Longitudinal stability is directly influenced by ? [ Formation assignment ]

Question 230-1 : Centre of gravity position wing dihedral the vertical stabiliser elevator deflection only

exemple 330 Centre of gravity position. — Centre of gravity position.

An aeroplane with a cg location behind the centre of pressure of the wing can ?

Question 230-2 : Upwards zero downwards upwards or downwards depending on elevator deflection

exemple 334 Upwards. — . /com en/com080 910 jpg.the force from the tailplane must be upwards to maintain a straight and level flight Upwards.

In a skidding turn the nose pointing inwards compared with a co ordinated turn ?

Question 230-3 : I too small ii displaced towards the high wing i too large ii displaced towards the high wing i too small ii displaced towards the low wing i too large ii displaced towards the low wing

exemple 338 (i) too small, (ii) displaced towards the high wing. — .a skidding turn results from an excess of centrifugal force over the horizontal lift component pulling the airplane toward the outside of the turn the rate of turn is too great for the angle of bank correction of a skidding turn thus involves a reduction in the rate of turn an increase in bank or a combination of the two changes . /com en/com080 913 jpg. (i) too small, (ii) displaced towards the high wing.

The most forward cg location may be limited by .1 insufficient flare capability ?

Question 230-4 : 1 3 2 3 1 2

Which statement concerning longitudinal stability and control is correct ?

Question 230-5 : A bob weight and a down spring have the same effect on the stick force stability a down spring only improves the manoeuvre stability a down spring has the same function as a stick pusher a bob weight reduces the stick force per g

exemple 346 A bob-weight and a down-spring have the same effect on the stick force stability. — .bob weights are sometimes known as counter weights their purpose is to change the amount of control force required to deflect the control column under different g loadings normally the amount of force the pilot must apply to the control column assuming reversible controls varies with airspeed only however by installing a bob weight the aeronautical engineer can make it more difficult to pull on the control column as g force increases the purpose of the bob weight is to reduce the likely hood the pilot will overstress the aircraft . /com en/com080 949 jpg.the down spring produces a mechanical load on the elevator causing it to move toward the nosedown position if not otherwise balanced . /com en/com080 949a jpg.they have the same effect on the stick force stability the difference is that a bob weight increases stick force stability according to g while a down spring increases stick force stability according to stick displacement A bob-weight and a down-spring have the same effect on the stick force stability.

When a turn is initiated adverse yaw is ?

Question 230-6 : The tendency of an aeroplane to yaw in the opposite direction of turn mainly due to the difference in induced drag on each wing a momentary yawing motion opposite to the turn due to an incorrect differential aileron movement the tendency of an aeroplane to yaw in the opposite direction of turn mainly due to the difference in aileron form drag the tendency of an aeroplane to yaw in the same direction of turn due to the different wing speeds

exemple 350 The tendency of an aeroplane to yaw in the opposite direction of turn mainly due to the difference in induced drag on each wing. — .the solution is to use differential aileron deflection the aileron linkage causes the up going aileron the move through a larger angle than the down going aileron this increases the drag on the up aileron and reduces it on the down aileron and so reduces the difference in drag between the two wings The tendency of an aeroplane to yaw in the opposite direction of turn mainly due to the difference in induced drag on each wing.

During the take off roll when the pilot raises the tail in a tail wheeled ?

Question 230-7 : Gyroscopic precession asymmetric blade effect torque reaction slipstream

exemple 354 Gyroscopic precession. — Gyroscopic precession.

Assuming no pilot input the motion of the aeroplane in the diagram shows . err ?

Question 230-8 : Dynamic longitudinal stability dynamic longitudinal instability neutral dynamic longitudinal stability static longitudinal instability

exemple 358 Dynamic longitudinal stability. — Dynamic longitudinal stability.

Assuming no pilot input the motion of the aeroplane in the diagram shows . err ?

