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Comparing the differences between a horizontal trimmable stabiliser and an ? [ Formation assignment ]

Question 238-1 : I is correct ii is correct i is incorrect ii is incorrect i is incorrect ii is correct 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 forces .these forces depend on 1/2 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 exemple 338 I is correct, ii is correct.I is correct, ii is correct.

Comparing the differences between a horizontal trimmable stabiliser and an ?

Question 238-2 : I is incorrect ii is correct i is incorrect ii is incorrect i is correct ii is correct 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 forces .these forces depend on 1/2 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 .comparing 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 difficulty ..correct 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 aeroplanes ..the 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 en/com080 1186a jpg... /com en/com080 1186b jpg. trimmable horizontal stabilizer on an airbus a319 exemple 342 I is incorrect, ii is correct.I is incorrect, ii is correct.

Outboard ailerons if present are normally used ?

Question 238-3 : In low speed flight only in high speed flight only at transonic and supersonic speeds only when the landing gear is up

exemple 346 In low speed flight only.In low speed flight only.

The elevator deflection required for a given manoeuvre will be ?

Question 238-4 : Larger at low ias when compared to high ias larger for an aft cg position when compared to a forward position the same for all cg positions the same at all speeds

exemple 350 Larger at low ias when compared to high ias.Larger at low ias when compared to high ias.

The elevator deflection required for a given manoeuvre will be ?

Question 238-5 : Smaller for a aft cg position when compared to an forward position larger for an aft cg position when compared to a forward position larger at high ias when compared to low ias the same at all speeds

.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 point .forward 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 exemple 354 Smaller for a aft cg position when compared to an forward position.Smaller for a aft cg position when compared to an forward position.

The function of ailerons is to rotate the aeroplane about the ?

Question 238-6 : Longitudinal axis lateral axis normal axis yaw axis

exemple 358 Longitudinal axis.Longitudinal axis.

What is the primary input for an artificial feel system ?

Question 238-7 : Ias mach number tas static pressure

exemple 362 Ias.Ias.

Rotation about the longitudinal axis of an aeroplane can be achieved by ?

Question 238-8 : Aileron deflection and/or rudder deflection symmetrical spoiler deflection and/or elevator deflection speed brake extension or wing flap deflection elevator deflection and/or slat extension

exemple 366 Aileron deflection and/or rudder deflection.Aileron deflection and/or rudder deflection.

Flutter may be caused by a ?

Question 238-9 : Distortion by bending and torsion of the structure causing increasing vibration in the resonance frequency low airspeed aerodynamic wing stall roll control reversal high airspeed aerodynamic wing stall

.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 .vdo925.vdo926 exemple 370 Distortion by bending and torsion of the structure causing increasing vibration in the resonance frequency.Distortion by bending and torsion of the structure causing increasing vibration in the resonance frequency.

Which load factor determines va ?

Question 238-10 : Manoeuvring limit load factor manoeuvring ultimate load factor gust load factor at 66 ft/s gust manoeuvring flap limit load factor

.va means design manoeuvring speed .va is defined in cs 25 certificate specification large aeroplanes as vs1 x square root of n where n is the limiting load factor . 2376 exemple 374 Manoeuvring limit load factor.Manoeuvring limit load factor.

The shape of the gust load diagram is also determinated by the following three ?

Question 238-11 : 25 50 66 35 55 66 25 55 75 15 56 65

. 2386 exemple 378 25, 50, 66.25, 50, 66.

Which combination of speeds is applicable for structural strength in gust clean ?

Question 238-12 : 50 ft/sec and vc 66 ft/sec and vd 65 ft/sec at all speeds 55 ft/sec and vb

.see certification specifications and acceptable means of compliance for large aeroplanes cs 25 on the easa website .cs 25 335 design airspeeds .the selected design airspeeds are equivalent.airspeeds eas for vb vc and vd the following apply .max gust intensity speed vb +/ 66 ft/sec .design cruise speed vc 50 ft/sec .design dive speed vd 25 ft/sec exemple 382 50 ft/sec and vc.50 ft/sec and vc.

