The hydraulic device which functionality is comparable to an electronic diode is a ?
Assessment > Aerodrome
Source: Telepilote theorique examen 19
Hydraulic fluid entering the hydraulic pump is slightly pressurised to ?
In the hydraulic press schematically shown what balancing Force would be acting on the right hand side The diagram is not to scale 824 ?
Assuming an accumulator pre charged with air to 1000 psi and hydraulic system pressurised to 1500 psi accumulator gauge will read Prevent cavitation in pump. Part of an accumulator's job to store energy in form of hydraulic fluid under pressure that can be used short time if main system fails or needs help at peak times pressure gauges installed in hydraulic pneumatic systems are used to indicate existing hydraulic pneumatic pressures the accumulator gauge will read 1500 psi if main system fails it will read 1000 psi. 
Internal leakage in a hydraulic system will cause An increased fluid temperature. As there internal leakage hyd pump will cycle on off (depending on pump type) to maintain system pressure increasing friction with pump fluid thus increasing fluid temp. 
On large aeroplanes equipped with power brakes main source of power derived from The aeroplane's hydraulic system. As there internal leakage hyd pump will cycle on off (depending on pump type) to maintain system pressure increasing friction with pump fluid thus increasing fluid temp. 
When powering up a hydraulic system level in reservoir will The aeroplane's hydraulic system. The air occupies space that would otherwise be occupied hydraulic fluid thus when hydraulic system becomes pressurized some fluids flows into different pipes. Question 19-8
An accumulator in a hydraulic system will Store fluid under pressure. The air occupies space that would otherwise be occupied hydraulic fluid thus when hydraulic system becomes pressurized some fluids flows into different pipes. Question 19-9
In typical hydraulic system represented in graphic assuming hydraulic pressure throughout and no internal leakage 825 A condition of hydraulic lock exists no movement of piston will take place. a condition of hydraulic lock exists no movement of piston will take place. Question 19-10
A hydraulic shuttle valve Enables an alternate supply to operate an actuator. the shuttle valve sometimes fluid must come from more than one source to meet demands of a complex system at other times an emergency system might be needed to provide pressure if normal system fails (the emergency system will usually only actuate essential components) the shuttle valve can isolate normal system from an alternate or emergency one a typical shuttle valve contains three ports normal system inlet alternate system inlet an outlet inside shuttle valve there a sliding part predictably called shuttle whose purpose to seal off an inlet port which itself will contain a shuttle seat when a shuttle valve in its normal position fluid can flow freely from normal system inlet port to actuating unit the shuttle seated against alternate system inlet port held there normal system pressure where it remains until alternate system activated fluid under pressure then directed from alternate system to shuttle valve forcing shuttle to seal off normal inlet port fluid from alternate system then has a free flow to outlet port. Question 19-11
To protect against excessive system pressure a hydraulic system usually incorporates A high pressure relief valve. The pressure relief valve there to dump fluid back to reservoir when pressure in system gets too high as it will do when system not being used the engine driven pump working all time . Question 19-12
The ram air turbine rat provides emergency hydraulic power Flight controls in event of loss of engine driven hydraulic power. a ram air turbine (rat) a small turbine that connected to a hydraulic pump or electrical generator installed in an aircraft used as a power source the rat generates power from airstream due to speed of aircraft. Question 19-13
A hydraulic low pressure alert the first indication of The pump output pressure being insufficient. The pressure transmitter located at pump output. Question 19-14
For an aeroplane hydraulic supply circuit correct statement The accumulators constitute a reserve of hydraulic fluid maintained under pressure a pneumatic back pressure (air or nitrogen). The pressure transmitter located at pump output. Question 19-15
The reservoirs of a hydraulic system can be pressurized By bleed air from engine. The pressure transmitter located at pump output. Question 19-16
A pressure regulator used in a hydraulic system In conjunction with a constant delivery type pump. A constant delivery pump forces a fixed or unvarying quantity of fluid through outlet port during each revolution of pump the pressure regulator unloads or relieves power driven pump when desired pressure in system reached thus it often referred to as an unloading valve when a constant delivery type pump being operated pressure in line between pump selector valve builds up to a desired point a valve in pressure regulator automatically opens fluid bypassed back to reservoir. Question 19-17
