Question 268-1 : Spoilers mounted on the wing upper surface can be used to ? [ Theoretical lift off ]

Question 268-2 : In straight flight as speed is reduced whilst trimming to keep the stick force zero ?

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

com encom080 641jpg

Question 268-3 : If the airspeed is doubled whilst maintaining the same control surface deflection the aerodynamic force on this control surface will ?

Become four times greater.

Recall the lift equation lift = cl x 12 rho x v² x swhere lift equals the coefficient of lift x dynamic pressure x velocity squared x surface area of the air foilif speed is doubled dynamic pressure aerodynamic force is 12 rho x v² will be four times greater

Question 268-4 : What kind of horizontal control surface is shown in the figure err a 081 1016 ?

All flying tail.

The figure shows a 'moving tailplane' or 'all flying tail' com encom080 1016jpgall flying tail on a robin dr 400

Question 268-5 : Comparing the differences between a horizontal trimmable stabiliser and an elevator trim tab which of these statements are correct or incorrect i when trimmed for zero elevator stick force an elevator trim tab causes more dragii an elevator trim tab enables a larger cg range ?

I is correct ii is incorrect.

Trimming in pitch is achieved by a small trim tab at the rear of the elevator or by moving the whole tailplane the stabiliser these both produce aerodynamic forcesthese forces depend on 12 rho v² cl which changes with the amount of deflection changes in angle of attack and s the surface area a stabiliser is much bigger that a trim tab it will produce much larger forces for the same ias and deflectioncomparing the differences between a horizontal trimmable stabiliser and an elevator trim tab correct elevator trim tab statements when trimmed for zero elevator stick force an elevator trim tab causes more drag a trim tab runaway causes less control difficulty a jammed trim tab causes less control difficultycorrect horizontal trimmable stabiliser statements a horizontal trimmable stabiliser enables a larger cg range a stabiliser trim is a more powerful means of trimming the effects of a stabiliser trim runaway are more serious a stabiliser trim is more suitable for jet transport aeroplanes because of their large speed range a stabiliser trim is more suitable to cope with the large trim changes generated by the high lift devices on most jet transport aeroplanesthe horizontal stabilizer which can be used either by itself or in addition to a trimming tab is more effective than trim tabs at high mach numbers the incidence can be varied to balance out of trim forces com encom080 1186ajpg com encom080 1186bjpg trimmable horizontal stabilizer on an airbus a319

Question 268-6 : Comparing the differences between a horizontal trimmable stabiliser and an elevator trim tab which statement is correct i a trim tab is less suitable for jet transport aeroplanes because of their large speed rangeii a trim tab is a more powerful means of trimming ?

I is correct ii is incorrect.

Trimming in pitch is achieved by a small trim tab at the rear of the elevator or by moving the whole tailplane the stabiliser these both produce aerodynamic forcesthese forces depend on 12 rho v² cl which changes with the amount of deflection changes in angle of attack and s the surface area a stabiliser is much bigger that a trim tab it will produce much larger forces for the same ias and deflectioncomparing the differences between a horizontal trimmable stabiliser and an elevator trim tab correct elevator trim tab statements when trimmed for zero elevator stick force an elevator trim tab causes more drag a trim tab runaway causes less control difficulty a jammed trim tab causes less control difficultycorrect horizontal trimmable stabiliser statements a horizontal trimmable stabiliser enables a larger cg range a stabiliser trim is a more powerful means of trimming the effects of a stabiliser trim runaway are more serious a stabiliser trim is more suitable for jet transport aeroplanes because of their large speed range a stabiliser trim is more suitable to cope with the large trim changes generated by the high lift devices on most jet transport aeroplanesthe horizontal stabilizer which can be used either by itself or in addition to a trimming tab is more effective than trim tabs at high mach numbers the incidence can be varied to balance out of trim forces com encom080 1186ajpg com encom080 1186bjpg trimmable horizontal stabilizer on an airbus a319

Question 268-7 : Comparing the differences between a horizontal trimmable stabiliser and an elevator trim tab which of these statements are correct or incorrect i a stabiliser trim is more suitable to cope with the large trim changes generated by the high lift devices on most jet transport aeroplanesii a trim tab ?

I is correct ii is correct.

Trimming in pitch is achieved by a small trim tab at the rear of the elevator or by moving the whole tailplane the stabiliser these both produce aerodynamic forcesthese forces depend on 12 rho v² cl which changes with the amount of deflection changes in angle of attack and s the surface area a stabiliser is much bigger that a trim tab it will produce much larger forces for the same ias and deflection a stabiliser trim is more suitable to cope with the large trim changes generated by the high lift devices on most jet transport aeroplanes a trim tab runaway causes less control difficulty

Question 268-8 : Comparing the differences between a horizontal trimmable stabiliser and an elevator trim tab which of these statements are correct or incorrect i when trimmed for zero elevator stick force a horizontal trimmable stabiliser causes more dragii a horizontal trimmable stabiliser enables a larger cg ?

I is incorrect ii is correct.

