DGCA POF 17. Revision Questions Set 01

Results

Q1. A unit of measurement of pressure is:

kg/square dm.

kg/cubic metre.

newtons.

psi.

Ans: – psi.

Q2. Which of the following are the correct SI units?

Density is kilograms per cubic metre, force is newtons.

Density is newtons per cubic metre, force is kilograms.

Density is kilograms per newton, force is newton-metre squared.

Density is kilograms per square metre, force is kilograms.

Ans: – Density is kilograms per cubic metre, force is newtons.

Q3. What is the SI unit of density?

m V squared.

kg/square cm.

kg - metres.

kg/cubic metre.

Ans: – kg/cubic metre.

Q4. What is the SI unit which results from multiplying kg and m/s squared?

Newton.

Psi.

Joule.

Watt.

Ans: – Newton.

Q5. Which of the following expressions is correct?

A=Ftimes M

F=Mtimes A

M=Ftimes A

A=M/F

Ans: – F=Mtimes A

Q6. Which of the following is the equation for power?

N/m.

Nm/s.

Pa/s squared.

Kg/m/s squared.

Ans: – Nm/s.

Q7. At a constant CAS when flying below sea level an aircraft will have:

a higher TAS than at sea level.

a lower TAS than at sea level at ISA conditions.

the same TAS as at sea level.

the same TAS, but an increased IAS.

Ans: – a lower TAS than at sea level at ISA conditions.

Q8. Static pressure acts:

parallel to airflow.

parallel to dynamic pressure.

in all directions.

downwards.

Ans: – in all directions.

Q9. TAS is:

higher than the speed of the undisturbed airstream around the aircraft.

lower than the speed of the undisturbed airstream around the aircraft.

lower than IAS at ISA altitudes below sea level.

equal to IAS, multiplied by air density at sea level.

Ans: – lower than IAS at ISA altitudes below sea level.

Q10. The difference between IAS and TAS will:

increase with decreasing temperature.

increase with increasing density.

remain constant at all times.

decrease with decreasing altitude.

Ans: – decrease with decreasing altitude.

Q11. As a smooth flow of subsonic air at a velocity less than M 0.4 flows through a divergent duct: (i) static pressure(ii) velocity

(i) increases and (ii) decreases

(i) increases and (ii) increases

(i) decreases and (ii) decreases

(i) decreases and (ii) increases

Ans: – (i) increases and (ii) decreases

Q12. As subsonic air flows through a convergent duct: (i) static pressure(ii) velocity

(i) increases and (ii) decreases

(i) increases and (ii) increases

(i) decreases and (ii) decreases

(i) decreases and (ii) increases

Ans: – (i) decreases and (ii) increases

Q13. Bernoulli’s Theorem states:

dynamic pressure increases and static pressure increases.

dynamic pressure increases and static pressure decreases.

dynamic pressure is maximum at stagnation point.

there is zero pressure at zero dynamic pressure.

Ans: – dynamic pressure increases and static pressure decreases.

Q14. Consider a uniform flow of air at velocity V in a streamtube. If the temperature of the air in the tube is raised:

the mass flow remains constant and velocity V decreases.

the mass flow will increase and velocity V remain constant.

the mass flow will decrease and velocity V will remain constant.

the mass flow remains constant and the velocity V will increase.

Ans: – the mass flow remains constant and the velocity V will increase.

Q15. In a subsonic flow venturi, the relationship between the total pressure, static pressure and dynamic pressure of undisturbed air and air in the throat will be: (i) Dynamic pressure will be constant, static pressure will decrease.(ii) Total pressure will be constant, dynamic pressure will increase.

both (i) and (ii) are correct.

(i) is correct and (ii) is incorrect.

(i) is incorrect and (ii) is correct.

both (i) and (ii) are incorrect.

Ans: – (i) is incorrect and (ii) is correct.

Q16. In accordance with Bernoulli’s Theorem, where PT= Total Pressure, PS= Static pressure and q= Dynamic pressure:

PT+PS=q

PT=PS-q

PT-PS=q

PS+PT=q

Ans: – PT-PS=q

Q17. The Principle of Continuity states that in a streamtube of decreasing cross-sectional area, the speed of a subsonic and incompressible airflow will:

remain the same.

decrease.

increase.

sonic.

