1. Cessna Citation II Flight Controls
Dr. Kurt Barnhart
AST 473

2. Flight Controls Overview Primary Flight Controls Ailerons Rudder
Elevator
-Manually actuated by rudder pedals and control column
-Can be immobilized by control locks on ground
-Mechanical Trim in all three axis + elec. Elev. trim

3. Flight Controls Secondary Flight Controls- Electric flaps
Hydraulic speedbrakes
-Stall Warning- stall strip on leading edge of each wing- aerodynamic buffet
-Yaw damping- autopilot

4. Flight Controls
General- control inputs are transmitted via cables and bellcranks
Rudder pedals are 3 position adjustable via a spring latch on rudder pedals-side
Fences on inboard edge of rt. Aileron and inboard edge of left aileron trim tab- air ailerons in returning to neutral

5. Flight Controls
Rudder, rt. Elevator and left aileron- mechanical trim tabs actuated from cockpit
Pilot’s and co-pilot’s (optional) cnt’l wheel have a pitch trim switch
Control locks- on primary flight controls and throttles- operated from cockpit:
Neutralize controls & idle throttles
Rotate handle (CW) 45 deg. & pull until handle returns to horizontal- to release- rotate CCW & push in until horizontal- DO NOT TOW WHEN LOCKED!

6. Flight Controls
Trim systems- standard mechanical- cockpit actuated & indicated
Rudder trim- only servo tab on aircraft- deflects at half rate of rudder- aids pilot movement
Elec. Trim- outboard horn of ea. cnt’l wheel- pilot’s inputs overrides co-pilots
AP/TRIM DISC on cont’l wheel or pulling PITCH TRIM CB- controls runaway trim

7. Flight Controls Secondary control
Fowler flaps- 0 – 40 deg., mechanically interconnected- prevents flap asymmetry and allows operation by one elec. Actuator
Speedbrakes- slotted panels on top & bottom of ea. Wing fwd. of flaps:
Used for increased descent rates
Increased drag and lift destruction on lndg.

8. Flight Controls Flaps- Detented @ 15 deg. Position (T/O & lndg.)
Handle movement actuates switch- energizes two motors- position mechanically indicated on cockpit
Motors interconnected mechanically & actuated mechanically- normally operate in unison but one motor provides sufficient for normal operation

9. Flight Controls Flap Operation-
Moving flap handle- activates 1 of 2 switches in center pedestal- supplies pwr. To motors
At selected position- position indicator mechanically repositions cnt’l sw. to remove pwr. From motors
Mechanical drag- holds flaps in position
Limit sw.- prevent overrun up or down
No D.C.- N Flaps- fail in position
Travel time- 6 sec. 0 -full down, 3 sec. back

10. Flight Controls Speedbrakes- 2 positions- up & down 2 hyd. Actuators
Solenoid valve
4 speedbrake segments
SPD BRAKE EXTENDED annunciator
Pedestal control switch

11. Flight Controls Speedbrake Operation:
Placing speedbrake sw. in EXTEND-
Closes hyd. Bypass valve (HYD. PRESS ON lt.)
Energizes speedbrake solenoid valve- press. To speedbrakes- forces them out of mech. Downlocks
Safety valve- also closed
2 position switch- spring loaded to retract- (can be held ext. above 85% N(2)- early models only)
At full travel press. Builds, bypass valve opens, annunciator goes out- solenoid valve neutralizes- trapping hyd. Press in actuators- holding extension

12. Flight Controls Speedbrake Retraction- Place switch in retract
Hyd. Sys. Pressurizes
Safety valve opens (de-energizes)
Solenoid valve directs press. For retraction
Annunciator goes out- “Boards” retract into mechanical locks- system depressurizes
Locks- 2 pins on lower board panel- hydraulically forced into retaining clips.

13. Flight Controls
Most models- if throttles above 85% N(2)- solenoid valve and bypass valve position for retraction
Safety valve- if elec. Failure w/ boards out- spring loads open- allows boards to blow down
If elec. Failure w/ boards retraction- no actuation possible

14. Flight Controls
Stall Warning- stall strip on leading edge of ea. Wing for aerodynamic buffet
Buffet- VS(1) +10 (clean) and VSO + 5 (dirty)

15. Flight Controls Yaw Damping- function of autopilot
Consists of automatic application of rudder against transient motion in YAW
YD automatically engaged w/ autopilot
Not required for flight
Can be engaged w/o autopilot by pushing YD ENGAGE sw. on autopilot
Disengaged by pressing AP/TRIM DISC on cnt’l wheel

16. THE END