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The diagram shown in annex represents a jet fuel system The fuel flow measurement is carried out 868 ?

Control > visibility

exemple reponse 129
After high pressure valve (item 4). Fuel rate is measured after passing through main engine fuel shutoff valve the fuel flow rate can be read on display unit is also sent to flight management system .

Source: Telepilote theorique examen 24

The purpose of the barometric correction in a fuel controller is to ?

exemple reponse 130
The purpose of barometric correction in a fuel controller to Maintain correct fuel to air mass ratio when altitude increases. The fuel control unit (fcu) controls fuel flow a given thrust setting variations in air intake pressure (p1) require that fuel flow to burners changed accordingly so that a fixed r p m maintained a selected throttle position at all altitudes airspeeds this achieved the expansion or contraction of a capsule influenced p1 pressure which in turn modifies fuel flow accordingly this capsule known as barometric pressure capsule (b p c ) incorporated in an 'altitude sensing unit' within f c u the goal not to maintain a constant fuel flow whatever altitude is goal to maintain correct fuel to air mass ratio when altitude increases or decreases to maintain a given thrust whatever altitude is.

At Reference In flight with centre tank empty and APU operating a fuel unbalance is detected quantity in tank 1 < quantity in tank 2 Rebalancing of the two tanks is 872 ?

exemple reponse 131
At reference in flight with centre tank empty and apu operating a fuel unbalance detected quantity in tank 1 < quantity in tank 2 rebalancing of two tanks 872 Possible with 'crossfee open tank pumps 'off' tank 2 pumps 'on'. The fuel control unit (fcu) controls fuel flow a given thrust setting variations in air intake pressure (p1) require that fuel flow to burners changed accordingly so that a fixed r p m maintained a selected throttle position at all altitudes airspeeds this achieved the expansion or contraction of a capsule influenced p1 pressure which in turn modifies fuel flow accordingly this capsule known as barometric pressure capsule (b p c ) incorporated in an 'altitude sensing unit' within f c u the goal not to maintain a constant fuel flow whatever altitude is goal to maintain correct fuel to air mass ratio when altitude increases or decreases to maintain a given thrust whatever altitude is.

  • exemple reponse 132
    One of purposes of fuel system booster pumps to be submerged in fuel To facilitate priming of pumps. The pumps are cooled the fuel lubricated it to achieve these functions pumps would not need to be submerged in fuel action of flow through pumps would suffice it important that pumps only pump fuel not air to this end ensuing pumps are submerged in fuel will keep them primed with fuel.

  • exemple reponse 133
    The vapour lock A stoppage in a fuel feeding line caused a fuel vapour bubble. The pumps are cooled the fuel lubricated it to achieve these functions pumps would not need to be submerged in fuel action of flow through pumps would suffice it important that pumps only pump fuel not air to this end ensuing pumps are submerged in fuel will keep them primed with fuel.

  • exemple reponse 134
    The pressurising function of pressurising and dump valve in a gas turbine engine fuel system To admit fuel to nozzles only if fuel pressure high enough sufficient atomisation. a pressurising dump valve used with a duplex fuel nozzle at a preset pressure pressurising valve opens allows fuel to flow into main manifold as well as pilot or primary manifold the dump valve allows manifold fuel to be dumped into drains tank when engine shut down to prevent fuel boiling in manifold due to residual engine heat.

  • exemple reponse 135
    Fuel pumps submerged in fuel tanks of a multi engine aircraft are Centrifugal low pressure type pumps. They are known as 'lp pump also 'booster pump (less than 3 bars 40 psi) engine driven pumps would come under engine fuel system dividing line being made at low pressure cock or valve.