Ans: – increase.

Q18. The Principle of Continuity states that in a tube of increasing cross-sectional area, the speed of a subsonic and incompressible airflow will:

remain the same.

decrease.

sonic.

increase.

Ans: – decrease.

Q19. What are the units for wing loading and dynamic pressure?

N/square metre and N/square metre.

Nm and Nm.

N and N/square metre.

N/square metre and joules.

Ans: – N/square metre and N/square metre.

Q20. When considering the Principle of Continuity for incompressible subsonic flow, what happens in a streamtube with a change in cross-sectional area?

The density at the throat will be the same as the density at the mouth.

The density at the throat will be less than the density at the mouth.

The density at the throat will be greater than the density at the mouth.

Cannot say without knowing the change in cross-sectional area of the streamtube.

Ans: – The density at the throat will be the same as the density at the mouth.

Q21. When considering the Principle of Continuity for subsonic flow, what happens in a streamtube for a change in cross-sectional area?

RHO 1=RHO~2

RHO 1>RHO~2

RHO 2>RHO~1

Cannot say without knowing the change in cross-sectional area of the streamtube.

Ans: – RHO 1=RHO~2

Q22. Which of the following creates lift?

An accelerated air mass.

A retarded air mass.

A change in direction of mass flow.

A symmetrical aerofoil at zero angle of attack in a high speed flow.

Ans: – An accelerated air mass.

Q23. Which of the following statements about a venturi in a subsonic airflow is correct? (i) The dynamic pressure in the undisturbed flow and in the throat are equal.(ii) The total pressure in the undisturbed flow and in the throat are equal.

(i) is correct and (ii) is incorrect.

(i) is incorrect and (ii) is correct.

(i) and (ii) are correct.

(i) and (ii) are incorrect.

Ans: – (i) is incorrect and (ii) is correct.

Q24. A line from the centre of curvature of the leading edge to the trailing edge, equidistant from the top and bottom wing surface is the:

camber line.

upper camber line.

mean chord.

mean aerodynamic chord.

Ans: – camber line.

Q25. A symmetrical aerofoil section at C_L=0 will produce?

A negative (nose-down) pitching moment.

A positive (nose-up) pitching moment.

Zero pitching moment.

No aerodynamic force.

Ans: – Zero pitching moment.

Q26. Angle of attack is the angle between:

undisturbed airflow and chord line.

undisturbed airflow and mean camber line.

local airflow and chord line.

local airflow and mean camber line.

Ans: – undisturbed airflow and chord line.

Q27. How is the thickness of an aerofoil section measured?

As the ratio of wing angle.

Related to camber.

As the percentage of chord.

In metres.

Ans: – As the percentage of chord.

Q28. Lift and drag respectively are normal and parallel to:

the chord line.

the longitudinal axis.

the horizon.

the relative airflow.

Ans: – the relative airflow.

Q29. The angle between the aeroplane longitudinal axis and the chord line is:

angle of incidence.

glide path angle.

angle of attack.

climb path angle.

Ans: – angle of incidence.

Q30. The term angle of attack is defined as:

the angle between the relative airflow and the horizontal axis.

the angle between the wing chord line and the relative wind.

the angle that determines the magnitude of the lift force.

the angle between the wing and tailplane incidence.

Ans: – the angle between the wing chord line and the relative wind.

Q31. What is the angle of attack?

Angle of the chord line to the relative free stream flow.

Angle of the chord line to the fuselage datum.

Angle of the tailplane chord to the wing chord.

Angle of the tailplane chord to the fuselage datum.

Ans: – Angle of the chord line to the relative free stream flow.

Q32. When considering the coefficient of lift and angle of attack of aerofoil sections:

a symmetrical section at zero angle of attack will produce a small positive coefficient of lift.

an asymmetrical section at zero angle of attack will produce zero coefficient of lift.

a symmetrical section at zero angle of attack will produce zero coefficient of lift.

aerofoil section symmetry has no effect on lift coefficient.

Ans: – a symmetrical section at zero angle of attack will produce zero coefficient of lift.

