1 Airplanes and Aerodynamics

21. How will frost on the wings of an airplane affect takeoff performance? A. Frost will disrupt the smooth flow of air over the wing, adversely affecting its lifting capability. B. Frost will change the camber of the wing, increasing its lifting capability. C. Frost will cause the airplane to become airborne with a higher angle of attack, decreasing the stall speed.

Answer (A) is correct. DISCUSSION: Frost does not change the basic shape of the wing but the roughness of its surface spoils the aerodynamic smooth flow of air, thus causing an increase in drag and an early airflow separation over the wing, resulting in a loss of lift. Answer (B) is incorrect. Frost will decrease (not increase) lift during takeoff and has no effect on the wing camber. Answer (C) is incorrect. A layer of frost on an airplane will increase drag, which increases (not decreases) the stall speed.

1. What is one purpose of wing flaps? A. To enable the pilot to make steeper approaches to a landing without increasing the airspeed. B. To relieve the pilot of maintaining continuous pressure on the controls. C. To decrease wing area to vary the lift.

Answer (A) is correct. DISCUSSION: Extending the flaps increases the wing camber and the angle of attack of the wing. This increases wing lift and induced drag, which enables the pilot to make steeper approaches to a landing without an increase in airspeed. Answer (B) is incorrect. Trim tabs (not wing flaps) help relieve control pressures. Answer (C) is incorrect. Wing area usually remains the same, except for certain specialized flaps that increase (not decrease) the wing area.

23. How does frost affect the lifting surfaces of an airplane on takeoff? A. Frost may prevent the airplane from becoming airborne at normal takeoff speed. B. Frost will change the camber of the wing, increasing lift during takeoff. C. Frost may cause the airplane to become airborne with a lower angle of attack at a lower indicated airspeed.

Answer (A) is correct. DISCUSSION: Frost that is not removed from the surface of an airplane prior to takeoff may make it difficult to get the airplane airborne at normal takeoff speed. The frost disrupts the airflow over the wing, which increases drag. Answer (B) is incorrect. The smoothness of the wing, not its curvature, is affected and lift is decreased (not increased). Answer (C) is incorrect. Ground effect (not frost) may cause an airplane to become airborne with a lower angle of attack at a lower indicated airspeed.

33. An airplane has been loaded in such a manner that the CG is located aft of the aft CG limit. One undesirable flight characteristic a pilot might experience with this airplane would be A. a longer takeoff run. B. difficulty in recovering from a stalled condition. C. stalling at higher-than-normal airspeed.

Answer (B) is correct. DISCUSSION: The recovery from a stall in any airplane becomes progressively more difficult as its center of gravity moves backward. Generally, airplanes become less controllable, especially at slow flight speeds, as the center of gravity is moved backward. Answer (A) is incorrect. An airplane with an aft CG has less drag, resulting in a shorter, not longer, takeoff run. Answer (C) is incorrect. An airplane with an aft CG flies at a lower angle of attack, resulting in a lower, not higher, stall speed.

31. An airplane said to be inherently stable will A. be difficult to stall. B. require less effort to control. C. not spin.

Answer (B) is correct. DISCUSSION: An inherently stable airplane will usually return to the original condition of flight (except when in a bank) if disturbed by a force such as air turbulence. Thus, an inherently stable airplane will require less effort to control than an inherently unstable one. Answer (A) is incorrect. Stability of an airplane has an effect on stall characteristic, not on the difficulty level of entering a stall. Answer (C) is incorrect. An inherently stable aircraft will spin.

7. Which of the following is true concerning flaps? A. Flaps are attached to the leading edge of the wing and are used to increase wing lift. B. Flaps allow an increase in the angle of descent without increasing airspeed. C. Flaps are high drag devices deployed from the wings to reduce lift.

Answer (B) is correct. DISCUSSION: Flaps are attached to the trailing edge of the wing and are used during approach and landing to increase wing lift. This allows an increase in the angle of descent without increasing airspeed. Answer (A) is incorrect. Flaps are attached to the trailing edge, not the leading edge, of the wing. Answer (C) is incorrect. Spoilers, not flaps, are high-drag devices deployed from the wings to reduce lift and increase drag.

49. (Refer to Figure on page 38) The airspeed indicated by points A and J is A. maximum structural cruising speed. B. normal stall speed. C. maneuvering speed.