The extreme right limitation for both gust and manoeuvre diagrams is created by ?

Question 238-13 : Vd vc vflutter vmo

. 2386.see certification specifications and acceptable means of compliance for large aeroplanes cs 25 on the easa website .cs 25 335 design airspeeds .the selected design airspeeds are equivalent airspeeds eas for vb vc and vd the following apply .max gust intensity speed vb +/ 66 ft/sec .design cruise speed vc 50 ft/sec . design dive speed vd 25 ft/sec exemple 386 Vd.Vd.

What can happen to the aeroplane structure flying at a speed just exceeding va ?

Question 238-14 : It may suffer permanent deformation if the elevator is fully deflected upwards it may break if the elevator is fully deflected upwards it may suffer permanent deformation because the flight is performed at too large dynamic pressure it will collapse if a turn is made

exemple 390 It may suffer permanent deformation if the elevator is fully deflected upwards.It may suffer permanent deformation if the elevator is fully deflected upwards.

What is the limit load factor of a large transport aeroplane ?

Question 238-15 : 2 5 4 4 3 75 6

.an aeroplane's rated strength is a measure of the load the wings can carry without being damaged .large transport aeroplane 1g to +2 5g flaps up 1 to 2 5 flaps extended 0 to 2 0 .other aircrafts .normal and commuter 1 52 to +3 8.utility 1 76 to +4 4.acrobatic 3 to +6 exemple 394 2.52.5

The maximum acceptable cruising altitude is limited by a minimum acceptable ?

Question 238-16 : Turbulence may induce mach buffet turbulence may exceed the limit load factor a sudden necessary bankangle may exceed the limit load factor mach buffet will occur immediately

.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 aircraft .the 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 exemple 398 Turbulence may induce mach buffet.Turbulence may induce mach buffet.

Va is ?

Question 238-17 : The maximum speed at which maximum elevator deflection up is allowed the maximum speed at which rolls are allowed the speed at which a heavy transport aeroplane should fly in turbulence the speed that should not be exceeded in the climb

.va = sqrt 2 5 vs exemple 402 The maximum speed at which maximum elevator deflection up is allowed.The maximum speed at which maximum elevator deflection up is allowed.

Vmo ?

Question 238-18 : Should be not greater than vc should be chosen in between vc and vd is equal to the design speed for maximum gust intensity should not be less than vd

.vc is a design speed not an operating speed vd is the design dive speed if you go there the wings will come off .vmo/mmo may be equal to but may not be greater than vc the design cruise speed the reasoning behind that is that if you are flying at vmo/mmo and you get a disturbance nose down the speed will increase hopefully you will be able to recover before vd exemple 406 Should be not greater than vc.Should be not greater than vc.

For an aeroplane with one fixed value of va the following applies va is ?

Question 238-19 : The speed at which the aeroplane stalls at the manoeuvring limit load factor at mtow the maximum speed in smooth air the speed at which unrestricted application of elevator control can be used without exceeding the maximum manoeuvring limit load factor just another symbol for the rough air speed

.va is the design manoeuvring speed it is the highest speed at which maximum elevator deflection up is allowed .the 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 exemple 410 The speed at which the aeroplane stalls at the manoeuvring limit load factor at mtow.The speed at which the aeroplane stalls at the manoeuvring limit load factor at mtow.

Load factor is increased by ?

Question 238-20 : Upward gusts an increase in aeroplane mass a decrease in air density forward cg movement

.gusts will produce change in the angle of attack thus load factor will increase for an upward gust and decrease for a downward gust exemple 414 Upward gusts.Upward gusts.

The positive manoeuvring limit load factor for a light aeroplane in the utility ?

Question 238-21 : 4 4 2 5 3 8 6

.an aeroplane's rated strength is a measure of the load the wings can carry without being damaged .light aeroplane can take total loads in three categories .normal 1 52 to +3 8.utility 1 76 to +4 4.aerobatic 3 to +6 exemple 418 4.4.4.4.

Which statement is correct about the gust load on an aeroplane ias and all ?

