protection systems book 1 Flashcards
during flight in certain conditions, ice may accumulate on all the forward facing areas of the aircraft. these accumulations have the following effects on an aircraft:
- a _________ in lift due to a change in aerofoil section and loss of ________ flow of air around leading edges and top surfaces
- an ________ in drag for the same reasons that cause a loss of lift. the rough surface increases skin friction
- _________ propeller efficiency because of the change in blade shape. there is the possibility of damage to the fuselage as a result of ice being thrown from he propellers
- there may be a loss of _______ due to ice restricting or preventing movement of _______ surfaces
- an _______ in weight causing loss of height. a change in the distribution of the weight can cause a change in the trim of the aircraft and possibly a loss of stability
- ________ of pitot static heads
- loss of ______ through the forward facing cabin windows or windshields
during flight in certain conditions, ice may accumulate on all the forward facing areas of the aircraft. these accumulations have the following effects on an aircraft:
- a DECREASE in lift due to a change in aerofoil section and loss of STREAMLINE flow of air around leading edges and top surfaces
- an INCREASE in drag for the same reasons that cause a loss of lift. the rough surface increases skin friction
- DECREASES propeller efficiency because of the change in blade shape. there is the possibility of damage to the fuselage as a result of ice being thrown from he propellers
- there may be a loss of CONTROL due to ice restricting or preventing movement of CONTROL surfaces
- an INCREASE in weight causing loss of height. a change in the distribution of the weight can cause a change in the trim of the aircraft and possibly a loss of stability
- BLOCKAGE of pitot static heads
- loss of VISION through the forward facing cabin windows or windshields
ice will only form on an aircraft when it is flying in cloud or precipitation where the water droplets are ___________
ice will only form on an aircraft when it is flying in cloud or precipitation where the water droplets are SUPERCOOLED
ice formation
an aerofoil with a relatively _____ radius leading edge, flying at slow or moderate airspeed creates a large pressure wave ahead of the leading edge. this forces the air around the aerofoil contour, carrying most of the moisture with it. some of the droplets are too heavy to make the tun and impact the leading edge. collection efficiencies are approximately __%
a _____ radius leading edge does not generate a large pressure wave and the ice collection efficiency can be as high as __%
on any aircraft the leading edge of the horizontal stabiliser has a _______ radius than that of the wing. the stabiliser therefore has a _______ collection efficiency than the wing. the stabiliser may accumulate a _____ amount of ice while there is little or no build up on the wing
ice formation
an aerofoil with a relatively LARGE radius leading edge, flying at slow or moderate airspeed creates a large pressure wave ahead of the leading edge. this forces the air around the aerofoil contour, carrying most of the moisture with it. some of the droplets are too heavy to make the tun and impact the leading edge. collection efficiencies are approximately 45%
a SMALL radius leading edge does not generate a large pressure wave and the ice collection efficiency can be as high as 95%
on any aircraft the leading edge of the horizontal stabiliser has a SMALLER radius than that of the wing. the stabiliser therefore has a HIGHER collection efficiency than the wing. the stabiliser may accumulate a LARGE amount of ice while there is little or no build up on the wing
glaze icing or runback icing (clear)
- MOST DANGEROUS as has much greater spoiling effect on airflow
- temp range from _- -__ celcius
- small portion of droplet freezes at stagnation point which releases _____ heat, delaying freezing of remainder of droplet which runs back over aerofoil and freezes
- droplets unite in liquid state and little or no ___ trapped between them
- transparent or translucent ice with ______ surface appearance
- accumulates _______ and can form beyond effective area of de-iced or anti-iced surfaces
glaze icing or runback icing (clear)
- MOST DANGEROUS as has much greater spoiling effect on airflow
- temp range from 2- -10 celcius
- small portion of droplet freezes at stagnation point which releases LATENT heat, delaying freezing of remainder of droplet which runs back over aerofoil and freezes
- droplets unite in liquid state and little or no AIR trapped between them
- transparent or translucent ice with GLOSSY surface appearance
- accumulates RAPIDLY and can form beyond effective area of de-iced or anti-iced surfaces
mixed ice (glime)