Answer (B) is correct. DISCUSSION: Points A and J are the normal stall speed (Vs1). At this speed in the clean configuration, the airplane will stall. The normal stall speed is shown on the airspeed indicator at the low-speed end of the green arc. Answer (A) is incorrect. Maximum structural cruising speed (VNo) is indicated by points D and G. Answer (C) is incorrect. Maneuvering speed (VA) is indicated by points C and H.

24. What is ground effect? A. The result of the interference of the surface of the Earth with the airflow patterns about an airplane. B. The result of an alteration in airflow patterns increasing induced drag about the wings of an airplane. C. The result of the disruption of the airflow patterns about the wings of an airplane to the point where the wings will no longer support the airplane in flight.

Answer (A) is correct. DISCUSSION: Ground effect is due to the interference of the ground (or water) surface with the airflow patterns about the airplane in flight. As the wing encounters ground effect, there is a reduction in the upwash, downwash, and the wingtip vortices. The result is a reduction in induced drag. Thus, for a given angle of attack, the wing will produce more lift in ground effect than it does out of ground effect. Answer (B) is incorrect. The result of the alteration in airflow patterns about the wing decreases, not increases, the induced drag. Answer (C) is incorrect. The disruption of the airflow patterns about the wing decreases induced drag, which causes an increase, not decrease, in lift at a given angle of attack.

25. Floating caused by the phenomenon of ground effect will be most realized during an approach to land when at A. less than the length of the wingspan above the surface. B. twice the length of the wingspan above the surface. C. a higher-than-normal angle of attack.

Answer (A) is correct. DISCUSSION: Ground effect is most usually recognized when the airplane is within one-half of the length of its wingspan above the surface. It may extend as high as a full wingspan length above the surface. Due to an alteration of the airflow about the wings, induced drag decreases, which reduces the thrust required at low airspeeds. Thus, any excess speed during the landing flare may result in considerable floating. Answer (B) is incorrect. Ground effect generally extends up to only one wingspan length, not two. Answer (C) is incorrect. Floating will occur with excess airspeed, which results in a lower- than-normal, not higher-than-normal, angle of attack.

20. During a spin to the left, which wing(s) is/are stalled? A. Both wings are stalled. B. Neither wing is stalled. C. Only the left wing is stalled.

Answer (A) is correct. DISCUSSION: In order to enter a spin, an airplane must always first be stalled. Thereafter, the spin is caused when one wing is less stalled than the other wing. In a spin to the left, the right wing is less stalled than the left wing. Answer (B) is incorrect. Both wings must be at least partially stalled through the spin. Answer (C) is incorrect. Both wings are stalled; the right wing is simply less stalled than the left.

10. The four forces acting on an airplane in flight are A. lift, weight, thrust, and drag. B. lift, weight, gravity, and thrust. C. lift, gravity, power, and friction.

Answer (A) is correct. DISCUSSION: Lift is produced by the wings and opposes weight, which is the result of gravity. Thrust is produced by the engine/propeller and opposes drag, which is the resistance of the air as the airplane moves through it. Answer (B) is incorrect. Gravity reacts with the airplane's mass, thus producing weight, which opposes lift. Answer (C) is incorrect. Gravity results in weight, power produces thrust, and friction is a cause of drag. Power, gravity, velocity, and friction are not aerodynamic forces in themselves.

6. Which statement is true concerning primary flight controls? A. The effectiveness of each control surface increases with speed because there is more airflow over them. B. Only when all three primary flight controls move in sequence do the airflow and pressure distribution change over and around the airfoil. C. Primary flight controls include ailerons, rudder, elevator, and trim systems.

Answer (A) is correct. DISCUSSION: Rudder, aileron, and elevator effectiveness increase with speed because there is more airflow over the surface of the control device. Answer (B) is incorrect. Movement of any primary flight control surface changes the airflow and pressure distribution over and around the airfoil. Answer (C) is incorrect. The primary flight controls do not include trim systems; these are considered secondary flight controls.

8. Which device is a secondary flight control? A. Spoilers. B. Ailerons. C. Stabilators.

Answer (A) is correct. DISCUSSION: Spoilers are high-drag devices that assist an aircraft in slowing down and losing altitude without gaining extra speed. They are common on gliders and some high-speed aircraft. Answer (B) is incorrect. Ailerons control the roll of the aircraft and are a primary flight control surface. Answer (C) is incorrect. Stabilators function as both a horizontal stabilizer and an elevator, which makes them a primary control surface.

