When compared with the volumetric fuel flowmeter the mass fuel flowmeter takes into account the fuel ?
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Source: Telepilote theorique examen 38
The electronic tachometer sensor is composed of ?
The advantages of a D C generator tachometer are 1 easy transmission of the information 2 independence of the information relative to the airborne electrical power supply3 freedom from any ?
The advantages of single phase a c generator tachometer are 1 suppression of spurious signals due to a d c generator commutator2 importance of line resistance on information value3 independence of information in relation to airborne electrical power supply4 ease of transmission of informationthe combination regrouping all correct statements A notched wheel rotating in front of an electro magnet. the single phase ac generator tachometer doesn't have a dc commutator ring thus no spurious signals the measurement independent of aircraft power supply. 
The disadvantages of a single phase a c generator tachometer are 1 presence of spurious signals due to a d c generator commutator 2 importance of line resistance on information value 3 influence of temperature on tachometer information the combination regrouping all correct statements A notched wheel rotating in front of an electro magnet. the single phase ac generator tachometer brushless thus no spurious signals the measurement independent of aircraft power supply but one disadvantage of a single phase ac generator the possibility of values transmitted being affected line resistance. 
Torque can be determined measuring Oil pressure at fixed crown of an epicycloidal reducer of main engine gearbox. operating principle of a epicyclic reducer with fixed crown input drive applied to a central or sun gear (1) which three or more pinions or planet gears (2) are set in rotation these in turn rotate in mesh with internal teeth of a fixed crown (fixed ring gear) (3) the shafts of planet gears (4) mounted to a planet carrier (5) are translated along a circumferential trajectory made thus to revolve around sun gear the result that planet carrier (5) to which output assembly mounted (shaft bearings seals etc ) rotates at a lower speed than that of sun gear (1) torque can be determined measuring oil pressure at fixed crown of an epicycloidal reducer of main engine gearbox. 
The engine instrument utilising an aneroid pressure diaphragm the Manifold pressure gauge. operating principle of a epicyclic reducer with fixed crown input drive applied to a central or sun gear (1) which three or more pinions or planet gears (2) are set in rotation these in turn rotate in mesh with internal teeth of a fixed crown (fixed ring gear) (3) the shafts of planet gears (4) mounted to a planet carrier (5) are translated along a circumferential trajectory made thus to revolve around sun gear the result that planet carrier (5) to which output assembly mounted (shaft bearings seals etc ) rotates at a lower speed than that of sun gear (1) torque can be determined measuring oil pressure at fixed crown of an epicycloidal reducer of main engine gearbox. Question 38-8
To permit turbine exit temperatures to be measured gas turbines are equipped with thermometers which work on following principle Manifold pressure gauge. a thermocouple type thermometer consists of two metal conductors of different type connected at two points the operating principle of a thermocouple a conductor that subject to a thermal gradient generates a voltage this voltage measured interpreted a thermocouple thermometer (millivoltmeter). Question 38-9
A 'bourdon tube' used in Manifold pressure gauge. a thermocouple type thermometer consists of two metal conductors of different type connected at two points the operating principle of a thermocouple a conductor that subject to a thermal gradient generates a voltage this voltage measured interpreted a thermocouple thermometer (millivoltmeter). Question 38-10
If an epr set at a constant barometric pressure with an increasing oat thrust Manifold pressure gauge. Thrust the force generated the engines thrust 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 therefore a decrease in thrust but engine management system does trim fuel automatically to maintain selected thrust settings changes in oat. Question 38-11
In a compensated capacitance type quantity indicating system contents gauge of a half full fuel tank indicates a fuel mass of 8000 kg if a temperature rise increased volume of fuel 5% indicated fuel mass would Manifold pressure gauge. the capacity of a capacitor depends on nature of dielectric in which it immersed fuel has twice capacitance of air so a full tank has twice capacitive reactance as en empty one if a temperature rise increases fuel volume fuel weight remains same. Question 38-12
On an multi engine aircraft a synchroscope used to 1 reduce structural vibration and noise2 have symmetrical thrust and fuel consumption correct 2 incorrect. Cqb15 august 2012 the purpose of a synchroscope to reduce structural vibration noise the synchronizing system ensures that propeller speeds are all same this achieved 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 electrically trimming engine speeds until all signals are equal. Question 38-13
