The humidity of the air supply to a passenger cabin should Be maintained between 30% and 70% Be not less than 60% Not be greater than 50%.
The minimum acceptable quantity of fresh air supplied to the cabin by an air conditioning system, is 0.5 lb of air per person per minute One lb of air per person per minute 0.4 lb of air per person per minute
.
The carbon monoxide content of air entering the cabin, should not exceed
One part in 200 On e part in 2000 One part in 20,000.
The speed of movement of air around ventilated compartments must not fall below 120 feet per minute 40 feet per minute 10 feet per minute.
Which of the following statements is correct in respect of contamination of the air supply in air conditioning system Small amounts of toxic gases are acceptable providing that not more than one part in a million of carbon monoxide is admitted to the system No toxic gases are permitted to enter the system One part of 20,000 of carbon dioxide by volume, and up to 3% of carbon monoxide by volume, are allowed to enter the system during a five minute period.
In a ram air system, the combustion heater is supplied with Fuel from a separate a reservoir and air from the engine inlet manifold Fuel from the aircraft’s fuel tanks and air from the exhaust manifold Fuel from a separate reservoir and ambient air boosted by a small blower.
The mass flow delivery from engine driven blowers is controlled by Spill valves Chock valves Variations in engine speed.
The spill valves in a compressor system is activated by The non-return valve The cabin pressure controller The mass flow controller.
An engine driven compressor supplies charge air at Ambient temperature An increased temperature A decrease temperature
.
Operation of a choke valve increases the temperature of the air supply by
Demanding a higher cabin pressure Producing a higher duct pressure Producing a higher output pressure.
The supply from a mass flow controller will Increase with increase in altitude Vary with any change in volume and density Remain at a constant value regardless of any change in volume, temperature or altitude.
A silencer is included in an air conditioning system in order to reduce The noise made by the compressor/s The noise form the high speed air flow within the system The engine noise carrying through the ducting
.
Mass flow controllers utilise
A by-pass valve A variable orifice valve A pressure reducing valve.
In a bleed air system
Very hot supply air is taken from the jet compressor stages Ram air is compressed and delivered from spill valves Cold supply air is taken from the jet compressor stages before combustion.
In a displacement blower bootstrap system The turbine compresses and heats the supply air The compressor causes the supply air to expand and cool The turbine causes the supply air to expand and cool.
A heat exchanger Provides an additional supply of ram air for emergency operations Increases the temperature of the initial supply of charge Reduces the temperature of the initial supply of charge air.
In a heat exchanger The charge air temperature is increased Charge air and ram air are mixed in a chamber Charge air flows through ducts over which ram air is directed.
A cold air unit produces a reduction in temperature by By-passing the air conditioning heating system Directing compressed ram air into a heater exchanger Expanding hot air across a turbine, which drives a compressor.
In a bootstrap cold air system, the first compressor is necessary To increase the pressure and temperature across the turbine To increases the pressure of low-pressure ram air To reduce the pressure and temperature drop across the turbine.
In a turbo-fan cold air unit Air is expanded over a turbine Air is forced through a condenser Air is continuously re-circulated until the required temperature is achieved.
A humidifier is fitted to air-conditioning systems in aircraft operating Any flight where cabin pressurizations required Extended flight at high altitude Extended flight at low altitude.
In a vapour cycle cooling heat is absorbed in
The liquid receiver and emitted at the condenser The condenser and emitted at the evaporator The evaporator and emitted at the condenser.
Temperature control in air conditioning systems is achieved by Controlling the amount of ram air directed to the heat exchangers Controlling the amount of air by-passing the cooling unit Controlling the amount of water vapour in the air supply with a water separator.
In a vapour cycle system supplied by bleed air The cold air required by the condenser to convert the refrigerant from vapour to liquid is supplied through a pre cooler from the bleed source The cold air required by the condenser to convert the refrigerant from vapour to liquid is supplied direct from the compressor The cold air required by the condenser to convert the refrigerant from vapour to liquid is either direct ram air or ambient air drawn by an extractor fan
.
A thermostat expansion valve, when fitted in a vapour cycle system Regulates the amount of liquid refrigerant supplied by the liquid receiver to the evaporator Regulates the amount of ram air supplied to the condenser, and the rate at which the refrigerant condense Regulates the amount of liquid refrigerant supplied by the liquid receiver to the condenser.
