# 80 - Principles of Flight Total questions: 91 --- ### Q1: With regard to the forces acting, how can stationary gliding be described? ^q1 - A) The sum of air forces acts along the direction of air flow - B) The sum the air forces acts along with the lift force - C) The lift force compensates the drag force - D) The sum of air forces compensates the gravity force **Correct: D)** > **Explanation:** --- ### Q2: What is the result of extending flaps with increasing aerofoil camber? ^q2 - A) Maximum permissable speed increases - B) Minimum speed increases - C) Minimum speed decreases - D) C.G. position moves forward **Correct: C)** > **Explanation:** --- ### Q3: Following a single-wing stall and pitch-down moment, how can a spin be prevented? ^q3 - A) Deflect all rudders opposite to lower wing - B) Rudder opposite lower wing, releasing elevator to build up speed - C) Pushing the elevator to build up speed to re-attach airflow on wings - D) Pulling the elevator to bring the plane back to normal attitude **Correct: B)** > **Explanation:** --- ### Q4: Stabilization around the lateral axis during cruise is achieved by the... ^q4 - A) Wing flaps. - B) Horizontal stabilizer - C) Airlerons. - D) Vertical rudder **Correct: B)** > **Explanation:** --- ### Q5: Flying with speeds higher than the never-exceed-speed (vNE) may result in... ^q5 - A) Reduced drag with increased control forces. - B) An increased lift-to-drag ratio and a better glide angle. - C) Too high total pressure resulting in an unusable airspeed indicator. - D) Flutter and mechanically damaging the wings. **Correct: D)** > **Explanation:** --- ### Q6: Considering longitudinal stability, which C.G. position is most dangerous with a normal gliding plane? ^q6 - A) Position beyond the front C.G. limit - B) Position too far aside permissable C.G. limits. - C) Position far back within permissable C.G. limits - D) Position beyond the rear C.G. limit **Correct: D)** > **Explanation:** --- ### Q7: The static pressure of gases work... ^q7 - A) In all directions. - B) Only in flow direction. - C) Only in the direction of the total pressure. - D) Only vertical to the flow direction. **Correct: A)** > **Explanation:** --- ### Q8: Bernoulli's equation for frictionless, incompressible gases states that... ^q8 - A) Total pressure = dynamic pressure - static pressure. - B) Total pressure = dynamic pressure + static pressure. - C) Static pressure = total pressure + dynamic pressure - D) Dynamic pressure = total pressure + static pressure. **Correct: B)** > **Explanation:** --- ### Q9: If surrounded by airflow (v > 0), any arbitrarily shaped body produces... ^q9 - A) Drag and lift. - B) Drag. - C) Lift without drag. - D) Constant drag at any speed. **Correct: B)** > **Explanation:** --- ### Q10: All aerodynamic forces can be considered to act on a single point. This point is called... ^q10 - A) Center of gravity. - B) Lift point. - C) Transition point. - D) Center of pressure. **Correct: D)** > **Explanation:** --- ### Q11: The center of pressure is the theoretical point of origin of... ^q11 - A) Only the resulting total drag. - B) Gravity forces of the profile. - C) All aerodynamic forces of the profile. - D) Gravity and aerodynamic forces. **Correct: C)** > **Explanation:** --- ### Q12: Number 2 in the drawing corresponds to the... See figure (PFA-010) Siehe Anlage 1 ^q12 - A) Profile thickness. - B) Chord line. - C) Chord line. - D) Angle of attack. **Correct: C)** > **Explanation:** --- ### Q13: Number 3 in the drawing corresponds to the... See figure (PFA-010) Siehe Anlage 1 ^q13 - A) Camber line. - B) Thickness. - C) Chord. - D) Chord line. **Correct: A)** > **Explanation:** --- ### Q14: The angle of attack is the angle between... ^q14 - A) The chord line and the longitudinal axis of an aeroplane. - B) The chord line and the oncoming airflow. - C) The wing and the fuselage of an aeroplane - D) The undisturbed airflow and the longitudinal axis of an aeroplane. **Correct: B)** > **Explanation:** --- ### Q15: The ratio of span and mean chord length is referred to as... ^q15 - A) Trapezium shape. - B) Tapering. - C) Aspect ratio. - D) Wing sweep. **Correct: C)** > **Explanation:** --- ### Q16: Which point on the aerofoil is represented by number 3? See figure (PFA-009) Siehe Anlage 2 ^q16 - A) Stagnation point - B) Separation point - C) Center of pressure - D) Transition point **Correct: D)** > **Explanation:** --- ### Q17: Which point on the aerofoil is represented by number 4? See figure (PFA-009) Siehe Anlage 2 ^q17 - A) Transition point - B) Stagnation point - C) Center of pressure - D) Separation point **Correct: D)** > **Explanation:** --- ### Q18: Which point on the aerofoil is represented by number 1? See figure (PFA-009) Siehe Anlage 2 ^q18 - A) Center of pressure - B) Stagnation point - C) Stagnation point - D) Transition point **Correct: C)** > **Explanation:** --- ### Q19: What pattern can be found at the stagnation point? ^q19 - A) The boundary layer starts separating on the upper surface of the profile - B) All aerodynamic forces can be considered as attacking at this single point - C) The laminar boundary layer changes into a turbulent boundary layer - D) Streamlines are divided into airflow above and below the profile **Correct: D)** > **Explanation:** --- ### Q20: What pressure pattern can be observed at a lift-generating wing profile at positive angle of attack? ^q20 - A) Low pressure is created above, higher pressure below the profile - B) Pressure above remains unchanged, higher pressure is created below the profile - C) High pressure is created above, lower pressure below the profile - D) Pressure below remains unchanged, lower pressure is created above the profile **Correct: A)** > **Explanation:** --- ### Q21: In which way does the position of the center of pressure move at a positively shaped profile with increasing angle of attack? ^q21 - A) It moves to the wing tips - B) It moves forward until reaching the critical angle of attack - C) It moves forward until reaching the critical angle of attack - D) It moves forward first, then backward **Correct: C)** > **Explanation:** --- ### Q22: Which statement about lift and angle of attack is correct? ^q22 - A) Increasing the angle of attack too far may result in a loss of lift and an airflow separation - B) Increasing the angle of attack results in less lift being generated by the aerofoil - C) Decreasing the angle of attack results in more drag being generated by the aerofoil - D) Too large angles of attack can lead to an exponential increase in lift **Correct: A)** > **Explanation:** --- ### Q23: Which statement about the airflow around an aerofoil is correct if the angle of attack increases? ^q23 - A) The stagnation point moves down - B) The center of pressure moves down - C) The center of pressure moves up - D) The stagnation point moves up **Correct: A)** > **Explanation:** --- ### Q24: Which statement about the airflow around an aerofoil is correct if the angle of attack decreases? ^q24 - A) The center of pressure moves aft - B) The center of pressure moves forward - C) The stagnation point moves down - D) The stagnation point remains constant **Correct: A)** > **Explanation:** --- ### Q25: The angle (alpha) shown in the figure is referred to as... See figure (PFA-003) DoF: direction of airflow Siehe Anlage 3 ^q25 - A) Lift angle. - B) Angle of attack. - C) Angle of incidence. - D) Angle of inclination **Correct: B)** > **Explanation:** --- ### Q26: In order to improve the stall characteristics of an aircraft, the wing is twisted outwards (the angle of incidence varies spanwise). This is known as... ^q26 - A) Arrow shape. - B) V-form - C) Geometric washout. - D) Aerodynamic washout. **Correct: C)** > **Explanation:** --- ### Q27: Which option states a benefit of wing washout? ^q27 - A) With the washout the form drag reduces at high speeds - B) Greater hardness because the wing can withstand more torsion forces - C) At high angles of attack