Filters in hydraulic systems often incorporate pop out indicators to Warn of an impending by pass situation. Filters are necessary in hydraulic systems filtering out contamination debris a filter may include a filter bypass provision a filter bypass allows fluid to flow around (bypass) filter when pressure across filter high (i e filter clogged) a bypass functions similar to a priority valve where pressure overcomes a spring when pressure sufficiently high. Question 19-18
Maximum power output and low mass of aeroplane hydraulic systems can be achieved with High system pressure low volume flow. Filters are necessary in hydraulic systems filtering out contamination debris a filter may include a filter bypass provision a filter bypass allows fluid to flow around (bypass) filter when pressure across filter high (i e filter clogged) a bypass functions similar to a priority valve where pressure overcomes a spring when pressure sufficiently high. Question 19-19
Parameters to monitor a hydraulic system in cockpit can be Pressure fluid temperature quantity. Filters are necessary in hydraulic systems filtering out contamination debris a filter may include a filter bypass provision a filter bypass allows fluid to flow around (bypass) filter when pressure across filter high (i e filter clogged) a bypass functions similar to a priority valve where pressure overcomes a spring when pressure sufficiently high. Question 19-20
The purpose of an accumulator in a hydraulic system To damp fluid pressure variations. Filters are necessary in hydraulic systems filtering out contamination debris a filter may include a filter bypass provision a filter bypass allows fluid to flow around (bypass) filter when pressure across filter high (i e filter clogged) a bypass functions similar to a priority valve where pressure overcomes a spring when pressure sufficiently high. Question 19-21
The viscosity of a hydraulic fluid should be The lowest to minimize power consumption resistance to flow. The viscosity must be as low as possible to limit power required the operation of system reducing resistance of flow. Question 19-22
The hydraulic systems which works correctly shown in figure 831 The lowest to minimize power consumption resistance to flow. The non return valve (the directional arrow) after pumps are unidirectional flow devices used primarily in hydraulic systems to eliminate potential damage caused fluid back pressure diagram n°2 the only one correct. Question 19-23
One of functions of an accumulator in a hydraulic system To damp pressure surges in system. The function of accumulator in hydraulic system to receive store excess oil pumped through system which used to compensate sudden increase in loads. Question 19-24
In a hydraulic system overheat detectors are mostly installed To damp pressure surges in system. The overheat detector fitted at pump to give indication of possible pump failure (t) the temperature probe location (q) quantity (p) pressure the electric motor driven pumps do a large part of work to produce flow the hydraulic system harder they work hotter they get the engine driven pumps are not fitted with an overheat detector since engines already have overheat fire detection systems. Question 19-25
Which of these statements about an aeroplane's hydraulic system correct The filters pressure relief valve(s) by pass valve(s) the fire shut off valve are safety features installed in system. The overheat detector fitted at pump to give indication of possible pump failure (t) the temperature probe location (q) quantity (p) pressure the electric motor driven pumps do a large part of work to produce flow the hydraulic system harder they work hotter they get the engine driven pumps are not fitted with an overheat detector since engines already have overheat fire detection systems. Question 19-26
The level in a hydraulic reservoir will Fluctuate with accumulator pressure. The overheat detector fitted at pump to give indication of possible pump failure (t) the temperature probe location (q) quantity (p) pressure the electric motor driven pumps do a large part of work to produce flow the hydraulic system harder they work hotter they get the engine driven pumps are not fitted with an overheat detector since engines already have overheat fire detection systems. Question 19-27
Purposes of an accumulator in an hydraulic system are 1 to damp pressure fluctuations 2 to cool hydraulic fluid 3 to serve as a limited alternate source of pressure 4 to serve as a main pressure source normal operation the combination that regroups all of correct statements Fluctuate with accumulator pressure. The overheat detector fitted at pump to give indication of possible pump failure (t) the temperature probe location (q) quantity (p) pressure the electric motor driven pumps do a large part of work to produce flow the hydraulic system harder they work hotter they get the engine driven pumps are not fitted with an overheat detector since engines already have overheat fire detection systems. Question 19-28
The purpose of an accumulator in an hydraulic system to Fluctuate with accumulator pressure. The overheat detector fitted at pump to give indication of possible pump failure (t) the temperature probe location (q) quantity (p) pressure the electric motor driven pumps do a large part of work to produce flow the hydraulic system harder they work hotter they get the engine driven pumps are not fitted with an overheat detector since engines already have overheat fire detection systems. Question 19-29