  • Question 24-8

    Which statement correct i the freezing point jet a at a lower temperature than that jet b ii the flash point jet a at a lower temperature than that jet b I incorrect ii incorrect. jet b has a higher napthalene content that helps prevent freezing (gelling) at low temperatures but in practice that not a useful property of jet b (see below) jet fuel a blend of many different hydrocarbons that each have their own specific freezing point so it not really possible to quote a freezing point temperature the 'pour point' the term used in aviation industry to specify minimum safe temperature anti ice additives such as 'prist' are used in jet a at cold temperatures so that it can still be pumped without reducing fuel flow at 70°c more than sufficient any jet aircraft even at 10 15°c below first component to freeze (usually paraffin wax) jet fuel can still be pumped the accepted minimum fuel temperature safe flight jet a 40°c jet a 1 47°c jet b 65°c flight crews must monitor fuel temperature to ensure that fuel does not cool to below pour point jet b has a flash point of below 0°c jet a around 38°c a low flash point a useful property to start a jet engine in cold weather but reduces amount of energy stored in fuel remember that lower flash point more 'volatile' fuel is.

  • Question 24-9

    Which statement correct i the freezing point jet a at a higher temperature than that jet b ii the flash point jet a at a higher temperature than that jet b I correct ii correct. jet b has a higher napthalene content that helps prevent freezing (gelling) at low temperatures but in practice that not a useful property of jet b (see below) jet fuel a blend of many different hydrocarbons that each have their own specific freezing point so it not really possible to quote a freezing point temperature the 'pour point' the term used in aviation industry to specify minimum safe temperature anti ice additives such as 'prist' are used in jet a at cold temperatures so that it can still be pumped without reducing fuel flow at 70°c more than sufficient any jet aircraft even at 10 15°c below first component to freeze (usually paraffin wax) jet fuel can still be pumped the accepted minimum fuel temperature safe flight jet a 40°c jet a 1 47°c jet b 65°c flight crews must monitor fuel temperature to ensure that fuel does not cool to below pour point jet b has a flash point of below 0°c jet a around 38°c a low flash point a useful property to start a jet engine in cold weather but reduces amount of energy stored in fuel remember that lower flash point more 'volatile' fuel is.

  • Question 24-10

    Which statement correct i the freezing point jet a at about same temperature as that jet b ii the flash point jet a at a higher temperature than that jet b I incorrect ii correct. jet b has a higher napthalene content that helps prevent freezing (gelling) at low temperatures but in practice that not a useful property of jet b (see below) jet fuel a blend of many different hydrocarbons that each have their own specific freezing point so it not really possible to quote a freezing point temperature the 'pour point' the term used in aviation industry to specify minimum safe temperature anti ice additives such as 'prist' are used in jet a at cold temperatures so that it can still be pumped without reducing fuel flow at 70°c more than sufficient any jet aircraft even at 10 15°c below first component to freeze (usually paraffin wax) jet fuel can still be pumped the accepted minimum fuel temperature safe flight jet a 40°c jet a 1 47°c jet b 65°c flight crews must monitor fuel temperature to ensure that fuel does not cool to below pour point jet b has a flash point of below 0°c jet a around 38°c a low flash point a useful property to start a jet engine in cold weather but reduces amount of energy stored in fuel remember that lower flash point more 'volatile' fuel is.

  • Question 24-11

    The fuel oil heat exchanger Cools oil heats fuel. jet b has a higher napthalene content that helps prevent freezing (gelling) at low temperatures but in practice that not a useful property of jet b (see below) jet fuel a blend of many different hydrocarbons that each have their own specific freezing point so it not really possible to quote a freezing point temperature the 'pour point' the term used in aviation industry to specify minimum safe temperature anti ice additives such as 'prist' are used in jet a at cold temperatures so that it can still be pumped without reducing fuel flow at 70°c more than sufficient any jet aircraft even at 10 15°c below first component to freeze (usually paraffin wax) jet fuel can still be pumped the accepted minimum fuel temperature safe flight jet a 40°c jet a 1 47°c jet b 65°c flight crews must monitor fuel temperature to ensure that fuel does not cool to below pour point jet b has a flash point of below 0°c jet a around 38°c a low flash point a useful property to start a jet engine in cold weather but reduces amount of energy stored in fuel remember that lower flash point more 'volatile' fuel is.

