Question 267-1 : One method to compensate adverse yaw is ? [ Theoretical lift off ]

Question 267-2 : Flaperons are controls which combine the function of ?

Ailerons and flaps.

Question 267-3 : In general transport aeroplanes with power assisted flight controls are fitted with an adjustable stabiliser instead of trim tabs on the elevator this is because ?

Effectiveness of trim tabs is insufficient for those aeroplanes.

Question 267-4 : A jet aeroplane equipped with inboard and outboard ailerons is cruising at its normal cruise mach number in this case ?

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 aileronto 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

Question 267-5 : Which of the following statements concerning control is correct ?

In a differential aileron control system the control surfaces have a larger upward than downward maximum 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 encom080 300ajpgwith 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 encom080 300bjpg

Question 267-6 : When are outboard ailerons if present de activated ?

Flaps and slats retracted or speed above a certain value.

Question 267-7 : Which statement about stick force per g is correct ?

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

Question 267-8 : Examples of aerodynamic balancing of control surfaces are ?

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 2762when you move the control surface it generates an area of high pressure and an area of low pressurethis differential pressure creates a compensation force acting in the same way of the pilot's action

Question 267-9 : Which phenomenon is counteracted with differential aileron deflection ?

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 yawwith 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

Question 267-10 : An aeroplane has a servo tab controlled elevator what will happen if the elevator jams during flight ?

Pitch control sense is reversed.

com encom080 378jpgonly the tab is left functioning it is not connected to the elevator but works in the unnatural sense to drive the elevator in the natural sense so with the elevator locked you only have very limited control from the tab only and in the unnatural sense and of course you have no trim or balance fuction left

Question 267-11 : A horn balance in a control system has the following purpose ?

To decrease stick forces.

A horn balance is a method of aerodynamic balancing for the ailerons elevators and rudders and is used to produce a balancing moment in order to reduce amount of force required to move the controlsflutter is prevented by the use of mass balancing by adding weights to the control surface to move their cg not by horn balancingexample of horn balance 1537

Question 267-12 : An increase in geometric dihedral in a steady sideslip condition at constant speed would ?

Increase the required lateral control force.

Stability is the ability of the aircraft to return to equalibrium without input from the pilotequalibrium is where all the forces are zeroit does not mean that the aircraft returns to the same heading or altitude but that the relative airflow is in such a position that the aircraft will be balanced in the question we are trying to hold the aircraft in a steady side slip which means we are holding the aircraft out of equalibriuma stable aircraft with geometric dihedral will try to oppose thisso we will be required to hold greater forces to maintain the angle which is opposing the natural tendency of the aircraftif we increase the geometric dihedral even further we will need more effort to hold that sideslip as stability will be increased

Question 267-13 : When a jet transport aeroplane takes off with the cg at the forward limit and the trimmable horizontal stabiliser ths is positioned at the maximum allowable nose down position for take off ?

Rotation will require a higher than normal stick force.

Question 267-14 : Which statement is correct i on fully hydraulic powered flight controls there is no need for mass balancingii on fully hydraulic powered flight controls there is no need for trim tabs ?

I is incorrect ii is correct.

Flight control force balance can normally be achieved hydraulically as part of the actuator sizing you have to remember that even though fly by wire aircraft receive their control inputs electronically the control surfaces are still powered by the hydraulic system s which are sized to overcome mass balance and flight loads but to prevent flutter mass balancing is required and also in case of manual reversion total hydraulic failure and with a fully hydraulic powered flight controls there is no need for trim tabs you can move the controls where you like and use an artificial trim

Question 267-15 : An aeroplane performs a right turn the slip indicator is left of neutral one way to co ordinate the turn is to apply ?

More left rudder.

In a skidding turn the ball will be displaced in the opposite direction of turn in the direction of turn for a slipping turn com encom080 593jpgone way to co ordinate the turn is to apply more left rudder

Question 267-16 : When roll spoilers are extended the part of the wing on which they are mounted ?

Experiences a reduction in lift which generates the desired rolling moment in addition there is a local increase in drag which suppresses adverse yaw.

Question 267-17 : When power assisted controls are used for pitch control ?

A part of the aerodynamic forces is still felt on the column.

Question 267-18 : The pitch angle is defined as the angle between the ?

Longitudinal axis and the horizontal plane.

682the angle of attack should not be confused with the pitch angle or attitude of aircraft which are angles relative to the horizontal while the angle of attack is in respect to the relative airflow

Question 267-19 : Which statement in respect of a trimmable horizontal stabiliser is correct ?

An aeroplane with a forward cg requires the stabiliser leading edge to be lower than for one with an aft cg in the same trimmed condition.

1567if the cg is moved aft it results in a larger nose down pitching moment which has to be compensated for by placing a download on the tailplane this can be achieved by deflecting the elevator up although this results in high trim drag at higher airspeeds on large aircraft small movements of the variable incidence stabiliser allow the trimming to be carried out but with reduced trim dragan upward deflection of the elevator is required to trim the aircraft so think of the stabiliser as a large elevator with its trailing edge moving in the same direction as the elevator to achieve this you must therefore lower the leading edge of the stabiliser to produce the necessary downloadnote once in a trimmed condition on fully powered flying controls the elevator will then align itself with the stabiliser to reduce the tail load and also the loads acting on the hinges and servo actuator on power assisted controls there is however no guarantee that this occurs due to downwash and configuration effects that can alter the flow over the surface it is also fair to say that trim drag also increases fuel consumption

Question 267-20 : An example of differential aileron deflection during initiation of left turn is ?

