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The advantages of an 'electric' fuel float gauge are .1 easy construction.2 ? [ Admission airport ]

Question 54-1 : 1 1 2 3 4 5 2 3 4 5 2 3 4

Admin .in 1904 the first float arm gas gauge appeared a float mounted on a hinged arm moved a mechanical pointer on gauge on the outside of the fuel tank to indicate the fuel level .idea was taken one step further when vehicles started to get better electrical systems by connecting the hinged float arm to a rheostat this allows an electrically operated fuel gauge to be mounted in the vehicle's dashboard and that's the basic operating principle that's still in use today .but airplane attitude and accelerations will affect the accuracy of the indication due to the movements of the fuel in the tank temperature will modify the volume thus the indication exemple 154 1.1.

The disadvantages of an 'electric' fuel float gauge are . 1 the design is ?

Question 54-2 : 2 3 4 1 1 2 3 4 2 3 4 5

exemple 158 2, 3, 4.2, 3, 4.

On an electronic flight instrument system efis the following fuel flow ?

Question 54-3 : 1 1 2 1 2 3 1 3

An efis displays fuel flow to engine it displays also fuel used since last reset fuel flow is usually shown in kilograms per hour exemple 162 1.1.

The aircraft outside air temperature 'probe' measures the ?

Question 54-4 : 'total' air temperature minus kinetic heating effects in order to obtain the static temperature 'static' air temperature minus kinetic heating effects in order to obtain the total temperature 'total' air temperature minus compressibility effects in order to obtain the static temperature 'static' air temperature minus compressibility effects in order to obtain the total temperature

Admin .this question has been seen in july 2022 with this correct answer . total air temperature this must be corrected for ram rise and recovery factor to obtain the static air temperature .the other wrong answers remain unchanged exemple 166 'total' air temperature minus kinetic heating effects in order to obtain the static temperature.'total' air temperature minus kinetic heating effects in order to obtain the static temperature.

A millivoltmeter measuring the electromotive force between the 'hot junction' ?

Question 54-5 : Cold junction is maintained constant hot junction is maintained constant cold junction is maintained at 15 °c hot junction is maintained at 15 °c

exemple 170 Cold junction is maintained constant.Cold junction is maintained constant.

The gauge indicating the quantity of fuel measured by a capacity gauging system ?

Question 54-6 : Twice that of air and varies directly with density the same as that of air and varies directly with density twice that of air and varies inversely with density the same as that of air and varies inversely with density

Admin .the dielectric constant or permittivity of fuel is determined by establishing the ratio of the electrical capacitance of a tank filled with fuel as compared with the electrical capacitance of the tank when filled with air measurements of the dielectric constant of a fuel at various temperatures show that the dielectric constant is a linear function of temperature decreasing with increasing temperature and varying with the applied frequency .dielectric of air at 70°f = 0 85 .dielectric of jet fuel at 70°f = 1 7 exemple 174 Twice that of air and varies directly with density.Twice that of air and varies directly with density.

When compared with the volumetric fuel flowmeter the mass fuel flowmeter takes ?

Question 54-7 : Density temperature pressure turbulent flow in the line

Admin .the mass fuel flow meter allows the measurement of the mass consumption of fuel the mass fuel flowmeter takes into account the fuel density exemple 178 Density.Density.

The electronic tachometer sensor is composed of ?

Question 54-8 : A notched wheel rotating in front of an electro magnet a circular magnet with four poles the rotor of a single phase a c generator the rotor of a three phase a c generator

The advantages of a d c generator tachometer are . 1 easy transmission of the ?

Question 54-9 : 1 2 2 3 1 2 3 1 3

Admin .d c generator tachometer consists of a small armature which is coupled to the machine whose speed is to be measured this armature revolves in the field of a permanent magnet the electro magnetic force emf generated is proportational to the product of flux and speed since the flux of the permanent magnet is constant the voltage generated is proportational to speed .the polarity of output voltage indicates the direction of rotation this electro magnetic force emf is measured with the help of moving coil voltmeter having a uniform scale and calibrated directly in terms of speed .but d c generator tachometer has a dc commutator ring which causes spurious signals exemple 186 1, 2.1, 2.

