Centre of Gravity Questions

8/3/2019 Centre of Gravity Questions

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The main reason for having the centre of gravity below the pivot point in a card-type magneticcompass is:

A) To cancel out the systems pendulosity and its tendency to oscillatebackwards and forwards about its equilibrium position.

B) To compensate for the horizontal magnetic component H such that themagnet system is within approx. 2 of the true horizontal between 60 Nand 40 S.

C) To make it less sensitive to hard- and soft-iron magnetism in the aircraft.D) To compensate for the vertical magnetic component Z such that the

magnet system is within approx. 2 of the true horizontal between 60 Nand 40 S.

The position of the centre of gravity can always be determined by:

A) dividing the total moment by the total mass

B) subtracting the total mass from the total momentC) dividing the total mass by the total momentD) subtracting the total moment from the total mass

What effect has a centre of gravity close to the forward limit?

A) A better rate of climb capabilityB) A decreased induced dragC) A reduced rate of climbD) A reduction in the specific fuel consumption

If the centre of gravity is near the forward limit the aeroplane will:

A) benefit from reduced drag due to the decrease in angle of attackB) tend to over rotate during take-off C) require less power for a given airspeedD) require elevator trim which will result in an increase in fuel

consumption

The centre of gravity of an aeroplane is that point through which the total mass of the aeroplaneis said to act.The weight acts in a direction:

A) parallel to the gravity vectorB) governed by the distribution of the mass within the aeroplaneC) always parallel to the aeroplane's vertical axisD) at right angles to the flight path

With the centre of gravity on the forward limit which of the following is to be expected?

A) A decrease of the stalling speedB) A decrease in the landing speedC) A decrease in range


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D) A tendency to yaw to the right on take-off

If nose wheel moves aft during gear retraction, how will this movement affect the location of thecentre of gravity (cg) on the aeroplane?

A) It will not affect the cg locationB) It will cause the cg to move forwardC) It will cause the cg to move aftD) The cg location will change, but the direction cannot be told the

information given

If the centre of gravity of an aeroplane moves forward during flight the elevator control will:

A) become heavier making the aeroplane more difficult to manoeuvre inpitch

B) become heavier making the aeroplane more easy to manoeuvre inpitch

C) become lighter making the aeroplane more easy to manoeuvre in pitchD) become lighter making the aeroplane more difficult to manoeuvre in

pitch

An aeroplane is loaded with its centre of gravity towards the rear limit. This will result in:

A) a reduced fuel consumption as a result of reduced dragB) a reduction in power required for a given speedC) an increased risk of stalling due to a decrease in tailplane momentD) an increase in longitudinal stability

Which of the following is most likely to affect the range of centre of gravity positions on anaeroplane?

A) Elevator and tail plane (horizontal stabiliser) effectiveness in all flightconditions

B) The need to minimise drag forces and so improve efficiencyC) Location of the undercarriageD) The need to maintain a low value of stalling speed

In calculations with respect to the position of the centre of gravity a reference is made to adatum. The datum is:

A) a reference plane which is chosen by the aeroplane manufacturer. Itsposition is given in the aeroplane Flight or Loading Manual

B) calculated from the data derived from the weighing procedure carriedout on the aeroplane after any major modification

C) calculated from the loading manifestD) an arbitrary reference chosen by the pilot which can be located

anywhere on the aeroplaneThe centre of gravity is that _____ (i) on an aircraft through which the total _____ (ii) is


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considered to act vertically _____ (iii).

A) (i) point (ii) mass (iii) downwardsB) (i) datum (ii) moment (iii) downwardsC) (i) point (ii) moment (iii) upwardsD) (i) datum (ii) mass (iii) upwards

The mass and centre of gravity of an aircraft must be established by actual weighing:

A) by the owner operator before the first flight of the dayB) by the operator prior to initial entry of aircraft into serviceC) by the engineers before commencing serviceD) by the pilot on entry of aircraft into service

The determination of the centre of gravity in relation to the mean aerodynamic chord:

A) consists of defining the centre of gravity longitudinally in relation to

the position of the aerodynamic convergence pointB) consists of defining the centre of gravity longitudinally in relation tothe length of the mean aerodynamic chord and the trailing edge

C) consists of defining the centre of gravity longitudinally in relation tothe length of the mean aerodynamic chord and the leading edge

D) consists of defining the centre of gravity longitudinally in relation tothe position of the aerodynamic centre of pressure

The centre of gravity location of the aeroplane is normally computed along the:

A) longitudinal axis

B) horizontal axisC) vertical axisD) lateral axis

Which of the following is unlikely to have any effect on the position of the centre of gravity on anaeroplane in flight?

A) Lowering the landing gearB) Normal consumption of fuel for a swept wing aeroplaneC) Movement of cabin attendants going about their normal dutiesD) Changing the tailplane (horizontal stabiliser) incidence angle

An aeroplane has its centre of gravity located 7 metres from the datum line and it has a mass of 49000 N. The moment about the datum is:

A) 343 000 NmB) 7000 NmC) 1.43 NmD) 34 300 Nm


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The distance from the datum to the Centre of Gravity of a mass is known as:

A) the indexB) the momentC) the moment arm or balance armD) the lever

The centre of gravity of an aeroplane is at 25% of the Mean Aerodynamic Chord. This means thatthe centre of gravity of the aeroplane is situated at 25% of the length of:

A) the mean aerodynamic chord in relation to the trailing edgeB) the mean aerodynamic chord in relation to the datumC) the aeroplane in relation to the leading edgeD) the mean aerodynamic chord in relation to the leading edge

What is the effect of the centre of gravity on fuel consumption?