Q33. When considering the lift and drag forces on an aerofoil section:

they are only normal to each other at one angle of attack.

they both depend on the pressure distribution on the aerofoil section.

they vary linearly.

lift is proportional to drag.

Ans: – they both depend on the pressure distribution on the aerofoil section.

Q34. Where does the lift act on the wing?

Suction.

Always forward of the CG.

Centre of Gravity.

Centre of Pressure.

Ans: – Centre of Pressure.

Q35. Which of the following creates lift?

A slightly cambered aerofoil.

An aerofoil in a high speed flow.

Air accelerated upwards.

Air accelerated downwards.

Ans: – An aerofoil in a high speed flow.

Q36. Which of the following is the greatest factor causing lift?

Suction above the wing.

Increased pressure below the wing.

Increased airflow velocity below the wing.

Decreased airflow velocity above the wing.

Ans: – Suction above the wing.

Q37. Which of the following statements is correct?

Lift acts perpendicular to the horizontal and drag parallel in a rearwards direction.

Drag acts parallel to the chord and opposite to the direction of motion of the aircraft and lift acts perpendicular to the chord.

Lift acts at right angles to the top surface of the wing and drag acts at right angles to lift.

Drag acts in the same direction as the relative wind and lift perpendicular to the relative wind.

Ans: – Drag acts in the same direction as the relative wind and lift perpendicular to the relative wind.

Q38. If IAS is doubled, by which of the following factors should the original C_L be multiplied to maintain level flight?

0-25

0.5

2-0

Ans: – 0-25

Q39. On entering ground effect:

more thrust is required.

less thrust is required.

ground effect has no effect on thrust required.

lift decreases.

Ans: – less thrust is required.

Q40. On the approach to land, ground effect will begin to be felt at:

twice the wingspan above the ground.

half the wingspan above the ground.

when the angle of attack is increased.

upon elevator deflection.

Ans: – half the wingspan above the ground.

Q41. The formula for lift is:

L=W

L=2 rho V squared SC_1

L=1/2 rho V squared overlineSC_L

L= rho VS C

Ans: – L=1/2 rho V squared overlineSC_L

Q42. The influence of ground effect on landing distance will:

decrease landing distance.

increase landing distance.

have no effect on landing distance.

depend on flap position.

Ans: – decrease landing distance.

Q43. Two identical aircraft of the same weight fly at different altitudes. All other important factors remaining constant, assuming no compressibility and ISA conditions, what is the TAS of each aircraft?

The same.

Greater in the higher aircraft.

Greater in the lower aircraft.

Less in the higher aircraft.

Ans: – Greater in the higher aircraft.

Q44. What do ‘S’ and ‘q’ represent in the lift equation?

Static pressure and chord.

Wingspan and dynamic pressure.

Wing area and dynamic pressure.

Wing area and static pressure.

Ans: – Wing area and dynamic pressure.

Q45. What effect on induced drag does entering ground effect have?

Increase.

Decrease.

Remain the same.

Induced drag will increase, but profile drag will decrease.

Ans: – Decrease.

Q46. What is the C_L and C_D ratio at normal angles of attack:

C_L higher.

C_D^L higher.

the same.

C_i much higher.

Ans: – C_i much higher.

Q47. What is the MAC of a wing?

Area of wing divided by the span.

The same as the mean chord of a rectangular wing of the same span.

The mean chord of the whole aeroplane.

The 25% chord of a swept wing.

Ans: – The same as the mean chord of a rectangular wing of the same span.

Q48. When an aircraft enters ground effect:

the lift vector is inclined rearwards which increases the thrust required.

the lift vector is inclined forwards which reduces the thrust required.

the lift vector is unaffected, the cushion of air increases.

the lift vector is inclined forward which increases the thrust required.

Ans: – the lift vector is inclined forwards which reduces the thrust required.

Q49. When an aircraft enters ground effect:

the induced angle of attack increases.

lift decreases and drag increases.

lift increases and drag decreases.

the aircraft will be partially supported on a cushion of air.

Ans: – lift increases and drag decreases.