The advantages of single phase a c generator tachometer are .1 the suppression ?

Question 54-10 : 1 3 1 2 3 4 2 3 4 2 4

Admin .the single phase ac generator tachometer doesn't have a dc commutator ring thus no spurious signals .the measurement is independent of aircraft power supply

The disadvantages of a single phase a c generator tachometer are . 1 the ?

Question 54-11 : 2 1 2 3 1 2 1 3

Admin .the single phase ac generator tachometer is brushless thus no spurious signals .the measurement is independent of aircraft power supply but one disadvantage of a single phase ac generator is the possibility of the values transmitted being affected by line resistance exemple 194 2.2.

Torque can be determined by measuring the ?

Question 54-12 : Oil pressure at the fixed crown of an epicycloidal reducer of the main engine gearbox frequency of an impulse tachometer attached to a transmission shaft quantity of light passing through a rack wheel attached to a transmission shaft phase difference between 2 impulse tachometers attached to a transmission shaft

Admin .operating principle of a epicyclic reducer with fixed crown . 994.input drive is applied to a central or sun gear 1 by which three or more pinions or planet gears 2 are set in rotation these in turn rotate in mesh with the internal teeth of a fixed crown fixed ring gear 3 .the shafts of the planet gears 4 mounted to a planet carrier 5 are translated along a circumferential trajectory and made thus to revolve around the sun gear the result is that the planet carrier 5 to which the output assembly is mounted shaft bearings seals etc rotates at a lower speed than that of the sun gear 1 .torque can be determined by measuring the oil pressure at the fixed crown of an epicycloidal reducer of the main engine gearbox exemple 198 Oil pressure at the fixed crown of an epicycloidal reducer of the main engine gearbox.Oil pressure at the fixed crown of an epicycloidal reducer of the main engine gearbox.

The engine instrument utilising an aneroid pressure diaphragm is the ?

Question 54-13 : Manifold pressure gauge oil pressure gauge fuel pressure gauge oil temperature gauge

exemple 202 Manifold pressure gauge.Manifold pressure gauge.

To permit turbine exit temperatures to be measured gas turbines are equipped ?

Question 54-14 : Thermocouple bi metallic strip liquid expansion gas pressure

Admin . 993.a thermocouple type thermometer consists of two metal conductors of different type connected at two points the operating principle of a thermocouple is a conductor that is subject to a thermal gradient generates a voltage .this voltage is measured and interpreted by a thermocouple thermometer millivoltmeter exemple 206 Thermocouple.Thermocouple.

A 'bourdon tube' is used in ?

Question 54-15 : Pressure sensors vibration detectors smoke detectors turbine temperature probes

exemple 210 Pressure sensors.Pressure sensors.

If an epr is set at a constant barometric pressure with an increasing oat the ?

Question 54-16 : Remains constant varies according to the characteristics of the engine increases decreases

Thrust is the force generated by the engines .thrust is the acceleration of a mass of air .thrust = mass x acceleration.mass = density x volume.therefore a decrease in density due to an increasing oat would result in less mass being accelerated and therefore a decrease in thrust but the engine management system does trim fuel automatically to maintain selected thrust settings for changes in oat exemple 214 Remains constant.Remains constant.

In a compensated capacitance type quantity indicating system the contents gauge ?

Question 54-17 : Remain the same increase by 5% decrease by 5% increase by 10%

Admin .the capacity of a capacitor depends on the nature of the dielectric in which it is immersed fuel has twice the capacitance of air so a full tank has twice the capacitive reactance as en empty one .if a temperature rise increases the fuel volume the fuel weight remains the same exemple 218 Remain the same.Remain the same.

