At Reference In a pressurized aircraft whose cabin altitude is 8000 ft a crack in a cabin window makes it necessary to reduce the differential pressure to 5 psi The ?
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Source: Telepilote theorique examen 23
The pressurisation system of an aeroplane ?
In a turbo compressor air conditioning system bootstrap system the supply of air behind the primary heat exchanger is ?
The purpose of cabin air flow control valves in a pressurization system to Maintain a constant sufficient mass air flow to ventilate cabin minimise cabin pressure surges. Cabin pressurization controlled during all phases of airplane operation the cabin pressure control system the system uses bleed air supplied to distributed the air conditioning system pressurization ventilation are controlled modulating outflow valve the overboard exhaust valve pressurization outflow cabin air outflow controlled the outflow valve the overboard exhaust valve a small amount also exhausted through toilet galley vents miscellaneous fixed vents by seal leakage outflow valve the outflow valve the overboard exhaust exit the majority of air circulated through passenger cabin passenger cabin air drawn through foot level grills down around aft cargo compartment where it provides heating is discharged overboard through outflow valve note the answer discharge cabin air to atmosphere if cabin pressure rises above selected altitude we are talking about pressure relief valves who provide safety pressure relief limiting differential pressure to a maximum of 9 1 psi a negative relief valve prevents external atmospheric pressure from exceeding internal cabin pressure. 
If pressure in cabin tends to become lower than outside ambient air pressure Negative pressure relief valve will open. All pressurised aircraft have negative pressure relief valves that will open enable cabin pressure to increase at same rate as ambient pressure should cabin/ambient differential try to go negative aircraft are structurally designed a positive differential (cabin pressure higher than ambient) under normal operation pressure controller can cope but in emergencies negative pressure relief valves will function. 
Cabin air cs 25 aeroplanes usually taken from The high pressure compressor from low pressure compressor if necessary. The air taken from engine at a suitable pressure temperature from compressors on a modern high bypass engine that would mean high pressure compressor but it really dependant on type. 
Under normal flight conditions cabin pressure controlled Regulating discharge of air through outflow valve(s). The air taken from engine at a suitable pressure temperature from compressors on a modern high bypass engine that would mean high pressure compressor but it really dependant on type. Question 23-8
Pneumatic mechanical ice protection systems are mainly used Regulating discharge of air through outflow valve(s). Pneumatic mechanical ice protection systems are mainly used wings more precisely leading edge wing tail surfaces this a de icing system only it has to be turn on after a bit of ice has build up when activated rubber boots are pressurized with air they expand breaking ice off leading edge surfaces . Question 23-9
With regard to pneumatic mechanical devices that afford ice protection only correct statement They can only be used as de icing devices. Pneumatic mechanical ice protection systems are mainly used wings more precisely leading edge wing tail surfaces this a de icing system only it has to be turn on after a bit of ice has build up when activated rubber boots are pressurized with air they expand breaking ice off leading edge surfaces . Question 23-10
Concerning electrically powered ice protection devices only true statement On modern aircraft electrically powered thermal devices are used to prevent icing on small surfaces (pitot static windshield ). Pneumatic mechanical ice protection systems are mainly used wings more precisely leading edge wing tail surfaces this a de icing system only it has to be turn on after a bit of ice has build up when activated rubber boots are pressurized with air they expand breaking ice off leading edge surfaces . Question 23-11
The elements specifically protected against icing on transport aircraft are 1 engine air intake and pod 2 front glass shield 3 radome 4 pitot tubes and waste water exhaust masts 5 leading edge of wing 6 cabin windows 7 trailing edge of wings 8 electronic equipment compartment the combination regrouping all correct statements On modern aircraft electrically powered thermal devices are used to prevent icing on small surfaces (pitot static windshield ). Pneumatic mechanical ice protection systems are mainly used wings more precisely leading edge wing tail surfaces this a de icing system only it has to be turn on after a bit of ice has build up when activated rubber boots are pressurized with air they expand breaking ice off leading edge surfaces . Question 23-12
The wing anti ice system has to protect The leading edge or slats either partially or completely. In jet aeroplanes thermal anti ice system primarily supplied bleed air from engines (bleed air from hp compressor) the wing anti ice system has to protect leading edge or slats either partially or completely engine intake frontal area of elevator the vertical stabiliser. Question 23-13
In jet aeroplanes 'thermal anti ice system' primarily supplied Bleed air from engines. In jet aeroplanes thermal anti ice system primarily supplied bleed air from engines (bleed air from hp compressor) the wing anti ice system has to protect leading edge or slats either partially or completely engine intake frontal area of elevator the vertical stabiliser. Question 23-14
The icing system which mostly used the wings of modern turboprop aeroplanes Bleed air from engines. In jet aeroplanes thermal anti ice system primarily supplied bleed air from engines (bleed air from hp compressor) the wing anti ice system has to protect leading edge or slats either partially or completely engine intake frontal area of elevator the vertical stabiliser. Question 23-15
