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ATPL 21 AIRCRAFT GENERAL KNOWLEDGE – AIRFRAME AND SYSTEMS |
| 21.02 AIRFRAME |
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1
Smoke detectors fitted on transport aircraft are of the following type :
Optical or ionization |
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2
A constant speed drive aims at ensuring
That the electric generator produces a constant frequency. |
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3
Load shedding means .. of electric generators
Temporarily or permanent switching off of certain electric users to avoid overload |
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4
The services connected to a supply bus-bar are normally in:
Parallel, so that isolating individual loads decreases the bus-bar current consumption. |
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5
The moving part in an ac generator is usually referred to as the :
Rotor. |
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6
(for this question use annex 021-10164a) the smoke detection in the aircraft cargo compartments is carried out by four sensors: c1, c2, c3 and c4. they are associated with the logic circuit as described in the annex. the repeating bell is activated when:
The c1 and c2 sensors detect smoke. |
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7
The measured output power components of a constant frequency ac system are :
Kva and kvar. |
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8
Frequency wild in relation to a ac generation system means the generator :
Output frequency varies with engine speed. |
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9
If the frequency of the supply in a series capacitive circuit is increased, the current flowing in the circuit will :
Increase. |
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10
In an aeroplane utilising a constant frequency ac power supply, dc power is obtained from a :
Transformer rectifier unit. |
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11
On an aeroplane utilising ac as primary power supplies, the batteries are charged in flight from :
A transformer rectifier unit. |
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12
When operating two ac generators unparalleled, the phase relationship of each generator:
Is unimportant. |
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13
Assuming a csd fault is indicated, the csd should be disconnected :
During engine operation only. |
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14
The function of a csd in an ac generating system is to:
Drive the generator at a constant speed. |
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15
The frequency of an ac generator is dependent on the :
Number of pairs of poles and the speed of the moving part. |
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16
The frequency of an ac generator is dependent upon the :
Number of pairs of poles and the speed of the rotor. |
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17
The function of a constant speed drive (csd) in an ac generating system is to :
Drive the generator at a constant speed. |
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18
If two constant frequency ac generators are operating independently, then the phase relationship of each generator:
Is unimportant. |
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19
To ensure correct load sharing between ac generators operating in parallel :
Both real an reactive loads must be matched. |
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20
A csd of an ac generator may be disconnected in flight. the primary reason(s) for disconnection are :
Low oil pressure and/or high oil temperature of the generator drive. |
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21
A csd unit which has been disconnected in flight :
May be reset on the ground only, after engine shut-down. |
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22
When ac generators are operated in paralllel, they must be of the same:
Voltage and frequency. |
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23
The purpose of a voltage regulator is to control the output voltage of the :
Generator at varying loads and speeds. |
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24
A 3 phase ac generator has 3 separate stator windings spaced at :
120�? . |
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25
On the flight deck, an oil operated csd unit is normally provided with means of monitoring the:
Oil over-temperature and low oil pressure. |
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26
An ac generator driven by a csd unit :
Requires a voltage controller to maintain constant voltage under load. |
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27
The main purpose of a constant speed drive unit is to:
Maintain a constant frequency. |
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28
When the ac generators are connected in parallel, the reactive loads are balanced by means of the:
Energizing current. |
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29
As regards the generator contol unit (gcu) of an ac generator, it can be said that: 1. the gcu controls the ac generator voltage 2. modern gcus are provided with a permanent indication to record the failure 3. all the commands originating from the control panel are applied via the gcu, except dog clutch release 4. the auxiliary power unit (apu) provides the excitation of the ac generator as soon as the apu starts up the combination regrouping all the correct statements is :
2, 3 |
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30
Smoke detector systems are installed in the
Upper cargo compartments (class e). |
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31
A magnetic circuit- breaker is:
A protection system that has a quick tripping response. |
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32
In an aircraft electrical system where ac generators are not paralleled mounted, the changover relay allows :
Power supply to the faulty ac generators busbar. |
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33
Pulling the fire shutoff handle causes a number of devices to disconnect. in respect of the ac generator it can be said that the:
Exciter control relay and the generator breaker open. |
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34
The speed of an asynchronous four-pole motor fed at a frequency of 400 hertz is:
12000 revolutions per minute. |
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35
As regards three-phase ac generators, the following conditions must be met for paralleling ac generators: 1. equal voltage 2. equal current 3. equal frequencies 4. same phase rotation 5. voltages of same phase the combination regrouping all the correct statements is :
1, 3, 4, 5 |
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36
Ion detectors are devices used in aircraft for systems protection. they detect :
Smoke. |
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37
The auxiliary power unit (apu) has its own ac generator which:
Supplies the aircraft with three-phase 115- 200 v, 400 hz ac. |
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38
In a turbo-jet, the purpose of the turbine is to ...
Drive the compressor by using part of the energy from the exhaust gases |
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39
(use the appendix to answer this question) the gas turbine illustrated is of the following type:
Free turbine and centrifugal compressor |
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40
On detection of a persistent overvoltage fault on an ac generator connected to the aircraft ac busbars, the on-board protection device opens:
The exciter breaker and the generator breaker. |
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41
When a persistent top excitation limit fault on an ac generator connected to the mains with another ac generator, the overexcitation protection device opens:
The exciter breaker, the generator breaker and the tie breaker. |
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42
When a persistent overexcitation fault is detected on only one ac generator, the protection device opens the :
Exciter breaker and generator breaker. |
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43
When an underspeed fault is detected on an ac generator connected to the aircraft ac busbar, the protection device opens the:
Generator breaker. |
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44
On starting, in a brushless ac generator with no commutator rings, the generator is activated by:
A set of permanent magnets. |
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45
The advantages of alternating current on board an aircraft are: 1. simple connection 2. high starting torque 3. flexibility in use 4. lighter weight of equipment 5. easy to convert into direct current 6. easy maintenance of machines the combination of correct statements is:
3, 4, 5, 6 |
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46
In flight, if the constant speed drive (csd) temperature indicator is in the red arc the:
Pilot must disconnect it, and the generator is not available for the rest of flight. |
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47
The most widely used electrical frequency in aircraft is :
400 hz. |