1. PRINCIPLES OF FLIGHT
CHAPTER 4
CONTROLS

2. CONTROLS TO MAKE THE AIRCRAFT DO WHAT THE PILOT
PRINCIPLES OF FLIGHT
CONTROLS
TO MAKE THE AIRCRAFT DO WHAT THE PILOT
REQUIRES, THE PILOT MUST HAVE A MEANS
OF CONTROL OF THE AIRCRAFT.
THREE MAIN CONTROLS ARE PROVIDED :-
ELEVATORS
AILERONS
RUDDER
THEIR FUNCTION IS TO MOVE THE AIRCRAFT
ABOUT IT’S 3 AXIS.

3. PRINCIPLES OF FLIGHT
Elevators
Rudder
Ailerons

4. THE PILOT USES THESE CONTROLS TO MAKE THE AIRCRAFT MOVE IN : -
PRINCIPLES OF FLIGHT
THE PILOT USES THESE CONTROLS TO MAKE
THE AIRCRAFT MOVE IN : -
PITCH – WHERE THE NOSE OF THE
AIRCRAFT RISES (PITCHING UP)
OR FALLS (PITCHING DOWN).
CONTROL USED - ELEVATORS
ROLL - WHEN ONE WING RISES THE
OTHER WING FALLS. RIGHT WING
DOWN IS ROLLING RIGHT.
CONTROL USED - AILERONS
YAW - WHEN THE NOSE OF THE AIRCRAFT
MOVES LEFT (LEFT YAW) OR RIGHT
(RIGHT YAW).
CONTROL USED - RUDDER

5. PITCHING, ROLLING AND YAWING IS ALWAYS DESCRIBED RELATIVE TO THE
PRINCIPLES OF FLIGHT
MOVEMENT
PITCHING, ROLLING AND YAWING IS
ALWAYS DESCRIBED RELATIVE TO THE
PILOT RATHER THAN THE HORIZON.
PILOT RATHER THAN THE HORIZON.
THE PITCHING PLANE
PILOT USES ELEVATORS
ELEVATORS ARE USUALLY TWO
MOVEABLE PARTS HINGED TO THE
TRAILING EDGE OF THE TAILPLANE.
THEY ARE LINKED TO THE PILOT’S
CONTROL COLUMN.

6. MOVING THE CONTOL COLUMN FORWARD MOVES THE ELEVATORS DOWN, INCREASING
PRINCIPLES OF FLIGHT
MOVING THE CONTOL COLUMN FORWARD
MOVES THE ELEVATORS DOWN, INCREASING
THE ANGLE OF ATTACK AND PRODUCING
MORE LIFT.
PRODUCING MORE LIFT MOVES THE
AIRCRAFT AROUND IT’S LATERAL AXIS
AND PITCHES THE NOSE DOWN.
THE AIRCRAFT DESCENDS AND THE SPEED
INCREASES.

7. THE AIRCRAFT WILL CONTINUE TO PITCH OVER
PRINCIPLES OF FLIGHT
CONTROL COLUMN
ELEVATOR
FORCE
LATERAL AXIS
AIRCRAFT DESCENDS
AND SPEED INCREASES
LATERAL AXIS
CONTROL COLUMN
TO NUETRAL
ELEVATOR
FORCE
NUETRAL
THE AIRCRAFT WILL CONTINUE TO PITCH OVER
UNTIL THE CONTROL COLUMN IS PUT BACK IN
THE NUETRAL POSITION.

8. WHATEVER THE ATTITUDE OF THE AIRCRAFT
PRINCIPLES OF FLIGHT
WHATEVER THE ATTITUDE OF THE AIRCRAFT
THE REACTION TO MOVING THE CONTROL
COLUMN IS THE SAME.