  • Question 24-12

    Fuel gas turbine engines usually heated in order to Prevent icing up of lp filter. jet b has a higher napthalene content that helps prevent freezing (gelling) at low temperatures but in practice that not a useful property of jet b (see below) jet fuel a blend of many different hydrocarbons that each have their own specific freezing point so it not really possible to quote a freezing point temperature the 'pour point' the term used in aviation industry to specify minimum safe temperature anti ice additives such as 'prist' are used in jet a at cold temperatures so that it can still be pumped without reducing fuel flow at 70°c more than sufficient any jet aircraft even at 10 15°c below first component to freeze (usually paraffin wax) jet fuel can still be pumped the accepted minimum fuel temperature safe flight jet a 40°c jet a 1 47°c jet b 65°c flight crews must monitor fuel temperature to ensure that fuel does not cool to below pour point jet b has a flash point of below 0°c jet a around 38°c a low flash point a useful property to start a jet engine in cold weather but reduces amount of energy stored in fuel remember that lower flash point more 'volatile' fuel is.

  • Question 24-13

    Fuel flow information gas turbine engines Measured in line between fuel control unit the engine burners. jet b has a higher napthalene content that helps prevent freezing (gelling) at low temperatures but in practice that not a useful property of jet b (see below) jet fuel a blend of many different hydrocarbons that each have their own specific freezing point so it not really possible to quote a freezing point temperature the 'pour point' the term used in aviation industry to specify minimum safe temperature anti ice additives such as 'prist' are used in jet a at cold temperatures so that it can still be pumped without reducing fuel flow at 70°c more than sufficient any jet aircraft even at 10 15°c below first component to freeze (usually paraffin wax) jet fuel can still be pumped the accepted minimum fuel temperature safe flight jet a 40°c jet a 1 47°c jet b 65°c flight crews must monitor fuel temperature to ensure that fuel does not cool to below pour point jet b has a flash point of below 0°c jet a around 38°c a low flash point a useful property to start a jet engine in cold weather but reduces amount of energy stored in fuel remember that lower flash point more 'volatile' fuel is.

  • Question 24-14

    Which statement correct i the freezing point jet a at a lower temperature than that jet b ii the flash point jet a at a higher temperature than that jet b I incorrect ii correct. Jet kerosene (jet a1 or jet a) jet gasoline (jet b) aviation gasoline (avgas) are names given fuel jet b has a higher napthalene content that helps prevent freezing (gelling) at low temperatures but in practice that not a useful property of jet b jet fuel a blend of many different hydrocarbons that each have their own specific freezing point so it not really possible to quote a freezing point temperature the 'pour point' the term used in aviation industry to specify minimum safe temperature anti ice additives such as 'prist' are used in jet a at cold temperatures so that it can still be pumped without reducing fuel flow at 70°c more than sufficient any jet aircraft even at 10 15°c below first component to freeze (usually paraffin wax) jet fuel can still be pumped the accepted minimum fuel temperature safe flight jet a 40°c jet a 1 47°c jet b 65°c flight crews must monitor fuel temperature to ensure that fuel does not cool to below pour point jet b has a flash point of below 0°c jet a around 38°c a low flash point a useful property to start a jet engine in cold weather but reduces amount of energy stored in fuel remember that lower flash point more 'volatile' fuel is.

  • Question 24-15

    Which statement correct i the freezing point jet a at a lower temperature than that jet b ii the flash point jet a at about same temperature as that jet b I incorrect ii incorrect. Jet kerosene (jet a1 or jet a) jet gasoline (jet b) aviation gasoline (avgas) are names given fuel jet b has a higher napthalene content that helps prevent freezing (gelling) at low temperatures but in practice that not a useful property of jet b (see below) jet fuel a blend of many different hydrocarbons that each have their own specific freezing point so it not really possible to quote a freezing point temperature the 'pour point' the term used in aviation industry to specify minimum safe temperature anti ice additives such as 'prist' are used in jet a at cold temperatures so that it can still be pumped without reducing fuel flow at 70°c more than sufficient any jet aircraft even at 10 15°c below first component to freeze (usually paraffin wax) jet fuel can still be pumped the accepted minimum fuel temperature safe flight jet a 40°c jet a 1 47°c jet b 65°c flight crews must monitor fuel temperature to ensure that fuel does not cool to below pour point jet b has a flash point of below 0°c jet a around 38°c a low flash point a useful property to start a jet engine in cold weather but reduces amount of energy stored in fuel remember that lower flash point more 'volatile' fuel is.