the effectiveness of the aileron is retained as long as possible - D) Structurally the wing is made more rigid against rotation **Correct: C)** > **Explanation:** --- ### Q28: Which statement concerning the angle of attack is correct? ^q28 - A) Increasing the angle of attack results in decreasing lift - B) The angle of attack cannot be negative - C) A too large angle of attack may result in a loss of lift - D) The angle of attack is constant throughout the flight **Correct: C)** > **Explanation:** --- ### Q29: When increasing the airflow speed by a factor of 2 while keeping all other parameters constant, how does the parasite drag change approximately? ^q29 - A) It decreases by a factor of 2 - B) It increases by a factor of 2 - C) It decreases by a factor of 4 - D) It increases by a factor of 4 **Correct: D)** > **Explanation:** --- ### Q30: The drag coefficient... ^q30 - A) Is proportional to the lift coefficient - B) Increases with increasing airspeed. - C) May range from zero to an infinite positive value - D) Cannot be lower than a non-negative, minimal value. **Correct: D)** > **Explanation:** --- ### Q31: Pressure compensation on an wing occurs at the... ^q31 - A) Wing tips. - B) Leading edge. - C) Trailing edge. - D) Wing roots **Correct: A)** > **Explanation:** --- ### Q32: Which of the following options is likely to produce large induced drag? ^q32 - A) Large aspect ratio - B) Small aspect ratio - C) Low lift coefficients - D) Tapered wings **Correct: B)** > **Explanation:** --- ### Q33: Which parts of an aircraft mainly affect the generation of induced drag? ^q33 - A) The front part of the fuselage. - B) The outer part of the ailerons. - C) The lower part of the gear. - D) The wing tips. **Correct: D)** > **Explanation:** --- ### Q34: Where is interference drag generated? ^q34 - A) At the ailerons - B) At the the gear - C) At the wing root - D) Near the wing tips **Correct: C)** > **Explanation:** --- ### Q35: Pressure drag, interference drag and friction drag belong to the group of the... ^q35 - A) Parasite drag - B) Main resistance. - C) Induced drag. - D) Total drag. **Correct: A)** > **Explanation:** --- ### Q36: How do induced drag and parasite drag change with increasing airspeed during a horizontal and stable cruise flight? ^q36 - A) Parasite drag decreases and induced drag increases - B) Induced drag decreases and parasite drag increases - C) Parasite drag decreases and induced drag decreases - D) Induced drag increases and parasite drag increases **Correct: B)** > **Explanation:** --- ### Q37: Which of the listed wing shapes has the lowest induced drag? ^q37 - A) Rectangular shape - B) Trapezoidal shape - C) Elliptical shape - D) Double trapezoidal shape **Correct: C)** > **Explanation:** --- ### Q38: Which effect does a decreasing airspeed have on the induced drag during a horizontal and stable cruise flight? ^q38 - A) The induced drag will slightly decrease - B) The induced drag will collapse - C) The induced drag will increase - D) The induced drag will remain constant **Correct: C)** > **Explanation:** --- ### Q39: Which statement about induced drag during the horizontal cruise flight is correct? ^q39 - A) Induced drag decreases with increasing airspeed - B) Induced drag has a minimum at a certain speed and increases at higher as well as lower speeds - C) Induced drag has a maximum at a certain speed and decreases at higher as well as lower speeds - D) Induced drag increases with increasing airspeed **Correct: A)** > **Explanation:** --- ### Q40: Which kinds of drag contribute to total drag? ^q40 - A) Interference drag and parasite drag - B) Induced drag and parasite drag - C) Induced drag, form drag, skin-friction drag - D) Form drag, skin-friction drag, interference drag **Correct: B)** > **Explanation:** --- ### Q41: How do lift and drag change when approaching a stall condition? ^q41 - A) Lift decreases and drag increases - B) Lift and drag increase - C) Lift increases and drag decreases - D) Lift