Q50. When considering an angle of attack versus coefficient of lift graph for a cambered aerofoil, where does the lift curve intersect the vertical C_L axis?

above the origin.

below the origin.

at the point of origin.

to the left of the origin.

Ans: – above the origin.

Q51. When in level flight at 1cdot3V_5 what is the C_L a percentage of C_LMAX?

59%.

77%.

130%.

169%.

Ans: – 59%.

Q52. Which of the following is the cause of wing tip vortices?

Air spilling from the top surface to the bottom surface at the wing tip.

Air spilling from the bottom surface to the top surface at the wing tip.

Air spilling from the bottom surface to the top surface at the left wing tip and from the top surface to the bottom surface at the right wing tip.

Spanwise flow vector from the tip to the root on the bottom surface of the wing.

Ans: – Air spilling from the bottom surface to the top surface at the wing tip.

Q53. Which of the following is the correct definition of aspect ratio?

Span divided by tip chord.

Chord divided by span.

Span divided by mean chord.

Chord divided by span, measured at the 25% chord position.

Ans: – Span divided by mean chord.

Q54. Which of the following most accurately describes the airflow which causes wing tip vortices?

From the root to the tip on the top surface and from the tip to the root on the bottom surface over the wing tip.

From the root to the tip on the top surface and from the tip to the root on the bottom surface over the trailing edge.

From the tip to the root on the top surface and from the root to the tip on the bottom surface over the trailing edge.

From the tip to the root on the top surface and from the root to the tip on the bottom surface over the wing tip.

Ans: – From the tip to the root on the top surface and from the root to the tip on the bottom surface over the wing tip.

Q55. Wing tip vortices are caused by unequal pressure distribution on the wing which results in airflow from:

bottom to top round the trailing edge.

top to bottom round the trailing edge.

bottom to top round wing tip.

top to bottom round wing tip.

Ans: – bottom to top round wing tip.

Q56. With flaps deployed, at a constant IAS in straight and level flight, the magnitude of tip vortices:

increases or decreases depending upon the initial angle of attack.

increases.

decreases.

remains the same.

Ans: – decreases.

Q57. A high aspect ratio wing:

increases induced drag.

decreases induced drag.

is structurally stiffer than a low aspect ratio.

has a higher stall angle than a low aspect ratio.

Ans: – decreases induced drag.

Q58. An aircraft is flying straight and level; if density halves, aerodynamic drag will:

increase by a factor of four.

increase by a factor of two.

decrease by a factor of two.

decrease by a factor of four.

Ans: – decrease by a factor of two.

Q59. At a constant IAS, induced drag is affected by:

aircraft weight.

changes in thrust.

angle between chord line and longitudinal axis.

wing location.

Ans: – aircraft weight.

Q60. C_Di is proportional to which of the following?

C_L

C_LMAX

C_L squared.

the square root of the C.

Ans: – C_LMAX

Q61. Considering the lift to drag ratio, in straight and level flight which of the following is correct?

L/D is maximum at the speed for minimum total drag.

L/D maximum decreases with increasing lift.

L/D is maximum when lift equals weight.

L/D is maximum when lift equals zero.

Ans: – L/D is maximum at the speed for minimum total drag.

Q62. High aspect ratio:

reduces parasite drag.

reduces induced drag.

increases stalling speed.

increases manoeuvrability.

Ans: – reduces induced drag.

Q63. How does aerodynamic drag vary when airspeed is doubled?

Ans: – 4

Q64. If dynamic (kinetic) pressure increases, what is the effect on total drag (if all important factors remain constant)?

Drag decreases.

Drag increases.

It has no effect on drag.

Drag only changes with changing ground speed.

Ans: – Drag increases.

Q65. If IAS is increased from 80 kt to 160 kt at a constant air density, TAS will double. What would be the effect on (i) C_Di and (ii) Di?

(i) 2 (ii) 2

(i) 4 (ii) 2

(i) frac14 (ii) 4

(i) frac116 (ii) frac14

Ans: – (i) frac116 (ii) frac14

Q66. If pressure increases, with OAT and TAS constant, what happens to drag?

Increase.

Decrease.

Remain constant.

(Generated Option)

Ans: – Increase.