11. When are the four forces that act on an airplane in equilibrium? A. During unaccelerated level flight. B. When the aircraft is accelerating. C. When the aircraft is at rest on the ground.

Answer (A) is correct. DISCUSSION: The four forces (lift, weight, thrust, and drag) that act on an airplane are in equilibrium during unaccelerated level flight. Answer (B) is incorrect. Thrust must exceed drag in order for the airplane to accelerate. Answer (C) is incorrect. When the airplane is at rest on the ground, there are no aerodynamic forces acting on it other than weight (gravity).

30. What determines the longitudinal stability of an airplane? A. The location of the CG with respect to the center of lift. B. The effectiveness of the horizontal stabilizer, rudder, and rudder trim tab. C. The relationship of thrust and lift to weight and drag.

Answer (A) is correct. DISCUSSION: The location of the center of gravity with respect to the center of lift determines, to a great extent, the longitudinal stability of the airplane. Positive stability is attained by having the center of lift behind the center of gravity. Then the tail provides negative lift, creating a downward tail force, which counteracts the nose's tendency to pitch down. Answer (B) is incorrect. The rudder and rudder trim tab control the yaw, not the pitch. Answer (C) is incorrect. The relationship of thrust and lift to weight and drag affects speed and altitude, not longitudinal stability.

3. What is the purpose of the rudder on an airplane? A. To control yaw. B. To control overbanking tendency. C. To control roll.

Answer (A) is correct. DISCUSSION: The rudder is used to control yaw, which is rotation about the airplane's vertical axis. Answer (B) is incorrect. The ailerons (not the rudder) control overbanking. Overbanking tendency refers to the outside wing traveling significantly faster than the inside wing in a steep turn and generating incremental lift to raise the outside wing higher unless corrected by aileron pressure. Answer (C) is incorrect. Roll is movement about the longitudinal axis and is controlled by ailerons.

9. Trim systems are designed to do what? A. They relieve the pilot of the need to maintain constant pressure on the flight controls. B. They are used during approach and landing to increase wing lift. C. They move in the opposite direction from one another to control roll.

Answer (A) is correct. DISCUSSION: Trim systems are used to relieve the pilot of the need to maintain constant pressure on the flight controls. They include trim tabs, anti-servo tabs, and ground adjustable tabs. Answer (B) is incorrect. Flaps, not trim systems, are used during approach and landing to increase lift. This allows an increase in the angle of descent without increasing airspeed. Answer (C) is incorrect. Ailerons are control surfaces attached to each wing that move in the opposite direction from one another to control roll about the longitudinal axis.

12. What is the relationship of lift, drag, thrust, and weight when the airplane is in straight-and-level flight? A. Lift equals weight and thrust equals drag. B. Lift, drag, and weight equal thrust. C. Lift and weight equal thrust and drag.

Answer (A) is correct. DISCUSSION: When the airplane is in straight-and-level flight (assuming no change of airspeed), it is not accelerating, and therefore lift equals weight and thrust equals drag. Answer (B) is incorrect. Lift eauals weight and drag equals thrust. Answer (C) is incorrect. Lift and weight are equal and thrust and drag are equal, but the four are not equal to each other.

47. (Refer to Figure on page 38) A positive load factor of 2 at 80 mph would cause the airplane to A. stall. B. break apart. C. operate normally, as it is within the normal operating range.

Answer (A) is correct. DISCÚSSION: The Velocity vs. G-loads chart (Fig. 72) has indicated airspeed on the horizontal axis and load factor on the vertical axis. Locate the intersection of 2 on the vertical axis and 80 on the horizontal axis. Notice that operating where these coordinates intersect, which is the blue shaded area, would be indicative of a stalled condition. Answer (B) is incorrect. The airspeed causing the airplane to break apart is not measured or documented. Answer (C) is incorrect. The chart has indicated that the airplane would be in a stalled condition and not measured or documented within the red area. The red area is where the airplane is subjected to structural damage.

15. The term "angle of attack" is defined as the angle between the A. chord line of the wing and the relative wind. B. airplane's longitudinal axis and that of the air striking the airfoil. C. airplane's center line and the relative wind.

