A/C STRUCTURE AND DESIGN 2023

A point mass of 1 kg is rotating about an axis passing through it What is the moment of inertia of the point mass about this axis?

A. Zero

B. Infinite

C. 1 kg m^2

D. 2 kg m^2

A

For a given aircraft at a given condition, the limit load is constant. The ultimate load is dictated by the factor of safety. Choose which of the following statements are correct in relation to the factor of safety and ultimate load.

A. The factor of safety is constant at 1.5 therefore, ultimate load is also constant.

B. As the factor of safety increases, the ultimate load increases.

C. As the ultimate load increases, the factor of safety decreases.

D. As the factor of safety increases, the ultimate load decreases

*B (dating C for some reason)

Nose wheel shimmy" may be described as

A. The oscillatory movement of the nose wheel when extended prior to landing

B. Aircraft vibration caused by the nose wheel upon extension of the gear

C. A possibly damaging vibration of the nose wheel when moving on the ground

D. The amount of free movement of the nose wheel before steering takes effect

C

Stress developed due to the contact pressure between separate bodies.

Tensile Stress

Shearing Stress

Torsional Stress

Bearing Stress

Shearing Stress

The lift coefficient (CL) of an aircraft in steady horizontal flight is 0.4. Increase of angle of attack of 1 degree will increase CL by 0.09. A vertical up gust instantly changes the angle of attack by 5 degrees. The load factor will be

2.32

1.53

1.92

2.13

2.13

OPR is defined as

A. the ratio of the pressures at the engine exhaust plane and the throat

B. the ratio of the pressures at the throat and the exhaust plane

C. the ratio of the pressures at the engine exhaust plane and inlet front face

D. the ratio of the pressure at the end of the diffuser section to the inlet of the burner section

C

This weight is the summation of payload weight, fuel weight, crew weight, and the aircraft's structural weight

A. Design Take-off Weight

Normal Gross Weight

Empty Weight

Maximum Take-off Weight

A

A steel propeller shaft 14 in. in diameter and 18 ft long is used to transmit 5000 hp at 189 rpm. If G=12x10^6 psi, determine the maximum shearing stress.

3089.6 psf

3095.1 psi

3094.6 psf

3194.6 psi

3094.6 psf

FAR 23.2130 laid down the design requirements for

Take-off

Landing

Acrobatics

Cruising

Landing

Which of the following is true? The airplane must be free from flutter, control reversal, and divergence.

A. For any flight phase

B. During critical phases of flight only

C. At all speeds within and sufficiently beyond the structural design envelope

D.At all conditions except only when it is required to give additional pilot sensation during stalling conditions

C

The stability with reference to disturbances in the plane of symmetry

Vertical Stability

Longitudinal Stability

Flight Stability

Lateral Stability

Longitudinal Stability

It occurs in intentional flight maneuvers in which the air loads on the wing are down or when the airplane strikes sudden downdrafts while in level flight.

NLAA

PHAA

PLAA

NHAA

NHAA

*PHAA - highest AOA

*PLAA - smallest AOA

*NLAA- Sudden decrease

A cylindrical pressure vessel has an internal diameter of 2 m and is fabricated from plates 20 mm thick. If the pressure inside the vessel is 1.5 N/mm2 and, in addition, the vessel is subjected to an axial tensile load of2500 kN, calculate the direct stress on a plane inclined at an angle of 60o to the axis of the vessel.

19.9 N/mm^2

24 N/mm^2

20 N/mm^2

32.4 N/mm^

19.9 N/mm^2

For a normal production aircraft, leaks and protuberance drags can be estimated as

a. 10-20% of the parasite drag for jet transports or bombers

b. 2-5% of the parasite drag for jet transports or bombers

c. 9-20% of the parasite drag for jet transports or bombers

d. 7-15% of the parasite drag for jet transports or bombers

b

This condition occurs in intentional flight maneuver in which the air loads on the wing are down

a. Sleep Turns

b. Negative High Angle of Attack

c. Negative Low Angle of attack

d. Positive Low Angle of Attack

b

The shape of the gust load diagram is also determined by the following three vertical speed in ft/s (clean configuration)

a. 15,56,65

b. 25,55,75

c. 35,55,66

d. 25,50,66

d

The velocity-load factor diagram is also known as the__________

Flight Limits

Gust Limit

Flight Envelope

Flight Operations minimum

Flight Envelope

An airplane intended to be certified as a commuter category under FAR part 23 has the following specifications: design gross weight is 3,100 lb, wingspan is 34 ft, MAC is 4.75 ft, and maximum lift coefficient is 1.35 with flaps retracted. What is the required positive limit maneuvering load factor?