Trimming in pitch is achieved by a small trim tab at the rear of the elevator or by moving the whole tailplane the stabiliser these both produce aerodynamic forcesthese forces depend on 12 rho v² cl which changes with the amount of deflection changes in angle of attack and s the surface area a stabiliser is much bigger that a trim tab it will produce much larger forces for the same ias and deflectioncomparing the differences between a horizontal trimmable stabiliser and an elevator trim tab correct elevator trim tab statements when trimmed for zero elevator stick force an elevator trim tab causes more drag a trim tab runaway causes less control difficulty a jammed trim tab causes less control difficultycorrect horizontal trimmable stabiliser statements a horizontal trimmable stabiliser enables a larger cg range a stabiliser trim is a more powerful means of trimming the effects of a stabiliser trim runaway are more serious a stabiliser trim is more suitable for jet transport aeroplanes because of their large speed range a stabiliser trim is more suitable to cope with the large trim changes generated by the high lift devices on most jet transport aeroplanesthe horizontal stabilizer which can be used either by itself or in addition to a trimming tab is more effective than trim tabs at high mach numbers the incidence can be varied to balance out of trim forces com encom080 1186ajpg com encom080 1186bjpg trimmable horizontal stabilizer on an airbus a319

Question 268-9 : Outboard ailerons if present are normally used ?

In low speed flight only.

Question 268-10 : The elevator deflection required for a given manoeuvre will be ?

Larger at low ias when compared to high ias.

Question 268-11 : The elevator deflection required for a given manoeuvre will be ?

Smaller for a aft cg position when compared to an forward position.

The question is about longitudinal stability cg position affects longitudinal static stability and control response the magnitude of the stick force required to pitch for an aircraft with manual controls is determined by the distance the cg is forward of the neutral pointforward movement of the cg will increase stability and reduce the control response for the same manoeuvre a smaller elevator deflection is required for a aft cg than for a forward cg

Question 268-12 : The function of ailerons is to rotate the aeroplane about the ?

Longitudinal axis.

Question 268-13 : What is the primary input for an artificial feel system ?

Ias.

Question 268-14 : Rotation about the longitudinal axis of an aeroplane can be achieved by ?

Aileron deflection andor rudder deflection.

Question 268-15 : Rotation around the lateral axis is called ?

Pitching.

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Question 268-16 : Rotation around the longitudinal axis is called ?

Rolling.

com encom080 547ajpg

Question 268-17 : Flutter may be caused by a ?

Distortion by bending and torsion of the structure causing increasing vibration in the resonance frequency.

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 aircraftvdo925vdo926

Question 268-18 : Which load factor determines va ?

Manoeuvring limit load factor.

Va means design manoeuvring speedva is defined in cs 25 certificate specification large aeroplanes as vs1 x square root of n where n is the limiting load factor 2376

Question 268-19 : The shape of the gust load diagram is also determinated by the following three vertical speed in fts clean configuration ?

25 50 66.

2386

Question 268-20 : Which combination of speeds is applicable for structural strength in gust clean configuration ?

50 ftsec and vc.

See certification specifications and acceptable means of compliance for large aeroplanes cs 25 on the easa websitecs 25335 design airspeeds the selected design airspeeds are equivalentairspeeds eas for vb vc and vd the following apply max gust intensity speed vb + 66 ftsecdesign cruise speed vc 50 ftsecdesign dive speed vd 25 ftsec

Question 268-21 : The extreme right limitation for both gust and manoeuvre diagrams is created by the speed ?

Vd.

2386see certification specifications and acceptable means of compliance for large aeroplanes cs 25 on the easa websitecs 25335 design airspeeds the selected design airspeeds are equivalent airspeeds eas for vb vc and vd the following apply max gust intensity speed vb + 66 ftsecdesign cruise speed vc 50 ftsec design dive speed vd 25 ftsec

Question 268-22 : What can happen to the aeroplane structure flying at a speed just exceeding va ?

It may suffer permanent deformation if the elevator is fully deflected upwards.

Question 268-23 : What is the limit load factor of a large transport aeroplane ?

25.

An aeroplane's rated strength is a measure of the load the wings can carry without being damagedlarge transport aeroplane 1g to +25g flaps up 1 to 25 flaps extended 0 to 20 other aircrafts normal and commuter 152 to +38utility 176 to +44acrobatic 3 to +6

Question 268-24 : The maximum acceptable cruising altitude is limited by a minimum acceptable load factor because exceeding that altitude ?

Turbulence may induce mach buffet.