The basic principle of a capacitance fuel gauge system that Capacity of a capacitor depends on nature of dielectric in which it immersed. a capacitance type fuel gauge system consists of a variable capacitor located in fuel tank an amplifier an indicator the complete circuit forms an electrical bridge which continuously being rebalanced as a result of differences between capacitances of tank capacitor a reference capacitor the signal produced due to differences in signals amplified to operate a motor the motor then drives pointer to indicate capacitance change of tank capacitor thus change in fuel quantity indicated we have seen basic construction of this system now let us discuss how electrical capacitance principle utilized the capacitance type fuel gauge system in aircraft the capacitors which are to be installed in fuel tanks the fuel quantity measurement must be different in construction from those normally employed in electrical equipment the plates of capacitors take form of two tubes mounted concentrically with a narrow air space between them these plates extend full depth of a fuel tank capacitance depends on some factors which are area of plates distance between two plates the dielectric constant of material between two plates of capacitors now in this capacitance type fuel gauge system two factors plate area distance between plates are fixed the dielectric here the fuel in tank of aircraft the flow of a momentary current into a capacitor establishes a potential difference across its plates the dielectric i e fuel in aircraft's fuel tanks contains no free electrons so current cannot flow through it but it should be remembered that potential difference sets up a state of stress in atoms comprising it. Question 38-14
Assuming that cas remains constant if total pressure probe blocked ias Remains constant during level flight increases during a climb decreases during a descent. with a blocked pitot pressure in capsule fixed (like an altimeter) when aircraft climbs the static in case decreases capsule expands the reading on instrument increases (like an altimeter) to hold ias constant in climb (i e not allow capsule to expand) actual airspeed will have to decrease remember that with a blocked pitot asi over reads in climb under reads in descent with constant ias blocked pitot real ias and therefore tas will decrease until aircraft stalls. Question 38-15
Gas turbine engine rotational speed rpm usually sensed using either A 3 phase ac tachometer generator or an ac phonic wheel system. with a blocked pitot pressure in capsule fixed (like an altimeter) when aircraft climbs the static in case decreases capsule expands the reading on instrument increases (like an altimeter) to hold ias constant in climb (i e not allow capsule to expand) actual airspeed will have to decrease remember that with a blocked pitot asi over reads in climb under reads in descent with constant ias blocked pitot real ias and therefore tas will decrease until aircraft stalls. Question 38-16
The output from an engine vibration transducer Always filtered to remove unwanted frequencies. virations are picked up 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 initial acceleration signal not practical use depending on engine type the bearing location displacement speed (usually noted in inch per second ips) used the vibration frequency filtered the cockpit indication to indicate only vibration in a frequency band corresponding to spool speed n1 n2 n3 that's why engines can have vibrations which are not related to spools rotating speed not being indicated in cockpit. Question 38-17
The sensor s feeding epr indicator are Pressure probes one located upstream from compressor inlet the other downstream from turbine outlet. virations are picked up 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 initial acceleration signal not practical use depending on engine type the bearing location displacement speed (usually noted in inch per second ips) used the vibration frequency filtered the cockpit indication to indicate only vibration in a frequency band corresponding to spool speed n1 n2 n3 that's why engines can have vibrations which are not related to spools rotating speed not being indicated in cockpit. Question 38-18
The rpm indicator or tachometer of a piston engine can include a small red arc within arc normally used green arc in rpm range corresponding to this small red arc Propeller generates vibration continuous rating forbidden. virations are picked up 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 initial acceleration signal not practical use depending on engine type the bearing location displacement speed (usually noted in inch per second ips) used the vibration frequency filtered the cockpit indication to indicate only vibration in a frequency band corresponding to spool speed n1 n2 n3 that's why engines can have vibrations which are not related to spools rotating speed not being indicated in cockpit. Question 38-19
A three phase electrical tachometer consists of A three phase generator a synchronous motor a magnetic tachometer. virations are picked up 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 initial acceleration signal not practical use depending on engine type the bearing location displacement speed (usually noted in inch per second ips) used the vibration frequency filtered the cockpit indication to indicate only vibration in a frequency band corresponding to spool speed n1 n2 n3 that's why engines can have vibrations which are not related to spools rotating speed not being indicated in cockpit. Question 38-20
Cas can be obtained from following data Eas pressure altitude. to get from cas via eas to tas we use pressure altitude temperature to go back from tas via eas to cas we would again use pressure altitude temperature eas cas corrected compressibiliy compressibility related to pressure altitude. Question 38-21
The properties of a single phase electrical tachometer are 1 indication depending on line resistance2 independance from aircraft airborne power supply3 simple designthe combination that regroups all of correct statements Eas pressure altitude. a single phase electrical tachometer (inductive probe) requires an external power supply signal processing the indication depends on line resistance it a simple design tachometer. Question 38-22