  • Question 24-16

    Which statement correct i the freezing point jet a at a higher temperature than that jet b ii the flash point jet a at a lower temperature than that jet b I correct ii incorrect. Jet kerosene (jet a1 or jet a) jet gasoline (jet b) aviation gasoline (avgas) are names given fuel jet b has a higher napthalene content that helps prevent freezing (gelling) at low temperatures but in practice that not a useful property of jet b jet fuel a blend of many different hydrocarbons that each have their own specific freezing point so it not really possible to quote a freezing point temperature the 'pour point' the term used in aviation industry to specify minimum safe temperature anti ice additives such as 'prist' are used in jet a at cold temperatures so that it can still be pumped without reducing fuel flow at 70°c more than sufficient any jet aircraft even at 10 15°c below first component to freeze (usually paraffin wax) jet fuel can still be pumped the accepted minimum fuel temperature safe flight jet a 40°c jet a 1 47°c jet b 65°c flight crews must monitor fuel temperature to ensure that fuel does not cool to below pour point jet b has a flash point of below 0°c jet a around 38°c a low flash point a useful property to start a jet engine in cold weather but reduces amount of energy stored in fuel remember that lower flash point more 'volatile' fuel is.

  • Question 24-17

    Specific fuel consumption a turbo prop engine can be expressed in kg per Hour per unit of shaft power. Jet kerosene (jet a1 or jet a) jet gasoline (jet b) aviation gasoline (avgas) are names given fuel jet b has a higher napthalene content that helps prevent freezing (gelling) at low temperatures but in practice that not a useful property of jet b jet fuel a blend of many different hydrocarbons that each have their own specific freezing point so it not really possible to quote a freezing point temperature the 'pour point' the term used in aviation industry to specify minimum safe temperature anti ice additives such as 'prist' are used in jet a at cold temperatures so that it can still be pumped without reducing fuel flow at 70°c more than sufficient any jet aircraft even at 10 15°c below first component to freeze (usually paraffin wax) jet fuel can still be pumped the accepted minimum fuel temperature safe flight jet a 40°c jet a 1 47°c jet b 65°c flight crews must monitor fuel temperature to ensure that fuel does not cool to below pour point jet b has a flash point of below 0°c jet a around 38°c a low flash point a useful property to start a jet engine in cold weather but reduces amount of energy stored in fuel remember that lower flash point more 'volatile' fuel is.

  • Question 24-18

    The dc pump in left main tank operates automatically to provide fuel to 873 Apu when ac power not available the apu selector on. Jet kerosene (jet a1 or jet a) jet gasoline (jet b) aviation gasoline (avgas) are names given fuel jet b has a higher napthalene content that helps prevent freezing (gelling) at low temperatures but in practice that not a useful property of jet b jet fuel a blend of many different hydrocarbons that each have their own specific freezing point so it not really possible to quote a freezing point temperature the 'pour point' the term used in aviation industry to specify minimum safe temperature anti ice additives such as 'prist' are used in jet a at cold temperatures so that it can still be pumped without reducing fuel flow at 70°c more than sufficient any jet aircraft even at 10 15°c below first component to freeze (usually paraffin wax) jet fuel can still be pumped the accepted minimum fuel temperature safe flight jet a 40°c jet a 1 47°c jet b 65°c flight crews must monitor fuel temperature to ensure that fuel does not cool to below pour point jet b has a flash point of below 0°c jet a around 38°c a low flash point a useful property to start a jet engine in cold weather but reduces amount of energy stored in fuel remember that lower flash point more 'volatile' fuel is.

