|
ATPL 21 AIRCRAFT GENERAL KNOWLEDGE – AIRFRAME AND SYSTEMS |
| 21.01 LOADS / STRESSES / FATIGUE / CORROSION / MAINTENANCE |
|
1
A lower limit of a control area shall be established at a height above the ground level or water of not less than:
200 metres. |
|
2
The crank assembly consists of
Crankshaft, connecting rods and pistons. |
|
3
Ignition systems of piston engines are :
Independant from the electrical system of the aircraft. |
|
4
The purpose of the proximity of the emergency evacuation path marking system is to :
Replace the overhead emergency lighting during an emergency evacuation with a thick smoke. |
|
5
A unit that converts electrical dc into ac is :
An inverter. |
|
6
In a four-stroke piston engine, the only "driving" stroke is :
Firing-expansion |
|
7
On four-stroke piston engines, the theoretical valve and ignition settings are readjusted in order to increase the:
Overall efficiency |
|
8
Low oil pressure is sometimes the result of a
Worn oil pump |
|
9
The reason for the fact that an aeroplane designed for long distances cannot simply be used for short haul flights at higher frequencies is that
The lifetime of the fatigue sensitive parts has been based on a determined load spectrum |
|
10
In modern aircraft, a pilot can actuate the feather system by :
Pulling the rpm lever backwards. |
|
11
An impulse coupling used on a magneto for a piston engine is for
Providing a retarded spark for engine |
|
12
A manual inflation handle:
Serves to actuate inflation of a slide when automatic inflation fails |
|
13
On-board electrical systems are protected against faults of the following type: 1. ac generator over- voltage 2. ac generator under- voltage 3. over-current 4. over-speed 5. under-frequency 6. undue vibration of ac generators the combination of correct statements is :
1,2,4,5 |
|
14
The difference between (1) a fuse and (2) a circuit breaker is:
(1)not resettable, (2)resettable. |
|
15
The power output of a normally aspirated piston engine increases with increasing altitude at constant manifold air pressure (map) and rpm because of the :
Lower back pressure. |
|
16
In twin-engine aeroplanes with right turning propellers
The left engine is the critical motor. |
|
17
An asymmetric loading (p-factor) on the propeller exists ..
If the aeroplane has a large angle of attack. |
|
18
The "slipstream effect" of a propeller is most prominent at:
Low airspeeds with high power setting. |
|
19
What will happen to the geometrical pitch angle of a "constant speed propeller" if the manifold pressure is increased ?
It will increase |
|
20
The "constant speed propeller" has
Only above and below the design point a better efficiency than the fixed propeller with the same design speed. |
|
21
Which of the following qualitative statements about a fixed propeller optimized for cruise condition, is true for the take-off case? the angle of attack of the propeller :
Blade is relatively high. |
|
22
The conditions which can cause knocking are :
High manifold pressure and low revolutions per minute. |
|
23
During climb with constant throttle and rpm lever setting (mixture being constant) the :
Manifold air pressure (map) decreases. |
|
24
An egt (exhaust gas temperature) indicator for a piston engine is used to :
Assist the pilot to settle correct mixture. |
|
25
With which instrument(s) do you monitor the power output of an aeroplane fitted with a fixed pitch propeller?
Rpm indicator. |
|
26
One of the advantages of a turbosupercharger is that :
It uses the exhaust gas energy which normally is lost. |
|
27
What can be the consequence during a descent with a fully open throttle if the waste gate is seized ?
The manifold air pressure (map) value may exceed the maximum allowed value. |
|
28
During climb with constant manifold air pressure (map) and rpm indication and constant mixture setting, the power output of a piston engine :
Increases. |
|
29
In general, in twin- engine aeroplanes with "constant speed propeller"
The oil pressure turns the propeller blades towards smaller pitch angle. |
|
30
The conditions under which you obtain the highest engine power are :
Cold and dry air at high pressure. |
|
31
The power of a piston engine decreases during climb with a constant power lever setting, because of the decreasing :
Air density. |
|
32
The torque of an aeroplane engine can be measured at the: propeller.