Answer (A) is correct. DISCÚSSION: The angle of attack is the angle between the wing chord line and the direction of the relative wind. The wing chord line is a straight line from the leading edge to the trailing edge of the wing. The relative wind is the direction of the airflow relative to the wing when the wing is moving through the air. Answer (B) is incorrect. Angle of attack is the angle between the wing chord line and the relative wind, not the airplane's longitudinal axis. Answer (C) is incorrect. The centerline of the airplane and its relationship to the relative wind is not a factor in defining angle of attack. Angle of attack is the relationship between the wing chord line and the relative wind.

37. In what flight condition are torque effects more pronounced in a single-engine airplane? A. Low airspeed, high power, high angle of attack. B. Low airspeed, low power, low angle of attack. C. High airspeed, high power, high angle of attack.

Answer (A) is correct. DISCÚSSION: The effect of torque increases in direct proportion to engine power and inversely to airspeed. Thus, at low airspeeds, high angles of attack, and high power settings, torque is the greatest. Answer (B) is incorrect. Torque effect is the greatest at high (not low) power settings, and high (not low) angle of attack. Answer (C) is incorrect. Torque effect is the greatest at low (not high) airspeeds.

45. During an approach to a stall, an increased load factor will cause the aircraft to A. stall at a higher airspeed. B. have a tendency to spin. C. be more difficult to control.

Answer (A) is correct. DISCÚSSION: The greater the load (whether from gross weight or from centrifugal force), the more lift is required. Therefore, an aircraft will stall at higher airspeeds when the load and/or load factor is increased. Answer (B) is incorrect. An aircraft's tendency to spin is not related to an increase in load factors. Answer (C) is incorrect. An aircraft's stability (not load factor) determines its controllability.

4. Which is not a primary flight control surface? A. Flaps. B. Stabilator. C. Ailerons.

Answer (A) is correct. DISCÚSSION: The three primary flight controls of an airplane are the ailerons, the elevator (or stabilator), and the rudder. Answer (B) is incorrect. The stabilator, or elevator, is a primary flight control surface. Answer (C) is incorrect. Ailerons are a primary flight control surface.

35. What is the effect of advancing the throttle in flight? A. Both aircraft groundspeed and angle of attack will increase. B. Airspeed will remain relatively constant but the aircraft will climb. C. The aircraft will accelerate, which will cause a turn to the right.

Answer (A) is correct. DISCÚSSION: When advancing the throttle, initially the groundspeed increases due to the corresponding increase in airspeed. This causes the aircraft to pitch up, increasing the angle of attack. Airspeed and lift continue to increase until the opposing forces equalize. Then, the aircraft will climb at ad relatively constant airspeed due to the increase in lift caused by excess thrust and additional airflow over the wing. Answer (B) is incorrect. When advancing the throttle, initially the airspeed and groundspeed increase, and the angle of attack will increase. The aircraft will climb at a relatively constant airspeed after the opposing forces equalize. Answer (C) is incorrect. When power is applied to a single-engine aircraft, it will tend to turn to the left due to the left-turning tendency created by the engine and propeller.

29. What force makes an airplane turn? A. The horizontal component of lift. B. The vertical component of lift. C. Centrifugal force.

Answer (A) is correct. DISCÚSSION: When the wings of an airplane are not level, the lift is not entirely vertical and tends to pull the airplane toward the direction of the lower wing. An airplane is turned when the pilot coordinates rudder, aileron, and elevator to bank in order to attain a horizontal component of lift. Answer (B) is incorrect. The vertical component of lift opposes weight and controls vertical, not horizontal, movement. Answer (C) is incorrect. The horizontal component of lift opposes centrifugal force, which acts toward the outside of the turn.

36. Loading an airplane to the most aft CG will cause the airplane to be A. less stable at all speeds. B. less stable at slow speeds, but more stable at high speeds. C. less stable at high speeds, but more stable at low speeds.

Answer (A) is correct. DISČÚSSION: Airplanes become less stable at all speeds as the center of gravity is moved backward. The rearward center of gravity limit is determined largely by considerations of stability. Answer (B) is incorrect. Ăn aft CG will cause the airplane to be less stable at all speeds. Answer (C) is incorrect. An aft CG will cause the airplane to be less stable at all speeds.

44. The amount of excess load that can be imposed on the wing of an airplane depends upon the A. position of the CG. B. speed of the airplane. C. abruptness at which the load is applied.

