- •Textbook Series
- •Contents
- •1 Overview and Definitions
- •Overview
- •General Definitions
- •Glossary
- •List of Symbols
- •Greek Symbols
- •Others
- •Self-assessment Questions
- •Answers
- •2 The Atmosphere
- •Introduction
- •The Physical Properties of Air
- •Static Pressure
- •Temperature
- •Air Density
- •International Standard Atmosphere (ISA)
- •Dynamic Pressure
- •Key Facts
- •Measuring Dynamic Pressure
- •Relationships between Airspeeds
- •Airspeed
- •Errors and Corrections
- •V Speeds
- •Summary
- •Questions
- •Answers
- •3 Basic Aerodynamic Theory
- •The Principle of Continuity
- •Bernoulli’s Theorem
- •Streamlines and the Streamtube
- •Summary
- •Questions
- •Answers
- •4 Subsonic Airflow
- •Aerofoil Terminology
- •Basics about Airflow
- •Two Dimensional Airflow
- •Summary
- •Questions
- •Answers
- •5 Lift
- •Aerodynamic Force Coefficient
- •The Basic Lift Equation
- •Review:
- •The Lift Curve
- •Interpretation of the Lift Curve
- •Density Altitude
- •Aerofoil Section Lift Characteristics
- •Introduction to Drag Characteristics
- •Lift/Drag Ratio
- •Effect of Aircraft Weight on Minimum Flight Speed
- •Condition of the Surface
- •Flight at High Lift Conditions
- •Three Dimensional Airflow
- •Wing Terminology
- •Wing Tip Vortices
- •Wake Turbulence: (Ref: AIC P 072/2010)
- •Ground Effect
- •Conclusion
- •Summary
- •Answers from page 77
- •Answers from page 78
- •Questions
- •Answers
- •6 Drag
- •Introduction
- •Parasite Drag
- •Induced Drag
- •Methods of Reducing Induced Drag
- •Effect of Lift on Parasite Drag
- •Aeroplane Total Drag
- •The Effect of Aircraft Gross Weight on Total Drag
- •The Effect of Altitude on Total Drag
- •The Effect of Configuration on Total Drag
- •Speed Stability
- •Power Required (Introduction)
- •Summary
- •Questions
- •Annex C
- •Answers
- •7 Stalling
- •Introduction
- •Cause of the Stall
- •The Lift Curve
- •Stall Recovery
- •Aircraft Behaviour Close to the Stall
- •Use of Flight Controls Close to the Stall
- •Stall Recognition
- •Stall Speed
- •Stall Warning
- •Artificial Stall Warning Devices
- •Basic Stall Requirements (EASA and FAR)
- •Wing Design Characteristics
- •The Effect of Aerofoil Section
- •The Effect of Wing Planform
- •Key Facts 1
- •Super Stall (Deep Stall)
- •Factors that Affect Stall Speed
- •1g Stall Speed
- •Effect of Weight Change on Stall Speed
- •Composition and Resolution of Forces
- •Using Trigonometry to Resolve Forces
- •Lift Increase in a Level Turn
- •Effect of Load Factor on Stall Speed
- •Effect of High Lift Devices on Stall Speed
- •Effect of CG Position on Stall Speed
- •Effect of Landing Gear on the Stall Speed
- •Effect of Engine Power on Stall Speed
- •Effect of Mach Number (Compressibility) on Stall Speed
- •Effect of Wing Contamination on Stall Speed
- •Warning to the Pilot of Icing-induced Stalls
- •Stabilizer Stall Due to Ice
- •Effect of Heavy Rain on Stall Speed
- •Stall and Recovery Characteristics of Canards
- •Spinning
- •Primary Causes of a Spin
- •Phases of a Spin
- •The Effect of Mass and Balance on Spins