Question 230-9 : Neutral dynamic longitudinal stability dynamic longitudinal instability dynamic longitudinal stability static longitudinal instability

exemple 362 Neutral dynamic longitudinal stability. — .static stability is the initial tendency of the aircraft following removal of a disturbing force ~ dynamic stability is what happens after this initial reaction .if the aeroplane continues to oscillate about equilibrium with no reduction in amplitude therefore the aeroplane in the diagram has neutral dynamic longitudinal stability Neutral dynamic longitudinal stability.

Which of the following statements is correct .i a high limit load factor ?

Question 230-10 : I is correct and ii is incorrect i is correct and ii is correct i is incorrect and ii is incorrect i is incorrect and ii is correct

exemple 366 I is correct and ii is incorrect. — .passenger aircraft are stressed to 2 5 g the normal limit load factor as you manoeuvre the aircraft from trim you will feel an increase in stick force up to the limit load factor this is the stick force gradient stick for per g .the stick force limit is defined by cs23/25 so you cannot exceed the max value if you were to increase the limit load factor the stick force per g would decrease reduced stick force gradient .stick forces are specified in cs23/25 certification specifications not in the aeroplane flight manual I is correct and ii is incorrect.

What is the recommended action following failure of the yaw damper s of a jet ?

Question 230-11 : Reduce altitude and mach number no action is required increase mach number to improve aerodynamic damping of any subsequent dutch roll motion manually recover any subsequent dutch roll motion using rudder

exemple 370 Reduce altitude and mach number. — Reduce altitude and mach number.

Where on the curve in the diagram does the aeroplane exhibit neutral static ?

Question 230-12 : Point 2 part 1 part 3 the whole curve

exemple 374 Point 2. — . positive static longitudinal stability means that a nose down moment occurs after encountering an up gust it is a stabilising effect since the airplane coming back to his previous position .regarding the angle of attack you have while flying the response to a gust will varies .part 1 when angle of attack is increased the response is a tendency to a nose down moment stability .point 2 at this point when angle of attack is increased the response is neutral when the airplane is flying at point 2's aoa when it encounters an up gust it will stop at the new angle of attack .part 3 when angle of attack is increased the response is a tendency to a nose up moment instability Point 2.

Excessive static lateral stability is an undesirable characteristic for a ?

Question 230-13 : It would impose excessive demands on roll control during a sideslip performing co ordinated turns would be very difficult it would result in a proportional decline in static directional stability it would result in excessive wing loading during a co ordinated turn

exemple 378 It would impose excessive demands on roll control during a sideslip. — .the illustration shows an aeroplane in a right sideslip the right wing has an increased effective angle of attack and the left wing has a decreased effective angle of attack this generates a stabilising rolling moment to the left . /com en/com080 1263 jpg.for the pilot to hold the aeroplane in this sideslip for a crosswind landing would require enough stick force to oppose the stabilising rolling moment excessive static lateral stability is too large it would impose excessive demands on roll control during a sideslip crosswind landing .during a co ordinated turn there is no sideslip so static lateral stability is not a factor and none of the other answers are correct It would impose excessive demands on roll control during a sideslip.

Where on the curve in the diagram does the aeroplane exhibit static ?

Question 230-14 : Part 1 point 2 part 3 the whole curve

exemple 382 Part 1. — . positive static longitudinal stability means that a nose down moment occurs after encountering an up gust it is a stabilising effect since the airplane coming back to his previous position .regarding the angle of attack you have while flying the response to a gust will varies .part 1 when angle of attack is increased the response is a tendency to a nose down moment stability .point 2 at this point when angle of attack is increased the response is neutral when the airplane is flying at point 2's aoa when it encounters an up gust it will stop at the new angle of attack .part 3 when angle of attack is increased the response is a tendency to a nose up moment instability Part 1.

Where on the curve in the diagram does the aeroplane exhibit static ?

Question 230-15 : Part 3 point 2 part 1 the whole curve

exemple 386 Part 3. — . positive static longitudinal stability means that a nose down moment occurs after encountering an up gust it is a stabilising effect since the airplane coming back to his previous position .regarding the angle of attack you have while flying the response to a gust will varies .part 1 when angle of attack is increased the response is a tendency to a nose down moment stability .point 2 at this point when angle of attack is increased the response is neutral when the airplane is flying at point 2's aoa when it encounters an up gust it will stop at the new angle of attack .part 3 when angle of attack is increased the response is a tendency to a nose up moment instability Part 3.