9. PRINCIPLES OF FLIGHT
C130 ELEVATORS

10. MOVING THE CONTROL COLUMN BACK HAS THE OPPOSITE EFFECT.
PRINCIPLES OF FLIGHT
MOVING THE CONTROL COLUMN BACK HAS
THE OPPOSITE EFFECT.

11. PRINCIPLES OF FLIGHT
VC10 ELEVATORS

12. THE PILOT USES AILERONS.
PRINCIPLES OF FLIGHT
THE ROLLING PLANE
THE PILOT USES AILERONS.
AILERONS ARE USUALLY TWO MOVEABLE
PARTS HINGED TO THE TRAILING EDGE OF
THE WINGS AND PLACED CLOSE TO THE
WINGTIPS TO GIVE MAXIMUM LEVERAGE
ABOUT THE C of G.
THEY ARE LINKED TO THE PILOT’S CONTROL
COLUMN.

13. BY MOVING THE CONTROL COLUMN TO THE LEFT, THE LEFT AILERON RISES AND
PRINCIPLES OF FLIGHT
BY MOVING THE CONTROL COLUMN TO
THE LEFT, THE LEFT AILERON RISES AND
THE RIGHT LOWERS.
LEFT WING
RIGHT WING
AILERON AND WING CHORD LINE
CHANGE IN ANGLE OF ATTACK
WING CHORD LINE
WING CHORD LINE
AILERON AND WING
CHORD LINE
RAISING THE LEFT AILERON REDUCES IT’S
ANGLE OF ATTACK AND THEREFORE
PRODUCES LESS LIFT. THIS CAUSES THE
WING TO DROP.
THE OPPOSITE OCCURS ON THE RIGHT WING.

14. STRAIGHT AND LEVEL FLIGHT
PRINCIPLES OF FLIGHT
THE ROLLING PLANE
STRAIGHT AND LEVEL FLIGHT
CONTROL COLUMN RIGHT
LEFT AILERON DOWN, RIGHT AILERON UP
AIRCRAFT ROLLS RIGHT

15. WHEN THE AIRCRAFT ACHIEVES THE REQUIRED
PRINCIPLES OF FLIGHT
WHEN THE AIRCRAFT ACHIEVES THE REQUIRED
BANK ANGLE THE CONTROL COLUMN IS PLACED
CENTRAL.
AILERONS NOW FLARE WITH THE WING AND
THE AIRCRAFT MAINTAINS THE PRESENT BANK
ANGLE.

16. THE EFFECT ON EACH WING IS DIFFERENT
PRINCIPLES OF FLIGHT
ON LARGE AIRCRAFT
THE EFFECT ON EACH WING IS DIFFERENT
AS THE LIFT CHANGE IS MORE PRONOUNCED
ON THE DOWN MOVING AILERON.
THEREFORE THE DOWN MOVING AILERON
IS DEFLECTED LESS THAN THE UP MOVING.
LEFT WING
RIGHT WING
UP IS USUALLY 2 TIMES THE MOVEMENT
OF DOWN
THIS IS KNOWN AS DIFFERENTIAL AILERON.

17. PRINCIPLES OF FLIGHT
C130 AILERONS

18. THE YAWING PLANE THE PILOT USES THE RUDDER.
PRINCIPLES OF FLIGHT
THE YAWING PLANE
THE PILOT USES THE RUDDER.
ON MOST AIRCRAFT THE RUDDER IS A
SINGLE CONTROL SURFACE HINGED TO THE
TRAILING EDGE OF THE FIN WHERE IT HAS
MOST EFFECT.
THE PILOT USES THE RUDDER.
FIN
RUDDER

19. TO YAW TO THE LEFT, THE PILOT PUSHES THE
PRINCIPLES OF FLIGHT
TO YAW TO THE LEFT, THE PILOT PUSHES THE
LEFT RUDDER PEDAL WHICH DEFLECTS THE
RUDDER LEFT.
FIN
RUDDER
CHORD LINE
FORCE
THIS CAUSES AN ANGLE OF ATTACK ON
THE FIN AND CAUSES A FORCE TO PUSH
THE FIN RIGHT AND THEREFORE THE NOSE
OF THE AIRCRAFT MOVES LEFT.

