fuel systems Flashcards
an aviation fuel should have the following qualities:
- capable of being _______ and flow easily under all operating conditions
- enable engine _______ at all ground conditions and give satisfactory __lighting characteristics
- give _________ combustion under all conditions
- have as high a ________ value as possible
- minimum _________ effects on combustion systems or turbine blades
- minimum corrosive effects of fuel system components
- adequate ___________ for fuel system components
- reduce _____ risks to a minimum
an aviation fuel should have the following qualities:
- capable of being PUMPED and flow easily under all operating conditions
- enable engine STA RTING at all ground conditions and give satisfactory RElighting characteristics
- give EFFICIENT combustion under all conditions
- have as high a CALORIFIC value as possible
- minimum CORROSIVE effects on combustion systems or turbine blades
- minimum corrosive effects of fuel system components
- adequate LUBRICATION for fuel system components
- reduce FIRE risks to a minimum
AVGAS 100LL
now only used for _____ aircraft
colour of AVGAS 100LL is ____
the fuel grade identification marking for AVGAS 100LL is a single ____ band followed by a ___ rectangle with AVGAS 100LL written in _____
AVGAS 100LL
now only used for LIGHT aircraft
colour of AVGAS 100LL is BLUE
the fuel grade identification marking for AVGAS 100LL is a single BLUE band followed by a RED rectangle with AVGAS 100LL written in WHITE
AVTUR (JET A1 CONTAINING FS__)
the freezing point of jet A1 is around -__ celsius
the colour of jet A1 is _____/_________
the fuel grade identification markings for jet A1 is ___ _____ bands followed by a _____ rectangle, with jet A1 written in _____
AVTUR (JET A1 CONTAINING FSII)
the freezing point of jet A1 is around -47 celsius
the colour of jet A1 is CLEAR/COLOURLESS
the fuel grade identification markings for jet A1 is TWO BLACK bands followed by a BLACK rectangle, with jet A1 written in WHITE
FUEL SYSTEM BLANKS/COVERS
non-standard blanks must ___ be used
FUEL SYSTEM BLANKS/COVERS
non-standard blanks must NOT be used
FUEL SYSTEM ICING INHIBITOR
___ crystals can form in fuel tanks and pipelines at the very low temperatures encountered at ________
generally, this ice is formed from water that was ________ in the fuel when the aircraft was refuelled, but separated from the fuel as the temperature dropped
most aircraft have _______ on their main fuel tank filters to melt any ice that collects, which would otherwise reduce fuel flow
FUEL SYSTEM ICING INHIBITOR
ICE crystals can form in fuel tanks and pipelines at the very low temperatures encountered at ALTITUDE
generally, this ice is formed from water that was DISSOLVED in the fuel when the aircraft was refuelled, but separated from the fuel as the temperature dropped
most aircraft have HEATERS on their main fuel tank filters to melt any ice that collects, which would otherwise reduce fuel flow
MICROBIOLOGICAL CONTAMINATION
cladosporium resinae
the spores can exist in a _______ state in kerosene fuels in most parts of the world but they will propagate when water is present and the temperature is between __ and __ celsius
the general geographical zone where the conditions are favourable to fungal growths is between latitudes of __ degrees north to __ degrees south
MICROBIOLOGICAL CONTAMINATION
cladosporium resinae
the spores can exist in a DORMANT state in kerosene fuels in most parts of the world but they will propagate when water is present and the temperature is between 15 and 35 celsius
the general geographical zone where the conditions are favourable to fungal growths is between latitudes of 30 degrees north to 30 degrees south
FUEL QUALITY CONTROL
after a refuelling vehicle has been filled from a storage tank, it should be left to stand for at least __ minutes, then approximately one _______ of fuel should be drawn from the sump in order to check its quality. if ________ is found, further samples should be taken, until the result is satisfactory. _________ water in kerosene will give the fuel a cloudy appearance, and ____ water may often be readily visible, but in any case, a chemical water ________ method should be used.
