The component that converts hydraulic pressure into linear motion is called ?
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The hydraulic device which functionality is comparable to an electronic diode is a ?
Hydraulic fluid entering the hydraulic pump is slightly pressurised to ?
In hydraulic press schematically shown what balancing force would be acting on right hand side the diagram 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 5 psi, 25 psi,psi, 5 psi. 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, a decreased fluid temperature, an increased fluid pressure, fluid loss. 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, master cylinders, brake actuators, pressure to rudder pedals. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 8
When powering up a hydraulic system level in reservoir will Decrease slightly, always remain same, initially increase with system pressurisation, increase as ambient temperature decreases. The air occupies space that would otherwise be occupied hydraulic fluid, thus when hydraulic system becomes pressurized some fluids flows into different pipes. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 9
An accumulator in a hydraulic system will Store fluid under pressure, increase pressure surges within system, reduce fluid temperature pressure, reduce fluid temperature only. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 10
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, piston free to move in response to external forces since pressures are equal, piston moves to left due to pressure acting on differential areas, piston moves to right due to equal pressure acting on differential areas. a condition of hydraulic lock exists no movement of piston will take place. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 11
A hydraulic shuttle valve Enables an alternate supply to operate an actuator, a non return valve, allows two units to be operated one pressure source, regulates pump delivery pressure. 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 Landing Gear, Wheels, Tyres, Brakes 19 Answer 12
To protect against excessive system pressure a hydraulic system usually incorporates A high pressure relief valve, a standby hydraulic pump, an accumulator, auxiliary hydraulic motors. 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 Landing Gear, Wheels, Tyres, Brakes 19 Answer 13
The ram air turbine rat provides emergency hydraulic power Flight controls in event of loss of engine driven hydraulic power, nose wheel steering after aeroplane has landed, undercarriage selection automatic brake system, flap extension only. 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 Landing Gear, Wheels, Tyres, Brakes 19 Answer 14
A hydraulic low pressure alert the first indication of The pump output pressure being insufficient, reservoir level being at a minimum acceptable level, a leak in reservoir return line, hydraulic system accumulator becoming deflated. The pressure transmitter located at pump output. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 15
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), pumps are always electric due to high pressures which they must deliver ( 4to 2 kg/cm²), regulation system deals only with emergency operation is not applied to all hydraulic services but only those considered as essential, security components comprise filters, pressure relief valves, by passes, the fire shut off valve. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 16
The reservoirs of a hydraulic system can be pressurized By bleed air from engine, in flight only, the air conditioning system, an auxiliary system. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 17
A pressure regulator used in a hydraulic system In conjunction with a constant delivery type pump, in conjunction with a variable delivery type pump, to ensure that an equal pressure flow delivered to critical components such as servo actuators, as an interface between system the cockpit indicators. 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 Landing Gear, Wheels, Tyres, Brakes 19 Answer 18
Filters in hydraulic systems often incorporate pop out indicators to Warn of an impending by pass situation, indicate that filter clogged unfiltered oil passing around system, warn of a hydraulic system overheat, indicate that filter due maintenance. 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 Landing Gear, Wheels, Tyres, Brakes 19 Answer 19
Maximum power output and low mass of aeroplane hydraulic systems can be achieved with High system pressure low volume flow, medium system pressure low volume flow, medium system pressure high volume flow, low system pressure high volume flow. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 20
Parameters to monitor a hydraulic system in cockpit can be Pressure, fluid temperature quantity, pressure hydraulic pump output, pressure fluid viscosity, pressure rpm of hydraulic pump. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 21
The purpose of an accumulator in a hydraulic system To damp fluid pressure variations, to eliminate fluid flow variations, to bypass pumps in hydraulic system, to enable starting of some devices. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 22
The viscosity of a hydraulic fluid should be The lowest to minimize power consumption resistance to flow, the lowest to provide excellent lubrication properties, the highest to minimize power consumption resistance to flow, the highest to provide excellent lubrication properties. The viscosity must be as low as possible to limit power required the operation of system, reducing resistance of flow. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 23
The hydraulic systems which works correctly shown in figure 831 N°2, n°4, n°3, n°. 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 Landing Gear, Wheels, Tyres, Brakes 19 Answer 24
One of functions of an accumulator in a hydraulic system To damp pressure surges in system, to store fluid, to increase flow, to act as a pressure relief valve. The function of accumulator in hydraulic system to receive store excess oil pumped through system, which used to compensate sudden increase in loads. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 25
In a hydraulic system overheat detectors are mostly installed At pumps, in reservoirs, at actuators, at coolers. 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 Landing Gear, Wheels, Tyres, Brakes 19 Answer 26
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 pumps are always electrically driven because they need to deliver a high pressure of 3psi, a hydraulic leak in a return line does not affect functioning of hydraulic system, the hydraulic reservoir contains a membrane is pressurised nitrogen on one side of this membrane. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 27
The level in a hydraulic reservoir will Fluctuate with accumulator pressure, always remain same, initially increase with system pressurisation, increase as ambient temperature decreases. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 28
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 , 3, 2, 4,, 4, 2, 3. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 29
The purpose of an accumulator in an hydraulic system to Store energy, store fluid, cool fluid, store pressure. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 30
The type of hydraulic fluid which has greatest resistance to cavitation Synthetic fluid, mineral oil based fluid, vegetable oil based fluid (caster oil), water glycol based fluid. 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 Landing Gear, Wheels, Tyres, Brakes 19 Answer 31
Filtration in a hydraulic system usually ensured Filters in both pressure return lines, a filter in pressure line only, a filter on return line only, the use of sealed containers only during replenishment. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 32
The relationship between pressure force and area Force = pressure x area, pressure = force x area, pressure = area x distance, force = volume / area Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 33
In a commercial transport aeroplane landing gear normal operating system usually Hydraulically driven, electrically driven, mechanically driven, pneumatically driven. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 34
Generally on modern jet transport aircraft how can landing gear be extended if there a complete hydraulic system failure Mechanically, electrically, by hydraulic accumulators, pneumatically. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 35
The type of brake unit found on most transport aeroplanes a Multiple disk brake, belt brake, drum type brake, single disk brake. Question Landing Gear, Wheels, Tyres, Brakes 19 Answer 36
The reason fitting thermal plugs to aeroplane wheels that they Release air from tyre in event of overheating, prevent brakes from overheating, prevent heat transfer from brake disks to tyres, release air from tyre in event of overpressure. 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 Landing Gear, Wheels, Tyres, Brakes 19 Answer 37
Thermal plugs are installed in Wheel rims, cargo compartments, fire warning systems, cabin windows. 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 Landing Gear, Wheels, Tyres, Brakes 19 Answer 38
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 3psi, 42 psi,8 psi,2 psi. 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 Landing Gear, Wheels, Tyres, Brakes 19 Answer 39
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 , 2 4, 3,, 2, 3, 4 5, 2 4. 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 Landing Gear, Wheels, Tyres, Brakes 19 Answer 40
When a landing gear wheel hydroplaning its friction factor around
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