Gear box which is located between the engine and the |
|
33
The power of a piston engine which will be measured by using a friction brake is :
Brake horse power. |
|
34
The power output of a piston engine can be calculated by :
Torque times rpm. |
|
35
The ignition occurs in each cylinder of an four- stroke engine (tdc = top dead center)
Before tdc at each second crankshaft revolution. |
|
36
The useful work area in an ideal otto engine indicator diagram is enclosed by the following gas state change lines
2 adiabatic and 2 isochoric lines. |
|
37
The number of emergency exits in transport aeroplanes
Must be arranged to allow all passengers and all crew members to leave the aeroplane within 90 sec. through 50 % of the available emergency exits. |
|
38
The kind of compressor normally used as a supercharger is :
A radial compressor. |
|
39
If a current is passed through a conductor which is positioned in a magnetic field :
A force will be exerted on the conductor. |
|
40
The capacity of a battery is expressed in terms of :
Ampere-hours. |
|
41
A test to assess the state of charge of a lead-acid battery would involve :
Comparing the "on- load" and "off-load" battery voltages. |
|
42
When an "open circuit" occurs in an electrical supply system, the
Loss of continuity will prevent its working functioning. |
|
43
When two dc generators are operating in parallel, control of load sharing is achieved by :
An equalising circuit which, in conjunction with the voltage regulators, varies the field excitation current of the generators. |
|
44
In a two generator system, a differential relay will ensure that :
Generator voltages are almost equal before the generators are paralleled. |
|
45
The very rapid magnetic field changes (flux) around the primary coil in a magneto are accomplished by the:
Contact breaker points opening. |
|
46
The compression ratio of a piston engine is the ratio of the: that with the piston at top dead centre.
Volume of the cylinder with the piston at bottom dead centre to |
|
47
Prolonged running at low rpm may have an adverse effect on the efficiency of the:
Sparking plugs. |
|
48
The purpose of the venturi in a carburettor is to:
Create the depression necessary to cause fuel before the mixture carburettor jets. |
|
49
An aircraft electrical circuit which uses the aircraft structure as a return path to earth, may be defined as a
Single pole circuit. |
|
50
The purpose of a distributor in an ignition system is to distribute:
Secondary current to the sparking plugs. |
|
51
The reading on the oil pressure gauge is the:
Pressure of the oil on the outlet side of the pressure pump. |
|
52
A turbocharger system is normally driven by:
The exhaust system. |
|
53
A turbocharger consists of a :
Compressor and turbine mounted on a common shaft. |
|
54
The mixture control for a carburettor achieves its control by:
Varying the fuel supply to the main discharge tube. |
|
55
In an aircraft equipped with a dc main power system, ac for instrument operation may be obtained from :
An inverter. |
|
56
The true statement among the following in relation to the application of ohm"s law is :
Current in a circuit is directly proportional to the applied electromotive force. |
|
57
When a battery is almost fully discharged there is a tendency for the :
Voltage to decrease under load. |
|
58
Immediately after starting engine(s) with no other electrical services switched on, an ammeter showing a high charge rate to the battery :
Would be normal and is only cause for concern if the high charge rate persists. |
|
59
Circuit breakers protecting circuits may be :
Used in ac and dc circuits. |
|
60
A "trip-free" type circuit breaker is a circuit protection device which :
Will not allow the contacts to be held closed while a current the circuit. |
|
61
Connecting two 12 volt 40 ampere-hour capacity batteries in series will result in a total voltage and capacity respectively of :
24 volts, 40 ampere- hours. |
|
62
A bus-bar is :
A distribution point for electrical power. |
|
63
When carrying out battery condition check using the aircraft"s voltmeter :
A load should be applied to the battery in order to give a better indication of condition. |
|
64
When a conductor cuts the flux of a magnetic field :
An electromotive force (emf) is induced in the flemings left hand rule. |
|
65
In order that dc generators will achieve equal load sharing when operating in parallel, it is necessary to ensure that :
Their voltages are almost equal. |
|
66
A circuit breaker :
May be reset manually after the fault has been rectified. |
|
67
A current limiter fuse in a dc generation system is used to :
Allow a short term overload before rupturing. |
|
68
The primary purpose of bonding the metallic parts of an aircraft is to :
Provide safe distribution of electrical charges and currents. |
|
69
If the ground wire between the magneto and the ignition switch becomes disconnected, the most noticeable result will be that the engine
Cannot be shut down by turning the switch to the off position. |
|
70
If an engine fails to stop with the magneto switch in off position, the cause may be :
Excessive carbon formation in cylinder head. |
|
71
An impulse magneto coupling
Gives a retarded spark at starting |
|
72
A condenser in parallel with breaker points will coil
Intensify current in secondary winding |
|
73
Spark timing is related to engine speed in the way that the:
Faster the engine functions, the more the spark is advanced |
|
74
An aircraft magneto is switched off by
Grounding the primary circuit |
|
75
With respect to a piston engined aircraft, ice in the carburettor :
May form at oat"s higher than +10�? c. |
|
76
When leaning the mixture for the most economic cruise fuel flow, excessive leaning will cause :
High cylinder head and exhaust gas temperature |
|
77
The oil system for a piston engine incorporates an oil cooler that is fitted :
In the return line to the oil tank after the oil has passed through the scavenge pump |
|
78
An exit is considered to be out of service when the following elements are inoperative the: 1. external door opening mechanism 2. internal door opening mechanism 3. door opening aid device 4. open door locking system 5. auxiliary means of evacuation 6. emergency lighting the combination regrouping all the correct statements is:
1, 2, 3, 4, 5, 6 |
|
79
To ensure that the fuel flow is kept directly proportional to the volume of air flowing through the choke, thus preventing the main jet supplying excessive fuel as engine speed is increased, a carburettor is fitted with :
A diffuser |
|
80
In a piston engine if the ratio of air to fuel, by weight, is approximately 9:1, the mixture is said to be :
Rich |
|
81
Which of the following factors would be likely to increase the possibility of detonation occurring within a piston engine ?