FUEL QUALITY CONTROL
after a refuelling vehicle has been filled from a storage tank, it should be left to stand for at least 10 minutes, then approximately one GALLON of fuel should be drawn from the sump in order to check its quality. if SEDIMENT is found, further samples should be taken, until the result is satisfactory. SUSPENDED water in kerosene will give the fuel a cloudy appearance, and FREE water may often be readily visible, but in any case, a chemical water DETECTION method should be used.
MINIMUM FUE FLOW REQUIREMENTS
it is a design requirement that the aircraft fuel system must be capable of delivering a supply in ______ of engine demand under the most _______ operating conditions. these conditions being ____ power at ___ level with an almost _____ tank
MINIMUM FUE FLOW REQUIREMENTS
it is a design requirement that the aircraft fuel system must be capable of delivering a supply in EXCESS of engine demand under the most ADVERSE operating conditions. these conditions being FULL power at SEA level with an almost EMPTY tank
RIGID REMOVEABLE FUEL TANKS
the tank is usually constructed of _________ components welded together. a _____ or baffle(s) may be installed inside the tank to reduce the free movement of fuel called _____. the baffles are attached to the tank structure with ________ to allow a flow of fuel but reducing the surge action of the fuel
RIGID REMOVEABLE FUEL TANKS
the tank is usually constructed of ALUMINIUM components welded together. a BAFFLE or baffle(s) may be installed inside the tank to reduce the free movement of fuel called SURGE. the baffles are attached to the tank structure with APERTURES to allow a flow of fuel but reducing the surge action of the fuel
INTEGRAL FUEL TANKS
integral fuel tanks are formed within the aircraft _______ by sealing compartments like ____ sections during manufacture. internal ________ both divide the wing into a number of tanks and also prevent ______. external or _______ pipes connect the tanks to the fuel system.
INTEGRAL FUEL TANKS
integral fuel tanks are formed within the aircraft STRUCTURE by sealing compartments like WING sections during manufacture. internal DIAPHRAGMS both divide the wing into a number of tanks and also prevent SURGE. external or INTERNAL pipes connect the tanks to the fuel system.
FUEL PUMPS. ELECTRIC
these pumps are usually called _______ pumps when supplying fuel to the engines and ________ pumps when used to transfer fuel between tanks. however, both these functions are usually __________ and they can also have a jettison facility, where they then may also be called ________ pumps.
these are ___ positive displacement pumps
FUEL PUMPS. ELECTRIC
these pumps are usually called BOOSTER pumps when supplying fuel to the engines and TRANSFER pumps when used to transfer fuel between tanks. however, both these functions are usually COMBINED and they can also have a jettison facility, where they then may also be called JETTISON pumps.
these are NOT positive displacement pumps
FUEL PUMPS. OPERATION
a _____ seal is fitted between the pump and the _____, therefore any leakage which does occur will be drained _________. if any fuel is seen to be dripping from this drain, the booster pump should be ________
FUEL PUMPS. OPERATION
a GLAND seal is fitted between the pump and the MOTOR, therefore any leakage which does occur will be drained OVERBOARD. if any fuel is seen to be dripping from this drain, the booster pump should be REPLACED
PUMP POSITION. FULLY IMMERSED ‘WET BAY’
the centrifugal booster pump is normally attached directly to the ______ surface of the tank itself, for example, in integral fuel tanks
the pump is mounted o that it can be removed without _______ the tank, providing the pump incorporates a ‘_______ type’ chamber
this chamber can be isolated from the fuel in the tank by operating a simple _____ mechanism, then draining the small quantity of fuel left in the chamber before removing the inner pump.
the advantage of these ‘canister type’ pumps is that, if failure of the pump occurs, the down time of the aircraft is greatly ________ as the tanks do not require draining.
some fully immersed pumps fitted inside the tanks may be, by design, __________ or even triplicated in case of failure. therefore, the minimum equipment list may authorise flight with at least one ______ pump
PUMP POSITION. FULLY IMMERSED ‘WET BAY’
the centrifugal booster pump is normally attached directly to the LOWER surface of the tank itself, for example, in integral fuel tanks
the pump is mounted o that it can be removed without DRAINING the tank, providing the pump incorporates a ‘CANISTER type’ chamber
this chamber can be isolated from the fuel in the tank by operating a simple LEVER mechanism, then draining the small quantity of fuel left in the chamber before removing the inner pump.
