1. The purpose of the turbine in the cold air unit is to:- (a) reduce the air temperature.
(b) increase the air temperature.
(c) provide additional cooling for the heat exchanger.
2. In the air cycle cooling system an increase in charge air temperature is provided by the:-
(a) turbine.
(b) intercooler.
(c) compressor.
3. Air leaving the turbine of the cold air unit flows to the:- (a) intercooler.
(b) cabin.
(c) compressor.
4. In the cold air unit, the turbine rotates within a:- (a) nozzle ring.
(b) diffuser ring.
(c) pressure ring.
5. In a brake turbine cold air unit, the compressor is subjected to:-
(a) ram air.
(b) ambient air.
(c) charge air.
6. The cooling medium for heat conversion through the heat exchangers is:-
(a) ram air.
(b) charge air.
(c) ambient air.
1 . (a ) 2 . (c ) 3 . (b ) 4 . (a ) 5 . (b ) 6 . (a )
1. The water extractor is normally located:- (a) before the cold air unit.
(b) between the cold air unit and the outlet to the cabin.
(c) between the cold air unit compressor and turbine.
2. An air to air heat exchanger is provided to:- (a) reduce the air supply temperature.
(b) increase the air supply temperature.
(c) provide an emergency ram air supply.
3. The most common method by which cabin humidity is increased is tor-
fa) inject water into the cabin blower.
(b) use an atomising spray of water into the conditioned air as it enters the cabin.
(c) use a venturi humidifier.
4. A pre-cooler unit is normally a:- (a) heat exchanger.
(b) mechanical refrigeration device.
(c) cooling fan within the system.
5. A water separator should be installed in a pressurisation system to :-
(a) collect any rain accompanying the ram air.
(b) extract water from the cabin before it is discharged to atmosphere.
(c) extract surplus water from the charge air.
6. Secondary heat exchangers are located:-
(a) between the compressor of the cold air unit and the aircraft engine compressor.
(b) between cold air unit compressor outlet and turbine inlet.
(c) after the water separator.
1 . (b 2 . ( a 3 . (b 4 . ( a 5 . ( c 6 . (b
1. In a typical duct leakage protection system sensor, an increase in temperature will cause :-
(a) an increase in resistance.
(b) a decrease in resistance.
(c) no effect upon the sensing element.
2. The function of the pack flow control valve when- the recirculation fan is running is to:-
(a) reduce the amount of air from the engine compressor.
Co) open the fan air valve 50%.
(c) increase the amount of air being drawn from the engine compressor.
3. To ensure the correct mixing of the conditioned air, the mixing chamber has:-
(a) jet pumps.
(b) baffles.
(c) swirl devices.
4. When installing overheat sensors, the recommended minimum radii for bends is:-
(a) 3 inches.
(b) h inch.
(c) 6 inches.
Recirculation system filters are located:- (a) before the recirculation fan.
(b) after the recirculation fan.
(c) on the outlet of the manifold duct.
1. The control of ventilating and pressurising air being released from the aircraft is achieved by the:-
(a) pressure controller/discharge valve combination.
(b) pressure controller/dump valve combination.
(c) discharge valve/inwards relief valve combination.
2. In a pneumatic pressurisation system, positive pressure signals from the controller will cause:-
(a) the discharge valve to move towards closed.
(b) the discharge valve to move towards open.
(c) an excessive rate of cabin air discharge.
3. In an electrically operated pressurisation system, air pressure signals entering the controller are converted to electrical signals by:~
(a) an AUTO/MANUAL switch on the control panel.
(b) a transducer.
(c) a potentiometer.
4. Electrically driven discharge valves are usually equipped with more than one motor. The reason for this is :
(a) to provide the extra power needed to drive large valves against the high mass of air used in large jets.
(b) that more motors provide for finer adjustment of the valve position.
(c) to provide a means of back up if a particular motor or its electrical supply fails.
1 . (a ) 2 . (a ) 3 . (b ) 4 . (c )
1. Inward relief valves will operate when:-
(a) depressurising the aircraft after descent.
(b) cabin altitude exceeds aircraft altitude.
(c) aircraft altitude exceeds cabin altitude.
2. Cabin differential pressure is the difference between:- (a) 8,000 ft and sea level.
(b) ISA conditions and aircraft altitude.
(c) cabin pressure and ambient pressure.
3. During a normal pressurised climb following take-off:- (a) the cabin ROC is less than the aircraft's ROC.
(b) the cabin ROC is more than the aircraft's ROC.
(c) The ROC is constant.
4. Failure of the normal Max. Diff. control is catered for by fitting:-
(a) safety relief valves.
(b) inward relief valves.
(c) altitude selector valves.
5. Cabin altitude during pressurised flight is:-
(a) the altitude at which cabin altitude equals ambient pressure.
(b) the pressure altitude of the cabin corrected to mean sea level conditions.
(c) the altitude corresponding to cabin pressure irrespective of the altitude of the aircraft.
1. (b) 2. (c) 3. (a) 4. (a) 5. (c)
1. A ditching control is used to:- (a) close all valves and inlets.
(b) rapidly inflate flotation bags.
