L-1011 Flight Controls: Primary Flight Controls Description (27-1)

The L-1011 Flight Controls are basically conventional surfaces which are fully hydraulic powered. There are no "tabs" on any surfaces. The primary flight controls are used to control or steer the aircraft; they are:

• Stabilizer
• Ailerons
• Spoilers
• Rudder

The secondary flight controls are used to improve slow speed performance by increasing lift and drag; they are:

• Flaps
• Slats

Here is a more detailed description of the primary and secondary flight control elements:

The Primary Flight Controls (PFC) consists of the movable surfaces that control the aircraft around the three control axes. These controls are fully hydraulic. Rudder and Aileron Trim is provided by a mechanical means. There are no external Trim Tabs used on any of the control surfaces on the L-1011.

Stabilizer/Elevator 

Pitch control is accomplished by positioning the movable flying horizontal stabilizer. The entire stabilizer and elevator move as a single control unit.

Ailerons 

Like other large jet aircraft, inboard and outboard ailerons are used. A difference is that all four ailerons are full time. The outboard ailerons do not lock out in cruise flight. This feature allows the use of Action Controls (ACS) whereby wing bending is reduced at higher weights by use of symmetrical outboard aileron inputs.

Spoilers 

The twelve Spoiler Panels, six on each wing, perform four functions: They act as speed brakes, augment roll, provide direct lift control (DLC) and serve as automatic ground spoilers.

Rudder 

The Rudder is a single control surface. It operates to provide YAW Stability Augmentation, Full Time Turn Coordination and Runway Alignment during automatic landings as well as the traditional rudder functions.