20. THE YAWING PLANE FLYING STRAIGHT LEFT RUDDER PEDAL PUSHED FORWARD,
PRINCIPLES OF FLIGHT
THE YAWING PLANE
FLYING STRAIGHT
LEFT RUDDER PEDAL
PUSHED FORWARD,
RIGHT PEDAL WILL
MOVE BACK,
RUDDER MOVES LEFT

21. THE YAWING PLANE FORCE APPLIED TO FIN AND AIRCRAFT NOSE
PRINCIPLES OF FLIGHT
THE YAWING PLANE
FORCE APPLIED TO FIN
AND AIRCRAFT NOSE
MOVES LEFT ABOUT
THE NORMAL AXIS.
i.e. LEFT YAW.
NORMAL
AXIS
BRINGING THE RUDDER
PEDALS BACK TO THE
NUETRAL POSITION,
CENTRALISES THE
RUDDER AND THE AIRCRAFT
NOSE STOPS MOVING AND
MAINTAINS THE PRESENT
HEADING.

22. PRINCIPLES OF FLIGHT
C130 RUDDER

23. TRIM TABS THE WEIGHT AND POSITION OF THE C of G
PRINCIPLES OF FLIGHT
TRIM TABS
THE WEIGHT AND POSITION OF THE C of G
CAN CHANGE IN FLIGHT DUE TO:-
BURNING FUEL
DROPPING BOMBS
FIRING AMMUNITION
DROPPING STORES OR MEN BY
PARACHUTE
THE CENTRE OF PRESSURE WILL ALSO
CHANGE DUE TO CHANGES IN:-
ENGINE POWER
THE WEIGHT AND POSITION OF THE C of G
CAN CHANGE IN FLIGHT DUE TO:-
BURNING FUEL
DROPPING BOMBS
FIRING AMMUNITION
DROPPING STORES OR MEN BY
PARACHUTE
THE CENTRE OF PRESSURE WILL ALSO
CHANGE DUE TO CHANGES IN:-
ENGINE POWER
ALTITUDE
SPEED
THE WEIGHT AND POSITION OF THE C of G
CAN CHANGE IN FLIGHT DUE TO:-
BURNING FUEL
DROPPING BOMBS
FIRING AMMUNITION
DROPPING STORES OR MEN BY
PARACHUTE
THE CENTRE OF PRESSURE WILL ALSO
CHANGE DUE TO CHANGES IN:-
THE WEIGHT AND POSITION OF THE C of G
CAN CHANGE IN FLIGHT DUE TO:-
BURNING FUEL
DROPPING BOMBS
FIRING AMMUNITION
DROPPING STORES OR MEN BY
PARACHUTE
THE CENTRE OF PRESSURE WILL ALSO
CHANGE DUE TO CHANGES IN:-
ENGINE POWER
ALTITUDE
THE WEIGHT AND POSITION OF THE C of G
CAN CHANGE IN FLIGHT DUE TO:-
BURNING FUEL
DROPPING BOMBS
FIRING AMMUNITION
THE WEIGHT AND POSITION OF THE C of G
CAN CHANGE IN FLIGHT DUE TO:-
THE WEIGHT AND POSITION OF THE C of G
CAN CHANGE IN FLIGHT DUE TO:-
BURNING FUEL
THE WEIGHT AND POSITION OF THE C of G
CAN CHANGE IN FLIGHT DUE TO:-
BURNING FUEL
DROPPING BOMBS
THE WEIGHT AND POSITION OF THE C of G
CAN CHANGE IN FLIGHT DUE TO:-
BURNING FUEL
DROPPING BOMBS
FIRING AMMUNITION
DROPPING STORES OR MEN BY
PARACHUTE