(c) rapidly depressurise the cabin.
2. A dump valve may be used to:-
(a) close the discharge valves when ditching.
(b) rapidly reduce cabin altitude.
(c) clear the cabin of smoke or fumes.
3. If the dump valve was inadvertently left open, the cabin would:-
(a) fail to pressurise.
(b) be pressurised to a lower altitude.
(c) be pressurised to a higher altitude.
4. In an electrically controlled pressurisation system, manual operation of the discharge valves is achieved:-
(a) mechanically.
(b) electrically.
(c) pneumatically.
5. Manual control of the pressurisation system is provided to:-
(a) allow for ground pressure tests.
(b) cater for failure of the system to operate
1. Hollow section pressurised area door seals are usually inflated by:-
(a) a small nitrogen gas cylinder fitted to each door.
(b) the difference in pressure between cabin and ambient.
(c) using the aircraft's pneumatic system.
2. Leakage of cabin pressure through a damaged door or hatch seal has a noticeable effect on aircraft performance, particularly if the door is located:-
(a) near the front of the aircraft.
(b) at the rear of the aircraft.
(c) immediately behind the wing areas.
3. Pressurisation loads on the door are transmitted to the fuselage structure:-
(a) via the door seal.
(b) through the door latches or pins.
(c) only on doors of the plug type.
4. Door unsafe warnings are usually only operated when:- (a) the cabin is pressurised.
(b) the cabin is unpressurised.
(c) the door locking mechanism is not fully locked.
5. Door pressure locks are usually fitted to:~
(a) prevent the door from being opened whenever the cabin is pressurised.
(b) automatically lock the doors when the cabin is pressurised.
(c) automatically unlock the doors when the cabin is de-pressurised.
OXYGEN
1. The quantity of oxygen that the cylinders are capable of carrying depends on:-
(a) how long the aircraft can remain airborne.
(b) how many passengers and crew can be carried.
(c) the maximum altitude the aircraft is designed to fly at.
2. Supply lines in the cabin distribution ring main are made from:-
(a) stainless steel.
(b) brass.
(c) light alloy.
3. Oxygen is available at the passenger drop down masks:- (a) as soon as the masks have dropped.
(b) when the crew switch the oxygen on.
(c) when the mask is pulled after drop down.
4. The colour coded tape for oxygen pipelines has:- (a) black rectangles and green colour band.
(b) black diamonds and green colour band.
(c) green rectangles and black colour band.
5. What is the purpose of the cylinder shut off valve?
(a) To prevent overcharging.
(b) To prevent leakage when changing a bottle.
(c) To prevent leakage during parking of the aircraft.
6. PSUs are automatically opened when cabin altitude exceeds:- (a) 10,000 ft.
1. Why can't medical oxygen be used to replenish an aircraft system?
(a) It is not pure enough.
(b) It contains too much moisture.
(c) It contains additives.
2. Permanent brain damage can occur through lack of oxygen.
This condition is called:
(a) hypoxia.
(b) asphyxia.
(c) anoxia.
3. What is meant by the minimum dispatch pressure?
(a) The least oxygen needed for the number of passengers and crew for the duration of the flight.
(b) The minimum oxygen content the aircraft can contain.
(c) The amount of oxygen that must be left in a cylinder to prevent water ingress.
4. Aviation oxygen is:- (a) 100% pure.
(b) 90% pure.
(c) 99.5% pure.
5. Purging oxygen systems is carried out to:- (a) purify the system and rid it of moisture.
(b) ensure correct operation of the oxygen system.
(c) remove water from the cylinders.
6. If grease were found on an oxygen valve you were about to fit, you should:-
(a) clean the grease off with a clean lint-free rag.
(b) use a rag dipped in methylated spirits and allow the valve to dry thoroughly.
(c) reject the valve.
1 . (b ) 2 . (c ) 3 . (a ) 4 . (c ) 5 . (a ) 6 . (c )
1. In order to isolate bottles it is normal to incorporate a:- (a) non return valve.
(b) ON/OFF manual valve.
(c) a pressure regulator valve.
2. Oxygen masks are left plugged into the regulator:- (a) to prevent leaks from the regulator.
(b) for storage requirements.
(c) to enable the mask to operate as soon as it is fitted.
3. Reservoir bags on passenger masks are for:- (a) storing an immediate supply of oxygen.
(b) to take exhaled air from the users mouth.
(c) to make up the loss of oxygen due to the poorly fitted mask.
4. The smoke set can be used in cases of decompression due to:-
(a) the full face mask.
(b) its portability.
(c) automatic altitude compensation regulator.
5. How is oxygen prevented from escaping into the flight deck when the normal/100% lever on the regulator is at normal?
(a) The normal/100% lever covers the air hole.
(b) By a screw blank.
(c) By a NRV.
6. Oxygen is supplied to the mask only when the user breathes in by the action of:-
(a) a diaphragm deflected by reduction of pressure.
(b) a check valve in the mask.
(c) the operation of the ON/OFF switch.
1 . (b ) 2 . (c ) 3 . (a ) 4 . (c ) 5 . (c ) 6 . (a )