Answer (B) is correct. DISCUSSION: The amount of excess load that can be imposed on the wing depends upon how fast the airplane is flying. At low speeds, the maximum available lifting force of the wing is only slightly greater than the amount necessary to support the weight of the airplane. Thus, any excess load would simply cause the airplane to stall. At high speeds, the lifting capacity of the wing is so great (as a result of the greater flow of air over the wings) that a sudden movement of the elevator controls (strong gust of wind) may increase the load factor beyond safe limits. This is why maximum speeds are established by airplane manufacturers. Answer (A) is incorrect. The position of the CG affects the stability of the airplane but not the total load the wings can support. Answer (C) is incorrect. It is the amount of load, not the the abruptness of the load. However, abruptness of the maneuver can affect the amount of the load.

14. (Refer to Figure on page 52) The acute angle A is the angle of A. incidence. B. attack. C. dihedral.

Answer (B) is correct. DISCUSSION: The angle between the relative wind and the wing chord line is the angle of attack. The wing chord line is a straight line from the leading edge to the trailing edge of the wing. Answer (A) is incorrect. The angle of incidence is the acute angle formed by the chord line of the wing and the longitudinal axis of the airplane. Answer (C) is incorrect. The dihedral is the angle at which the wings are slanted upward from the wing root to the wingtip.

16. The angle between the chord line of an airfoil and the relative wind is known as the angle of A. lift. B. attack. C. incidence.

Answer (B) is correct. DISCUSSION: The angle of attack is the acute angle between the chord line of the wing and the direction of the relative wind. Answer (A) is incorrect. The angle of lift is a nonsense term. Answer (C) is incorrect. The angle of incidence is the acute angle formed by the chord line of the wing and the longitudinal axis of the airplane.

5. The elevator controls movement around which axis? A. Longitudinal. B. Lateral. C. Vertical.

Answer (B) is correct. DISCUSSION: The elevator is the primary control device for changing the pitch attitude of an airplane about the lateral axis. Answer (A) is incorrect. Ailerons are control surfaces attached to each wing that move in the opposite direction from one another to control roll about the longitudinal axis. Answer (C) is incorrect. The rudder controls movement of the aircraft about its vertical axis.

34. What causes an airplane (except a T-tail) to pitch nosedown when power is reduced and controls are not adjusted? A. The CG shifts forward when thrust and drag are reduced. B. The downwash on the elevators from the propeller slipstream is reduced and elevator effectiveness is reduced. C. When thrust is reduced to less than weight, lift is also reduced and the wings can no longer support the weight.

Answer (B) is correct. DISCUSSION: The relative wind on the tail is the result of the airplane's movement through the air and the propeller slipstream. When that slipstream is reduced, the horizontal stabilizer (except a T-tail) will produce less negative lift and the nose will pitch down. Answer (A) is incorrect. The CG is not affected by changes in thrust or drag. Answer (C) is incorrect. Thrust and weight have no relationship to each other.

38. The left turning tendency of an airplane caused by P-factor is the result of the A. clockwise rotation of the engine and the propeller turning the airplane counterclockwise. B. propeller blade descending on the right, producing more thrust than the ascending blade on the left. C. gyroscopic forces applied to the rotating propeller blades acting 90° in advance of the point the force was applied.

Answer (B) is correct. DISCÚSSION: Asymmetric propeller loading (P-factor) occurs when the airplane is flown at a high angle of attack. The downward-moving blade on the right side of the propeller (as seen from the rear) has a higher angle of attack, which creates higher thrust than the upward-moving blade on the left. Thus, the airplane yaws around the vertical axis to the left. Answer (A) is incorrect. Torque reaction (not P-factor) is a result of the clockwise rotation of the engine and the propeller turning the airplane counterclockwise. Answer (C) is incorrect. Gyroscopic precession (not P-factor) is a result of the gyroscopic forces applied to the rotating propeller blades acting 90° in advance of the point the force was applied.

18. As altitude increases, the indicated airspeed at which a given airplane stalls in a particular configuration will A. decrease as the true airspeed decreases. B. decrease as the true airspeed increases. C. remain the same regardless of altitude.