The type of hydraulic fluid which has greatest resistance to cavitation Fluctuate with accumulator pressure. cavitation occurs when a liquid moves within tubing or pipes at very fast speeds causing absolute pressure of liquid to drop drastically this process occurs with little loss of heat if absolute pressure drops below vapour pressure of liquid cavitation will form this phenomenon more serious in viscous liquids than in thin liquids cavitation causes separation of gases that are within liquid (such as air or water vapour) from liquid itself bubbles would form then collapse in case of a liquid entering suction side of a pump pressure would be low for liquid to move from one place to another it would have to expend energy thus causing a further decrease in pressure the hydraulic fluid used will be synthetic because of high temperatures involved the lesser risk of cavitation compared other fluids (mineral oil or vegetable oil based fluids). Question 19-30
Filtration in a hydraulic system usually ensured Filters in both pressure return lines. cavitation occurs when a liquid moves within tubing or pipes at very fast speeds causing absolute pressure of liquid to drop drastically this process occurs with little loss of heat if absolute pressure drops below vapour pressure of liquid cavitation will form this phenomenon more serious in viscous liquids than in thin liquids cavitation causes separation of gases that are within liquid (such as air or water vapour) from liquid itself bubbles would form then collapse in case of a liquid entering suction side of a pump pressure would be low for liquid to move from one place to another it would have to expend energy thus causing a further decrease in pressure the hydraulic fluid used will be synthetic because of high temperatures involved the lesser risk of cavitation compared other fluids (mineral oil or vegetable oil based fluids). Question 19-31
The relationship between pressure force and area Force = pressure x area. cavitation occurs when a liquid moves within tubing or pipes at very fast speeds causing absolute pressure of liquid to drop drastically this process occurs with little loss of heat if absolute pressure drops below vapour pressure of liquid cavitation will form this phenomenon more serious in viscous liquids than in thin liquids cavitation causes separation of gases that are within liquid (such as air or water vapour) from liquid itself bubbles would form then collapse in case of a liquid entering suction side of a pump pressure would be low for liquid to move from one place to another it would have to expend energy thus causing a further decrease in pressure the hydraulic fluid used will be synthetic because of high temperatures involved the lesser risk of cavitation compared other fluids (mineral oil or vegetable oil based fluids). Question 19-32
In a commercial transport aeroplane landing gear normal operating system usually Hydraulically driven. cavitation occurs when a liquid moves within tubing or pipes at very fast speeds causing absolute pressure of liquid to drop drastically this process occurs with little loss of heat if absolute pressure drops below vapour pressure of liquid cavitation will form this phenomenon more serious in viscous liquids than in thin liquids cavitation causes separation of gases that are within liquid (such as air or water vapour) from liquid itself bubbles would form then collapse in case of a liquid entering suction side of a pump pressure would be low for liquid to move from one place to another it would have to expend energy thus causing a further decrease in pressure the hydraulic fluid used will be synthetic because of high temperatures involved the lesser risk of cavitation compared other fluids (mineral oil or vegetable oil based fluids). Question 19-33
Generally on modern jet transport aircraft how can landing gear be extended if there a complete hydraulic system failure Hydraulically driven. cavitation occurs when a liquid moves within tubing or pipes at very fast speeds causing absolute pressure of liquid to drop drastically this process occurs with little loss of heat if absolute pressure drops below vapour pressure of liquid cavitation will form this phenomenon more serious in viscous liquids than in thin liquids cavitation causes separation of gases that are within liquid (such as air or water vapour) from liquid itself bubbles would form then collapse in case of a liquid entering suction side of a pump pressure would be low for liquid to move from one place to another it would have to expend energy thus causing a further decrease in pressure the hydraulic fluid used will be synthetic because of high temperatures involved the lesser risk of cavitation compared other fluids (mineral oil or vegetable oil based fluids). Question 19-34
The type of brake unit found on most transport aeroplanes a Hydraulically driven. cavitation occurs when a liquid moves within tubing or pipes at very fast speeds causing absolute pressure of liquid to drop drastically this process occurs with little loss of heat if absolute pressure drops below vapour pressure of liquid cavitation will form this phenomenon more serious in viscous liquids than in thin liquids cavitation causes separation of gases that are within liquid (such as air or water vapour) from liquid itself bubbles would form then collapse in case of a liquid entering suction side of a pump pressure would be low for liquid to move from one place to another it would have to expend energy thus causing a further decrease in pressure the hydraulic fluid used will be synthetic because of high temperatures involved the lesser risk of cavitation compared other fluids (mineral oil or vegetable oil based fluids). Question 19-35