Question 238-22 : 1 is correct and 2 is incorrect 1 and 2 are correct 1 and 2 are incorrect 1 is incorrect and 2 is correct

exemple 422 1 is correct and 2 is incorrect.1 is correct and 2 is incorrect.

Which statement regarding the gust load factor on an aeroplane is correct all ?

Question 238-23 : 1 and 2 are correct 1 is correct and 2 is incorrect 1 is incorrect and 2 is correct 1 and 2 are incorrect

.wing area decreases > aspect ratio decreases hence gust load factor decreases .speed increases > gust load factor increases.aspect ratio increases > gust load factor increases.altitude increases > gust load factor decreases due to less dynamic pressure .weight increases > gust load factor decreases due to more mass to accelerate exemple 426 1 and 2 are correct.1 and 2 are correct.

When flutter damping of control surfaces is obtained by mass balancing these ?

Question 238-24 : In front of the hinge below the hinge above the hinge behind 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 . 813.to counteract this phenomenon the control surface's cg must be as close as possible of the hinge the torsion axis exemple 430 In front of the hinge.In front of the hinge.

Which of the following statements is true ?

Question 238-25 : Flight in severe turbulence may lead to a stall and/or structural limitations being exceeded flap extension in severe turbulence at constant speed increases both the stall speed and the structural limitation margins by increasing the flap setting in severe turbulence at constant speed the stall speed will be reduced and the risk for exceeding the structural limits will be decreased flap extension in severe turbulence at constant speed moves the centre of pressure aft which increases the structural limitation margins

exemple 434 Flight in severe turbulence may lead to a stall and/or structural limitations being exceeded.Flight in severe turbulence may lead to a stall and/or structural limitations being exceeded.

The relationship between the stall speed vs and va eas for a large transport ?

Question 238-26 : Va >= vs * sqrt 2 5 va > vs * sqrt 2 5 va < vs * sqrt 2 5 va

.va is defined in cs 25 certificate specification large aeroplanes as vs1 x square root of n where n is the limiting load factor .thus va can be equal to vs but may not be less than vs1g x square root of limit load factor . 2 5g is the limit load factor for a large transport aeroplane exemple 438 Va >= vs * sqrt(2.5)Va >= vs * sqrt(2.5)

The positive manoeuvring limit load factor for a large transport aeroplane with ?

Question 238-27 : 2 0 1 5 2 5 3 75

.normal and commuter 1 52 to +3 8.utility 1 76 to +4 4.acrobatic 3 to +6.transport 1 to +2 5 flaps up 1 to 2 5 flaps extended 0 to 2 0 exemple 442 2.0.2.0.

The manoeuvring speed va expressed as indicated airspeed of a transport ?

Question 238-28 : Depends on aeroplane mass and pressure altitude is a constant value is independent of aeroplane mass but dependent on pressure altitude depends on aeroplane mass and is independent of pressure altitude

exemple 446 Depends on aeroplane mass and pressure altitude.Depends on aeroplane mass and pressure altitude.

Vle is defined as the ?

Question 238-29 : Maximum landing gear extended speed maximum speed at which the landing gear may be extended or retracted maximum flap extended speed maximum authorised speed

.velocity landing extended exemple 450 Maximum landing gear extended speed.Maximum landing gear extended speed.

Which statement is correct about the gust load factor on an aeroplane .i when ?

Question 238-30 : I is incorrect ii is correct i is incorrect ii is incorrect i is correct ii is correct i is correct ii is incorrect

.wing area decreases > aspect ratio decreases hence gust load factor decreases .speed increases > gust load factor increases.aspect ratio increases > gust load factor increases.altitude increases > gust load factor decreases due to less dynamic pressure .weight increases > gust load factor decreases due to more mass to accelerate exemple 454 I is incorrect, ii is correct.I is incorrect, ii is correct.

The gust load factor due to a vertical upgust increases when ?

Question 238-31 : The gradient of the cl alpha graph increases weight increases altitude increases wing loading 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 decreases .speed increases > gust load factor increases.aspect ratio increases > gust load factor increases..altitude increases > gust load factor decreases due to less dynamic pressure .weight increases > gust load factor decreases due to more mass to accelerate exemple 458 The gradient of the cl-alpha graph increases.The gradient of the cl-alpha graph increases.

