orient Thai 742 in reverse and the Kruger flaps are still deployed.

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Photo © Kok Chwee SIM


I'm scratching my head on this one.

AC_B777
In life, some days you are the bug..... some days you are the windshield!
 
Mr.BA
Posts: 3310
Joined: Sun Sep 24, 2000 12:26 pm

RE: 744 Slat Configuration

Sat May 11, 2002 10:06 am

Was at the airport yesterday. Noticed this no all the landing B744s except the classics. Would be interested to know why too! Thanks!

Boeing747 万岁!
 
Mr.BA
Posts: 3310
Joined: Sun Sep 24, 2000 12:26 pm

RE: 744 Slat Configuration

Sat May 11, 2002 10:06 am

Sorry I meant on not no.
Boeing747 万岁!

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