Left aileron 5° up right aileron 2° down.

com encom080 510jpgthe 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

Question 267-21 : An aeroplane is provided with spoilers and both inboard and outboard ailerons roll control during cruise is provided by ?

Inboard ailerons and roll spoilers.

Question 267-22 : Mass balancing of control surfaces is used to ?

Prevent flutter of control surfaces.

Flutter is a dangerous phenomenon encountered in flexible structures subjected to aerodynamic forces as the airspeed increases there may be a point at which the structural damping is insufficient to damp out the motions which are increasing due to aerodynamic energy being added to the airfoil this vibration can cause structural failure and therefore considering flutter characteristics is an essential part of designing an aircraft 813to counteract this phenomenon the control surface's cg must be as close as possible of the hinge the torsion axis

Question 267-23 : In what phase of flight are the outboard ailerons if fitted not active ?

Cruise.

Question 267-24 : The most important factor determining the required position of the trimmable horizontal stabiliser ths for take off is the ?

Position of the aeroplane's centre of gravity.

Question 267-25 : What is the position of the elevator in relation to the trimmable horizontal stabiliser of an aeroplane with fully hydraulically operated flight controls that is in trim ?

Elevator deflection is zero.

A fully hydraulically operated flight controls is an irreversible system and the trim is a redatum as there is no physical connection between the stick and control therefore there will be no elevator deflection when trimmed

Question 267-26 : In straight flight as speed is increased whilst trimming to keep the stick force zero ?

The elevator is deflected further downwards and the trim tab further upwards.

com encom080 641jpg

Question 267-27 : Rotation around the longitudinal axis is called ?

Rolling.

com encom080 547ajpg

Question 267-28 : Rotation around the normal axis is called ?

Question 267-29 : Which of these statements about a trimmable horizontal stabiliser is correct ?

A trimmed aeroplane with an aft cg requires the stabiliser leading edge to be higher than in the case of a forward cg in the same condition.

com frcom080 298jpgwith a forward cg the tailplane must produce a high downward force to stabilise the aircraft if the cg moves aft closer to the centre of lift the downward force is reduced thetrimmable horizontal stabiliser leading edge is higher than in the case of a forward cg to keep the balance of lift and total weight constant

Question 267-30 : When comparing an elevator trim system with a stabiliser trim system which of these statements is correct ?

An elevator trim is more sensitive to flutter.

On a stabiliser trim system the whole tailplane is moving this large surface is less sensitive to flutter than an elevator trim system the elevator trim tab system is a small auxiliary control surface hinged at the trailing edge of the elevators

Question 267-31 : When comparing a stabiliser trim system with an elevator trim system which of these statements is correct ?

An elevator trim is less suitable for aeroplanes with a large cg range.

A horizontal trimmable stabiliser enables a larger cg range and is more suitable to cope with the large trim changes generated by the high lift devices on most jet transport aeroplaneson a stabiliser trim system the whole tailplane is moving this large surface is less sensitive to flutter than an elevator trim system the elevator trim tab system is a small auxiliary control surface hinged at the trailing edge of the elevators

Question 267-32 : Comparing the differences between a horizontal trimmable stabiliser and an elevator trim tab which of these statements are correct or incorrect i the effects of a stabiliser trim runaway are more seriousii a jammed trim tab causes less control difficulty ?

I is correct ii is correct.

The effects of a trim tab runaway are more serious > wrongthe effects of a stabiliser trim runaway are more serious > correcta jammed stabiliser trim causes less control difficulty > wronga jammed trim tab causes less control difficulty > correctstabiliser trim runaway is more serious because it requires more force to be exerted by the pilot to overcome the movement of the stabiliser trim because stabilisers pivot around a central hinge point they are extremely sensitive to control inputs and aerodynamic loads antiservo tabs are incorporated on the trailing edge to decrease sensitivity they deflect in the same direction as the stabilisator this results in an increase in the force required to move the stabiliserwhereas a jammed trim tab is less serious because it requires less force to be exerted by the pilot in order to overcome it

Question 267-33 : Which aerodynamic design features can be used to reduce control forces ?

Horn balance balance tab servo tab.

Question 267-34 : In general control forces are reduced by ?

A horn balance servo tab and spring tab.

Question 267-35 : What are the primary roll controls on a conventional aeroplane ?

The ailerons.

Question 267-36 : Artificial feel is required ?

With fully powered flight controls.

Question 267-37 : Consider an aeroplane with 1 a trim tab2 fully powered hydraulic controls and an adjustable horizontal stabiliserfor both cases and starting from a trimmed condition how will the neutral position of the control column change after trimming for a speed increase ?

Question 267-38 : The tab in the figure represents err a 081 946 ?

A servo tab.

Question 267-39 : The tab in the figure represents err a 081 947 ?

A balance tab that also functions as a trim tab.

Question 267-40 : When comparing a stabiliser trim system with an elevator trim system which of these statements is correct ?

A stabiliser trim is able to compensate larger changes in pitching moments.