During pressurized flight the pressure differential is The difference between the aircraft cabin pressure and the mean sea level pressure The difference between the aircraft cabin pressure and the ambient pressure The difference between the ambient pressure and the mean sea level pressure.
During pressurized flight the maximum rate of cabin altitude change when descending is governed by The maximum pressure differential The maximum negative pressure differential
Passenger comfort.
A cabin is said to be pressurized when A constant pressure differential can be maintained up to any altitude A cabin pressure altitude of 8000 ft can be maintained up to maximum operational altitude A cabin pressure altitude of 15000 ft can be maintained up to maximum operational altitude.
Maximum permissible negative pressure differential is limited to 0.5-psi 4.16psi 1.0psi.
When cabin air is pressurized the percentage of oxygen present Increases Decreases Remain the same.
Cabin altitude is The altitude of the cabin barometrically corrected to standard atmospheric conditions The altitude corresponding to the cabin pressure irrespective of aircraft altitude The altitude at which there is no positive pressure differential.
After an aircraft has taken off, and is in the initial climb stage, the discharge valve will Continue moving Remain in the position set prior to takeoff Close fully.
To increase the cabin altitude, the discharge valves are Opened Closed Manually controlled by the crew.
An inward relief valve operates Via a pressure controller if there is a negative pressure differential Via a mass flow controller if there is a negative pressure differential Automatically if there is a negative pressure differential
.
If the pressure differential in an aircraft cabin, stabilizes at a value very slightly above the design maximum The safety valve has failed The mass flow controller is unserviceable The pressure controller is incorrectly set.
If an aircraft cabin is been pressurized at a constant rate during a climb, the cabin vertical speed indicator will show A zero indication A descent A climb.
During level flight at cruising altitude, the position of the discharge valve will be Fully closed Partially open That selected by the pressure controller datum prior to departure.
A pressure relief valve and a negative differential valve Ensure that the toilet and galley areas are maintained at a slightly lower pressure than the main pressure cabin Control the rate of cabin air flow and the rate of cabin pressurization Control the maximum positive and negative differential pressures.
An aircraft is given climb clearance from a sea level aerodrome to 16,000ft,and maintains a constant rate of climb of 1,000ft per minute .If the cabin altitude selector is set to 8,000ft and the rate of climb is 500ft per minute There will be no change in cabin pressure until the aircraft passes 8,000 ft There will be a steady decrease in cabin pressure over a 32 minute period There will be a steady decrease in cabin pressure over a 16 minute period.
During a steady climb in a pressurized aircraft Cabin pressure increases more rapidly than atmospheric pressure Cabin pressure decreases more rapidly than atmospheric pressure Cabin pressure and atmospheric decrease at a similar rate.
If the differential control in the pressure controller fails, over pressurization is automatically prevented by The inward relief valve The safety relief valve Activating the dump control.
The pressurization ditching control is used for Closing all valves and inlets Rapid and total depressurization of the cabin Automatic inflation of all flotation devices.
When the aircraft reaches the maximum cabin pressure differential The mass flow controller stops delivering air to the pressure cabin The outflow valves closed fully The outflow valves open.
During level flight, to further increase the cabin altitude The outflow valve must be brought closer to the closed position The mass flow of air supply form the conditioning system must be increased The outflow valve must be brought closer to the open position.
What is the purpose of a pressure controller when compared with an pneumatic discharge valve It spills air to the atmosphere as a result of signals from the discharge valve It maintains a constant pressure at the discharge valve head It spills air to the atmosphere when the discharge valve is unable to maintain the maximum differential pressure
.
When carrying out cabin pressurization function test, it is preferable to use A ground supply unit An auxiliary power unit The aircraft engines.
When carrying out a cabin pressurization leak rate test ,it is preferable to use A ground supply unit An auxiliary power unit The aircraft engines.
During a function test All flying control should be check through a limited movement range only The flying controls should not be operated The flying controls should be operated through their full range of movement.
During a leak rate test; all pilots and static connection should be Loosen to prevent high-pressure damage Correctly connected Completely disconnected.
Which of the following components should be isolated when running a full cabin pressurization function test The cabin pressure controller and the outflow valve assembly The inward relief valve, the pressure controller and the air conditioning duct
non-return valve The dump valve system, which operates, automatically when the aircraft is on
the ground.
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