the advantage of these ‘canister type’ pumps is that, if failure of the pump occurs, the down time of the aircraft is greatly REDUCED as the tanks do not require draining.
some fully immersed pumps fitted inside the tanks may be, by design, DUPLICATED or even triplicated in case of failure. therefore, the minimum equipment list may authorise flight with at least one FAILED pump
JET PUMPS
these pumps use a supply of fuel from the ‘_______ pump’ to induce a flow of fuel through a ________ connected to a pipeline
the pipeline is ducted to the ______ areas of the fuel tank drawing this fuel towards the booster pumps
the jet pump has no moving parts relying on the motive flow from the booster pump to move the fuel within the tank preventing __________ and supplying the booster pump
JET PUMPS
these pumps use a supply of fuel from the ‘BOOSTER pump’ to induce a flow of fuel through a VENTURI connected to a pipeline
the pipeline is ducted to the REMOTE areas of the fuel tank drawing this fuel towards the booster pumps
the jet pump has no moving parts relying on the motive flow from the booster pump to move the fuel within the tank preventing STAGNATION and supplying the booster pump
FUEL SYSTEM COMPONENTS. VENT SYSTEM
all fuel tanks must have provision for both ______ and _______ venting. the vent system must ensure that any large changes in pressure __________ do not build up between the fuel tank and the outside atmosphere
any large changes in pressure differential could cause serious structural _______ and fuel _____. the ideal condition is for a small ________ pressure acting on the fuel
conditions which require fuel venting are as follows:
- the inflow and outflow of ___ as the aircraft changes altitude
- the changes in fuel capacity as the aircraft is being _______ and defuelled
- the changes of fuel _______ as the fuel is being used by the engines
- the effects of ___________ changes which would cause expansion and contraction of the aircraft fuel contents (e.g. ground air temp +40 celsius, flight air temp -40 celsius)
- the allowance to discharge excess fuel to atmosphere should the __________ valve fail to close when the tank is filled
FUEL SYSTEM COMPONENTS. VENT SYSTEM
all fuel tanks must have provision for both INWARDS and OUTWARDS venting. the vent system must ensure that any large changes in pressure DIFFERENTIAL do not build up between the fuel tank and the outside atmosphere
any large changes in pressure differential could cause serious structural DAMAGE and fuel LEAKS. the ideal condition is for a small POSITIVE pressure acting on the fuel
conditions which require fuel venting are as follows:
- the inflow and outflow of AIR as the aircraft changes altitude
- the changes in fuel capacity as the aircraft is being REFUELLED and defuelled
- the changes of fuel CONTENTS as the fuel is being used by the engines
- the effects of TEMPERATURE changes which would cause expansion and contraction of the aircraft fuel contents (e.g. ground air temp +40 celsius, flight air temp -40 celsius)
- the allowance to discharge excess fuel to atmosphere should the REFUELLING valve fail to close when the tank is filled
FUEL VENT SYSTEM OPERATION
each fuel tank is both inwardly and outwardly vented to relive both excess fuel/vapour into the ____/surge tank
the inward vent is ____ ended but the outward vent has a _____ valve fitted to minimise fuel ________ between tanks and into the vent/surge tank, with changes aircraft attitude.
vented fuel which collects in the vent/surge tank is usually _________ to the fuel tanks. the method by which the fuel is returned may be a continuous ‘___ pump’ operation or an __________ ‘electrically operated pump’ system
FUEL VENT SYSTEM OPERATION
each fuel tank is both inwardly and outwardly vented to relive both excess fuel/vapour into the VENT/surge tank
the inward vent is OEPN ended but the outward vent has a FLOAT valve fitted to minimise fuel TRANSFER between tanks and into the vent/surge tank, with changes aircraft attitude.
vented fuel which collects in the vent/surge tank is usually RETURNED to the fuel tanks. the method by which the fuel is returned may be a continuous ‘JET pump’ operation or an INTERMITTENT ‘electrically operated pump’ system
VALVES
low _______ valves, cross ____ valves and _____ engine valves are usually ____ type, full flow valves and may be either __________ or __________ operated.
these are ___ position valves only, and either internal or external _________ stops are provided, to limit movement to __ degrees. a ______ indication of valve position is also provided.