Q67. If the frontal area of an object in an airstream is increased by a factor of three, by what factor does drag increase?

1.5

Ans: – 3

Q68. If the IAS is increased by a factor of 4, by what factor would the drag increase?

Ans: – 16

Q69. In a stream tube, if density is halved, drag will be reduced by a factor of:

Ans: – 2

Q70. In straight and level flight, which of the following would cause induced drag to vary linearly if weight is constant?

1/V

1/V squared.

V squared.

Ans: – 1/V squared.

Q71. In subsonic flight, which is correct for V? MD

Parasite drag greater than induced drag.

C_L C_D are minimum.

Parasite and induced drag are equal.

Induced drag is greater than parasite drag.

Ans: – Parasite and induced drag are equal.

Q72. Induced drag can be reduced by:

increased taper ratio.

decreased aspect ratio.

use of a wing tip with a thinner aerofoil section.

increased aspect ratio.

Ans: – increased aspect ratio.

Q73. The advantage of a turbulent boundary layer over a laminar boundary layer is:

decreases energy.

thinner.

increased skin friction.

less tendency to separate.

Ans: – less tendency to separate.

Q74. The effect of winglets is:

elliptical pressure distribution increases.

reduction in induced drag.

decrease in stall speed.

longitudinal static stability increases.

Ans: – reduction in induced drag.

Q75. What does parasite drag vary with?

Square of the speed.

C_LMAX.

Speed.

Surface area.

Ans: – Square of the speed.

Q76. What effect does aspect ratio have on induced drag?

Increased aspect ratio increases induced drag.

Increased aspect ratio reduces induced drag.

Changing aspect ratio has no effect.

Induced drag will equal 1-3 x aspect ratio/chord ratio.

Ans: – Increased aspect ratio reduces induced drag.

Q77. What happens to total drag when accelerating from C_LMAX to maximum speed?

Increases.

Increases then decreases.

Decreases.

Decreases then increases.

Ans: – Decreases then increases.

Q78. What is interference drag?

Airflow retardation over the aircraft structure due to surface irregularities.

Drag caused by high total pressure at the leading edges when compared to the lower pressure present at the trailing edge.

Drag caused by the generation of lift.

Drag due to the interaction of individual boundary layers at the junction of aircraft major components.

Ans: – Drag due to the interaction of individual boundary layers at the junction of aircraft major components.

Q79. What is the cause of induced angle of attack?

Downwash from trailing edge in the vicinity of the wing tips.

Change in flow from effective angle of attack.

The upward inclination of the free stream flow around the wing tips.

Wing downwash altering the angle at which the airflow meets the tailplane.

Ans: – Downwash from trailing edge in the vicinity of the wing tips.

Q80. C_Di is the ratio of?

frac12 rho V squared.

frac12 rho V squared S.

Ans: – (C) squared to AR.

Q81. What phenomena causes induced drag?

Wing tip vortices.

Wing tanks.

The increased pressure at the leading edge.

The spanwise flow, inward below the wing and outward above.

Ans: – Wing tip vortices.

Q82. When compared to a laminar boundary layer:

a turbulent boundary layer has more kinetic energy.

a turbulent boundary layer is thinner.

less skin friction is generated by a turbulent layer.

a turbulent boundary layer is more likely to separate.

Ans: – a turbulent boundary layer has more kinetic energy.

Q83. When considering the aerodynamic forces acting on an aerofoil section:

lift and drag increase linearly with an increase in angle of attack.

lift and drag act normal to each other only at one angle of attack.

lift and drag increase exponentially with an increase in angle of attack.

lift increases linearly and drag increases exponentially with an increase in angle of attack.

Ans: – lift increases linearly and drag increases exponentially with an increase in angle of attack.

Q84. When considering the properties of a laminar and turbulent boundary layer, which of the following statements is correct?

Friction drag is the same.

Friction drag higher in laminar.

Friction drag higher in turbulent.

Separation point is most forward with a turbulent layer.

Ans: – Friction drag higher in turbulent.

Q85. When the undercarriage is lowered in flight:

form drag will increase and the aircraft's nose-down pitching moment will be unchanged.

induced drag will increase and the aircraft's nose-down pitching moment will increase.

form drag will increase and the aircraft's nose-down pitching moment will increase.

induced drag will decrease and the aircraft's nose-down pitching moment will increase.