2.41

3.93

4.4

3.8

3.8

The minimum propeller clearance requirement for conventional landing gear type is (2Pt)

8 inches

10 inches

9 inches

6 inches

9 inches

Above _______, an angle of attack less than stall is sufficient to produce enough G forces to exceed the G limit.

VA

VMCG

VS

VX

VA

Smoke detectors fitted on transport aircraft are of the following type

optical or ionization

chemical

magnetic

electrical

optical or ionization

What one major consideration in selecting an airfoil to be used for the tail plane design of an aircraft?

Zero-lift angle of attack

Minimum Drag Coefficient

Maximum lift coefficient

Lift curve slope

Lift curve slope

What type of flap system increases the wing area and changes the wing camber?

Split Flaps

Slotted Flaps

Plain Flaps

Fowler Flaps

Fowler Flaps

It is the maximum structural cruising speed that should not be exceeded except in smooth air, and then only with caution.

VNE

VS1

VNO

VR

VNO

Air speed corrected for instrument error and position error is called

Calibrated Air Speed

True Airspeed

Equivalent Air Speed

Air Speed Limitation

Calibrated Air Speed

What aluminum alloy group uses manganese as the major alloying element?

Group 3000

Group 4000

Group 5000

Group 2000

Group 3000

Corner speed is defined as

a.minimum instantaneous turn speed

b. maximum lift velocity

c. maximum aerodynamic efficiency

d. velocity for maximum instantaneous turn

d

The speed for best rate of climb is called

VY

VX

V2

VO

VY

This wing design is used primarily to reduce the adverse effects of transonic and supersonic flow

Elliptical Wing

Wing Sweep

Delta Wing

Low Aspect Ratio

Wing Sweep

For levels 1 and 2 low-speed airplanes, a climb gradient of ____ percent for landplanes and _____ percent for seaplanes and amphibians

8.3 and 6.7

1.2 and 3.9

3.8 and 6.0

6.9 and 4.2

8.3 and 6.7

The purpose of an ignition switch is to

a. connect the contact breaker and condenser in series with primary coil

b. connect the battery to the magneto

c. connect the secondary coil to the distributor

d. control the primary circuit of the magneto

D

The vertical speed indicator (VSI) is fed by

Total pressure

Static pressure

Dynamic Pressure

Differential Pressure

Static pressure

The industry-standard FEM program is the

Autodesk Fusion

CATIA

Anysys

NASTRAN

NASTRAN

If the CG is ahead of the neutral point (positive static margin), the pitching-moment derivative is _______ so the aircraft is _______.

A. minimum instantaneous turn speed

B. negative, unstable

C. positive, stable

D. maximum lift velocity

C

A material can return to normal after it has been deformed due to its elasticity.

A. True

B. At short intervals of deforming action

C. True until a certain limit

D. False

*C is more correct (dating A)

A structural element acted upon the forces or couples in an axial plane and designed to carry bending and shear loads.

Strut

Column and Tie

Truss

Beam

Beam

Calculate the tangential and longitudinal stresses in the steel, respectively, if a cylindrical steel pressure vessel 400 mm in diameter with a wall thickness of 20 mm, is subjected to an internal pressure of 4.5 MN/m^2.

32.5 and 2.25

22.5 and 45

45 and 22.5

32.5 and 22.5

45 and 22.5

The hydraulic oil, entering the hydraulic pump, is slightly pressurized to

Ensure sufficient pump output

Prevent cavitation in the pump

Prevent overheating of the pump

Prevent vapor locking

Prevent cavitation in the pump

This type creates lateral instability in high gross weight, high winged aircraft.

Canard

Dihedral

H-Wing

Anhedral

Anhedral

The advance ratio is sometimes called

Slip function

Power Coefficient

Speed-Power Coefficient

Thrust Coefficient

Slip function

For an aircraft with an unenclosed cockpit, such as a hang glider or ultralight, a seated person has a D/q of about

5 ft^2

6 ft^2

2 ft^2

7 ft^2

6 ft^2

Compared with the other types of wing vertical location, this type has more lateral dynamic stability.