On an multi engine aircraft a synchroscope is used to .1 reduce structural ?

Question 54-18 : 1 is correct 2 is incorrect 1 is correct 2 is correct 1 is incorrect 2 is correct 1 is incorrect 2 is incorrect

Cqb15 august 2012 ..the purpose of a synchroscope is to reduce structural vibration and noise the synchronizing system ensures that the propeller speeds are all the same this is achieved by an electrical system that compares speed signals from engine mounted generators out of balance signals using one engine as a master signal are automatically corrected by electrically trimming the engine speeds until all signals are equal exemple 222 1 is correct, 2 is incorrect.1 is correct, 2 is incorrect.

The basic principle of a capacitance fuel gauge system is that the ?

Question 54-19 : Capacity of a capacitor depends on the nature of the dielectric in which it is immersed internal resistance of a capacity depends on the nature of the dielectric in which it is immersed capacity of a capacitor depends only on the density of the liquid on which it is immersed electromotive force of a capacity depends on the nature of the dielectric in which it is immersed

Admin .a capacitance type fuel gauge system consists of a variable capacitor located in the fuel tank an amplifier and an indicator . the complete circuit forms an electrical bridge which is continuously being rebalanced as a result of the differences between the capacitances of the tank capacitor and a reference capacitor . the signal produced due to the differences in the signals is amplified to operate a motor . the motor then drives the pointer to indicate the capacitance change of the tank capacitor and thus change in the fuel quantity is indicated ..we have seen the basic construction of this system now let us discuss how the electrical capacitance principle is utilized for the capacitance type fuel gauge system in aircraft . the capacitors which are to be installed in the fuel tanks for the fuel quantity measurement must be different in construction from those normally employed in electrical equipment . the plates of the capacitors take the form of two tubes mounted concentrically with a narrow air space between them these plates extend the full depth of a fuel tank ..capacitance depends on some factors which are area of the plates distance between the two plates and the dielectric constant of the material between the two plates of the capacitors .now in this capacitance type fuel gauge system the two factors plate area and distance between plates are fixed and the dielectric here is the fuel in the tank of the aircraft . the flow of a momentary current into a capacitor establishes a potential difference across its plates . the dielectric i e fuel in the aircraft's fuel tanks contains no free electrons so the current cannot flow through it but it should be remembered that potential difference sets up a state of stress in the atoms comprising it exemple 226 Capacity of a capacitor depends on the nature of the dielectric in which it is immersed.Capacity of a capacitor depends on the nature of the dielectric in which it is immersed.

Assuming that the cas remains constant if the total pressure probe is blocked ?

Question 54-20 : Remains constant during level flight increases during a climb and decreases during a descent remains constant during level flight decreases during a climb and increases during a descent increases during level flight remains constant during a climb and a descent remains constant during all the phases of the flight

Admin .with a blocked pitot the pressure in the capsule is fixed like an altimeter when the aircraft climbs and the static in the case decreases the capsule expands and the reading on the instrument increases like an altimeter .to hold the ias constant in the climb i e not allow the capsule to expand the actual airspeed will have to decrease remember that with a blocked pitot the asi over reads in the climb and under reads in the descent with constant ias and blocked pitot the real ias and therefore tas will decrease until the aircraft stalls exemple 230 Remains constant during level flight, increases during a climb and decreases during a descent.Remains constant during level flight, increases during a climb and decreases during a descent.

Gas turbine engine rotational speed rpm is usually sensed using either ?

Question 54-21 : A 3 phase ac tachometer generator or an ac phonic wheel system a single phase ac tachometer generator or an ac phonic wheel system a 28vdc tachometer generator or an ac phonic wheel a 28vdc tachometer generator or a dc phonic wheel

exemple 234 A 3 phase ac tachometer generator or an ac phonic wheel system.A 3 phase ac tachometer generator or an ac phonic wheel system.

The output from an engine vibration transducer is ?