24. TRIM TABS AN ENGINE FAILURE ON A MULTI ENGINE
PRINCIPLES OF FLIGHT
TRIM TABS
AN ENGINE FAILURE ON A MULTI ENGINE
AIRCRAFT WOULD CAUSE ASYMETRIC POWER
WHICH THE PILOT WOULD HAVE TO OPPOSE BY USING RUDDER.
PILOT
APPLIES
RIGHT
RUDDER. X
THRUST
ASYMETRIC
THRUST
CAUSES YAW
LEFT.
COUNTERS
ASYMETRIC
THRUST.
TURNING
FORCE

25. TRIM TABS TRIMMING TABS A LATERAL UNBALANCE (POSIBLY UNEVEN
PRINCIPLES OF FLIGHT
TRIM TABS
A LATERAL UNBALANCE (POSIBLY UNEVEN
FUEL DISTRIBUTION) WOULD HAVE TO BE
CORRECTED BY THE PILOT USING AILERON.
LEFT WING
HEAVIER
THAN RIGHT
WING.
IN ALL THESE CONDITIONS A PILOT COULD
NOT FLY FOR LONG HOLDING THESE FORCES
WITHOUT SOME HELP.
THIS HELP COMES IN THE FORM OF:-
TRIMMING TABS

26. TRIM TABS THESE ARE USUALLY SMALL CONTROL
PRINCIPLES OF FLIGHT
TRIM TABS
THESE ARE USUALLY SMALL CONTROL
SURFACES ATTACHED TO THE TRAILING EDGE
OF THE AILERONS, ELEVATORS AND RUDDER
WHICH BY APPLYING SMALL MOVEMENTS
CAN REMOVE THE LOAD FROM THE PILOT.
EXAMPLE: ELEVATORS
TRIM TAB
TAILPLANE
ELEVATOR

27. PRINCIPLES OF FLIGHT
IF THE PILOT HAS TO MAINTAIN A BACKWARDS PRESSURE ON THE CONTROL COLUMN TO MAINTAIN LEVEL FLIGHT.
DOWNWARD FORCE TO KEEP
AIRCRAFT NOSE UP
BY MOVING THE TRIM TAB DOWN, THE INCREASE IN ANGLE OF ATTACK WILL CAUSE THE ELEVATOR FORCE TO BE COUNTERACTED.
DOWNWARD FORCE TO KEEP
AIRCRAFT NOSE UP
SMALLER FORCE
TO BALANCE
ELEVATOR FORCE
DIFFERENT LEVERAGE ARMS
SO TAKING THE LOAD
OFF THE PILOT.

28. TRIM TABS AILERON AND RUDDER TRIM TABS WORK ON THE SAME PRINCIPLE.
PRINCIPLES OF FLIGHT
TRIM TABS
AILERON AND RUDDER TRIM TABS WORK ON
THE SAME PRINCIPLE.
TRIM
TABS

29. TRIM TABS ON SOME AIRCRAFT THERE ARE NO ELEVATOR TRIM TABS.
PRINCIPLES OF FLIGHT
TRIM TABS
ON SOME AIRCRAFT THERE ARE NO ELEVATOR
TRIM TABS.
INSTEAD THE WHOLE TAILPLANE MOVES TO
TAKE OUT ANY LOADS FROM THE PILOT.
THIS CAN BE ACHIEVED BY A MECHANICAL
LINKAGE OR BY HYDRAULIC CONTROL.