and drag decrease **Correct: A)** > **Explanation:** --- ### Q42: In case of a stall it is important to... ^q42 - A) Increase the angle of attack and increase the speed. - B) Decrease the angle of attack and increase the speed. - C) Increase the angle of attack and reduce the speed. - D) Increase the bank angle and reduce the speed. **Correct: B)** > **Explanation:** --- ### Q43: During a stall, the lift... ^q43 - A) Decreases and drag increases. - B) Increases and drag increases. - C) Decreases and drag decreases - D) Increases and drag decreases. **Correct: A)** > **Explanation:** --- ### Q44: The critical angle of attack... ^q44 - A) Decreases with forward center of gravity position. - B) Changes with increasing weight. - C) Is independent of the weight. - D) Increases with backward center of gravity position. **Correct: C)** > **Explanation:** --- ### Q45: What leads to a decreased stall speed Vs (IAS)? ^q45 - A) Lower density - B) Decreasing weight - C) Lower altitude - D) Higher load factor **Correct: B)** > **Explanation:** --- ### Q46: Which statement regarding a spin is correct? ^q46 - A) During recovery the ailerons should be kept neutral - B) During the spin the speed constantly increases - C) During recovery the ailerons should be crossed - D) Only very old aeroplanes have a risk of spinning **Correct: A)** > **Explanation:** --- ### Q47: The laminar boundary layer on the aerofoil is located between... ^q47 - A) The stagnation point and the center of pressure. - B) The stagnation point and the transition point. - C) The transition point and the separation point. - D) The transition point and the center of pressure. **Correct: B)** > **Explanation:** --- ### Q48: What types of boundary layers can be found on an aerofoil? ^q48 - A) Laminar boundary layer along the complete upper surface with non-separated airflow - B) Turbulent layer at the leading wing areas, laminar boundary layer at the trailing areas - C) Turbulent boundary layer along the complete upper surface with separated airflow - D) Laminar layer at the leading wing areas, turbulent boundary layer at the trailing areas **Correct: D)** > **Explanation:** --- ### Q49: How does a laminar boundary layer differ from a turbulent boundary layer? ^q49 - A) The laminar boundary layer is thinner and provides more skin-friction drag - B) The turbulent boundary layer can follow the airfoil camber at higher angles of attack - C) The laminar boundary layer produces lift, the turbulent boundary layer produces drag - D) The turbulent boundary layer is thicker and provides less skin-friction drag **Correct: B)** > **Explanation:** --- ### Q50: What structural item provides lateral stability to an airplane? ^q50 - A) Wing dihedral - B) Vertical tail - C) Differential aileron deflection - D) Elevator **Correct: A)** > **Explanation:** --- ### Q51: Which statement describes a situation of static stability? ^q51 - A) An aircraft distorted by external impact will return to the original position - B) An aircraft distorted by external impact will tend to an even more deflected position - C) An aircraft distorted by external impact will maintain the deflected position - D) An aircraft distorted by external impact can return to its original position by rudder input **Correct: A)** > **Explanation:** --- ### Q52: Which constructive feature is shown in the figure? See figure (PFA-006) L: Lift Siehe Anlage 4 ^q52 - A) Lateral stability by wing dihedral - B) Differential aileron deflection - C) Directional stability by lift generation - D) Longitudinal stability by wing dihedral **Correct: A)** > **Explanation:** --- ### Q53: Longitudinal stability is referred to as stability around which axis? ^q53 - A) Lateral axis - B) Propeller axis - C) Longitudinal axis - D) Vertical axis **Correct: A)** > **Explanation:** --- ### Q54: Stability around which axis is mainly influenced by the center of gravity's longitudinal position? ^q54 - A) Longitudinal axis - B) Lateral axis - C) Gravity axis - D) Vertical axis **Correct: B)** > **Explanation:** --- ### Q55: What structural item provides directional stability to an airplane? ^q55 - A) Differential aileron deflection - B) Wing dihedral - C) Large elevator - D) Large vertical tail **Correct: D)** > **Explanation:** --- ### Q56: Rotation around the vertical axis is called... ^q56 - A) Slipping. - B) Pitching. - C) Yawing. - D) Rolling. **Correct: C)** > **Explanation:** --- ### Q57: Rotation around the lateral axis is called... ^q57 - A) Yawing. - B) Pitching. - C) Rolling. - D) Stalling. **Correct: B)** > **Explanation:** --- ### Q58: The critical angle of attack... ^q58 - A) Increases with a front centre of gravity - B) Is changed by different aircraft weights. - C) Is not changed by different aircraft weights. - D) Decreases with a rear centre of gravity. **Correct: C)** > **Explanation:** --- ### Q59: In straight and level flight with constant performance of the engine, the angle of attack at the wing is... ^q59 - A) Smaller than in a descent. - B) Greater than in a climb. - C) Greater than at take-off. - D) Smaller than in a climb. **Correct: D)** > **Explanation:** --- ### Q60: What is the function of the horizontal tail (among other things)? ^q60 - A) To stabilise the aeroplane around the longitudinal axis - B) To stabilise the aeroplane around the lateral axis - C) To initiate a curve around the vertical axis - D) To stabilise the aeroplane around the vertical axis **Correct: B)** > **Explanation:** --- ### Q61: The elevator moves an aeroplane around the... ^q61 - A) Vertical axis. - B) Longitudinal axis. - C) Elevator axis. - D) Lateral axis. **Correct: D)** > **Explanation:** --- ### Q62: What has to be considered with regard to the center of gravity position? ^q62 - A) By moving the elevator trim tab, the center of gravity can be shifted into a correct position. - B) Only correct loading can assure a correct and safe center of gravity position. - C) The center of gravity's position can only be determined during flight. - D) By moving the aileron trim tab, the center of gravity can be shifted into a correct position. **Correct: B)** > **Explanation:** --- ### Q63: Rudder deflections result in a turn of the aeroplane around the... ^q63 - A) Rudder axis. - B) Vertical axis. - C) Lateral axis - D) Longitudinal axis. **Correct: B)** > **Explanation:** --- ### Q64: Deflecting the rudder to the left causes... ^q64 - A) Pitching of the aircraft to the left - B) Yawing of the aircraft to the left. - C) Pitching of the aircraft to the right. - D) Yawing of the aircraft to the right. **Correct: B)** > **Explanation:** --- ### Q65: What is the advantage of differential aileron movement? ^q65 - A) The drag of the downwards deflected aileron is lowered and the adverse yaw is smaller - B) The total lift remains constant during aileron deflection - C) The ratio of the drag coefficient to lift coefficient is increased - D) The adverse yaw is higher **Correct: A)** > **Explanation:** --- ### Q66: Which design feature can compensate for adverse yaw? ^q66 - A) Which design feature can compensate for adverse yaw? - B) Differential aileron defletion - C) Full deflection of the aileron - D) Wing dihedral **Correct: B)** > **Explanation:** --- ### Q67: Differential aileron deflection is used to... ^q67 - A) Reduce wake turbulence. - B) Avoid a stall at low angles of attack. - C) Keep the adverse yaw low. - D) Increase the rate of descent. **Correct: C)** > **Explanation:** --- ### Q68: The right aileron deflects upwards, the left downwards. How does the aircraft react? ^q68 - A) Rolling to the left, no yawing - B) Rolling to the right, yawing to the left - C) Rolling to the left, yawing to the right - D) Rolling to the right, yawing to the right **Correct: B)** > **Explanation:** --- ### Q69: The aerodynamic rudder balance... ^q69 - A) Reduces the control surfaces. - B) Delays the stall. - C) Reduces the control stick forces. - D) Improves the rudder effectiveness. **Correct: C)** > **Explanation:** --- ### Q70: Which constructive feature has the purpose to reduce stearing forces? ^q70 - A) T-tail - B) Differential aileron deflection - C) Vortex generators - D) Aerodynamic rudder balance **Correct: D)** > **Explanation:** --- ### Q71: What is the function of the static rudder balance? ^q71 - A) To prevent control surface flutter - B) To trim the controls almost without any force - C) To increase the control stick forces - D) To limit the control stick forces **Correct: A)** > **Explanation:** --- ### Q72: The trim tab at the elevator is defelected upwards. In which position is the corresponding indicator? ^q72 - A) Neutral position - B) Nose-down position - C) Nose-up position - D) Laterally trimmed **Correct: B)** > **Explanation:** --- ### Q73: What describes wing loading? ^q73 - A) Wing area per weight - B) Drag per weight - C) Weight per wing area - D) Drag per wing area **Correct: C)** > **Explanation:** --- ### Q74: Through which factor listed below does the load factor increase during cruise flight? ^q74 - A) Lower air density - B) A forward centre of gravity - C) Higher aeroplane weight - D) An upward gust **Correct: D)** > **Explanation:** --- ### Q75: Point number 1 in the figure indicates which flight state? See figure (PFA-008) Siehe Anlage 5 ^q75 - A) Inverted flight - B) Slow flight - C) Stall - D) Best gliding angle **Correct: A)** > **Explanation:** --- ### Q76: Point number 5 in the figure indicates which flight state? See figure (PFA-008) Siehe Anlage 5 ^q76 - A) Slow flight - B) Best gliding angle - C) Inverted flight - D) Stall **Correct: A)** > **Explanation:** --- ### Q77: In a co-ordinated turn, how is the relation between the load factor (n) and the stall speed (Vs)? ^q77 - A) N is smaller than 1, Vs is greater than in straight and level flight. - B) N is greater than 1, Vs is smaller than in straight and level flight. - C) N is greater than 1, Vs is greater than in straight and level flight. - D) N is smaller than 1, Vs is smaller than in straight and level flight. **Correct: C)** > **Explanation:** --- ### Q78: How is the balance of forces affected during a turn? ^q78 - A) A lower lift force compensates for a lower net force as compared to level flight - B) Lift force must be increased to compensate for the sum of centrifugal and gravitational force - C) The horizontal component of the lift force during a turn is the centrifugal force - D) The net force results from superposition of gravity and centripetal forces **Correct: B)** > **Explanation:** --- ### Q79: During approch to the next updraft, the vertical speed indicator reads 3 m/s descent. Within the updraft you expect a mean rate of climb of 2 m/s. According McCready, how should you adjust the speed during approach of the updraft? ^q79 - A) The McCready ring should be set to 2 m/s, the recommended speed can be read at the McCready scale next to the sum of current rate of descent at expected rate of climb (5 m/s). - B) The McCready ring should be set to 3 m/s, the recommended speed can be read at the McCready scale next to the expected rate of climb (2 m/s). - C) The McCready ring should be set to 2 m/s, the recommended speed can be read at the McCready scale next to the current rate of descent (3 m/s). - D) Outside of thermal cells, the McCready ring should be set to 0 m/s, the recommended speed can be read at the McCready scale next to the current rate of descent (3 m/s). **Correct: C)** > **Explanation:** --- ### Q80: A sailplane is operated with additional water ballast. How do best gliding angle and speed of best glide change, when compared to flying without water ballast? ^q80 - A) Best gliding angle descreases, best glide speed decreases. - B) Best gliding angle remains unchanged, best glide speed increases. - C) Best gliding angle remains increases, best glide speed increases. - D) Best gliding angle remains unchanged, best glide speed decreases. **Correct: B)** > **Explanation:** --- ### Q81: What has to be