Swept Wing

High Wing

Mid Wing

Low Wing

High Wing

It includes any aft-facing flat surfaces as well as the projected aft-facing area for any portions of the aft fuselage that experience highly-separated airflow.

Transition Base

Chord base

Fillet

A base

A base

A model aircraft wing cantilever in attachment is to be tested inside a wind tunnel. Its dimensions are 50 mm wide by 150 mm high and 6 m long, in testing, the wing carries a load that varies uniformly from zero at the free end to 1000 N/m at the fuselage attachment. Compute the magnitude and location of the maximum flexural stress.

64 MPa at 5 m

24 MPa at 4 m

32 MPa at 6 m

42 MPa at 3 m

32 MPa at 6 m

What is the gust velocity for diving at 20,000 feet and bellow?

30 ft/s

25 ft/s

10 ft/s

50 ft/s

25 ft/s

The fuel cross-feed system

A. allows feeding of any engine from any fuel tank.

B. is only used to feed an engine from the tank of the opposite wing.

C. is only used on the ground for fuel transfer from one tank to another.

D. is only used in flight for fuel transfer from one tank to another.

Regulations for airworthiness standards for airplanes with a maximum take-off weight of less than 12,500 lbs can be found in ________.

FAR Part 29

FAR Part 23

FAR Part 25

FAR Part 21

FAR Part 23

The power of a piston engine which will be measured by using a friction brake

Indicated Horsepower

Brake Horsepower

Heat loss Power

Friction Horsepower

Brake Horsepower

A pitot tube covered by ice which blocks the ram air inlet will affect the following instrument/s

A. Altimeter only

B. Vertical Speed Indicator only

C. Airspeed indicator, altimeter, and vertical speed indicator

D. Airspeed indicator only

D

On modern transport aircraft, cockpit windows are protected against icing by

Anti-icing fluid

Electric Heating

Vinyl Coating

Rain repellent system

Electric Heating

The total aerodynamic force F at acting 6 deg (from the vertical axis) on the airplane has a magnitude of 6250 lb. Resolve this force into lift and drag.

Lift = 653 lb, Drag = 6220 lb

Lift = 6220 lb, Drag = 653 lb

Lift = 5847 lb, Drag = 3750 lb

Lift = 3750 lb, Drag = 5847 lb

Lift = 6220 lb, Drag = 653 lb

Secondary flight control surface that moves in the same position of the primary flight control surface.

Spring Tab

Servo Tab

Anti-servo Tab

Balance Tab

Anti-servo Tab

Compute the diameter required for a wooden two-bladed propeller. Assume sea level condition, BHP = 850 hp, Velocity = 328.5 fps, N = 1634 rpm. (2Pt)

10.5 ft

11.2 ft

9.7 ft

8.8 ft

10.5 ft

For all single-engine airplanes under acrobatic category with a VSO of more than 61 knots at maximum weight, the upward ultimate load factor need not exceed:

2.1 g

6.0 g

5.0 g

3.8 g

5.0 g

Which among the following statements about symmetrical and unsymmetrical airfoils is incorrect?

A. A symmetric airfoil at zero angle of attack produces identical velocity increases and static pressure decreases on both the upper and lower surfaces.

B. The first two digits of a 4-digit airfoil will give information whether an airfoil is unsymmetrical or not.

C. Because of positive camber, the area in the streamtube above the wing is larger than area in the streamtube below the wing and the airflow velocity above the wing is greater than the velocity below the wing.

D.An unsymmetrical airfoil is able to produce an uneven pressure distribution even at zero AOA.

C

The angle of incidence of an airplane

Is that angle between the relative wind and the chord of the wing.

Affects the dihedral of the wings.

Does not change in flight.

Does change in flight

Does not change in flight.

The calibrated power-off stalling speed or the minimum steady flight speed at which the aircraft is controllable in a specified configuration is designated by

VFE

VS0

VNO

VS1

VS1

Under FAR Part 23, which of the following is not considered as limited acrobatic operation?