- when complete freezing of water droplets on impact takes longer than ____ ice
- _____ water particles, ___ pressure
- _______ appearance
- extends ______ back over leading edge and not as _____ as rime ice
mixed ice (glime)
- when complete freezing of water droplets on impact takes longer than RIME ice
- LARGE water particles, LOW pressure
- OPAQUE appearance
- extends FURTHER back over leading edge and not as ROUGH as rime ice
rime ice
- ________ freezing of water particles on impact
- _____ water particles, very ___ temperature
- air trapped causing _____ texture and white _________ appearance
rime ice
- COMPLETE freezing of water particles on impact
- SMALL water particles, very LOW temperature
- air trapped causing LIGHT texture and white CRYSTALINE appearance
dry icing
- icing does not occur above _____m (_____ feet)
- however if ice crystals are present in sufficient volume, they can accumulate in ________ cooling ducts and _____ air intakes causing blockage
dry icing
- icing does not occur above 12000m (40000 feet)
- however if ice crystals are present in sufficient volume, they can accumulate in AUXILLARY cooling ducts and ENGINE air intakes causing blockage
hoar frost
- surface below ________ point 0 celsius
- forms in clear air, water vapour being converted directly into ice crystals forming a _____ ________ coating
- sometimes occurs on surface of the wings where _______ fuel tanks are fitted
hoar frost
- surface below FREEZING point 0 celsius
- forms in clear air, water vapour being converted directly into ice crystals forming a WHITE FEATHERY coating
- sometimes occurs on surface of the wings where INTEGRAL fuel tanks are fitted
de-icing and anti-icing
there are two basic methods of solving icing problems in aircraft:
- __-icing
- ____-icing
de-icing and anti-icing
there are two basic methods of solving icing problems in aircraft:
- DE-icing
- ANTI-icing
aerofoil ice protection
there are four primary methods used for aerofoil ice protection
- _______ - by ducting hot air along the inner surface of the aerofoil leading edges
- __________ - by fitting heater elements to the aerofoil leading edges
- _________ - the fitting of compressed air operated overshoes to the aerofoil leading edges. these pulsate and remove ice after it has formed
- _____ - by pumping a fluid having a low freezing point, from distributors fitted to the aerofoil leading edges
aerofoil ice protection
there are four primary methods used for aerofoil ice protection
- THERMAL - by ducting hot air along the inner surface of the aerofoil leading edges
- ELECTRICAL - by fitting heater elements to the aerofoil leading edges
- PNEUMATIC - the fitting of compressed air operated overshoes to the aerofoil leading edges. these pulsate and remove ice after it has formed
- FLUID - by pumping a fluid having a low freezing point, from distributors fitted to the aerofoil leading edges
thermal systems general
thermal anti icing uses heated air flowing through passages in the leading edges of wings, stabilisers and engine cowlings to prevent formation of ice. in modern aircraft the heated air is obtained from the turbine engine _____ ___ system.
air is distributed using perforated air ducting called _______ or spray tubing
thermal systems general
thermal anti icing uses heated air flowing through passages in the leading edges of wings, stabilisers and engine cowlings to prevent formation of ice. in modern aircraft the heated air is obtained from the turbine engine BLEED AIR system.
air is distributed using perforated air ducting called PICCOLO or spray tubing
thermal ice protection systems
the wing shut off valve is sprung loaded ____. it remains open until the tail de-icing _____ is actuated
approximately . minutes later, the timer relay automatically releases and shuts off the current to both valves. this causes the wing shut off valve to ____ and the tail shut off valve to _____
thermal ice protection systems
the wing shut off valve is sprung loaded OPEN. it remains open until the tail de-icing RELAY is actuated
approximately 2.5 minutes later, the timer relay automatically releases and shuts off the current to both valves. this causes the wing shut off valve to OPEN and the tail shut off valve to CLOSE
thermal ice protection systems
overheat switches close the anti ice valves if the air temperature in the ducts exceeds __ degrees during ground testing. in ______, the overheat circuit is not used
thermal ice protection systems
overheat switches close the anti ice valves if the air temperature in the ducts exceeds 90 degrees during ground testing. in FLIGHT, the overheat circuit is not used
duct maintenance
adequate safety precautions must be taken when inspecting duct sections under ________
duct maintenance
adequate safety precautions must be taken when inspecting duct sections under PRESSURE
electrical ice protection systems. general.