Answer (C) is correct. DISCUSSION: All the performance factors of an airplane are dependent upon air density. As air density decreases, the airplane stalls at a higher true airspeed. However, you cannot detect the effect of high density altitude on your airspeed indicator. Accordingly, an airplane will stall in a particular configuration at the same indicated airspeed regardless of altitude. Answer (A) is incorrect. True airspeed increases, not decreases, with increased altitude, and indicated airspeed at which an airplane stalls remains the same (does not decrease). Answer (B) is incorrect. The indicated airspeed of the stall does not change with increased altitude.

32. Changes in the center of pressure of a wing affect the aircraft's A. lift/drag ratio. B. lifting capacity. C. aerodynamic balance and controllability.

Answer (C) is correct. DISCUSSION: Center of pressure (CP) is the imaginary but determinable point at which all of the upward lift forces on the wing are concentrated. In general, at high angles of attack the CP moves forward, while at low angles of attack the CP moves aft. The relationship of the CP to center of gravity (CG) affects both aerodynamic balance and controllability. Answer (A) is incorrect. The lift/drag ratio is determined by angle of attack. Answer (B) is incorrect. Lifting capacity is affected by angle of attack, airspeed, and wing planform.

2. One of the main functions of flaps during approach and landing is to A. decrease the angle of descent without increasing the airspeed. B. permit a touchdown at a higher indicated airspeed. C. increase the angle of descent without increasing the airspeed.

Answer (C) is correct. DISCUSSION: Extending the flaps increases the wing camber and the angle of attack of the wing. This increases wing lift and induced drag, which enables the pilot to increase the angle of descent without increasing the airspeed. Answer (A) is incorrect. Extending the flaps increases lift and induced drag, which enables the pilot to increase (not decrease) the angle of descent without increasing the airspeed. Answer (B) is incorrect. Flaps increase lift at slow airspeed, which permits touchdown at a lower (not higher) indicated airspeed.

22. Why is frost considered hazardous to flight? A. Frost changes the basic aerodynamic shape of the airfoils, thereby increasing lift. B. Frost slows the airflow over the airfoils, thereby increasing control effectiveness. C. Frost spoils the smooth flow of air over the wings, thereby decreasing lifting capability.

Answer (C) is correct. DISCUSSION: Frost does not change the basic aerodynamic shape of the wing, but the roughness of its surface spoils the smooth flow of air, thus causing an increase in drag and an early airflow separation over the wing, resulting in a loss of lift. Answer (A) is incorrect. Frost is thin and does not change the basic aerodynamic shape of the airfoil. Frost causes a decrease in lift. Answer (B) is incorrect. The smooth flow of air over the airfoil is affected, not control effectiveness.

19. In what flight condition must an aircraft be placed in order to spin? A. Partially stalled with one wing low. B. In a steep diving spiral. C. Stalled.

Answer (C) is correct. DISCUSSION: In order to enter a spin, an airplane must always first be stalled. Thereafter, the spin is caused when one wing becomes less stalled than the other wing. Answer (A) is incorrect. The aircraft must first be fully stalled. Answer (B) is incorrect. A steep diving spiral has a relatively low angle of attack and thus does not produce a stall.

48. (Refer to Figure on page 38) What load factor would be created if positive 15 feet per second gusts were encountered at 120 mph? A. 2.8 B. 3.0 C. 2.0

Answer (C) is correct. DISCÚSSION: Begin at the bottom of Fig. 72 by locating 120 mph and then move up vertically to the positive 15-feet-per- second (+15 fps) diagonal white line. Next, move left horizontally to determine the load factor of 2.0. Answer (A) is incorrect. A load factor of 2.8 would be created if gusts of 30 fps were encountered at 120 mph. Answer (B) is incorrect. A load factor of 3.0 would be created if gusts in excess of 30 fps were encountered at 120 mph.

13. Which statement relates to Bernoulli's principle? A. For every action, there is an equal and opposite reaction. B. An additional upward force is generated as the lower surface of the wing deflects air downward. C. Air traveling faster over the curved upper surface of an airfoil causes lower pressure on the top surface.

Answer (C) is correct. DISCÚSSION: Bernoulli's principle states in part that the internal pressure of a fluid (liquid or gas) decreases at points where the speed of the fluid increases. This same principle applies to air flowing over the curved upper surface of a wing. Answer (A) is incorrect. Newton's Third Law of Motion states- that, for every action, there is an equal and opposite reaction. Answer (B) is incorrect. The additional upward force that is generated as the lower surface of the wing deflects air downward is related to Newton's Third Law of Motion.