  • Question 24-19

    What the density of jet a 1 Apu when ac power not available the apu selector on. Density of jet a 1 at 15 °c 0 804 kg/l.

  • Question 24-20

    What does expression 'usable fue mean The total amount of fuel that can be supplied to engine. Density of jet a 1 at 15 °c 0 804 kg/l.

  • Question 24-21

    Unusable fuel Sometimes minimised the incorporation of tank sump pads. Density of jet a 1 at 15 °c 0 804 kg/l.

  • Question 24-22

    In order to ensure that all fuel on board available to any engine on a multi engine aircraft it must be fitted with Sometimes minimised the incorporation of tank sump pads. Density of jet a 1 at 15 °c 0 804 kg/l.

  • Question 24-23

    Which statement true concerning structure and possible advantage of an integral fuel tank It built internally using aircraft structure this saves weight space. Density of jet a 1 at 15 °c 0 804 kg/l.

  • Question 24-24

    Fuel dump systems are required On all transport category aircraft where maximum take off weight significant higher than maximum landing weight. Density of jet a 1 at 15 °c 0 804 kg/l.

  • Question 24-25

    The ventilation system in a fuel tank Prevents low pressure or excessive overpressure in tank. Density of jet a 1 at 15 °c 0 804 kg/l.

  • Question 24-26

    The fuel tanks of aircrafts must be checked water Before first flight of day or after a long turnaround time. Density of jet a 1 at 15 °c 0 804 kg/l.

  • Question 24-27

    The functions of an lp booster pump in a gas turbine fuel system are to Avoid vapour locking prevent cavitation of hp fuel pump. Density of jet a 1 at 15 °c 0 804 kg/l.

  • Question 24-28

    Apu fuel can be provided Any ac fuel pump supplying fuel to left fuel manifold or the left main tank dc fuel pump. Cqb 15 september 2011.

  • Question 24-29

    The primary input signals a hydro mechanical gas turbine engine fuel control system include N2 compressor discharge pressure compressor inlet temperature fuel shut off thrust lever angle. fitted within hp fuel pump a 'hydro mechanical governor' which uses hydraulic pressure proportional to engine speed as its controlling parameter this system uses n2 compressor discharge pressure compressor inlet temperature fuel shut off thrust lever angle as primary input signals.

  • Question 24-30

    The primary reason venting an engine oil tank to Prevent excessive pressure in tank. fitted within hp fuel pump a 'hydro mechanical governor' which uses hydraulic pressure proportional to engine speed as its controlling parameter this system uses n2 compressor discharge pressure compressor inlet temperature fuel shut off thrust lever angle as primary input signals.

  • Question 24-31

    The cross feed fuel system can be used to 1 feed any engine from any fuel tank 2 dump unusable fuel 3 adjust fuel distribution4 to transfer fuel from one tank to another located in same wingthe combination that regroups all of correct statements Prevent excessive pressure in tank. using crossfeed an engine can draw fuel from a fuel tank located in opposite wing on most multi engine airplanes operation in crossfeed mode an emergency procedure used to extend airplane range endurance in one engine inoperative flight there are a few models that permit crossfeed as a normal fuel balancing technique in normal operation (fuel distribution adjustment).

  • Question 24-32

    If one of 12 cells of a lead acid battery dead battery Prevent excessive pressure in tank. using crossfeed an engine can draw fuel from a fuel tank located in opposite wing on most multi engine airplanes operation in crossfeed mode an emergency procedure used to extend airplane range endurance in one engine inoperative flight there are a few models that permit crossfeed as a normal fuel balancing technique in normal operation (fuel distribution adjustment).

  • Question 24-33

    When ac generators are connected in parallel reactive loads are balanced means of Prevent excessive pressure in tank. The energising current the current that controls voltage regulator so it will control voltage to balance reactive loads.

  • Question 24-34

    In order to produce an alternating voltage of 400 hz number of pairs of poles required in an ac generator running at 6000 rpm Prevent excessive pressure in tank. 400 = (6000/60) x pole pairs pole pairs = 4.