spray mats, also known as heater mats are available for both anti icing and de icing. anti-icing mats are supplied _____________ with electricity whilst de-icing mats are ______________ heated.
electrical ice protection systems. general.
spray mats, also known as heater mats are available for both anti icing and de icing. anti-icing mats are supplied CONTINUOUSLY with electricity whilst de-icing mats are INTERMITTENTLY heated.
electrical ice protection systems. general.
on intermittently heated sections, ____________ heated breaker strips are fitted between the intermittently heated areas. this ensures that the small areas of ice removed are small enough not to cause a hazard to the aircraft.
the power supplies normally used are ___V to ___V variable frequency AC for heating, and ___V AC and __V DC for control
electrical ice protection systems. general.
on intermittently heated sections, CONTINUOUSLY heated breaker strips are fitted between the intermittently heated areas. this ensures that the small areas of ice removed are small enough not to cause a hazard to the aircraft.
the power supplies normally used are 115V to 200V variable frequency AC for heating, and 115V AC and 28V DC for control
construction of heater mats
a typical heater mat consists of a ________ heater element sandwiched between layers of _____ _____ reinforced plastic
the outer layer of glass fibre is _______ than the inner layer
to protect the heater mat from rain or hail erosion and impact damage from runway debris, the heater mat is covered by an _______ _________ coating
construction of heater mats
a typical heater mat consists of a METALLIC heater element sandwiched between layers of GLASS FIBRE reinforced plastic
the outer layer of glass fibre is THINNER than the inner layer
to protect the heater mat from rain or hail erosion and impact damage from runway debris, the heater mat is covered by an EROSION RESISTANT coating
control and indication
the controller monitors a __________ sensor and keeps the leading edge and breaker strips at a _____________ temperature to prevent ice forming
the controllers monitor the system for proper _______ use, ___________ sensor function and minimum and maximum ____________. the system will switch off if an over temp is detected. the controller will illuminate an ____________ on the flight deck to alert the crew if there is a failure of the system
control and indication
the controller monitors a TEMPERATURE sensor and keeps the leading edge and breaker strips at a PREDETERMINED temperature to prevent ice forming
the controllers monitor the system for proper CURRENT use, TEMPERATURE sensor function and minimum and maximum TEMPERATURES. the system will switch off if an over temp is detected. the controller will illuminate an ANNUNCIATOR on the flight deck to alert the crew if there is a failure of the system
typical pneumatic de-icing system
- ______ tube inflates, cracking the ice
- _____ tubes inflate, lifting cracked ice, causing it to be blown off
typical pneumatic de-icing system
- CENTRE tube inflates, cracking the ice
- OUTER tubes inflate, lifting cracked ice, causing it to be blown off
pneumatic de icing system air supply
whenever the system is switched off, or at the end of an inflation stage, the de-icer boots are deflated by ______. the vacuum can be obtained from a ______ pump
in most _______ _______ types, vacuum is usually obtained from the venturi section of an _______ nozzle or ___ pump
pneumatic de icing system air supply
whenever the system is switched off, or at the end of an inflation stage, the de-icer boots are deflated by VACUUM. the vacuum can be obtained from a VACUUM pump
in most TURBINE POWERED types, vacuum is usually obtained from the venturi section of an EJECTOR nozzle or JET pump
deicer boot damage
irreparable damage is generally:
- cuts and tears longer than _.__” (19mm)
- cuts and tears which cross stitch lines or are within _.___” (3.2mm) of a stitch line
- ______ stitches
de-icer boots with irreparable damage must be _______
deicer boot damage
irreparable damage is generally:
- cuts and tears longer than 0.75” (19mm)