30. PRINCIPLES OF FLIGHT
MOVING
TAILPLANE
TRIM TABS

31. PRINCIPLES OF FLIGHT
TRIM TABS
MOVING TAILPLANE

32. HIGH LIFT DEVICES THESE DEVICES IMPROVE THE LIFT
PRINCIPLES OF FLIGHT
HIGH LIFT DEVICES
THESE DEVICES IMPROVE THE LIFT
CAPABILITIES OF THE WING AND IMPROVE
TAKE-OFF AND LANDING PERFORMANCE.
TYPES:-
FLAPS
SLATS
SLOTS
KRUGER FLAPS
DROOP SNOOT FLAPS

33. FLAPS - LANDING FOR A SAFE LANDING THE AIRCRAFT MUST BE
PRINCIPLES OF FLIGHT
FLAPS
- LANDING
FOR A SAFE LANDING THE AIRCRAFT MUST BE
ABLE TO FLY SLOW ENOUGH TO BE ABLE TO STOP ON THE RUNWAY AND HAVE A STEEP APPROACH ANGLE TO LET THE PILOT SEE THE RUNWAY.
AN AIRCRAFT WING IS DESIGNED FOR A SPECIFIC ROLE, NOT USUALLY FOR LANDING.
THEREFORE TO ACHIEVE A SAFE LANDING THE WING HAS TO BE MODIFIED.
THIS IS ACHIEVED BY USING: - FLAPS.
FLAPS ARE ATTACHED TO THE TRAILING EDGE OF THE WING AND ARE EXTENDED TO INCREASE THE WING AREA AND CHORD LENGTH.

34. PRINCIPLES OF FLIGHT
LANDING FLAP

35. FLAPS - TAKE-OFF A SMALL AMOUNT OF FLAP WILL PRODUCE
PRINCIPLES OF FLIGHT
FLAPS
- TAKE-OFF
A SMALL AMOUNT OF FLAP WILL PRODUCE
EXTRA LIFT BUT LITTLE DRAG AND SO ALLOW
A SHORTER TAKE-OFF DISTANCE.
TAKE-OFF FLAP

36. FLAPS PRINCIPLES OF FLIGHT TYPES OF FLAP GENERAL WING SECTION
SIMPLE OR PLAIN FLAP
SPLIT FLAP
FOWLER FLAP

37. FLAPS WHEN THE FLAPS ARE “UP” THEY ARE FLUSH
PRINCIPLES OF FLIGHT
FLAPS
WHEN THE FLAPS ARE “UP” THEY ARE FLUSH
WITH THE WING AND WHEN “DOWN” THEY
CAN BE UP TO 90° TO THE WING.
WHEN THE FLAPS ARE “UP” THEY ARE FLUSH
WITH THE WING AND WHEN “DOWN” THEY
CAN BE UP TO 90° TO THE WING.
WHEN THE FLAPS ARE “UP” THEY ARE FLUSH
WITH THE WING AND WHEN “DOWN” THEY
CAN BE UP TO 90° TO THE WING.
UP TO 60° THE INCREASE IN LIFT IS LARGE
AND THE INCREASE IN DRAG SMALL.
FROM 60° TO 90° THE INCREASE IN LIFT IS
SMALL AND THE INCREASE IN DRAG IS LARGE.

38. FLAPS A SMALL AMOUNT OF FLAP WILL ALLOW A
PRINCIPLES OF FLIGHT
FLAPS
A SMALL AMOUNT OF FLAP WILL ALLOW A
SLOWER STALLING SPEED BUT NOT GIVE AN
INCREASE IN APPROACH ANGLE.
A LARGE AMOUNT OF FLAP WILL GIVE A
STEEPER APPROACH ANGLE AND WILL ALLOW
A SLOWER STALLING SPEED.

39. FLAPS PRINCIPLES OF FLIGHT 15° LARGE INCREASE IN LIFT. VERY SMALL
60° SOME INCREASE
IN LIFT. LARGE
INCREASE IN DRAG
15° LARGE INCREASE
IN LIFT. VERY SMALL
INCREASE IN DRAG.
90° VERY SMALL
INCREASE IN LIFT.
HUGE INCREASE
IN DRAG.