The reason fitting thermal plugs to aeroplane wheels that they Release air from tyre in event of overheating. Tyres are fitted with thermal plug to release air from tyre in event of overheating after a landing (or a rejected take off) with overweight overspeed conditions tyres brakes are extremely hot thermal plug can malfunction on video you can see a tyre explosion . Question 19-36
Thermal plugs are installed in Release air from tyre in event of overheating. Tyres are fitted with thermal plug to release air from tyre in event of overheating after a landing (or a rejected take off) with overweight overspeed conditions tyres brakes are extremely hot thermal plug can malfunction on video you can see a tyre explosion . Question 19-37
In a hydraulic braking system an accumulator pre charged to 1200 psi if an electrically driven hydraulic pump started and provides a system pressure of 3000 psi pressure gauge which connected to gas section of accumulator will read Release air from tyre in event of overheating. The question states the pressure gauge connected to gas section of accumulator thus if electrically driven hydraulic pump started provides a system pressure of 3000 psi you will read a pressure of 3000 psi. Question 19-38
The modern anti skid processes are based on use of a computer whose input data 1 idle wheel speed measured 2 braked wheel speed measured 3 brake temperature measured 4 desired idle wheel train slipping rate5 tire pressurethe combination regrouping all correct statements Release air from tyre in event of overheating. 3 steps during landing roll 1) if wheels are not braked at all they all follow kinematics that is speed of airplane (and wheel radius of course) directly determine their angular speed deceleration if we would use only spoilers thrust reversers we would have pure kinematic deceleration of wheels hence no slipping (of course we presume that runway surface conditions are ideal) in this case all wheels are on their 'idle' speed all time in sense that they are not being braked externally the brakes they just 'naturally' decelerate together with airplane idling all time 2) but if brakes are applied during landing roll that means that at first moment none of wheels idle any more! now they are not just decelerating with airplane they are having an additional deceleration from brakes being applied on them that means that there some small physical slipping at contact area of tire the runway surface 3) now computer monitors situation has those braked wheels speed input now let's say simplicity that one of wheel some reason gains such a high angular deceleration which would soon lead to blockage (zero angular speed) of that wheel computer prevents that commanding servo on that wheel to reduce brakes on that particular wheel from that moment on that particular wheel idling at desired wheel train slipping rate. Question 19-39
When a landing gear wheel hydroplaning its friction factor around Release air from tyre in event of overheating. 3 steps during landing roll 1) if wheels are not braked at all they all follow kinematics that is speed of airplane (and wheel radius of course) directly determine their angular speed deceleration if we would use only spoilers thrust reversers we would have pure kinematic deceleration of wheels hence no slipping (of course we presume that runway surface conditions are ideal) in this case all wheels are on their 'idle' speed all time in sense that they are not being braked externally the brakes they just 'naturally' decelerate together with airplane idling all time 2) but if brakes are applied during landing roll that means that at first moment none of wheels idle any more! now they are not just decelerating with airplane they are having an additional deceleration from brakes being applied on them that means that there some small physical slipping at contact area of tire the runway surface 3) now computer monitors situation has those braked wheels speed input now let's say simplicity that one of wheel some reason gains such a high angular deceleration which would soon lead to blockage (zero angular speed) of that wheel computer prevents that commanding servo on that wheel to reduce brakes on that particular wheel from that moment on that particular wheel idling at desired wheel train slipping rate. Question 19-40
From following fuselage profile sort them from worst to best one concerning pressurization 818 Release air from tyre in event of overheating. N°1 clearly weakest would only be used on an unpressurised aircraft (twin otter example) n°2 geometrically strongest from a pressurisation point of view as hoop stresses can be uniform on whole cross section n°3 'double bubble' type where two circles intersect connected via a floor not best choice but clearly better than n°4 n°4 pressurization constraints will not be optimal on an oval format this question also exists with statement 'from following fuselage profile sort them from worst to best one concerning pressurization ' answer 1 4 3 2.
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