L-1011 Flight Controls: Direct Lift Control (DLC) (27-39)

Spoilers 1, 2, 3, and 4 are used for Direct Lift Control (DLC). The spoilers are driven automatically through the DLC/AGS servo. Here is the DLC engage logic:

• Flaps are set to more than 30º
• At least two throttles are below MCT
• At least two for the throttles are not in reverse. 
• There is no Airplane On Ground (AOG) signal received 
• The airplane is not in go-around mode 
• There is no stall warning 
• The DLC/AGS channels are powered and OK 

The DLC servo that controls spoiler panels 1, 2, 3 and 4 assists in pitch control by reducing the amount of pitch attitude change required to peek the airplane in the "slot" once landing flaps are selected. DLC servo inputs cause the spoilers to travel thereby increasing or reducing lift.

The spoiler handle located on the throttle quadrant follows all DLC inputs providing an indication to the crew of system operation.

L-1011 Flight Controls: Spoiler Roll Assist (27-38)

When the Flaps on the L-1011 are set to 4º or more, spoilers 2, 3, 4, 5 & 6 assist roll on the up aileron or down wing in the turn. Travel can be as much as 40º up on the spoiler for roll assist. What's important to remember is that the spoilers are up with the aileron. They are dwelled or silent on the other wing. 

L-1011 Flight Controls: Spoiler System (27-35)

The Lockheed L-1011 has six flat panels on each wing forward of the flaps. The panels hare hinged on the forward end and are driven up into the airstream by a single hydraulic actuator for each panel. The panels are numbered 1 to 6 from the fuselage toward the wing tip.

Here are the spoiler ranges for various flight conditions:

Flaps-Up - Speed Brakes
1 2 3 4 5 6
20º 30º 30º 60º 60º 60º

Flaps 4º to 33º - Speed Brakes 
1 2 3 4   5 6
N/A 60º 60º 60º 60º 60º

Roll Augmentation 

1 2 3 4 5 6

N/A 40º 40º 40º 40º 40º

Direct Lift Control (DLC)

1 2 3 4 5 6

10º 10º 10º 10º N/A N/A

Auto Ground Spoiler 

1 2 3 4 5 6

60º 60º 60º 60º N/A N/A

The spoilers have four modes of operation. They are:

1. speed brakes flaps up which are conventional
2. roll augmentation to assist aileron when flaps are extended
3. DLC during approaches and 
4. Automatic Ground Spoilers which operate on landings and rejected takeoffs. 

The System comprises of a speed brake lever either manual or boosted through ta DLC/AGS servo powered by hydraulic systems A and B. 

From the lever and servo, cable runs and roll systems deliver pilot or servo inputs to units called mixers located in the wheel wells. The mixers receive flap position and aileron position inputs and thereby shift accordingly setting up linkages causing the spoiler panels 2, 3 and 4 to work in the various modes. 

Another pair of right and left units called selectors located on the rear spars just inboard of the outboard ailerons receive pilot, flap and aileron inputs and schedule spoiler 5  and 6 right and left respectively from their two modes of operation. Number 1 spoiler control linkage is a bit different in that it uses a solid controller cable for inputs which cause it to work in its two modes.