_____ switches cut off power to the _____ at the fully open and fully closed positions, and the brake operates automatically as the motor is __-energised. the brake is ____________ released when a reverse selection is made. the limit switches may also be used to operate ________ indicator lights or magnetic indicators in the crew compartment
VALVES
low PRESSURE valves, cross FEED valves and INTER engine valves are usually BALL type, full flow valves and may be either MECHANICALLY or ELECTRICALLY operated.
these are TWO position valves only, and either internal or external MECHANICAL stops are provided, to limit movement to 90 degrees. a VISUAL indication of valve position is also provided.
LIMIT switches cut off power to the MOTOR at the fully open and fully closed positions, and the brake operates automatically as the motor is DE-energised. the brake is MAGNETICALLY released when a reverse selection is made. the limit switches may also be used to operate POSITION indicator lights or magnetic indicators in the crew compartment
VALVES. LP COCKS
LP cocks are used to isolate the ________ mounted fuel system from the engine
VALVES. LP COCKS
LP cocks are used to isolate the AIRFRAME mounted fuel system from the engine
VALVES. SUCTION VALVES
suction valves are fitted to permit fuel to be drawn from the tanks in the event of ________ pump failure. when the pump is operating normally, the pressure in the pipeline keeps the valve ______. if the pump fails, the suction created by the ______ driven pump will draw fuel through the suction valve thereby preventing the engine from being _______ of fuel
VALVES. SUCTION VALVES
suction valves are fitted to permit fuel to be drawn from the tanks in the event of BOOSTER pump failure. when the pump is operating normally, the pressure in the pipeline keeps the valve CLOSED. if the pump fails, the suction created by the ENGINE driven pump will draw fuel through the suction valve thereby preventing the engine from being STARVED of fuel
FUEL SYSTEMS. GENERAL
a simple fuel system may consist of a ______ feed tank, a _____, a shut off _____ and suitable rigid a flexible _____ between these components and the ______
FUEL SYSTEMS. GENERAL
a simple fuel system may consist of a GRAVITY feed tank, a FILTER, a shut off VALVE and suitable rigid and flexible PIPES between these components and the ENGINE
FUEL TANK COMPONENTS
each fuel tank is fitted with a ____ pipe which is vented to the outside of the ____ structure. this vent pipe ensures that _________ pressure is maintained within the fuel tank
a non-return valve (NRV) attached to the vent pipe inside the fuel tank prevents any fuel from ________ though the vent pipe. a small ____ in the NRV prevents any build up of pressure when the NRV is ______
on some light aircraft, a small amount of fuel ____ be drained off from both the ____ and main filter _____ to ensure that any concentration of _____ is removed prior to flight
FUEL TANK COMPONENTS
each fuel tank is fitted with a VENT pipe which is vented to the outside of the WING structure. this vent pipe ensures that ATMOSPHERIC pressure is maintained within the fuel tank
a non-return valve (NRV) attached to the vent pipe inside the fuel tank prevents any fuel from SIPHONING though the vent pipe. a small HOLE in the NRV prevents any build up of pressure when the NRV is CLOSED
on some light aircraft, a small amount of fuel MUST be drained off from both the TANK and main filter DRAINS to ensure that any concentration of WATER is removed prior to flight
THE SELECTOR VALVE/LP COCK
the selector valve enables the engine to be fed from ________ tanks or ____ tanks together and an has an on/off position to enable the fuel supply to be turned ___
THE SELECTOR VALVE/LP COCK
the selector valve enables the engine to be fed from INDIVIDUAL tanks or BOTH tanks together and an has an on/off position to enable the fuel supply to be turned OFF
BOOSTER PUMP
all fuel pumps are referred to as _______ pumps
the booster pump is ________ operated and is fitted to ensure a _______ fuel supply to the engine under all conditions such as:
- ____ting
- take ___
- clim____
- high _______
- turbu____
- lan____
all aircraft fuel systems are designed to provide adequate fuel for all engine requirements, even if the booster pump _____
BOOSTER PUMP
all fuel pumps are referred to as BOOSTER pumps