- cuts and tears which cross stitch lines or are within 0.125” (3.2mm) of a stitch line
- broken stitches
de-icer boots with irreparable damage must be REPLACED
testing a pneumatic de-icing system
- carried out at check periods specified in the ________ maintenance schedules
- carried out when a system ___________ occurs, major __________ is replaced or ______ to de-icer boot
- method of test depends on ___
testing a pneumatic de-icing system
- carried out at check periods specified in the APPROVED maintenance schedules
- carried out when a system MALFUNCTION occurs, major COMPONENT is replaced or REPAIR to de-icer boot
- method of test depends on AMM
testing a pneumatic de-icing system
depends on AMM but in general:
- tested using engine _____ ___ or using ______ ____ trolley
- ________ and ______ indicators should be checked to ensure that supplies are maintained at the specified values
- with system on, boots should _______ and _______ in correct _________ and for correct ____. pressure gauge should _________ accordingly
- if inflation or deflation is ________, may be caused by _________ in system or sticking ________ valves
- with system off, boots should _______ completely and lie flat against the leading edge of aerofoil
testing a pneumatic de-icing system
depends on AMM but in general:
- tested using engine BLEED AIR or using GROUND TEST trolley
- PRESSURE and VACUUM indicators should be checked to ensure that supplies are maintained at the specified values
- with system on, boots should INFLATE and DEFLATE in correct SEQUENCE and for correct TIME. pressure gauge should FLUCTUATE accordingly
- if inflation or deflation is SLUGGISH, may be caused by OBSTRUCTION in system or sticking SOLENOID valves
- with system off, boots should DEFLATE completely and lie flat against the leading edge of aerofoil
fluid ice protection systems. anti icing system
in the anti-icing mode a ___________ film of fluid is pumped continuously from the panels and prevents the formation of ice. this requires the aircraft to carry a large quantity of _____ which is _____ and could reduce the _______
fluid ice protection systems. anti icing system
in the anti-icing mode a PROTECTIVE film of fluid is pumped continuously from the panels and prevents the formation of ice. this requires the aircraft to carry a large quantity of FLUID which is HEAVY and could reduce the PAYLOAD
fluid ice protection systems. de icing system
in the deicing mode a certain amount of ice is _______ to form on the leading edges before the system is switched on. the glycol __________ breaks the ice adhering to the leading edges. the ice is then carried away by the ___ ____
fluid ice protection systems. de icing system
in the deicing mode a certain amount of ice is ALLOWED to form on the leading edges before the system is switched on. the glycol CHEMICALLY breaks the ice adhering to the leading edges. the ice is then carried away by the AIR FLOW
fluid ice protection system example.
the __________ (panel) is installed _____ with the aerofoil leading edge so there is no ___________ penalty on the aircraft when compared with pneumatic boots
fluid ice protection system example.
the DISTRIBUTOR (panel) is installed FLUSH with the aerofoil leading edge so there is no AERODYNAMIC penalty on the aircraft when compared with pneumatic boots
fluid ice protection system example. system operation.
in this example, ___ pumps are used. both are used for initial _______. after three minutes of operation, one stops and the other supplies the complete system. either pump can supply the system should the other fail. in ______ icing conditions ____ pumps can be operated at the same time to provide a ____ degree of protection. each pump is fitted with a ___-______ valve which prevents _______ flow during _____ feed operation
the liquid, pressurised to __psi is delivered through two _____ tubes, one feeding the wing ____________ unit and the other the tailplane proportioning unit. the proportioning units supply the leading edges. each line supplying the proportioning units incorporates a ______
fluid ice protection system example. system operation.
