On the real -800/900 (non ER/ non SFP) the slats extend to full drag when flaps 15 is selected, not flaps 10. But on the NGX the slats extend to full drag when flaps 10 is selected (which would be correct for the -600/700). Isn't this inaccurate for the -800/900? Please correct me if I'm wrong... Mitch Bowman

Completely wrong. 1,2,5 slats extended (they are not drag devices, slats are provided to increase lift, not the drag. The flaps when extended increase lift and drag.)10 and more full extended. This on normal 737s, same for the old series.

Completely wrong. 1,2,5 slats extended (they are not drag devices, slats are provided to increase lift, not the drag. The flaps when extended increase lift and drag.)10 and more full extended. This on normal 737s, same for the old series.

Slats are used to increase lift for certain flap settings and to increase drag for the others. When the slats are fully extended the position is actually called "low drag position". On the FS9 PMDG 737, the slats extended to FULL EXT at flaps 15 for the -800/-900 and at flaps 10 for the -600/-700. maybe that's why im confused abotut the NGX. Maybe it was wrong on the FS9 version, maybe it's wrong on the FSX version, that's what im trying to find out. Mitch Bowman

The leading edge (LE) flaps and slats increase the wing area and the wing camber. This increases lift to help improve the takeoff and landing performance of the airplane.

Functional DescriptionThe LE flaps have two positions: retract and extend. The LE flaps are at the retract position when the flap lever is in the 0 detent. The LE flaps are at the extend position when the flap lever is at any other detent.The LE slats have these three positions:RetractExtendFull extend.The LE slats are at the retract position when the flap lever is in the 0 detent. The LE slats are at the extend position when the flap lever is in the 1, 2, or 5 detents. The LE slats are at the full extend position when the flap lever is in the 10, 15, 25, 30, or 40 detents.Training

The only "drag" LE devices are the krueger flaps that are inboard of the wing. ;)Remember that slats goes from extended to full extended if approaching stall, they must create less drag than possible. The main purpose of the slats are to restore the airflow on the dorsal side of the wing.

As far as I can remember, in my old lessons about it, the only 737s in the series wich have a different slat extension are the 100-200.I worked starting from the 200ADV that already had the system of the classic/NG.The SFP changes the setting (memory of my old lessons) to extend slats to full extend at flaps 25Maybe I could not remember correctly all, but something similar about the short field package.

Slats are used to increase lift for certain flap settings and to increase drag for the others. When the slats are fully extended the position is actually called "low drag position". On the FS9 PMDG 737, the slats extended to FULL EXT at flaps 15 for the -800/-900 and at flaps 10 for the -600/-700. maybe that's why im confused abotut the NGX. Maybe it was wrong on the FS9 version, maybe it's wrong on the FSX version, that's what im trying to find out. Mitch Bowman

The NGX Version is correct.

They allow for a slower takeoff and landing speed by preventing the airflow over wing from separating at higher AOA. The higher AOA, creates more lift.