Static lateral stability will be increased by ?

Question 230-16 : Increasing wing sweepback reducing the size of the vertical tail the use of a low rather than high wing mounting increasing wing anhedral

exemple 390 Increasing wing sweepback. — .sweepback angle is the angle at which the wing points backwards from the root to the tip . /com en/com080 467 png.sweepback is used mainly on high speed aircraft and its primary purpose is to delay the formation of sonic shock waves which are produced at high speeds and cause a large increase in drag .the secondary effect of sweepback is to improve lateral stability when a side slip occurs the lower wing presents a larger span as seen from the direction of the approaching air and as with dihedral the effect is to roll the aircraft back towards the horizontal .in general as the sweepback angle is increased the dihedral angle will be reduced Increasing wing sweepback.

Static lateral stability will be increased by ?

Question 230-17 : The use of a high rather than low wing mounting reducing the size of the vertical tail increasing wing anhedral reducing wing sweepback

exemple 394 The use of a high, rather than low, wing mounting. — The use of a high, rather than low, wing mounting.

Turning motion in a steady level co ordinated turn is created by ?

Question 230-18 : The centripetal force the centrifugal force the thrust the drag

exemple 398 The centripetal force. — .for an aircraft to change direction a force is required to deflect it towards the centre of the turn this is called the centripetal force banking the aircraft inclines the lift it is the horizontal component of lift which causes the aircraft to turn . /com en/com080 1276 jpg.as the angle of bank increases the angle of attack must be increased to bring about a greater totallift the vertical component must be large enough to maintain level flight while the horizontalcomponent is large enough to produce the required centripetal force The centripetal force.

During a short period oscillation the altitude ?

Question 230-19 : Remains approximately constant whereas during a phugoid it varies significantly remains approximately constant as it does during a phugoid varies significantly as it does during a phugoid varies significantly whereas during a phugoid it remains approximately constant

exemple 402 Remains approximately constant, whereas during a phugoid it varies significantly. — Img /com en/com080 483a jpg. /com en/com080 483 jpg.vdo925 Remains approximately constant, whereas during a phugoid it varies significantly.

The purpose of a dorsal fin is to ?

Question 230-20 : Maintain static directional stability at large sideslip angles stabilise forebody vortices reduce tendency for spiral instability provide pitch and yaw control

exemple 406 Maintain static directional stability at large sideslip angles. — Maintain static directional stability at large sideslip angles.

Assuming no pilot input the motion of the aeroplane in the diagram shows . err ?

Question 230-21 : Static longitudinal stability and dynamic longitudinal instability static and dynamic longitudinal stability neutral dynamic longitudinal stability static longitudinal instability

exemple 410 Static longitudinal stability and dynamic longitudinal instability. — Static longitudinal stability and dynamic longitudinal instability.

The centre of gravity moving aft will ?

Question 230-22 : Increase the elevator up effectiveness decrease the elevator up effectiveness not affect the elevator up or down effectiveness increase or decrease the elevator up effectiveness depending on wing location

exemple 414 Increase the elevator up effectiveness. — An aft shift of centre of gravity will increase maneuverability and also make the nose 'seem' lighter so you would need less control input to change the pitch and therefore more effective Increase the elevator up effectiveness.

When the cg position is moved forward the elevator deflection for a manoeuvre ?

Question 230-23 : Larger smaller unchanged dependent on trim position

exemple 418 Larger. — The question is about longitudinal stability if your aircraft is less stable then smaller control deflections will get the response required aft cg however with a forward cg the aircraft is more stable so to manoeuvre you have to make a bigger stick deflection resulting in a bigger elevator deflection Larger.

Which of the following statements about a mach trimmer is correct ?