in this example, TWO pumps are used. both are used for initial PRIMING. after three minutes of operation, one stops and the other supplies the complete system. either pump can supply the system should the other fail. in SEVERE icing conditions BOTH pumps can be operated at the same time to provide a HIGH degree of protection. each pump is fitted with a NON-RETURN valve which prevents REVERSE flow during CROSS feed operation
the liquid, pressurised to 50psi is delivered through two NYLON tubes, one feeding the wing PROPORTIONING unit and the other the tailplane proportioning unit. the proportioning units supply the leading edges. each line supplying the proportioning units incorporates a FILTER
fluid ice protection system. distributer
- connector contains ________ tube which is accurately __________ to provide the required rate of fluid flow through the distributer
- metering of fluid to panel is done using ____________ units, these contain the appropriate number of metering tubes
- to prevent __________ corrosion, ______ sealing strips are fitted between stainless steel distributer panel and aerofoil structure. in some installations, ______ resin sealing compound is used
- to make panel removal easier, edges sprayed with thin coat of ____ to act as release agent. PTFE tape may be used in addition to this
fluid ice protection system. distributer
- connector contains METERING tube which is accurately CALIBRATED to provide the required rate of fluid flow through the distributer
- metering of fluid to panel is done using PROPORTIONING units, these contain the appropriate number of metering tubes
- to prevent ELECTROLYTIC corrosion, PLASTIC sealing strips are fitted between stainless steel distributer panel and aerofoil structure. in some installations, EPOXY resin sealing compound is used
- to make panel removal easier, edges sprayed with thin coat of PTFE to act as release agent. PTFE tape may be used in addition to this
fluid ice protection system. control and indication
the system may be switched on before take off. if icing is likely during the flight, it is recommended that the system is maintained fully primed by running the pump for approximately __ seconds every __ minutes
fluid ice protection system. control and indication
the system may be switched on before take off. if icing is likely during the flight, it is recommended that the system is maintained fully primed by running the pump for approximately 30 seconds every 90 minutes
fluid ice protection system maintenance.
after a distributer panel has been installed, a check should be made to ensure that a ______ and __________ profile is maintained both _____ wise and ____ wise. a test flight must be carried out to check the _____ characteristics of the aircraft
fluid ice protection system maintenance.
after a distributer panel has been installed, a check should be made to ensure that a SMOOTH and CONTINUOUS profile is maintained both CHORD wise and SPAN wise. a test flight must be carried out to check the STALL characteristics of the aircraft
fluid ice protection system. control and indication
the system may be switched on before take off. if icing is likely during the flight, it is recommended that the system is maintained fully primed by running the pump for approximately __ seconds every __ minutes
fluid ice protection system. control and indication
the system may be switched on before take off. if icing is likely during the flight, it is recommended that the system is maintained fully primed by running the pump for approximately 30 seconds every 90 minutes
fluid ice protection system maintenance.
after a distributer panel has been installed, a check should be made to ensure that a ______ and __________ profile is maintained both _____ wise and ____ wise. a test flight must be carried out to check the _____ characteristics of the aircraft
fluid ice protection system maintenance.
after a distributer panel has been installed, a check should be made to ensure that a SMOOTH and CONTINUOUS profile is maintained both CHORD wise and SPAN wise. a test flight must be carried out to check the STALL characteristics of the aircraft
ice detectors. serrated rotor ice detector head
under __ icing conditions there is no _________ torque and the switch contacts remain open. in icing conditions, ice builds up on the rotor and is shaved off by the rotor. this causes the switch contacts to _____, illuminating a warning _____ in the control cabin. once icing conditions cease, the knife edge cutter will no longer shave ice.
the torque loading will reduce and allow the motor to return to its normal position. this opens the witch contacts and switches ___ the warning light in the control cabin
ice detectors. serrated rotor ice detector head
under NO icing conditions there is no OPPOSING torque and the switch contacts remain open. in icing conditions, ice builds up on the rotor and is shaved off by the rotor. this causes the switch contacts to CLOSE, illuminating a warning LIGHT in the control cabin. once icing conditions cease, the knife edge cutter will no longer shave ice.
the torque loading will reduce and allow the motor to return to its normal position. this opens the witch contacts and switches OFF the warning light in the control cabin
windshield anti-icing. construction of windshields
windshield heating is provided for ____-_____ purposes. however, heating the _____ interlayer makes the windows more _________, and better able to withstand possible _________ with birds
windshield anti-icing. construction of windshields
windshield heating is provided for ANTI-ICING purposes. however, heating the VINYL interlayer makes the windows more RESILIENT, and better able to withstand possible COLLISION with birds
windshield anti-icing. control and indication.