A) The further forward the centre of gravity the greater the fuelconsumption compared to an aircraft with an aft centre of gravityB) The further the distance of the centre of gravity from the centre of

pressure the greater the fuel consumptionC) The further aft the centre of gravity the greater the fuel consumption

compared to an aircraft with a forward centre of gravityD) The centre of gravity has no effect on fuel consumption

The centre of gravity near, but still within, the aft limit:

A) increases the stalling speedB) decreases the maximum rangeC) improves the maximum rangeD) improves the longitudinal stability.

Aft centre of gravity (within the approved limits):

A) Improves longitudinal stabilityB) Increases stalling speedC) Increases maximum rangeD) Decreases maximum range

Moving the centre of gravity from the forward to the aft limit (gross mass, altitude and airspeedremain unchanged):

A) affects neither drag nor power requiredB) increases the induced dragC) decreases the induced drag and reduces the power requiredD) increases the power required

An airplane has been loaded in such a manner that the centre of gravity is located behind the aft


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centre of gravity limit. One undesirable flight characteristic a pilot might experience with thisairplane would be:

A) stalling at higher-than-normal airspeed.B) a longer takeoff run.C) the tendency of a wing to stall at high airspeed.D) difficulty in recovering from a stalled condition.

With the centre of gravity on the forward limit, the stalling speed would be:

A) lower than with the centre of gravity on the aft limit.B) the same as with the centre of gravity on the aft limit.C) higher than with the centre of gravity on the aft limit.D) independent of the centre of gravity position.

As the centre of gravity moves, recovery from a stall:

A) in unaffected by centre of gravity position, only by all up weight(AUW).B) is more difficult with the centre of gravity moving forward.C) is less difficult when the centre of gravity moves aft.D) is more difficult with the centre of gravity moving aft

Loading an airplane to the aft centre of gravity limit will cause the airplane to be:

A) more stable for all airspeeds.B) less stable for all airspeeds.C) less stable at high speed, but more stable at low speed.D) less stable at slow speed, but more stable at high speed.

For a normal stable aeroplane, the centre of gravity is located:

A) aft of the neutral point of the aeroplane.B) between the aft limit and the neutral point of the aeroplane.C) with a sufficient minimum margin ahead of the neutral point of the

aeroplane.D) at the neutral point of the aeroplane.

What is the effect of an aft shift of the centre of gravity on

1. static longitudinal stability and2. the required control deflection for a given pitch change?

A) (1) increases (2) reducesB) (1) reduces (2) reducesC) (1) increases (2) increasesD) (1) reduces (2) increases


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When an aeroplane with the centre of gravity forward of the centre of pressure of the combinedwing / fuselage is in straight and level flight, the vertical load on the tailplane will be:

A) downwards because it is always negative regardless of the position of the centre of gravity.

B) upwards.C) downwards.D) zero because in steady flight all loads are in equilibrium.

The max aft position of the centre of gravity is amongst others limited by the:

A) maximum elevator deflection.B) maximum longitudinal stability of the aeroplane.C) minimum value of the stick force per g.D) too small effect of the controls on the aeroplane.

The centre of gravity of an aircraft is on its most forward limit in straight and level flight. What

effect will this have on longitudinal stability?

A) A reduction in longitudinal stability will exist with no change in loadingon the tailplane.

B) A reduced download will exist on the tailplane with an associatedreduction in longitudinal stability.

C) An increased download will exist on the tailplane with an associatedincrease in longitudinal stability.

D) Longitudinal stability will be reduced with an increased downloadexisting on the tailplane.

The max aft position of the centre of gravity is amongst others limited by the:

A) Yaw damper.B) Roll spoilers.C) Rudder limiter.D) Spoiler mixer.

The centre of gravity moving aft will:

A) not affect the elevator up or down effectiveness.B) increase or decrease the elevator up effectiveness, depending on wing

location.C) decrease the elevator up effectiveness.D) increase the elevator up effectiveness.

In a mechanically controlled aeroplane, the most forward allowable position of the centre of gravity could be limited by the:

A) trim system, trim tab surface.B) engine thrust, engine location.


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C) elevator capability, elevator control forces.D) wing surface, stabilizer surface.

What is the effect on the aeroplanes static longitudinal stability of a shift of the centre of gravityto a more aft location and on the required control deflection for a certain pitch up or down?

A) The static longitudinal stability is smaller and the required controldeflection is larger.

B) The static longitudinal stability is larger and the required controldeflection is larger.

C) The static longitudinal stability is smaller and the required controldeflection is smaller.

D) The static longitudinal stability is larger and the required controldeflection is smaller.

Which statement about a jet transport aeroplane is correct, during take-off at the maximumallowable forward centre of gravity limit, while the THS (Trimmable Horizontal Stabilizer) has beenpositioned at the maximum allowable AND (Aeroplane Nose Down) position.

A) Nothing special will happen.B) The rotation will require extra stick force.C) If the THS position is just within the limits of the green band, the take

off warning system will be activated.D) Early nose wheel raising will take place.

Which statement about the trim position is true related to centre of gravity and adjustablestabiliser position?

A) A nose heavy aeroplane requires that the stabiliser leading edge islower than compared with a tail heavy aeroplane.

B) Because characteristic speeds at take off do not vary with centre of gravity location, the need for stabiliser adjustment is dependent onflap position only.

C) A nose heavy aeroplane requires that the stabiliser leading edge ishigher than compared with a tail heavy aeroplane.

D) At the forward limit for centre of gravity, stabiliser trim is adjustedmaximum Nose Down to obtain maximum elevator authority at takeoff rotation.

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Centre of Gravity Questions