Question 230-24 : A mach trimmer corrects the change in stick force stability of a swept wing aeroplane above a certain mach number a straight wing aeroplane always needs a mach trimmer for flying at mach numbers close to mmo a mach trimmer reduces the stick force stability of a straight wing aeroplane to zero at high mach numbers the mach trimmer corrects the natural tendency of a swept wing aeroplane to pitch up

exemple 422 A mach trimmer corrects the change in stick force stability of a swept wing aeroplane above a certain mach number. — A mach trim system provides speed stability at the higher mach numbers mach trim is automatically accomplished above mach 0 6 by adjusting the elevators with respect to the stabilizer as speed increases the flight control computers use mach information to compute a mach trim actuator position the mach trim actuator repositions the elevator feel and centering unit which adjusts the control column neutral position A mach trimmer corrects the change in stick force stability of a swept wing aeroplane above a certain mach number.

During initiation of a turn with speedbrakes extended the roll spoiler function ?

Question 230-25 : Downward on the upgoing wing and upward on the downgoing wing upward on the upgoing wing and downward on the downgoing wing on the upgoing wing only on the downgoing wing only

exemple 426 Downward on the upgoing wing and upward on the downgoing wing. — Img /com en/com080 134 jpg.while turning the outer wing has a higher speed thus it generates more lift as for the differential aileron deflection we need to equals the drag of the right and left aileron the speed brakes on the outer wing need to be deflect downward and upward for the inner wing Downward on the upgoing wing and upward on the downgoing wing.

Stick forces provided by an elevator feel system depend on ?

Question 230-26 : Elevator deflection dynamic pressure stabiliser position static pressure elevator deflection static pressure stabiliser position total pressure

exemple 430 Elevator deflection, dynamic pressure. — Elevator deflection, dynamic pressure.

Differential aileron deflection ?

Question 230-27 : Equals the drag of the right and left aileron is required to keep the total lift constant when ailerons are deflected increases the clmax is required to achieve the required roll rate

exemple 434 Equals the drag of the right and left aileron. — To generate lift we have to move air downwards and to roll into a banked attitude to turn we have to lift one wing while dropping the other to lift a wing we have to generate more lift and so we lower the aileron on that side we don't get something for nothing and so this extra lift increases the drag meanwhile dropping the other wing by moving the aileron upwards reduces the drag the increased drag generated by the down going aileron causes the nose to yaw in the opposite direction to the roll and this is called adverse yaw . /com en/com080 300a jpg.with differential ailerons one aileron is raised a greater distance than the other aileron is lowered for a given movement of the control wheel this produces an increase in drag on the descending wing the greater drag results from deflecting the up aileron on the descending wing to a greater angle than the down aileron on the rising wing while adverse yaw is reduced it is not eliminated completely . /com en/com080 300b jpg. Equals the drag of the right and left aileron.

Which kind of 'tab' is commonly used in case of manual reversion of fully ?

Question 230-28 : Servo tab spring tab balance tab anti balance tab

exemple 438 Servo tab. — .on fully powered controls a fail/safe system is included such that if the power fails or there is a fault the control of one or more primary control surface reverts to manual control conventional trailing edge tabs are not included in this system because the aeroplane is trimmed by adjusting the zero position of the artificial feel mechanism although powered controls do not require balance tabs some aeroplanes do have them fitted to relieve the servo and hinge loads in the case of manual reversion of fully powered flight controls a servo tab is commonly used together with control surface mass balancing to make the aeroplane easier to control Servo tab.

One advantage of a movable stabiliser system compared with an elevator trim ?

Question 230-29 : It is a more effective means of trimming the complete system structure and control mechanism weighs less it leads to greater stability in flight the system's complexity is reduced

exemple 442 It is a more effective means of trimming. — .the trimming stabiliser is a very powerful trimming system and its other advantage is that when you are trimmed out the elevator sits more or less in line with the stabilizer giving less trim drag It is a more effective means of trimming.

Which statement is correct about a spring tab ?