considered when operating a sailplane with water ballast? ^q81 - A) Best glide angle decreases. - B) Significant CG shifts. - C) Best glide speed decreases - D) It should stay below freezing level. **Correct: D)** > **Explanation:** --- ### Q82: What has to be considered when operating a sailplane equipped with camper flaps? ^q82 - A) During approach and landing, camber must not be changed from negative to positive. - B) During approach and landing, camber must not be changed from positive to negative. - C) During winch launch, camber must be set to full negative. - D) During winch launch, camber must be set to full positive. **Correct: B)** > **Explanation:** --- ### Q83: Extending airbrakes results in ... ^q83 - A) Less drag and more lift. - B) More drag and less lift. - C) More drag and more lift. - D) Less drag and less lift. **Correct: B)** > **Explanation:** --- ### Q84: The pressure compensation between wind upper and lower surface results in ... ^q84 - A) Induced drag by wing tip vortices - B) Laminar airflow by wing tip vortices. - C) Profile drag by wing tip vortices. - D) Lift by wing tip vortices. **Correct: A)** > **Explanation:** --- ### Q85: What engine design at a Touring Motor Glider (TMG) results in least drag? ^q85 - A) Engine and propeller mounted fix on the fuselage - B) Engine and propeller mounted stowable on the fuselage - C) Engine and propeller mounted fix at the aircraft's nose - D) Engine and propeller mounted fix at the horizontal stabilizer **Correct: B)** > **Explanation:** --- ### Q86: At stationary glide and the same mass, what is the difference when using a thick airfoild instead of a thinner airfoil? ^q86 - A) More drag, same lift - B) Less drag, less lift - C) More drag, less lift - D) Less drag, same lift **Correct: A)** > **Explanation:** --- ### Q87: What is shown by a profile polar? ^q87 - A) Ratio between minimum rate of descent and best glide - B) Ratio between total lift and drag depending on angle of attack - C) Ratio of cA and cD at different angles of attack - D) Lift coefficient cA at different angles of attack **Correct: C)** > **Explanation:** --- ### Q88: The glide ratio of a sailplane can be improved by which measures? ^q88 - A) Higher airplane mass, thin airfoil, taped gaps between wing and fuselage - B) Lower airplane mass, correct speed, retractable gear - C) Cleaning, correct speed, retractable gear, taped gaps between wing and fuselage - D) Forward C.G. position, correct speed, taped gaps between wing and fuselage **Correct: C)** > **Explanation:** --- ### Q89: What effect is referred to as adverse yaw? ^q89 - A) Aileron operation results in a yaw to the desired side due to less drag at the down-deflected aileron - B) Rudder operation results in a rolling moment to the opposite side due to more lift generated by the faster moving wing. - C) Aileron operation results in a yaw to the opposite side due to more drag at the up-deflected aileron - D) Aileron operation results in a yaw to the opposite side due to more drag at the down-deflected aileron **Correct: D)** > **Explanation:** --- ### Q90: What is meant by ground effect? ^q90 - A) Decrease of lift and increase of induced drag close to the ground - B) Increase of lift and decrease of induced drag close to the ground - C) Increase of lift and increase of induced drag close to the ground - D) Decrease of lift and decrease of induced drag close to the ground **Correct: B)** > **Explanation:** --- ### Q91: What is the diffeence between spin and spiral dive? ^q91 - A) Spin: stall at inner wing, speed increasing rapidly; Spiral dive: airflow at both wings, speed constant - B) Spin: stall at inner wing, speed constant; Spiral dive: airflow at both wings, speed increasing rapidly - C) Spin: stall at outer wing, speed constant; Spiral dive: airflow at both wings, speed increasing rapidly - D) Spin: stall at outer wing, speed increasing rapidly; Spiral dive: airflow at both wings, speed constant **Correct: B)** > **Explanation:** ---