All gust lines in the v n graph originate from a point where the ?

Question 238-32 : Speed = 0 load factor = +1 speed = 0 load factor = 0 speed = vs load factor = 0 speed = vb load factor = +1

. 2763.the 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 flight .the gust envelope is superimposed over the aircraft envelope to give reference points exemple 462 Speed = 0, load factor = +1Speed = 0, load factor = +1

An aeroplane in straight and level flight is subjected to a strong vertical ?

Question 238-33 : Aerodynamic centre of the wing centre of thrust centre of gravity neutral point

exemple 466 Aerodynamic centre of the wing.Aerodynamic centre of the wing.

How does va eas alter when the aeroplane's mass decreases by 19% ?

Question 238-34 : 10% reduction 4 36% reduction no change 19% reduction

.mass decreases by 19% .100% 19% = 81%.sqrt 0 81 = 0 9.va decreases by 10%

How can wing flutter be prevented ?

Question 238-35 : By locating mass in front of the torsion axis of the wing by increasing the aspect ratio of the wing by mounting the engines on the fuselage by installing the fuel tanks in the fuselage

.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 . 813.to counteract this phenomenon the control surface's cg must be as close as possible of the hinge the torsion axis exemple 474 By locating mass in front of the torsion axis of the wing.By locating mass in front of the torsion axis of the wing.

The lift coefficient cl of an aeroplane in steady horizontal flight is 0 35 an ?

Question 238-36 : 1 45 0 9 0 45 1 9

.1° => 0 079.2° => 0 158. 0 35 + 0 158 /0 35 = 1 45 exemple 478 1.451.45

The lift coefficient cl of an aeroplane in steady horizontal flight is 0 4 an ?

Question 238-37 : 2 13 1 09 2 3 18

.1° will increase cl by 0 09 .5° will increase cl by 5 x 0 09 = 0 45 . 0 45 + 0 4 /0 4 = 2 125 exemple 482 2.132.13

Vra is ?

Question 238-38 : The recommended turbulence penetration airspeed a speed just below mach buffet a speed just above low speed buffet the stall speed in turbulent conditions

.vra is defined as rough airspeed or turbulent air penetration speed .cs 25 1517 rough air speed vra . a a rough air speed vra for use as the recommended turbulence penetration air speed and a rough air mach number mra for use as the recommended turbulence penetration mach number must be established to ensure that likely speed variation during rough air encounters will not cause the overspeed warning to operate too frequently . b at altitudes where vmo is not limited by mach number in the absence of a rational investigation substantiating the use of other values vra must be less than vmo 35 ktas . c at altitudes where vmo is limited by mach number mra may be chosen to provide an optimum margin between low and high speed buffet boundaries exemple 486 The recommended turbulence penetration airspeed.The recommended turbulence penetration airspeed.

Which of the following statements is correct .i a dorsal fin increases the ?

Question 238-39 : I is correct ii is incorrect i is incorrect ii is correct i is correct ii is correct i is incorrect ii is incorrect

.dorsal and ventral fins contribute in exactly the same way to directional static stability a dorsal fin contributes positively to lateral static stability . 2764.if the aircraft is yawed to the left the dorsal and ventral fins will create a side force to the left the line of action of this force is well aft of the aircraft cg giving a yawing moment to the right a stabilising effect . 2765.the ventral fin being below the aircraft cg has a negative influence on lateral static stability . 2766 exemple 490 I is correct, ii is incorrect.I is correct, ii is incorrect.

The stall speed line in the manoeuvring load diagram runs through a point where ?

Question 238-40 : Speed = va load factor = limit load factor speed = vb load factor = gust load factor speed = vs load factor = 0 speed = 0 load factor = +1

.the stall line starts at a point where load factor = 0 and airspeed = 0 and runs through a point where the load factor reaches limit load factor for a large aeroplane +2 5g .this point is va design manoeuvring speed . 2767 exemple 494 Speed = va, load factor = limit load factor.Speed = va, load factor = limit load factor.

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