when the control circuit is switched on, electrical power is supplied to the windows but takes from _ to _ minutes to reach maximum value. this gradual build up is to prevent a _______ shock to the window which may cause it to fail
windshield anti-icing. control and indication.
when the control circuit is switched on, electrical power is supplied to the windows but takes from 2 to 4 minutes to reach maximum value. this gradual build up is to prevent a THERMAL shock to the window which may cause it to fail
windshield anti-icing. control and indication
___ sensing elements for automatic temperature control are provided. only ___ of the control elements is used, the other serves as a spare
windshields are often fitted with an additional __________ sensing element which takes over the function of the normal sensing element, if it should fail. the temperature is now controlled at a _______ temperature e.g. 55 celsius
the transformers used with window heat systems are often provided with a range of ________ tappings to enable different voltages to be connected to the windows. as the windows age, the __________ of the heating element alters (usually increases)
windshield anti-icing. control and indication
TWO sensing elements for automatic temperature control are provided. only ONE of the control elements is used, the other serves as a spare
windshields are often fitted with an additional OVERHEAT sensing element which takes over the function of the normal sensing element, if it should fail. the temperature is now controlled at a HIGHER temperature e.g. 55 celsius
the transformers used with window heat systems are often provided with a range of VOLTAGE tappings to enable different voltages to be connected to the windows. as the windows age, the RESISTANCE of the heating element alters (usually increases)
windshield anti-icing maintenance.
arcing is the flow of electricity between two points where there is a break in the _______. arcing usually occurs near the window ___-____. the heat from the arcing causes ______ or _____ marks in the interlayer and/or _________ in the windshield
windshield anti-icing maintenance.
arcing is the flow of electricity between two points where there is a break in the CIRCUIT. arcing usually occurs near the window BUS-BARS. the heat from the arcing causes BROWN or BLACK marks in the interlayer and/or CRACKING in the windshield
rain protection. pneumatic rain removal system.
windshield wipers tend to be inefficient for two reasons:
- the tendency of the airflow to reduce the wiper blade ________ on the window, causing ineffective wiping or streaking
- the difficulty in achieving ____ enough wiper action to clear the water during heavy rain falls
as a result, most wiper systems do not provide satisfactory vision in ______ rain
rain protection. pneumatic rain removal system.
windshield wipers tend to be inefficient for two reasons:
- the tendency of the airflow to reduce the wiper blade PRESSURE on the window, causing ineffective wiping or streaking
- the difficulty in achieving FAST enough wiper action to clear the water during heavy rain falls
as a result, most wiper systems do not provide satisfactory vision in HEAVY rain
rain protection. pneumatic rain removal system.
the pneumatic rain removal system uses high ________, high __________ engine compressor bleed air which is blown across the windshields. the air blast forms a ________ that prevents raindrops from striking the windshield surface
rain protection. pneumatic rain removal system.
the pneumatic rain removal system uses high PRESSURE, high TEMPERATURE engine compressor bleed air which is blown across the windshields. the air blast forms a BARRIER that prevents raindrops from striking the windshield surface
rain protection. hydrophobic coating
this is a rain __________ coating applied to the glass during manufacture. the raindrops maintain their _______ form and ___ easily off the glass without the need for windshield wipers
rain protection. hydrophobic coating
this is a rain REPELLANT coating applied to the glass during manufacture. the raindrops maintain their BEADED form and RUN easily off the glass without the need for windshield wipers
rain protection. typical rain repellant system.
the rain repellant is applied by __________ either the captains or copilots operating switch. when a switch is depressed, a _________ operated valve controlled by a ____ _____ circuit opens. this permits approximately _cc of _________ fluid to squirt onto the selected windshield. the switch must then be released to allow the time delay circuit to _____ before another ______ can be obtained.
rain protection. typical rain repellant system.
the rain repellant is applied by DEPRESSING either the captains or copilots operating switch. when a switch is depressed, a SOLENOID operated valve controlled by a TIME DELAY circuit opens. this permits approximately 5cc of REPELLANT fluid to squirt onto the selected windshield. the switch must then be released to allow the time delay circuit to RESET before another SQUIRT can be obtained.