40. FLAPS PRINCIPLES OF FLIGHT FULL FLAP – GOOD VIEW OF LANDING AREA
AND REDUCED STALLING SPEED
NO FLAP-POOR FORWARD VIEW

41. PRINCIPLES OF FLIGHT
FLAPS
GROB TUTOR – PLAIN FLAP

42. PRINCIPLES OF FLIGHT
FLAPS
SPITFIRE – SPLIT FLAP

43. PRINCIPLES OF FLIGHT
FLAPS
VC10 – FOWLER FLAP

44. FLAPS
PRINCIPLES OF FLIGHT
BOEING 747 – DOUBLE SLOTTED FOWLER FLAP

45. SLATS SLATS ARE ANOTHER DEVICE WHICH CAN
PRINCIPLES OF FLIGHT
SLATS
SLATS ARE ANOTHER DEVICE WHICH CAN
IMPROVE LOW SPEED HANDLING AND STALL
SPEED.
THEY ARE SMALL AEROFOIL SECTIONS ON
THE LEADING EDGE OF WINGS, WHICH WHEN
EXTENDED INCREASE LIFT AND AIRFLOW
CONTROL.
SLATS

46. SLATS THE DIAGRAM SHOWS AN AUTOMATIC SLAT
PRINCIPLES OF FLIGHT
SLATS
THE DIAGRAM SHOWS AN AUTOMATIC SLAT
WHICH IS HELD IN THE CLOSED POSITION BY
SPRINGS.

47. PRINCIPLES OF FLIGHT
SLATS
- AUTOMATIC SLAT
WHEN THE WING REACHES A HIGH ANGLE OF ATTACK, THE LIFT FORCES ON THE SLAT OVERCOME THE SPRINGS AND THE SLATS
EXTEND.
THE AIR CAN NOW FLOW BETWEEN THE SLAT
AND THE WING, CAUSING THE AIR TO
ACCELERATE OVER THE WING SO IMPROVING
THE AIRFLOW OVER THE WING.

48. SLATS USUALLY THE WING CRITICAL ANGLE IS 15°,
PRINCIPLES OF FLIGHT
SLATS
USUALLY THE WING CRITICAL ANGLE IS 15°,
BUT WITH SLATS THIS CAN INCREASE TO 25°.
THIS CAN BE A DIFFERENCE OF KTS IN
THE STALLING SPEED.

49. PRINCIPLES OF FLIGHT
SLATS
ON MOST LARGE AIRCRAFT THE SLATS ARE NOT AUTOMATIC BUT OPERATED FROM THE FLIGHT DECK IN CONJUNCTION WITH THE FLAPS FOR TAKE-OFF AND LANDING.

50. PRINCIPLES OF FLIGHT
LOCKHEED TRISTAR
SLATS

51. SLOTS AS THE ANGLE OF ATTACK OF THE WING
PRINCIPLES OF FLIGHT
SLOTS
AS THE ANGLE OF ATTACK OF THE WING
INCREASES THE EFFECT OF THE AIRFLOW
THROUGH THE SLOT INCREASES AND
SMOOTHS THE AIRFLOW OVER THE TOP
SURFACE OF THE WING, SO REDUCING
TURBULENCE.
SLOT
A SLOT CAN INCREASE THE CRITICAL ANGLE
TO ABOUT 20°.

52. KRUGER FLAPS THESE ARE SIMILAR TO SLATS AND HAVE THE
PRINCIPLES OF FLIGHT
KRUGER FLAPS
THESE ARE SIMILAR TO SLATS AND HAVE THE
SAME EFFECT, BUT ARE HINGED TO THE LEADING
EDGE OF THE WING AND EXTEND FORWARD.
INCREASES THE CRITICAL ANGLE TO 25o

53. PRINCIPLES OF FLIGHT
KRUGER FLAPS

54. DROOP SNOOT FLAP INCREASES THE CRITICAL ANGLE TO 20o
PRINCIPLES OF FLIGHT
DROOP SNOOT FLAP
INCREASES THE CRITICAL ANGLE TO 20o