Question 54-22 : Always filtered to remove unwanted frequencies inversely proportional to engine speed directly proportional to engine speed fed directly to the indicator in the cockpit without amplification or filtering

Admin .virations are picked up by accelerometers so you measure accelerations piezzo electric or capacity type pickups giving after conversion displacement / square second .a first integration will give displacement speed displacement per second a second integration will give displacement .each integration may introduce or amplify measurement errors but the initial acceleration signal is not practical for use depending on the engine type and the bearing location the displacement speed usually noted in inch per second ips is used .the vibration frequency is filtered for the cockpit indication to indicate only vibration in a frequency band corresponding to the spool speed n1 n2 n3 that's why engines can have vibrations which are not related to spools rotating speed not being indicated in the cockpit exemple 238 Always filtered to remove unwanted frequencies.Always filtered to remove unwanted frequencies.

The sensor s feeding the epr indicator is are ?

Question 54-23 : Pressure probes one located upstream from the compressor inlet and the other downstream from the turbine outlet temperature probes one located upstream from the compressor inlet and an other downstream from the turbine outlet tachometer located on the shaft of the n2 compressor tachometer located on the shaft of the n1 compressor

The rpm indicator or tachometer of a piston engine can include a small red arc ?

Question 54-24 : Propeller generates vibration continuous rating is forbidden rating is the maximum possible in continuous mode rating is the minimum usable in cruise propeller efficiency is minimum at this rating

exemple 246 Propeller generates vibration, continuous rating is forbiddenPropeller generates vibration, continuous rating is forbidden

A three phase electrical tachometer consists of ?

Question 54-25 : A three phase generator a synchronous motor and a magnetic tachometer three associated dynamos a speed probe and a phonic wheel three speed probes and a phonic wheel

exemple 250 A three-phase generator, a synchronous motor and a magnetic tachometer.A three-phase generator, a synchronous motor and a magnetic tachometer.

Cas can be obtained from the following data ?

Question 54-26 : Eas and pressure altitude eas and density altitude tas and pressure altitude tas and density altitude

Admin .to get from cas via eas to tas we use pressure altitude and temperature to go back from tas via eas to cas we would again use pressure altitude and temperature .eas is cas corrected for compressibiliy and compressibility is related to pressure altitude exemple 254 Eas and pressure altitude.Eas and pressure altitude.

The properties of a single phase electrical tachometer are .1 indication ?

Question 54-27 : 1 2 3 1 2 1 3 2 3

Admin .a single phase electrical tachometer inductive probe requires an external power supply for signal processing the indication depends on the line resistance and it is a simple design tachometer exemple 258 1, 2, 3.1, 2, 3.

Concerning a fuel gauge system a pilot is more interested by the ?

Question 54-28 : Mass of the fuel than the volume of the fuel volume of the fuel than the mass of the fuel volume of the fuel than the density of the fuel volume of the fuel than the permittivity of the fuel

exemple 262 Mass of the fuel than the volume of the fuel.Mass of the fuel than the volume of the fuel.

A float type fuel gauge . 1 gives a mass information. 2 gives information ?

Question 54-29 : 4 1 2 3 4 1 3 4 1

exemple 266 44

A magnetic tachometer consists of ?

Question 54-30 : A permanent magnet turning inside a non magnetic drag cup a single phase generator connected to a synchronous motor a single phase generator connected to a asynchronous motor a three phase generator connected to a synchronous motor

Magnetic tachometer .the magnetic tachometer consists of rotary bell shaped permanent magnet 1 and core 2 between which there is a narrow gap .arranged in this gap is hollow aluminum cylinder 3 held against rotation by coil spring 4 .the rotating magnetic field induces currents in cylinder 3 which tend to rotate the cylinder with a force whose torque is proportional to the speed of rotation of magnet 1 .a scale with uniform divisions is engraved on the outside circumference of cylinder 3 it indicates the speed rpm of magnet 1 and of the shaft whose speed is to be measured in opening 5 exemple 270 A permanent magnet turning inside a non magnetic drag cup.A permanent magnet turning inside a non magnetic drag cup.