rain protection. typical rain repellant system.
if the rain repellant is inadvertently applied to a dry windshield, the wipers must ___ be operated. the repellent must be washed off with ______, otherwise it will dry within a few hours.
rain protection. typical rain repellant system.
if the rain repellant is inadvertently applied to a dry windshield, the wipers must NOT be operated. the repellent must be washed off with WATER, otherwise it will dry within a few hours.
rain protection. maintenance.
blade tension onto the screen should be checked with an accurate _____ balance. the spring balance is attached to the end of the wiper arm where the _____ is attached. the force required is usually about __lbs. the force can be adjusted where necessary on the _____ _______ bolt
rain protection. maintenance.
blade tension onto the screen should be checked with an accurate SPRING balance. the spring balance is attached to the end of the wiper arm where the BLADE is attached. the force required is usually about 10lbs. the force can be adjusted where necessary on the BLADE TENSION bolt
probes, sensors and drain heating. waste water drain mast anti-icing.
the mast heater elements use ___V AC during flight. during each ______ operation the power supply changes to __V DC to provide low heat to prevent __________ of the element. changeover of the power supply is via the ______ __ ______ ___ sensing element.
probes, sensors and drain heating. waste water drain mast anti-icing.
the mast heater elements use 115V AC during flight. during each GROUND operation the power supply changes to 28V DC to provide low heat to prevent OVERHEATING of the element. changeover of the power supply is via the WEIGHT ON WEIGHT OFF sensing element.
engine thermal ice protection. control and indication
normally, engine intake icing can be expected at temperatures of +_ celsius to +__ celsius, with visible ________ present
engine thermal ice protection. control and indication
normally, engine intake icing can be expected at temperatures of +8 celsius to +10 celsius, with visible MOISTURE present
engine ice protection. electrical system.
when the system is in operation, the ___________ heated areas prevent ice formation, but the __________ heated areas allow ice to form during the ‘heat-off’ period. during the ‘heat on’ period, ________ of the ice is broken and it is then blown off. the cycling time of the intermittently heated elements is designed to ensure that the engine can accept the amount of ice that collects during the ‘____ ___’ period and yet ensure that the ‘____ __’ period is long enough to give adequate removal, without causing any ___-____ icing to occur behind the heated areas.
engine ice protection. electrical system.
when the system is in operation, the CONTINUOUSLY heated areas prevent ice formation, but the INTERMITTENTLY heated areas allow ice to form during the ‘heat-off’ period. during the ‘heat on’ period, ADHESION of the ice is broken and it is then blown off. the cycling time of the intermittently heated elements is designed to ensure that the engine can accept the amount of ice that collects during the ‘HEAT OFF’ period and yet ensure that the ‘HEAT ON’ period is long enough to give adequate removal, without causing any RUN-BACK icing to occur behind the heated areas.
engine ice protection. control and indication.
when the push switch is in the __ postion, the engine ice protection system comes into operation when the _____ ___ __________ (TAT) is below 5 celsius
engine ice protection. control and indication.
when the push switch is in the ON postion, the engine ice protection system comes into operation when the TOTAL AIR TEMPERATURE (TAT) is below 5 celsius
engine ice protection. control and indication.
the system stops operating when any of the following conditions apply:
- system switched ___
- TAT air temperature above _ celsius
- propeller RPM below ___
- timer control _______
engine ice protection. control and indication.
the system stops operating when any of the following conditions apply:
- system switched OFF
- TAT air temperature above 7 celsius
- propeller RPM below 600
- timer control FAILURE
engine ice protection. control and indication.
temperature sensors control the temperature of the continuously heated mats between __ and __ celsius. the cyclic heating of the other heater mats is controlled by a _____ timer and ______ unit
engine ice protection. control and indication.
temperature sensors control the temperature of the continuously heated mats between 50 and 70 celsius. the cyclic heating of the other heater mats is controlled by a CYCLIC timer and CONTROL unit