- •Spin Recovery
- •Special Phenomena of Stall
- •High Speed Buffet (Shock Stall)
- •Answers to Questions on Page 173
- •Key Facts 2
- •Questions
- •Key Facts 1 (Completed)
- •Key Facts 2 (Completed)
- •Answers
- •8 High Lift Devices
- •Purpose of High Lift Devices
- •Take-off and Landing Speeds
- •Augmentation
- •Flaps
- •Trailing Edge Flaps
- •Plain Flap
- •Split Flap
- •Slotted and Multiple Slotted Flaps
- •The Fowler Flap
- •Comparison of Trailing Edge Flaps
- •and Stalling Angle
- •Drag
- •Lift / Drag Ratio
- •Pitching Moment
- •Centre of Pressure Movement
- •Change of Downwash
- •Overall Pitch Change
- •Aircraft Attitude with Flaps Lowered
- •Leading Edge High Lift Devices
- •Leading Edge Flaps
- •Effect of Leading Edge Flaps on Lift
- •Leading Edge Slots
- •Leading Edge Slat
- •Automatic Slots
- •Disadvantages of the Slot
- •Drag and Pitching Moment of Leading Edge Devices
- •Trailing Edge Plus Leading Edge Devices
- •Sequence of Operation
- •Asymmetry of High Lift Devices
- •Flap Load Relief System
- •Choice of Flap Setting for Take-off, Climb and Landing
- •Management of High Lift Devices
- •Flap Extension Prior to Landing
- •Questions
- •Annexes
- •Answers
- •9 Airframe Contamination
- •Introduction
- •Types of Contamination
- •Effect of Frost and Ice on the Aircraft
- •Effect on Instruments
- •Effect on Controls
- •Water Contamination
- •Airframe Aging
- •Questions
- •Answers
- •10 Stability and Control
- •Introduction
- •Static Stability
- •Aeroplane Reference Axes
- •Static Longitudinal Stability
- •Neutral Point
- •Static Margin
- •Trim and Controllability
- •Key Facts 1
- •Graphic Presentation of Static Longitudinal Stability
- •Contribution of the Component Surfaces
- •Power-off Stability
- •Effect of CG Position
- •Power Effects
- •High Lift Devices
- •Control Force Stability
- •Manoeuvre Stability
- •Stick Force Per ‘g’
- •Tailoring Control Forces
- •Longitudinal Control
- •Manoeuvring Control Requirement
- •Take-off Control Requirement
- •Landing Control Requirement
- •Dynamic Stability
- •Longitudinal Dynamic Stability
- •Long Period Oscillation (Phugoid)
- •Short Period Oscillation
- •Directional Stability and Control
- •Sideslip Angle
- •Static Directional Stability
- •Contribution of the Aeroplane Components.
- •Lateral Stability and Control
- •Static Lateral Stability
- •Contribution of the Aeroplane Components
- •Lateral Dynamic Effects
- •Spiral Divergence
- •Dutch Roll
- •Pilot Induced Oscillation (PIO)
- •High Mach Numbers
- •Mach Trim
- •Key Facts 2
- •Summary
- •Questions
- •Key Facts 1 (Completed)
- •Key Facts 2 (Completed)
- •Answers
- •11 Controls
- •Introduction
- •Hinge Moments
- •Control Balancing
- •Mass Balance
- •Longitudinal Control
- •Lateral Control
- •Speed Brakes
- •Directional Control
- •Secondary Effects of Controls
- •Trimming
- •Questions
- •Answers
- •12 Flight Mechanics
- •Introduction
- •Straight Horizontal Steady Flight
- •Tailplane and Elevator
- •Balance of Forces
- •Straight Steady Climb
- •Climb Angle
- •Effect of Weight, Altitude and Temperature.