40. (Refer to Figure on page 36) If an airplane weighs 3,300 pounds, what approximate weight would the airplane structure be required to support during a 30° banked turn while maintaining altitude? A. 1,200 pounds. B. 3,100 pounds. C. 3,960 pounds.

Answer (C) is correct. DISCÚSSION: Look on the left side of the chart in Fig. 2 to see that, at a 30° bank angle, the load factor is 1.154. Thus, a 3,300-lb. airplane in a 30° bank would require its wings to support 3,808.2 lb. (3,300 lb. × 1.154). The closest answer choice to this value is 3,960 lb. Answer (A) is incorrect. An airplane supporting a load of 1,200 lb. in a 30° banked turn would weigh 1,000 lb., not 3,300 lb. Look on the left side of the chart in Fig. 2 to see that, at a 30° bank angle, the load factor is 1.154. Answer (B) is incorrect. An airplane supporting a load of 3,100 lb. in a 30° banked turn would weigh 2,583 lb., not 3,300 lb. Look on the left side of the chart in Fig. 2 to see that, at a 30° bank angle, the load factor is 1.154.

46. Structural damage or failure is more likely to occur in smooth air at speeds above A. VNO B. VA. C. VNE

Answer (C) is correct. DISCÚSSION: Never exceed speed (VNE) is a design limit speed where load factors could be exceeded with airspeeds in excess of VNE from a variety of phenomena. Operating above this speed is prohibited may since it result in damage or structural failure. Answer (A) is incorrect. VNO is the maximum structural cruising speed. Do not exceed this speed except in smooth air. Answer (B) is incorrect. VA is the design maneuvering speed. It is the speed below which you can move a single flight control one time to its full deflection for one axis of airplane rotation only (pitch, roll, or yaw), in smooth air, without risk of damage to the airplane.

41. (Refer to Figure on page 36) If an airplane weighs 2,300 pounds, what approximate weight would the airplane structure be required to support during a 60° banked turn while maintaining altitude? A. 2,300 pounds. B. 3,400 pounds. C. 4,600 pounds.

Answer (C) is correct. DISCÚSSION: Note on Fig. 2 that, at a 60° bank angle, the load factor is 2. Thus, a 2,300-lb. airplane in a 60° bank would require its wings to support 4,600 lb. (2,300 lb. × 2). Answer (A) is incorrect. An airplane supporting a load of 2,300 lb. in a 60° banked turn would weigh 1,150 lb., not 2,300 lb. Note on Fig. 2 that, at a 60° bank angle, the load factor is 2. Answer (B) is incorrect. An airplane supporting a load of 3,400 lb. in a 60° banked turn would weigh 1,700 lb., not 2,300 lb. Note on Fig. 2 that, at a 60° bank angle, the load factor is 2.

28. Ground effect is most likely to result in which problem? A. Settling to the surface abruptly during landing. B. Becoming airborne before reaching recommended takeoff speed. C. Inability to get airborne even though airspeed is sufficient for normal takeoff needs.

Answer (B) is correct. DISCÚSSION: Due to the reduction of induced drag in ground effect, the airplane may seem capable of becoming airborne well below the recommended takeoff speed. However, as the airplane rises out of ground effect (a height greater than the wingspan) with a deficiency of speed, the increase in induced drag may result in very marginal initial climb performance. In extreme cases, the airplane may become airborne initially, with a deficiency of airspeed, only to settle back on the runway when attempting to fly out of the ground effect area. Answer (A) is incorrect. The airplane will experience a little extra lift on landing due to the reduction in induced drag, causing it to float rather than settle abruptly. Answer (C) is incorrect. Ground effect would not hamper the airplane from becoming airborne if the airspeed were sufficient for normal takeoff. Ground effect may allow the airplane to become airborne before reaching the recommended takeoff speed.

27. An aircraft leaving ground effect during takeoff will A. experience a reduction in ground friction and require a slight power reduction. B. experience an increase in induced drag and a decrease in performance. C. require a lower angle of attack to maintain the same lift coefficient.

