Secondary Flight Controls

Secondary Flight Controls

1. Used to change lift, drag and trim

2. Consist Of

   • Lift Devices
   • Trim Devices

3. Lift Devices

   • Lift devices are:
     • Slats (Leading edge devices)
     • Flaps (Trailing edge devices)
     • Speed brakes
   • Speed Brakes
     • Increase drag and decrease lift
     • Operated symmetrically on each wing
   • Flaps & Slats
     • Used to increase lift for low speed flight
     • Flap extension increases wing area and camber
     • Both devices work together
   • Flaperons
     • Present on some aircraft types
     • Usually work as ailerons
       • When flaps extended down, flaperons deflected down symmetrically
         • Increases flap area
         • Known as Aileron Droop Function

4. Trim Devices

   • Roll, pitch and yaw systems
   • Compensate for imbalance of the aircraft
   • Trim-able Horizontal Stabilzer
     • Compensates for imbalance along the longitudinal axis
     • Pitch trim
     • Required because of greater possible imbalance around pitch axis
   • Ailerons
     • Roll trim
   • Yaw
     • Yaw trim

5. Basic Flight Control System

   • Control inputs
   • Control transmissions
     • Control runs which transmit inputs throughout the airframe
   • Control surface outputs

6. Mechanical Cockpit Controls

   • Control columns
     • Operate elevators
   • Control wheels
     • Operate ailerons and roll spoilers
   • Rudder pedals
     • Operate rudder

7. Combined Control Inputs

   • Ruddervators need a mixer unit
     • Combines control inputs from control column and rudder pedals
     • Mixer is mechanical on conventional aircraft

8. Side Stick Input

   • Fly by Wire
   • Operate primary flight controls
   • Left and right operates ailerons
   • Forward and back operates elevators

9. Secondary Flight Control Inputs

   • Located on the pedestal
   • Speed brake lever operate speed brakes
   • Flap lever controls both slats and flaps
   • Pitch trim wheels trim horizontal stabilizer
   • Aileron trim switch changes neutral position of ailerons
   • Rudder trim siwtch changes neutral position of the rudder
   • Control runs transmit pilot input to flying control surfaces