- •Power-on Descent
- •Emergency Descent
- •Glide
- •Rate of Descent in the Glide
- •Turning
- •Flight with Asymmetric Thrust
- •Summary of Minimum Control Speeds
- •Questions
- •Answers
- •13 High Speed Flight
- •Introduction
- •Speed of Sound
- •Mach Number
- •Effect on Mach Number of Climbing at a Constant IAS
- •Variation of TAS with Altitude at a Constant Mach Number
- •Influence of Temperature on Mach Number at a Constant Flight Level and IAS
- •Subdivisions of Aerodynamic Flow
- •Propagation of Pressure Waves
- •Normal Shock Waves
- •Critical Mach Number
- •Pressure Distribution at Transonic Mach Numbers
- •Properties of a Normal Shock Wave
- •Oblique Shock Waves
- •Effects of Shock Wave Formation
- •Buffet
- •Factors Which Affect the Buffet Boundaries
- •The Buffet Margin
- •Use of the Buffet Onset Chart
- •Delaying or Reducing the Effects of Compressibility
- •Aerodynamic Heating
- •Mach Angle
- •Mach Cone
- •Area (Zone) of Influence
- •Bow Wave
- •Expansion Waves
- •Sonic Bang
- •Methods of Improving Control at Transonic Speeds
- •Questions
- •Answers
- •14 Limitations
- •Operating Limit Speeds
- •Loads and Safety Factors
- •Loads on the Structure
- •Load Factor
- •Boundary
- •Design Manoeuvring Speed, V
- •Effect of Altitude on V
- •Effect of Aircraft Weight on V
- •Design Cruising Speed V
- •Design Dive Speed V
- •Negative Load Factors
- •The Negative Stall
- •Manoeuvre Boundaries
- •Operational Speed Limits
- •Gust Loads
- •Effect of a Vertical Gust on the Load Factor
- •Effect of the Gust on Stalling
- •Operational Rough-air Speed (V
- •Landing Gear Speed Limitations
- •Flap Speed Limit
- •Aeroelasticity (Aeroelastic Coupling)
- •Flutter
- •Control Surface Flutter
- •Aileron Reversal
- •Questions
- •Answers
- •15 Windshear
- •Introduction (Ref: AIC 84/2008)
- •Microburst
- •Windshear Encounter during Approach
- •Effects of Windshear
- •“Typical” Recovery from Windshear
- •Windshear Reporting
- •Visual Clues
- •Conclusions
- •Questions
- •Answers
- •16 Propellers
- •Introduction
- •Definitions
- •Aerodynamic Forces on the Propeller
- •Thrust
- •Centrifugal Twisting Moment (CTM)
- •Propeller Efficiency
- •Variable Pitch Propellers
- •Power Absorption
- •Moments and Forces Generated by a Propeller
- •Effect of Atmospheric Conditions
- •Questions
- •Answers
- •17 Revision Questions
- •Questions
- •Answers
- •Explanations to Specimen Questions
- •Specimen Examination Paper
- •Answers to Specimen Exam Paper
- •Explanations to Specimen Exam Paper
- •18 Index
14 Questions
Questions
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1. |
If an aircraft is flown at its design manoeuvring speed VA: |
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a. |
it is possible to subject the aircraft to a load greater than its limit load during |
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high ‘g’ manoeuvres. |
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b. |
it is only possible to subject the aircraft to a load greater than its limit load |
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during violent increases in incidence, i.e. when using excessive stick force to |
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pull-out of a dive. |
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c. |
it is not possible to exceed the limit load. |
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d. |
it is possible to subject the aircraft to a load greater than its limit load at high |
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TAS. |
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2. |
The speed VNE is: |
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a. |
the airspeed which must not be exceeded except in a dive. |
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b. |
the maximum airspeed at which manoeuvres approaching the stall may be |
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carried out. |
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c. |
the maximum airspeed at which an aircraft may be flown. |
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d. |
the maximum speed, above which flaps should not be extended. |
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3. |
Maximum structural cruising speed VNO is the maximum speed at which an |
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aeroplane can be operated during: |
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normal operations. |
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b. |
abrupt manoeuvres. |
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c. |
flight in smooth air. |
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d. |
flight in rough air. |
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4. |
The maximum allowable airspeed with flaps extended (VFE) is lower than cruising |
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speed because: |
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they are used only when preparing to land. |
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b. |
the additional lift and drag created would overload the wing and flap |
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structure at higher speeds. |
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c. |
flaps will stall if they are deployed at too high an airspeed. |
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d. |
too much drag is induced. |
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5. |
Why is VL E greater than V LO on the majority of large jet transport aircraft? |
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a. |
VLO is used when the aircraft is taking off and landing when the IAS is low. |
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b. |
Extending the gear at too high an airspeed would cause excessive parasite |
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drag. |
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c. |
Flying at too high an airspeed with the gear down would prevent retraction of |
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the forward retracting nose gear. |
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d. |
VLO is a lower IAS because the undercarriage doors are vulnerable to |