Concerning sequential pneumatic impulses used in certain leading edge icing devices one can affirm that 1 they prevent ice formation 2 they are triggered from flight deck after icing has become visible 3 a cycle lasts more than ten seconds 4 there are more than ten cycles per second the combination which regroups all correct statements Bleed air from engines. In jet aeroplanes thermal anti ice system primarily supplied bleed air from engines (bleed air from hp compressor) the wing anti ice system has to protect leading edge or slats either partially or completely engine intake frontal area of elevator the vertical stabiliser. Question 23-16
Generally large aeroplanes electrical heating ice protection used on Bleed air from engines. In jet aeroplanes thermal anti ice system primarily supplied bleed air from engines (bleed air from hp compressor) the wing anti ice system has to protect leading edge or slats either partially or completely engine intake frontal area of elevator the vertical stabiliser. Question 23-17
The wing ice protection system currently used most large jet transport aeroplanes a Bleed air from engines. On most modern jet aeroplanes thermal anti ice system primarily supplied bleed air from engines (bleed air from hp compressor) the wing anti ice system has to protect leading edge or slats either partially or completely engine intake frontal area of elevator the vertical stabiliser. Question 23-18
Pneumatic mechanical devices that provide ice protection Are usually used as de icing devices. On most modern jet aeroplanes thermal anti ice system primarily supplied bleed air from engines (bleed air from hp compressor) the wing anti ice system has to protect leading edge or slats either partially or completely engine intake frontal area of elevator the vertical stabiliser. Question 23-19
The anti icing method the wings of large jet transport aeroplanes most commonly used in flight Thermal (use of hot air). In large jet aeroplanes thermal anti ice system primarily supplied bleed air from engines (bleed air from hp compressor) the wing anti ice system has to protect leading edge or slats either partially or completely engine intake frontal area of elevator the vertical stabiliser. Question 23-20
Windshield heating of a transport aeroplane Essential to improve strength of cockpit windows. Windshield heating system employs a windscreen of special laminated construction heated electrically to prevent not only formation of ice mist but also to improve impact resistance of windscreen at low temperatures. Question 23-21
The heat the anti icing system of a turbofan engine intake provided Bleed air from hp compressor. In jet aeroplanes thermal anti ice system primarily supplied bleed air from engines (bleed air from hp compressor) the wing anti ice system has to protect leading edge or slats either partially or completely engine intake frontal area of elevator the vertical stabiliser. Question 23-22
The use of a hot air wing anti icing system Does not affect aerodynamic performance of wing causes a reduction in maximum thrust. In jet aeroplanes thermal anti ice system primarily supplied bleed air from engines (bleed air from hp compressor) the wing anti ice system has to protect leading edge or slats either partially or completely engine intake frontal area of elevator the vertical stabiliser since hot air tapped directly from a compressor stage temperature will rise in turbine which can limit thrust in order not to exceed maximum engine temperature. Question 23-23
Ice formation on turbofan engine intakes usually Prevented using compressor bleed air. In jet aeroplanes thermal anti ice system primarily supplied bleed air from engines (bleed air from hp compressor) the wing anti ice system has to protect leading edge or slats either partially or completely engine intake frontal area of elevator the vertical stabiliser since hot air tapped directly from a compressor stage temperature will rise in turbine which can limit thrust in order not to exceed maximum engine temperature. Question 23-24
The ice protection propellers of modern turboprop aeroplanes works Prevented using compressor bleed air. ice formation on a propeller blade produces distortion to aerofoil section causing a loss in efficiency possible unbalance destructive vibration the build up of ice must be prevented there are two systems in use protection provided either an anti icing fluid system or an electrically powered thermal de icing system on modern turboprop (cessna caravan pilatus pc 12 beechcraft 90 to 1900d dash 8 atr 42/72 etc ) ice protection propellers works electrically in electrical systems basis effective de icing formed resistance wire heating elements bonded to leading edges of propeller blades in case of turbine engine propellers wire woven or sprayed elements are also bonded to front shell of spinner depending on type of aircraft power heating elements either direct current or alternating current is applied in a controlled sequence a cyclic timer unit in turbo propeller engine installations propeller heating circuit forms part of a power unit de icing anti icing system the cyclic control integrated with engine air intake heating circuit cessna 208 caravan. Question 23-25
The heating facility the windshield of an aircraft Used on a continual basis as it reduces thermal gradients which adversely affect useful life of components. Howarthson the window heating system selected permanently on but heating elements are actually cycled on/off to maintain a constant temperature of window by keeping window warm not only keeps it clear of ice but increases its resistance to impact damage. Question 23-26