Concerning a fuel gauge system a pilot more interested the Mass of fuel than volume of fuel. a single phase electrical tachometer (inductive probe) requires an external power supply signal processing the indication depends on line resistance it a simple design tachometer. Question 38-23
A float type fuel gauge 1 gives a mass information 2 gives information independent of aircraft's manoeuvres and attitude changes 3 gives information all more accurate as tank full 4 typically a dc powered system the combination that regroups all of correct statements Mass of fuel than volume of fuel. a single phase electrical tachometer (inductive probe) requires an external power supply signal processing the indication depends on line resistance it a simple design tachometer. Question 38-24
A magnetic tachometer consists of A permanent magnet turning inside a non magnetic drag cup. Magnetic tachometer the magnetic tachometer consists of rotary bell shaped permanent magnet (1) core (2) between which there a narrow gap arranged in this gap hollow aluminum cylinder (3) held against rotation coil spring (4) the rotating magnetic field induces currents in cylinder (3) which tend to rotate cylinder with a force whose torque proportional to speed of rotation of magnet (1) a scale with uniform divisions engraved on outside circumference of cylinder (3) it indicates speed (rpm) of magnet (1) of shaft whose speed to be measured in opening (5). Question 38-25
Given following parameters in a capacitance fuel gauge correct formula a = area of platesd = distance between platese = dielectric permittivity Capacitance = e x a / d. Magnetic tachometer the magnetic tachometer consists of rotary bell shaped permanent magnet (1) core (2) between which there a narrow gap arranged in this gap hollow aluminum cylinder (3) held against rotation coil spring (4) the rotating magnetic field induces currents in cylinder (3) which tend to rotate cylinder with a force whose torque proportional to speed of rotation of magnet (1) a scale with uniform divisions engraved on outside circumference of cylinder (3) it indicates speed (rpm) of magnet (1) of shaft whose speed to be measured in opening (5). Question 38-26
A three phase electrical tachometer utilises a generator feeding A synchronous motor turning a drag cup. The electrical generator system utilises a small three phase tachometer generator driven the engine the output of this generator 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 mechanical system three phase electrical tachometer. Question 38-27
The operating principle of an inductive probe tachometer to measure Frequency of electric impulse created a notched wheel rotating in a magnetic field. The electrical generator system utilises a small three phase tachometer generator driven the engine the output of this generator 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 mechanical system three phase electrical tachometer. Question 38-28
The unit used to measure capacitance of a capacitor the Frequency of electric impulse created a notched wheel rotating in a magnetic field. the farad (symbol 'f') the si derived unit of capacitance the unit named after english physicist michael faraday a farad the charge in coulombs which a capacitor will accept the potential across it to change 1 volt a coulomb 1 ampere second example a capacitor with capacitance of 47 nf will increase 1 volt per second with a 47 na input current. Question 38-29
Any vibration displayed on an engine vibration monitoring system a turbojet Indicates rotor imbalance. The engine vibration monitoring on a turbojet engine indicates any vibration resulting from an imbalance on rotation parts of engine engine vibration may occur due to fan blade/spinner icing resulting in a rotor imbalance. Question 38-30
6000 psi approximately equivalent to Indicates rotor imbalance. 1 psi (pound per square inch) = 0 07 bar 1 bar = 15 psi. Question 38-31
1 bar equals how many pascals Indicates rotor imbalance. 1 bar = 100000 pa (pascal) = 1000 hpa (hectopascal). Question 38-32
What the relation between c and k c celsius° k kelvin Indicates rotor imbalance. fahrenheit = 1 8 x c + 32 kelvin = c + 273 15. Question 38-33
Which of these statements about temperature units are correct or incorrect 1 +20° celsius = 68° fahrenheit2 0° celsius = 273 15° kelvin I correct ii correct. fahrenheit = 1 8 x c + 32 kelvin = c + 273 15. Question 38-34
Which of these statements are correct or incorrect 1 +15° celsius = 273 15° kelvin2 +15° celsius = 59° fahrenheit I incorrect ii correct. fahrenheit = 1 8 x c + 32 kelvin = c + 273 15. Question 38-35
Which statement correct regarding relation between kelvin k fahrenheit f and celcius c temperatures 1 k = c 273 152 f = 1 8 x c + 32 I incorrect ii correct. fahrenheit = 1 8 x c + 32 kelvin = c + 273 15. Question 38-36
Which of these statements are correct or incorrect 1 +15° celsius = 288 15° kelvin2 +15° celsius = 59° fahrenheit I correct ii correct. fahrenheit = 1 8 x c + 32 kelvin = c + 273 15. Question 38-37
The correct relation I correct ii correct. Cqb15 february 2012 1 kg = 2 2 lbs 0 45 kg = 1 lb. Question 38-38
A pressure of 1013 25 hpa corresponding to I correct ii correct. a pressure of 1013 25 hpa corresponding exactly to 14 69596432068 psi 29 92 inches of mercury. Question 38-39
Given q = charge coulombs u = potential difference between plates volt c= capacitance farads the correct relationship between these parameters I correct ii correct. chrism should u not read v instead to comply with standard notation it should but we do not write questions we do not modify them this the official wording coulomb the quantity of electricity transported in 1 second a current of 1 ampere c the capacitance u the stored energy. Question 38-40
20 bar approximately equal to I correct ii correct. 1 psi (pound per square inch) = 0 07 bar 1 bar = 15 psi.
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