Given the following parameters in a capacitance fuel gauge the correct formula ?

Question 54-31 : Capacitance = e x a / d capacitance = e x d / a capacitance = a x d / e capacitance = e x d x a

exemple 274 Capacitance = e x a / dCapacitance = e x a / d

A three phase electrical tachometer utilises a generator feeding ?

Question 54-32 : A synchronous motor turning a drag cup directly a voltmeter directly a galvanometer directly a drag cup

The electrical generator system utilises a small three phase tachometer generator driven by the engine the output of this generator is then taken to an indicator which consists of a synchronous motor turning a drag cup assembly which moves a pointer over a scale as in the mechanical system . three phase electrical tachometer exemple 278 A synchronous motor turning a drag cup.A synchronous motor turning a drag cup.

The operating principle of an inductive probe tachometer is to measure the ?

Question 54-33 : Frequency of the electric impulse created by a notched wheel rotating in a magnetic field electromotive force produced by a dynamo or an alternator rotation speed of an asynchronous motor energized by an alternator magnetic field produced by a dynamo or an alternator

exemple 282 Frequency of the electric impulse created by a notched wheel rotating in a magnetic field.Frequency of the electric impulse created by a notched wheel rotating in a magnetic field.

The unit used to measure the capacitance of a capacitor is the ?

Question 54-34 : Farad hz joule watt

Admin .the farad symbol 'f' is the si derived unit of capacitance the unit is named after the english physicist michael faraday .a farad is the charge in coulombs which a capacitor will accept for the potential across it to change 1 volt a coulomb is 1 ampere second .example a capacitor with capacitance of 47 nf will increase by 1 volt per second with a 47 na input current exemple 286 Farad.Farad.

Any vibration displayed on an engine vibration monitoring system for a turbojet ?

Question 54-35 : Indicates rotor imbalance is directly proportional to engine speed varies inversely as the square of the engine speed is presented without any amplification or filtering

The engine vibration monitoring on a turbojet engine indicates any vibration resulting from an imbalance on the rotation parts of the engine engine vibration may occur due to fan blade/spinner icing resulting in a rotor imbalance exemple 290 Indicates rotor imbalance.Indicates rotor imbalance.

6000 psi is approximately equivalent to ?

Question 54-36 : 400 bar 40 bar 4 bar 4000 bar

Admin .1 psi pound per square inch = 0 07 bar .1 bar = 15 psi exemple 294 400 bar.400 bar.

1 bar equals how many pascals ?

Question 54-37 : 100000 pa 1000 pa 10 pa 100 pa

Admin .1 bar = 100000 pa pascal = 1000 hpa hectopascal exemple 298 100000 pa.100000 pa.

What is the relation between c and k . c celsius° k kelvin ?

Question 54-38 : C=k 273 15 k=c 273 15 k=c*1 8+32° c=k*1 8+32°

Admin .fahrenheit = 1 8 x c + 32.kelvin = c + 273 15 exemple 302 C=k-273.15C=k-273.15

Which of these statements about temperature units are correct or incorrect .1 ?

Question 54-39 : I is correct ii is correct i is incorrect ii is correct i is incorrect ii is incorrect i is correct ii is incorrect

Admin .fahrenheit = 1 8 x c + 32.kelvin = c + 273 15 exemple 306 I is correct, ii is correct.I is correct, ii is correct.

Which of these statements are correct or incorrect .1 +15° celsius = 273 15° ?

Question 54-40 : I is incorrect ii is correct i is correct ii is correct i is incorrect ii is incorrect i is correct ii is incorrect

Admin .fahrenheit = 1 8 x c + 32.kelvin = c + 273 15 exemple 310 I is incorrect, ii is correct.I is incorrect, ii is correct.

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