747 split spoilers

[Guest kyle joseph]

hi againmy FS is down after a hard drive crash so I have had some time to point out some things within fsI was wondering if this was just a limitation for the 747 for some reason or maybe it was forgotton or who knows...upon landing the 747's spoilers retract with the inner two outboard spoilers ahead of the outer twousually it is a split second lagbut sometimes it can last as long as two secondshas anybody else noticed thishttp://www.flightlevel350.com/Aircraft_Boe...Video-8037.htmlthat is a clear representation of what I am talking aboutthey retract the same way tooand how come the wings bounce when the flaps are raised and lowered?? while in the air

[Guest ssf]

I have seen this but all I can think of is that most of this has to do with the auto brakes settings.

[scandinavian13 5,192]

The slats are automatically retracted when reverse thrust is activated in order to avoid potential damage from the reverse thrust. You'll note it isn't until the cowlings begin to open that the slats begin to retract in the video you provided. This almost caused an accident in the case of a British Airways 744 a while ago because the logic (to retract the spoilers) faulted and retracted the slats on takeoff. Because the logic is inhibited in the air, the spoilers re-deployed, but the crew made the right decisions in between to keep the aircraft in the air.As far as the bouncing goes, can you be more specific?If you're talking about the wing flex/oscillations in the video that are more noticeable on final approach, my guess would be the wake generated by the flaps is causing a buffet in the air, which is disturbing the air over the outboard section of the wing. Also, keep in mind that the pilot could be pretty active on the controls during final approach, making minute adjustments to the flight path to hit the centerline. Because of this, the outboard ailerons are pretty active. When the ailerons move, torque is applied to the wing. Most of this torque is what rolls the aircraft, while some of the torque is lost in the flexibility of the wing, shown in a movement of the wing in the direction of the roll. Make a few corrections to the left and right and you'll get an oscillation. It's a loose and over-simplified version of what really happens, but I'm trying to describe it less on the aerodynamic principle and more on the background physics.