Ans: – form drag will increase and the aircraft’s nose-down pitching moment will increase.

Q86. Which of the following decreases induced drag?

Wing fences.

Anhedral.

Winglets.

Low aspect ratio planform.

Ans: – Winglets.

Q87. Which of the following is a characteristic of laminar flow boundary layer?

Constant velocity.

Constant temperature.

No flow normal to the surface.

No vortices.

Ans: – No flow normal to the surface.

Q88. Which of the following is the correct formula for drag?

frac12 rho V squared C_L

frac12 rho V (C) squared S

frac12 rho V squared AR C_D S

frac12 rho V squared C_D S

Ans: – frac12 rho V squared C_D S

Q89. Which statement about induced drag and tip vortices is correct?

Vortex generators diminish tip vortices.

Flow on upper and lower wing surfaces is towards the tip.

They both decrease at high angle of attack.

On the upper surface there is a component of flow towards the root, whilst on the lower surface it is towards the tip.

Ans: – On the upper surface there is a component of flow towards the root, whilst on the lower surface it is towards the tip.

Q90. A jet aircraft flying at high altitude encounters severe turbulence without encountering high speed buffet. If the aircraft decelerates, what type of stall could occur first?

Low speed stall.

Accelerated stall.

Deep stall.

Shock stall.

Ans: – Accelerated stall.

Q91. A swept wing aircraft stalls and the wake contacts the horizontal tail. What would be the stall behaviour?

Nose down.

Nose up and/or elevator ineffectiveness.

Tendency to increase speed after stall.

Nose up.

Ans: – Nose up and/or elevator ineffectiveness.

Q92. An aircraft at a weight of 237 402N stalls at 132 kt. At a weight of 356 103N it would stall at:

88 kt.

162 kt.

108 kt.

172 kt.

Ans: – 162 kt.

Q93. An aircraft at low subsonic speed will never stall:

as long as the CAS is kept above the power-on stall speed.

as long as the IAS is kept above the power-on stall speed.

as long as the maximum angle of attack is not exceeded.

as long as the pitch angle is negative.

Ans: – as long as the maximum angle of attack is not exceeded.

Q94. At high angle of attack, where does airflow separation begin?

Upper surface, towards the leading edge.

Lower surface, towards the trailing edge.

Upper surface, towards the trailing edge.

Lower surface, towards the leading edge.

Ans: – Upper surface, towards the trailing edge.

Q95. At the point of stall:

lift decreases, drag decreases.

lift constant, drag increases.

lift decreases, drag increases.

lift decreases, drag constant.

Ans: – lift decreases, drag increases.

Q96. During erect spin recovery the correct recovery actions are:

control stick pulled aft.

ailerons held neutral.

control stick sideways against bank.

control stick sideways towards bank.

Ans: – ailerons held neutral.

Q97. Force on the tail and its effect on V_5 due to CG movement:

if rearward movement of the CG gives a reduced down-force on the tail, V_5 will be higher.

if forward movement of the CG gives a reduced down-force on the tail, V_S will be higher.

if rearward movement of the CG gives a reduced down-force on the tail, V_5 will be reduced.

if rearward movement of the CG gives an increased down-force on the tail, V_s will be reduced.

Ans: – if rearward movement of the CG gives a reduced down-force on the tail, V_5 will be reduced.

Q98. How do vortex generators work?

Re-direct spanwise flow.

Take energy from free stream and introduce it into the boundary layer.

Reduce kinetic energy to delay separation.

Reduce the adverse pressure gradient.

Ans: – Take energy from free stream and introduce it into the boundary layer.

Q99. If a jet aircraft is at 60 degrees bank angle during a constant altitude turn, the stall speed will be:

1.60 greater.

1. 19 greater.

1.41 greater.

2.00 greater.

Ans: – 1.41 greater.

Q100. If the stalling speed in a 15 degree bank turn is 60 kt, what would the stall speed be in a 45 degree bank?

83 kt.

70 kt.

85 kt.

60 kt.

Ans: – 70 kt.

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