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aerodynamic loads when the gear is in transit, up or down. |
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6. |
The phenomenon of flutter is described as: |
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a. |
rapid oscillatory motion involving only rotation of the control surfaces, |
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associated with the shock waves produced around the control surfaces. |
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b. |
oscillatory motion of part or parts of the aircraft relative to the remainder of |
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the structure. |
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c. |
rapid movement of the airframe caused by vibration from the engines. |
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d. |
reversal of the ailerons caused by wing torsional flexibility. |
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14 |
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7. |
What is the purpose of fitting the engines to an aircraft using wing mounted |
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pylons? |
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They give increased ground clearance in roll. |
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b. |
They give improved longitudinal mass distribution. |
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c. |
The wing structure can be lighter because the engine acts as a mass balance |
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and also relieves wing bending stress. |
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d. |
They enable a longer undercarriage to be used which gives an optimum pitch |
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attitude for take-off and landing. |
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8. |
Aileron reversal at high dynamic pressures is caused by: |
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the down-going aileron increasing the semi-span angle of attack beyond the |
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critical. |
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b. |
flow separation ahead of the aileron leading edge. |
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c. |
uneven shock wave formation on the top and bottom surface of the aileron, |
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with the attendant movement in control surface CP, causing the resultant |
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force to act in the opposite direction from that intended. |
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d. |
dynamic pressure acting on the aileron twisting the wing in the opposite |
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direction, possibly causing the aircraft to bank in a direction opposite to that |
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intended. |
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9. |
Controls are mass balanced in order to: |
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eliminate control flutter. |
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b. |
aerodynamically assist the pilot in moving the controls. |
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10. |
c. |
provide equal control forces on all three controls. |
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If an aircraft weight is reduced by 15%, VA will: |
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d. |
return the control surface to neutral when the controls are released. |
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not change. |
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b. |
increase by 15%. |
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c. |
increase by 7.5%. |
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d. |
decrease by 7.5%. |
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11. |
VLO is defined as: |
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maximum landing gear operating speed. |
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b. |
maximum landing gear extended speed. |
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c. |
maximum leading edge flaps extended speed. |
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d. |
maximum flap speed. |
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12. |
If flutter is experienced during flight, the preferable action would be: |
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immediately increase speed beyond VMO / MMO, by sacrificing altitude if |
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necessary. |
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b. |
immediately close the throttles, deploy the speed brakes and bank the aircraft. |
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c. |
rapidly pitch-up to slow the aircraft as quickly as possible. |
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d. |
reduce speed immediately by closing the throttles, but avoid rapid changes in |
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attitude and/or configuration. |
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483
14 Questions
13.Which of the following statements are correct?
1.It is a design requirement that control reversal speeds must be higher than any speed to be achieved in flight.
2.The airframe must be made strong and stiff enough to ensure that the wing torsional divergence speed is higher, by a substantial safety margin, than any speed which will ever be achieved in any condition in flight.
3.Flying control surfaces are aerodynamically balanced to prevent flutter.
4.An aircraft is not a rigid structure.
5.Aeroelasticity effects are inversely proportional to IAS.
6.Control reversal speed is higher if the aircraft is fitted with outboard ailerons which are locked-out as the aircraft accelerates; the inboard ailerons alone controlling the aircraft in roll at higher speeds.
a.All the above statements are correct.
b.1, 2, 3 and 6.
c.1, 2, 4 and 6.
d.1, 3, 5 and 6.
Questions 14
484
Questions 14
Questions 14
485