Question 230-30 : At high ias it behaves like a servo tab at low ias it behaves like a servo tab at high ias it behaves like a fixed extension of the elevator its main purpose is to increase stick force per g

exemple 446 At high ias it behaves like a servo tab. — . /com en/com080 276 jpg.servo tabs rely on airflow over them in order to 'fly' the control surface into the desired position very handy for reducing stick forces unfortunately the higher the airspeed the more effective the tab so that gives us a system that get more effective as ias increases so the controls get lighter not a good situation .the spring tab .the easiest way to visualise this is to look at two extremes in the context of the strength of the spring compared to the aerodynamic forces present ..case 1 very low ias .if ias is low then aerodynamic forces are low so relatively the spring is strong now imagine its really strong by replacing it with a rigid link .now when you move the control column the flying control is directly moved and the tab doesn't do anything so this is now a basic control surface ..case 2 very high ias .if ias is high the aerodynamic forces are high relatively speaking the spring is weak now imagine its really weak by removing it altogether now when you move the column you are only moving the tab and that flies the control surface into position so this is now a servo tab system At high ias it behaves like a servo tab.

How is adverse yaw compensated for during entry into and roll out from a turn ?

Question 230-31 : Differential aileron deflection horn balanced controls anti balanced rudder control servo tabs

exemple 450 Differential aileron deflection. — .to generate lift we have to move air downwards and to roll into a banked attitude to turn we have to lift one wing while dropping the other to lift a wing we have to generate more lift and so we lower the aileron on that side we don't get something for nothing and so this extra lift increases the drag meanwhile dropping the other wing by moving the aileron upwards reduces the drag the increased drag generated by the down going aileron causes the nose to yaw in the opposite direction to the roll and this is called adverse yaw . /com en/com080 300a jpg.with differential ailerons one aileron is raised a greater distance than the other aileron is lowered for a given movement of the control wheel this produces an increase in drag on the descending wing the greater drag results from deflecting the up aileron on the descending wing to a greater angle than the down aileron on the rising wing while adverse yaw is reduced it is not eliminated completely . /com en/com080 300b jpg. Differential aileron deflection.

One method to compensate adverse yaw is ?

Question 230-32 : A differential aileron a balance tab an anti balance tab a balance panel

exemple 454 A differential aileron. — .to generate lift we have to move air downwards and to roll into a banked attitude to turn we have to lift one wing while dropping the other to lift a wing we have to generate more lift and so we lower the aileron on that side we don't get something for nothing and so this extra lift increases the drag meanwhile dropping the other wing by moving the aileron upwards reduces the drag the increased drag generated by the down going aileron causes the nose to yaw in the opposite direction to the roll and this is called adverse yaw . /com en/com080 300a jpg.with differential ailerons one aileron is raised a greater distance than the other aileron is lowered for a given movement of the control wheel this produces an increase in drag on the descending wing the greater drag results from deflecting the up aileron on the descending wing to a greater angle than the down aileron on the rising wing while adverse yaw is reduced it is not eliminated completely . /com en/com080 300b jpg. A differential aileron.

Flaperons are controls which combine the function of ?

Question 230-33 : Ailerons and flaps ailerons and elevator flaps and speed brakes flaps and elevator

exemple 458 Ailerons and flaps. — Ailerons and flaps.

In general transport aeroplanes with power assisted flight controls are fitted ?

Question 230-34 : Effectiveness of trim tabs is insufficient for those aeroplanes the pilot does not feel the stick forces at all mechanical adjustment of trim tabs creates too many problems trim tab deflection increases vmo

exemple 462 Effectiveness of trim tabs is insufficient for those aeroplanes. — Effectiveness of trim tabs is insufficient for those aeroplanes.

A jet aeroplane equipped with inboard and outboard ailerons is cruising at its ?

Question 230-35 : Only the inboard ailerons are active only the outboard aileron are active the inboard and outboard ailerons are active only the spoilers will be active not the ailerons

exemple 466 Only the inboard ailerons are active. — .the ailerons are normally situated at the wing tip to give the greatest moment for the force produced however this also means that they cause the maximum twisting and bending loads on the wing this can cause a loss of effectiveness or even reversal of the aileron .to reduce these effects the ailerons can be mounted further inboard alternatively two sets of ailerons may be fitted one set at the wing tip for use at low speeds when the forces involved are low and one set inboard for use at high speeds when the forces are greater and could cause greater structural distortion in summary outboard ailerons are low speed ailerons and inboard ailerons are high speed ailerons and only the inboard ailerons are used when the flaps are retracted Only the inboard ailerons are active.