Turns less than 60 deg

Spins

No specific

Cuban eights

Turns less than 60 deg

The design airspeeds selected for 14 CFR Part 23 airplanes are at which value

Indicated Airspeed

Ground Speed

Equivalent Airspeed

True Airspeed

Equivalent Airspeed

For FAR Part 23 airplanes, each engine mount and its supporting structure must be designed for a limit load factor in a lateral direction, for the side load on the engine mount, of not less than (2Pt)

1.15

1.33

1.25

2.25

1.33

For part 23 airplanes, if warning lights are installed in the cockpit, they must, unless otherwise approved by the Administrator, be

Green

Amber

Red

White

Red

The limit beyond which the material will no longer go back to its original shape when the load is removed, or it is the maximum stress that may be developed such that there is no permanent or residual deformation when the load is entirely removed.

Yield point

Rupture Strength

Elastic Limit

Ultimate Strength

Elastic Limit

For transport category airplanes, the negative maneuvering load factor at VC may not be less than:

-1

-6

-2.5

-0.5

-1

For normal category airplanes with two engines, during takeoff with one engine inoperative, the steady gradient of climb at an altitude of 400 ft above surface with gears retracted must be?

Greater than 1.25%

Greater than 3 %

Greater than 2 %

Less than 2 %

Greater than 2 %

When should special inspection procedures be followed to determine if any damage to the aircraft structure has occurred?

Annual Inspection

Progressive Inspection

100-hour inspection

Overweight landing

Overweight landing

During take-off, for an airplane of 6,000 pounds or less maximum weight, it must be possible, using a favorable combination of controls, to roll the airplane from a steady 30-degree banked turn through an angle of 60 degrees, so as to reverse the direction of the turn within

5 sec upon reaching V2

5 sec from initiation of roll

30 sec

4 sec from initiation of roll

5 sec from initiation of roll

Intercostals are

A. The distance from one coast of wing to the other.

B. Vertical struts joining the upper and lower wings of a biplane.

C. Longitudinal fuselage members attached at each end to adjacent frames.

D. Compression ribs in cantilever wings.

C

A spar web will take loads in

Axial

Tension

Bending

Shear

Shear

What type of joint is applicable for tubular construction and structural components?

Corner

Lap

Tee

Butt

Tee

Which is not a primary structural member?

Landing gear

Nacelle

Wing

Fuselage

Nacelle

What is smallest size cable that may be used in aircraft primary control systems?

1/8 in

1/5 in

1/16 in

1/4 in

1/8 in

A steel shaft 3 ft long that has a diameter of 4 in is subjected to a torque of 15 kip-ft. Determine the maximum shearing stress and the angle of twist. Use G = 12 × 106 psi.

13.2 deg

12.3 deg

1.23 deg

1.32 deg

1.23 deg

The useful load of an aircraft is the

A. Sum of the empty weight and the tare weight

B. Difference between the net weight and total weight

C. Difference between the max gross weight and empty weight

D. Sum of the empty weight and the maximum gross weight

C

Which of the ff. is the calibrated airspeed at which the airplane first becomes airborne?

VFTO

VLOF

V1

VR

VLOF

A damaged area where the result is a cross-sectional change caused by a sharp object and gives a continuous, sharp or smooth groove in the material.

Abrasion

Nicks

Gouge

Holes

Nicks

Which statement is true regarding a cantilever wing?

No external bracing is needed.

It has non-adjustable lift struts.

It requires only one lift strut on each side.

External bracing is needed.

No external bracing is needed.

Which of the following shall be reported to the Authority?

A. Aircraft structure that requires major repair

B. Engine shutdown during flight when external damage to the engine or aircraft structure occurs

C. All of the above

D. Cracks, permanent deformation, or corrosion of aircraft structure, if more than the maximum acceptable to the manufacturer or the Authority

C

ATA Chapter for Wings

ATA 59

ATA 57

ATA 53

ATA 55

ATA 57

It is the angle between the vertical and the line passing through the aircraft most forward C.G. and the contact point between tire and the ground.

Tipback Angle

Overturn Angle

Angle of Incidence

Tipforward Angle

Tipforward Angle

Is known as the measurement of height in inches perpendicular from a horizontal plane usually located at a ground, cabin floor, or some other easily referenced location.