  • Question 24-35

    In an ac power generation system constant speed drive csd 1 can be disconnected from engine shaft2 can be disconnected from generator3 a hydro mechanical system4 an electronic system5 can not be disconnected in flight6 can be disconnected in flightthe combination regrouping all correct statements Prevent excessive pressure in tank. The csd unit normally integral with generator therefore disconnect between csd the engine gearbox not between csd the generator therefore it's only csd that can be disconnected from engine gearbox the disconnect there the purpose of isolating a hydromechanical unit i e it might either be leaking oil overheating or causing load sharing system to do oddball things if you operate disconnect it will dump generator via csd i e rotational input from engine gearbox removed resolves oil leak/problem.

  • Question 24-36

    An inverter a Unit used to convert dc into ac. The csd unit normally integral with generator therefore disconnect between csd the engine gearbox not between csd the generator therefore it's only csd that can be disconnected from engine gearbox the disconnect there the purpose of isolating a hydromechanical unit i e it might either be leaking oil overheating or causing load sharing system to do oddball things if you operate disconnect it will dump generator via csd i e rotational input from engine gearbox removed resolves oil leak/problem.

  • Question 24-37

    In an aircraft electrical system where ac generators are not paralleled mounted changeover relay allows Power supply to faulty ac generators busbar. In an ac electrical power system where generators are not paralleled (a split busbar system) only one generator can supply a busbar at any given moment however one generator may supply two (or more) busbars should a generator fail then its busbar would not be powered the changeover relays allow a different generator to supply that busbar in addition to its own.

  • Question 24-38

    Pulling fire shutoff handle causes a number of devices to disconnect in respect of ac generator it can be said that Exciter control relay the generator breaker open. A control relay a 'magnetic switch' which can isolate a circuit so in effect same as a 'breaker' an 'exciter breaker' an 'exciter control relay' are in effect same thing an exciter breaker (exciter control relay) will isolate power to voltage regulator the generator breaker will isolate generator from bus bar the tie breaker will isolate two different bus bars from each other or can connect two generators to same bus bar in most cases you will want to keep bus bars connected so that you can use all your services so you will trip generator breaker to isolate generator from bus bar the exciter breaker so you effectively shut down that generator if you have 2 generators supplying same single bus bar then you will trip tie breaker to isolate generator the generator exciter breakers to isolate shut down generator.

  • Question 24-39

    On ground auxiliary power unit apu can provide 1 electricity2 air starting system3 hydraulic pressure4 air air conditioningthe combination which regroups all of correct statements Exciter control relay the generator breaker open. The primary purpose of an aircraft apu to provide power to start main engines turbine engines must be accelerated to a high rotational speed in order to provide sufficient air compression self sustaining operation smaller jet engines are usually started an electric motor while larger engines are usually started an air turbine motor before engines are to be turned apu started generally a battery once apu running it provides power (electric or pneumatic depending on design) to start aircraft's main engines apus are also used to run accessories while engines are shut down this allows cabin to be comfortable while passengers are boarding before aircraft's engines are started electrical power used to run systems preflight checks for information some apus are also connected to a hydraulic pump allowing crews to operate hydraulic equipment but the learning objectives apu not considered as a power source hydraulic pressure.

  • Question 24-40

    A thermal circuit breaker Protects system in event of overload/overheating. The primary purpose of an aircraft apu to provide power to start main engines turbine engines must be accelerated to a high rotational speed in order to provide sufficient air compression self sustaining operation smaller jet engines are usually started an electric motor while larger engines are usually started an air turbine motor before engines are to be turned apu started generally a battery once apu running it provides power (electric or pneumatic depending on design) to start aircraft's main engines apus are also used to run accessories while engines are shut down this allows cabin to be comfortable while passengers are boarding before aircraft's engines are started electrical power used to run systems preflight checks for information some apus are also connected to a hydraulic pump allowing crews to operate hydraulic equipment but the learning objectives apu not considered as a power source hydraulic pressure.


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