the booster pump is ELECTRICALLY operated and is fitted to ensure a POSITIVE fuel supply to the engine under all conditions such as:
- STARting
- take OFF
- climBING
- high ALTITUDE
- turbuLENCE
- lanDING
all aircraft fuel systems are designed to provide adequate fuel for all engine requirements, even if the booster pump FAILS
FUEL FEED
individual engines are usually fed from an ________ tank or _____ of tanks
_____-feed and _____-engine valves are provided to enable the engines to be fed from any desired group of tanks, and also to permit fuel _______ between tanks
FUEL FEED
individual engines are usually fed from an ASSOCIATED tank or GROUP of tanks
CROSS-feed and INTER-engine valves are provided to enable the engines to be fed from any desired group of tanks, and also to permit fuel TRANSFER between tanks
CASCADE DEVICE
refuelling pipes within the tanks are fitted with a cascade device, the purpose of which is to prevent _______ to the tank interior especially the _______, which would be the result if a pressurised ___ of fuel entered the tank
CASCADE DEVICE
refuelling pipes within the tanks are fitted with a cascade device, the purpose of which is to prevent DAMAGE to the tank interior especially the SEALANT, which would be the result if a pressurised JET of fuel entered the tank
ENSURING CORRECT FUEL USED
always ensure correct fuel is used as follows:
- aircraft refuelling _______ and any over wing _______ point should be clearly marked with the type of fuel to be used (e.g. jet A1)
- tanker/_______ should be clearly marked with the type of fuel to be used (e.g. jet A1)
- the ____ should clearly state the type of fuel to be used
ENSURING CORRECT FUEL USED
always ensure correct fuel is used as follows:
- aircraft refuelling STATION and any over wing FILLING point should be clearly marked with the type of fuel to be used (e.g. jet A1)
- tanker/HYDRANT should be clearly marked with the type of fuel to be used (e.g. jet A1)
- the AMM should clearly state the type of fuel to be used
FUELLING GENERAL OPERATION
fuelling can also be accomplished without _______ power by _________ operating the fuelling valves and using the quantity measuring ________
FUELLING GENERAL OPERATION
fuelling can also be accomplished without ELECTRICAL power by MANUALLY operating the fuelling valves and using the quantity measuring DRIPSTICK
FUEL JETTISON/FUEL DUMPING
many large aircraft are equipped with a means of _________ excess fuel in an emergency. fuel is pumped from each tank through a _____ pipe, which ensures that a pre-determined ________ of fuel remains
one of the booster pumps in each tank, may be run at a ______ speed for the jettisoning operation to offload the fuel, whilst the fuel feed to the engines is protected by ___-return valves
when a jettison pipe is in the _________ position it forms a seal at the manifold, and acts as a ______ jettison valve. the jettison valves are not _____ until this pipe is locked in the ________ position. both types of systems are controlled from a special _____ at the crew station, which contains ________ for the pumps and valves, and warning _____ or magnetic __________ to show the positions of the valves and jettison pipes
FUEL JETTISON/FUEL DUMPING
many large aircraft are equipped with a means of JETTISONING excess fuel in an emergency. fuel is pumped from each tank through a STAND pipe, which ensures that a pre-determined QUANTITY of fuel remains
one of the booster pumps in each tank, may be run at a HIGHER speed for the jettisoning operation to offload the fuel, whilst the fuel feed to the engines is protected by NON-return valves
when a jettison pipe is in the RETRACTED position it forms a seal at the manifold, and acts as a MASTER jettison valve. the jettison valves are not ARMED until this pipe is locked in the EXTENDED position. both types of systems are controlled from a special PANEL at the crew station, which contains SWITCHES for the pumps and valves, and warning LAMPS or magnetic INDICATORS to show the positions of the valves and jettison pipes
FUEL QUANTITY
for ___ stick and ____ stick fuel quantity measuring, the aircraft must be _________ both laterally and longitudinally to obtain accurate readings
FUEL QUANTITY
for DIP stick and DRIP stick fuel quantity measuring, the aircraft must be LEVELLED both laterally and longitudinally to obtain accurate readings
FUEL HEATING
