Leading Edge Devices
The secondary flight controls, high lift devices consisting of trailing edge (TE)
flaps and leading edge (LE) flaps and slats (LE devices), are powered by
hydraulic system B. Under certain conditions the power transfer unit (PTU)
automatically powers the LE devices. They can also be extended using standby
hydraulic pressure.
LE devices consist of four flaps and eight slats: two flaps inboard and four slats
outboard of each engine. Slats extend to form a sealed or slotted leading edge
depending on the TE flap setting. The TE devices consist of double slotted flaps
inboard and outboard of each engine.
When the FLAP lever is moved from the UP position to the 1, 2, or 5 position, the
TE flaps extend to the commanded position and the LE:
When the FLAP lever is moved beyond the 5 position the TE flaps extend to the
commanded position and the LE:
The LE devices sequence is reversed upon retraction.
Indicator lights on the center instrument panel provide overall LE devices position
status. The LE DEVICES annunciator panel on the aft overhead panel indicates
the positions of the individual flaps and slats.
The secondary flight controls, high lift devices consisting of trailing edge (TE)
flaps and leading edge (LE) flaps and slats (LE devices), are powered by
hydraulic system B. Under certain conditions the power transfer unit (PTU)
automatically powers the LE devices. They can also be extended using standby
hydraulic pressure.
LE devices consist of four flaps and eight slats: two flaps inboard and four slats
outboard of each engine. Slats extend to form a sealed or slotted leading edge
depending on the TE flap setting. The TE devices consist of double slotted flaps
inboard and outboard of each engine.
When the FLAP lever is moved from the UP position to the 1, 2, or 5 position, the
TE flaps extend to the commanded position and the LE:
- Flaps extend to the full extended position and
- Slats extend to the extend position.
When the FLAP lever is moved beyond the 5 position the TE flaps extend to the
commanded position and the LE:
- Flaps remain at the full extended position and
- Slats extend to the full extended position.
The LE devices sequence is reversed upon retraction.
Indicator lights on the center instrument panel provide overall LE devices position
status. The LE DEVICES annunciator panel on the aft overhead panel indicates
the positions of the individual flaps and slats.