The wing ice protection system currently used most large turboprop transport aeroplanes A pneumatic system with inflatable boots. On most turboprops this a de icing system (inflatable boots) . Question 23-27
Electrically powered ice protection devices on aircraft are Used as anti icing devices pitot tubes static ports windshield. On most turboprops this a de icing system (inflatable boots) . Question 23-28
On most transport aircraft low pressure pumps of fuel system are Centrifugal pumps driven an electric motor. The pumps in question are pumps in fuel tanks they are known as 'lp pump also 'booster pump (less than 3 bars 40 psi) engine driven pumps would come under engine fuel system dividing line being made at low pressure cock or valve. Question 23-29
The fuel supply system on a jet engine includes a fuel heating device upstream of main fuel filter so as to Prevent at low fuel temperature risk of ice formation from water contained in fuel. The pumps in question are pumps in fuel tanks they are known as 'lp pump also 'booster pump (less than 3 bars 40 psi) engine driven pumps would come under engine fuel system dividing line being made at low pressure cock or valve. Question 23-30
On most transport jet aircraft low pressure pumps of fuel system are supplied with electric power of following type Prevent at low fuel temperature risk of ice formation from water contained in fuel. Fuel delivered under pressure from fuel pumps located in fuel tanks this 115 v ac powered fuel pumps are cooled lubricated fuel passing through pump notice fuel pump pressure should be supplied to engines at all times at high altitude without fuel pump pressure thrust deterioration or engine flameout may occur. Question 23-31
The pressure usually produced the booster pumps of fuel supply system of a large jet transport aeroplane within following range Prevent at low fuel temperature risk of ice formation from water contained in fuel. Fuel delivered under pressure from fuel pumps located in fuel tanks this 115 v ac powered fuel pumps are cooled lubricated fuel passing through pump notice fuel pump pressure should be supplied to engines at all times at high altitude without fuel pump pressure thrust deterioration or engine flameout may occur. Question 23-32
In a gas turbine engine lubrication system oil to fuel heat exchanger provides Oil cooling through thermal exchange with fuel. Fuel delivered under pressure from fuel pumps located in fuel tanks this 115 v ac powered fuel pumps are cooled lubricated fuel passing through pump notice fuel pump pressure should be supplied to engines at all times at high altitude without fuel pump pressure thrust deterioration or engine flameout may occur. Question 23-33
The fuel cross feed system Allows feeding of any engine from any fuel tank. The engine fuel manifolds are interconnected use of crossfeed valve fuel pressure can be provided from a any fuel tank with operating fuel pumps to both engines opening fuel crossfeed valve continued crossfeed can result in a progressive fuel imbalance. Question 23-34
The purpose of baffles in an aeroplane's integral fuel tank to Restrict fuel movements in tank. Baffles in a fuel tank are a series of partitions (wall) to control rapid flow of fuel prevent its sloshing these partitions have holes that allow fuel to feed to tank outlet but they keep fuel from surging enough to uncover fuel outlet. Question 23-35
On a transport type aircraft fuel tank system vented through Ram air scoops on underside of wing. This question refers to vent/pressurisation system used on b737 it a little misleading in that tank ventilation pressurisation systems are combined the ram air scoop on lower surface of leading edge delivers air at pressure to fuel tanks that pressure controlled at a few psi above atmospheric the vent system. Question 23-36
The types of fuel tanks used on most modern transport aircraft are Ram air scoops on underside of wing. This question refers to vent/pressurisation system used on b737 it a little misleading in that tank ventilation pressurisation systems are combined the ram air scoop on lower surface of leading edge delivers air at pressure to fuel tanks that pressure controlled at a few psi above atmospheric the vent system. Question 23-37
The pressurization of fuel tanks maintained The fuel vent system. Each tank vented to outside air in order to maintain atmospheric pressure within tank air vents are designed to minimize possibility of their stoppage dirt ice formation in order to permit rapid changes in internal air pressure size of vent proportional to size of tank thus preventing collapse of tank in a steep dive or glide. Question 23-38
On a jet aircraft fuel heaters are The fuel vent system. Each tank vented to outside air in order to maintain atmospheric pressure within tank air vents are designed to minimize possibility of their stoppage dirt ice formation in order to permit rapid changes in internal air pressure size of vent proportional to size of tank thus preventing collapse of tank in a steep dive or glide. Question 23-39
The automatic fuelling shut off valve Stops fuelling as soon as a certain fuel level reached inside tank. Each tank vented to outside air in order to maintain atmospheric pressure within tank air vents are designed to minimize possibility of their stoppage dirt ice formation in order to permit rapid changes in internal air pressure size of vent proportional to size of tank thus preventing collapse of tank in a steep dive or glide. Question 23-40
During re fuelling automatic shut off valves will switch off fuel supply system when The fuel has reached a predetermined volume or mass. Each tank vented to outside air in order to maintain atmospheric pressure within tank air vents are designed to minimize possibility of their stoppage dirt ice formation in order to permit rapid changes in internal air pressure size of vent proportional to size of tank thus preventing collapse of tank in a steep dive or glide.
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