Wing Station

Aileron

Water Line

Buttock Line Or Butt Line

Water Line

At VMC, the rudder pedal force required to maintain control must not exceed:

50 lbs

200 lbs

100 lbs

150 lbs

150 lbs

If the ultimate bearing stress of a steel plate is 42,000 psi, what force is necessary to punch a 0.75in diameter hole in a 0.625in thick plate?

35 000 lbs

61 850 lbs

63 600 lbs

11 597 lbs

61 850 lbs

Which of the following is included in determining the empty weight?

Lavatory Pre-charge Water

Unusable Fuel

Waste Water

Potable Water

Unusable Fuel

Fuselage stringers are spaced from __________ inches apart around the largest cross section.

13 to 18

3 to 5

6 to 12

None of the above

6 to 12

The relationship between the load which will be imposed upon a given structural element and the amount it is capable of carrying safely.

Allowable Stress

Allowable Load

Margin of Safety

Stress Analysis

Margin of Safety

Certificate issued when a person alters a product by introducing a major change in type design, not great enough to require a new application for a type certificate.

Certificate of Airworthiness

Type Certificate Data Sheet

Supplemental Type Certificate

Design Certificate

Supplemental Type Certificate

The calibrated airspeed at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine still inoperative, and thereafter maintain straight flight at the same speed with an angle of bank of not more than 5 degrees.

VA

VC

VD

VMC

VMC

For each airplane, among the flight instruments required by Part 23, the instrument that most effectively indicates the attitude must be on the panel:

A. In the top center position

B. Directly below the instrument in the top center position

C. As identified by the applicant

D. Right of the instrument in top center position

A

The positive limit maneuvering load factor (n) for normal category airplanes:

2

6

4.4

3.8

3.8

An airplane with one pair of wings

Uniplane

Triplane

Biplane

Monoplane

Monoplane

A cylindrical steel pressure vessel 400 mm in diameter with a wall thickness of 20 mm is subjected to an internal pressure of 4.5 MN/m^2. Calculate the tangential stress in the steel.

45 MPa

40 MPa

55 MPa

35 MPa

45 MPa

Type of stress wherein the force is acting perpendicular to the area resisting the load

Normal Stress

Stress-Strain

Shear Stress

Bearing Stress

Normal Stress

This type of emergency exit has the following characteristics: a rectangular opening not less than 24 in wide by 48 in high with corner radii not greater than one third the width of the exit. This type of exit is located on each side of the fuselage at the aft portion of passenger compartment unless configuration of the airplane is such that some other location would afford a more effective means of evacuation. This type of exit is at floor-level.

Type III

Type I

Type IV

Type II

Type I

Under normal conditions per JAR 25, the cabin pressure altitude is not allowed to exceed.

10 000 ft

8 000 ft

4 000 ft

6 000 ft

8 000 ft

Control surface flutter

A. Provides additional lift for takeoff and landing in the event of engine failure.

B. Occurs at high angles of attack.

C. Is a destructive vibration that must be damped out within the flight envelope.

D. Is a means of predicting the critical safe life of the wing.

C

A force of 1000 N is acting at a point, making an angle of 60 deg with the horizontal. Determine the components of this force along the horizontal and vertical directions. (2Pt)

A.500 N, 966 N

B. 866 N, 400 N

C. 500 N, 766 N

D. 500 N, 866 N

D

A thin rod of mass 10 kg and length 1 m is rotating about an axis passing through its center of mass and making an angle of 30 degrees with its length. What is the moment of inertia of the rod about this axis?

A. 0.1 kg m^2

B. 0.5 kg m^2

C. 1 kg m^2

D. 2 kg m^2

B

A uniform rod of mass 10 kg and length 1 m is rotating about an axis passing through one end and perpendicular to its length. What is the moment of inertia of the rod about this axis?

A. 0.1 kg m^2

B. 0.5 kg m^2

C. 1 kgm^2

D. 2 kg m^2

D

1. The moment of a force of 25N about a point is 2.5Nm. Find the perpendicular distance of force from that point.

A. 10cm

B. 20cm

C. 30cm

D. 40cm

A

A spanner of length 10 cm is used to open a nut by applying a minimum force of 5.0 N. Calculate the moment of force required.

A. 51/10 m

B. 5 Nm

C. 0.5 N

D. 0.5 Nm

d