Answer (B) is correct. DISCÚSSION: During the takeoff phase of flight, ground effect produces some important relationships. The airplane leaving ground effect after takeoff encounters just the reverse of the airplane entering ground effect during landing; i.e., the airplane leaving ground effect will (1) require an increase in angle of attack to maintain the same lift coefficient (2) experience an increase in induced drag and thrust required (3) experience a decrease in stability and a nose-up change in moment, and (4) produce a reduction in static source pressure and an increase in indicated airspeed. Answer (A) is incorrect. While the aerodynamic characteristics of the tail surfaces and the fuselage are altered by ground effects, the principal effects due to proximity of the ground are the changes in the aerodynamic characteristics of the wing, not a reduction in ground friction. As the wing encounters ground effect and is maintained at a constant lift coefficient, there is consequent reduction in the upwash, downwash, and the wingtip vortices. Answer (C) is incorrect. The aircraft will require a higher angle of attack to maintain the same lift coefficient as when it was in ground effect.

26. What must a pilot be aware of as a result of ground effect? A. Wingtip vortices increase creating wake turbulence problems for arriving and departing aircraft. B. Induced drag decreases; therefore, any excess speed at the point of flare may cause considerable floating. C. A full stall landing will require less up elevator deflection than would a full stall when done free of ground effect.

Answer (B) is correct. DISCÚSSION: Ground effect reduces the upwash, downwash, and vortices caused by the wings, resulting in a decrease in induced drag. Thus, thrust required at low airspeeds will be reduced, and any excess speed at the point of flare may cause considerable floating. Answer (A) is incorrect. Wingtip vortices are decreased, not increased. Answer (C) is incorrect. A full stall landing will require more, not less, up elevator deflection since the wing will require a lower angle of attack in ground effect to produce the same amount of lift.

42. (Refer to Figure on page 36) If an airplane weighs 4,500 pounds, what approximate weight would the airplane structure be required to support during a 45° banked turn while maintaining altitude? A. 4,500 pounds. B. 6,750 pounds. C. 7,200 pounds.

Answer (B) is correct. DISCÚSSION: Look on the left side of the chart in Fig. 2 under 45° and note that the load factor curve is 1.414. Thus, 4,500-lb. airplane in a 45° bank would require its wings to support 6,363 lb. (4,500 lb. × 1.414). The closest answer choice to this value is 6,750 lb. Answer (A) is incorrect. An airplane supporting a load of 4,500 lb. in a 45° banked turn would weigh 3,000 lb., not 4,500 lb. Look on the left side of the chart under 45° and note that the load factor curve is 1.414. Answer (C) is incorrect. An airplane supporting a load of 7,200 lb. in a 45° banked turn wuld weigh 4,800 lb., not 4,500 lb. Look on the left side of the chart under 45° and note that the load factor curve is 1.414.

39. When does P-factor cause the airplane to yaw to the left? A. When at low angles of attack. B. When at high angles of attack. C. When at high airspeeds.

Answer (B) is correct. DISCÚSSION: P-factor or asymmetric propeller loading occurs when an airplane is flown at a high angle of attack because the downward-moving blade on the right side of the propeller (as seen from the rear) has a higher angle of attack, which creates higher thrust than the upward-moving blade on the left. Thus, the airplane yaws around the vertical axis to the left. Answer (A) is incorrect. At low angles of attack, both sides of the propeller have similar angles of attack and "pull" the airplane straight ahead. Answer (C) is incorrect. At high speeds, an airplane is not at a high angle of attack.

43. Which basic flight maneuver increases the load factor on an airplane as compared to straight-and- level flight? A. Climbs. B. Turns. C. Stalls.

Answer (B) is correct. DISCÚSSION: Turns increase the load factor because the lift from the wings is used to pull the airplane around a corner as well as to offset the force of gravity. The wings must carry the airplane's weight plus offset centrifugal force during the turn. For example, a 60° bank results in a load factor of 2; i.e., the wings must support twice the weight they do in level flight. Answer (A) is incorrect. The wings only have to carry the weight of the airplane once the airplane is established in a climb. Answer (C) is incorrect. In a stall, the wings are not producing lift.

17. The angle of attack at which an airplane wing stalls will A. increase if the CG is moved forward. B. change with an increase in gross weight. C. remain the same regardless of gross weight.

Answer (C) is correct. DISCUSSION: A given airplane wing will always stall at the same angle of attack regardless of airspeed, weight, load factor, or density altitude. Each wing has a particular angle of attack (the critical angle of attack) at which the airflow separates from the upper surface of the wing and the stall occurs. Answer (A) is incorrect. A change in CG will not change the wing's critical angle of attack. Answer (B) is incorrect. The critical angle of attack does not change when gross weight changes.