Mach buffet is a function of the speed of the airflow over the wing not necessarily the speed of the aircraft any time that too great a lift demand is made on the wing whether from too fast an airspeed or from too high an aoa angle of attack near the mmo the high speed buffet occurs there are also occasions when the buffet can be experienced at much lower speeds known as the low speed mach buffet an aircraft flown at a speed too slow for its weight and altitude necessitating a high aoa is the most likely situation to cause a low speed mach buffet this very high aoa has the effect of increasing airflow velocity over the upper surface of the wing until the same effects of the shock waves and buffet occur as in the high speed buffet situation the aoa of the wing has the greatest effect on inducing the mach buffet at either the high speed or low speed boundaries for the aircraftthe conditions that increase the aoa the speed of the airflow over the wing and chances of mach buffet is high altitudes the higher an aircraft flies the thinner the air and the greater the aoa required to produce the lift needed to maintain level flight heavy weights the heavier the aircraft the greater the lift required of the wing and all other things being equal the greater the aoa g loading an increase in the g loading on the aircraft has the same effect as increasing the weight of the aircraft whether the increase in g forces is caused by turns rough control usage or turbulence the effect of increasing the wing's aoa is the same

Question 268-25 : Va is ?

The maximum speed at which maximum elevator deflection up is allowed.

Va = sqrt 25 vs

Question 268-26 : Vmo ?

Question 268-27 : For an aeroplane with one fixed value of va the following applies va is ?

The speed at which the aeroplane stalls at the manoeuvring limit load factor at mtow.

Va is the design manoeuvring speed it is the highest speed at which maximum elevator deflection up is allowedthe question states an aeroplane with one fixed value of va thus the following applies va = vs1g x square root of the limit load factor and as vs varies with weight so does va

Question 268-28 : Load factor is increased by ?

Upward gusts.

Gusts will produce change in the angle of attack thus load factor will increase for an upward gust and decrease for a downward gust

Question 268-29 : The positive manoeuvring limit load factor for a light aeroplane in the utility category in the clean configuration is ?

44.

An aeroplane's rated strength is a measure of the load the wings can carry without being damagedlight aeroplane can take total loads in three categories normal 152 to +38utility 176 to +44aerobatic 3 to +6

Question 268-30 : Which statement is correct about the gust load on an aeroplane ias and all other factors of importance remaining constant 1 the gust load increases when the weight decreases2 the gust load increases when the altitude increases ?

1 is correct and 2 is incorrect.

Question 268-31 : Which statement regarding the gust load factor on an aeroplane is correct all other factors of importance being constant 1 increasing the aspect ratio of the wing will increase the gust load factor2 increasing the speed will increase the gust load factor ?

1 and 2 are correct.

Wing area decreases > aspect ratio decreases hence gust load factor decreasesspeed increases > gust load factor increasesaspect ratio increases > gust load factor increasesaltitude increases > gust load factor decreases due to less dynamic pressure weight increases > gust load factor decreases due to more mass to accelerate

Question 268-32 : When flutter damping of control surfaces is obtained by mass balancing these weights will be located with respect to the hinge of the control surface ?

In front of the hinge.

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 268-33 : Which of the following statements is true ?

Flight in severe turbulence may lead to a stall andor structural limitations being exceeded.

Question 268-34 : The relationship between the stall speed vs and va eas for a large transport aeroplane can be expressed in the following formula sqrt= square root ?

Va >= vs * sqrt 25.

Va is defined in cs 25 certificate specification large aeroplanes as vs1 x square root of n where n is the limiting load factorthus va can be equal to vs but may not be less than vs1g x square root of limit load factor 25g is the limit load factor for a large transport aeroplane

Question 268-35 : The positive manoeuvring limit load factor for a large transport aeroplane with flaps extended is ?

20.

Normal and commuter 152 to +38utility 176 to +44acrobatic 3 to +6transport 1 to +25 flaps up 1 to 25 flaps extended 0 to 20

Question 268-36 : The manoeuvring speed va expressed as indicated airspeed of a transport aeroplane ?

Depends on aeroplane mass and pressure altitude.

Question 268-37 : Vle is defined as the ?

Maximum landing gear extended speed.

Velocity landing extended

Question 268-38 : Which statement is correct about the gust load factor on an aeroplane i when the mass increases the gust load factor increasesii when the altitude decreases the gust load factor increases ?

I is incorrect ii is correct.

Wing area decreases > aspect ratio decreases hence gust load factor decreasesspeed increases > gust load factor increasesaspect ratio increases > gust load factor increasesaltitude increases > gust load factor decreases due to less dynamic pressure weight increases > gust load factor decreases due to more mass to accelerate

Question 268-39 : The gust load factor due to a vertical upgust increases when ?

The gradient of the cl alpha graph increases.

An increase of angle of attack increases lift thus when you fly at high angle of attack a gust will have more effect the gust load factor increases wing area decreases > aspect ratio decreases hence gust load factor decreasesspeed increases > gust load factor increasesaspect ratio increases > gust load factor increasesaltitude increases > gust load factor decreases due to less dynamic pressure weight increases > gust load factor decreases due to more mass to accelerate

Question 268-40 : All gust lines in the v n graph originate from a point where the ?

Speed = 0 load factor = +1.

2763the aircraft envelope starts from the origin so v = 0 and n = 0 but the gust envelope starts at v = 0 and n = 1 because we have n = 1 in straight and level flightthe gust envelope is superimposed over the aircraft envelope to give reference points