a manually controlled fuel heating system usually consists of a ________ differential switch on the fuel ______, which operates a warning ____ in the crew compartment, and an electrically operated valve on the heat _________, which is controlled by a switch ________ to the warning lamp
when fuel flow through the filter becomes restricted by ___, the differential pressure across the filter _________, until it is sufficient to operate the icing warning lamp
an automatically controlled fuel heating system consists of a _____________ controlled air inlet valve on he heat exchanger, which progressively ______ and _______ to maintain fuel outlet temperature within pre-set limits above _ celsius. actual fuel temperature is indicated on an instrument on the fuel control _____, but no action is required by the crew
FUEL HEATING
a manually controlled fuel heating system usually consists of a PRESSURE differential switch on the fuel FILTER, which operates a warning LAMP in the crew compartment, and an electrically operated valve on the heat EXCHANGER, which is controlled by a switch ADJACENT to the warning lamp
when fuel flow through the filter becomes restricted by ICE, the differential pressure across the filter INCREASES, until it is sufficient to operate the icing warning lamp
an automatically controlled fuel heating system consists of a THERMOSTATICALLY controlled air inlet valve on he heat exchanger, which progressively OPENS and CLOSES to maintain fuel outlet temperature within pre-set limits above 0 celsius. actual fuel temperature is indicated on an instrument on the fuel control PANEL, but no action is required by the crew
REFUELLING
the term fuelling embraces both fuelling and defuelling
before fuelling, it should be ensured that the fuelling vehicle contains the correct _____ of fuel, as shown at the fuelling points of the aircraft
fuelling should always be carried out at a place approved by the ________ authority. it must be at least __ metres (50 feet) from any building
no smoking signs must be displayed __ less than 15 metres (__ feet) from the fuelling area
ground power units may be operated provided they are at least _ metres (20 feet) from aircraft _______ and _______ positions
precautions should be taken to provide a ____ to earth for any ______ electricity which may be present or which may build up as a result of the fuel flow. the _______ and the fuelling ________ should be earthed to a point which is known to be __________, and the earthing wire on the fuelling pipe should be connected to the earth point provided on the _______ before connecting the ________ pipe or removing the tank filler cap. the earthing wire should remain in position until _____ the the fuelling pipe is disconnected or the tank filler cap is replace, as appropriate
as stated previously, after fuelling an aircraft, the fuel must be checked for ____________ after waiting for a period of time for the fuel to settle.
however, it may be commercially practical to carry out a check _______ fuelling
REFUELLING
the term fuelling embraces both fuelling and defuelling
before fuelling, it should be ensured that the fuelling vehicle contains the correct GRADE of fuel, as shown at the fuelling points of the aircraft
fuelling should always be carried out at a place approved by the AERODROME authority. it must be at least 15 metres (50 feet) from any building
no smoking signs must be displayed NOT less than 15 metres (50 feet) from the fuelling area
ground power units may be operated provided they are at least 6 metres (20 feet) from aircraft VENTING and FILLING positions
precautions should be taken to provide a PATH to earth for any STATIC electricity which may be present or which may build up as a result of the fuel flow. the AIRCRAFT and the fuelling VEHICLE should be earthed to a point which is known to be SATISFACTORY, and the earthing wire on the fuelling pipe should be connected to the earth point provided on the AIRCRAFT before connecting the FUELLING pipe or removing the tank filler cap. the earthing wire should remain in position until AFTER the the fuelling pipe is disconnected or the tank filler cap is replace, as appropriate
as stated previously, after fuelling an aircraft, the fuel must be checked for CONTAMINATION after waiting for a period of time for the fuel to settle.
however, it may be commercially practical to carry out a check BEFORE fuelling