Which of the following statements concerning control is correct ?

Question 230-36 : In a differential aileron control system the control surfaces have a larger upward than downward maximum deflection on some aeroplanes the servo tab also serves as a trim tab hydraulically powered control surfaces do not need mass balancing in general the maximum downward elevator deflection is larger than upward

.to generate lift we have to move air downwards and to roll into a banked attitude to turn we have to lift one wing while dropping the other to lift a wing we have to generate more lift and so we lower the aileron on that side we don't get something for nothing and so this extra lift increases the drag meanwhile dropping the other wing by moving the aileron upwards reduces the drag the increased drag generated by the down going aileron causes the nose to yaw in the opposite direction to the roll and this is called adverse yaw . /com en/com080 300a jpg.with differential ailerons one aileron is raised a greater distance than the other aileron is lowered for a given movement of the control wheel this produces an increase in drag on the descending wing the greater drag results from deflecting the up aileron on the descending wing to a greater angle than the down aileron on the rising wing while adverse yaw is reduced it is not eliminated completely . /com en/com080 300b jpg.

When are outboard ailerons if present de activated ?

Question 230-37 : Flaps and slats retracted or speed above a certain value flaps and/or slats extended or speed below a certain value landing gear retracted landing gear extended

exemple 474 Flaps (and slats) retracted or speed above a certain value. — Flaps (and slats) retracted or speed above a certain value.

Which statement about stick force per g is correct ?

Question 230-38 : The stick force per g must have both an upper and lower limit in order to ensure acceptable control characteristics the stick force per g increases when centre of gravity is moved aft the stick force per g can only be corrected by means of electronic devices stability augmentation in case of an unacceptable value if the slope of the fe n line becomes negative generally speaking this is not a problem for control of an aeroplane

exemple 478 The stick force per g must have both an upper and lower limit in order to ensure acceptable control characteristics. — The stick force per g must have both an upper and lower limit in order to ensure acceptable control characteristics.

Examples of aerodynamic balancing of control surfaces are ?

Question 230-39 : Servo tab spring tab seal between the wing trailing edge and the leading edge of control surface balance tab horn balance and mass balance mass in the nose of the control surface horn balance and mass balance spring tab servo tab and power assisted control

exemple 482 Servo tab, spring tab, seal between the wing trailing edge and the leading edge of control surface. — Illustration of a seal between the wing trailing edge and the leading edge of control surface . 2762.when you move the control surface it generates an area of high pressure and an area of low pressure .this differential pressure creates a compensation force acting in the same way of the pilot's action Servo tab, spring tab, seal between the wing trailing edge and the leading edge of control surface.

Which phenomenon is counteracted with differential aileron deflection ?

Question 230-40 : Adverse yaw aileron reversal sensitivity for spiral dive turn co ordination

exemple 486 Adverse yaw. — To generate lift we have to move air downwards and to roll into a banked attitude to turn we have to lift one wing while dropping the other to lift a wing we have to generate more lift and so we lower the aileron on that side we don't get something for nothing and so this extra lift increases the drag meanwhile dropping the other wing by moving the aileron upwards reduces the drag the increased drag generated by the down going aileron causes the nose to yaw in the opposite direction to the roll and this is called adverse yaw ..with differential ailerons one aileron is raised a greater distance than the other aileron is lowered for a given movement of the control wheel this produces an increase in drag on the descending wing the greater drag results from deflecting the up aileron on the descending wing to a greater angle than the down aileron on the rising wing while adverse yaw is reduced it is not eliminated completely Adverse yaw.

~

Exclusive rights reserved. Reproduction prohibited under penalty of prosecution.

9159 Free Training Exam