Using too lean a fuel/air mixture ratio |
|
82
The part of a piston engine that transforms reciprocating movement into rotary motion is termed the :
Crankshaft |
|
83
In a piston engine, the purpose of an altitude mixture control is to :
Correct for variations in the fuel/air ratio due to decreased air density at altitude. |
|
84
In addition to the fire hazard introduced, excessive priming should be avoided because :
It washes the lubricant of cylinder walls |
|
85
The primary purpose of a supercharger is to :
Maintain power at altitude |
|
86
An excessively rich mixture can be detected by :
Black smoke from exhaust. |
|
87
A piston engine compression ratio is the ratio of the :
Total volume to the clearance volume. |
|
88
Pre-ignition refers to the condition that may arise when :
The mixture is ignited by abnormal conditions within the cylinder before the spark occurs |
|
89
Overheating of a piston engine is likely to result from an excessively :
Weak mixture. |
|
90
The maximum horsepower output which can be obtained from an engine when it is operated at specified rpm and manifold pressure conditons established as safe for continuous operation is termed :
Rated power. |
|
91
A fuel strainer when fitted to a carburettor will be positioned :
Upstream of the needle valve. |
|
92
Specific fuel consumption is defined as the :
Mass of fuel required to produce unit power for aircraft. |
|
93
The octane rating of a fuel and compression ratio of a piston engine have which of the following relations?
The higher the octane rating is, the higher the possible compression ratio is |
|
94
The purpose of an ignition switch is to :
Control the primary circuit of the magneto |
|
95
Under normal running conditions a magneto draws primary current :
From a self-contained electro-magnetic induction system. |
|
96
On a normally aspirated aero-engine fitted with a fixed pitch propeller : the throttle.
Manifold pressure decreases as the aircraft climbs at a fixed throttle setting. |
|
97
The air in a piston engine turbo- supercharger centrifugal compressor :
Enters the eye of the impeller and leaves at a tangent to the periphery. |
|
98
In a piston engine, turbocharger boost pressure may be monitored by :
A manifold pressure gauge only. |
|
99
The working cycle of a four-stroke engine is :
Induction, compression, power, exhaust. |
|
100
If the ground wire between the magnetos and the ignition switch becomes disconnected the most noticeable result will be that:
The engine cannot be shut down by turning the ignition switch to the "off" position |
|
101
Fuel stored in aircraft tanks will accumulate moisture. the most practical way to minimize this when an aircraft is used every day or so is to :
Keep tanks topped off when the aircraft is not in use |
|
102
Fixed-pitch propellers are usually designed for maximum efficiency at :
Cruising speed |
|
103
Vapour lock is :
Vaporizing of fuel prior to reaching the carburettor |
|
104
For internal cooling,reciprocating engines are especially dependent on:
The circulation of lubricating oil |
|
105
The positions of the intake and exhaust valve at the end of the power stroke are :
Intake valve closed and exhaust valve open. |
|
106
The main purpose of the mixture control is to:
Adjust the fuel flow to obtain the proper fuel/air ratio |
|
107
In which sections of the carburettor would icing most likely occur?
Venturi and the throttle valve |
|
108
The operating principle of float-type carburettors is based on the:
Difference in air pressure at the venturi throat and the air inlet |
|
109
In an engine equipped with a float-type carburettor, the low temperature that causes carburettor ice is normally the result of:
Vaporization of fuel and expansion of the air in the carburettor |
|
110
Fuel/air ratio is the ratio between the:
Mass of fuel and mass of air entering the cylinder. |
|
111
Which statement is true concerning the effect of the application of carburettor heat?
It reduces the density of air entering the carburettor, thus enriching the fuel/air mixture |
|
112
In a generator, the constant speed drive (csd): 1- may be disconnected from the engine shaft. 2- may be disconnected from the generator. 3- is a hydro- mechanical system. 4- is an electronic system. 5- may not be disconnected in flight. 6- may be disconnected in flight. the combination regrouping all the correct statements is :
1, 3, 6 |
|
113
A static inverter is a:
Transistorized unit used to convert dc into ac. |
|
114
The correct formula to calculate the multi- cylinder engine displacement is :
Piston area * piston stroke * number of cylinders |
|
115
In most cases aeroplane piston engines are short stroke engines. this permits a :
Lighter construction. |
|
116
When changing power on engines equipped with constant-speed propeller, engine overload is avoided by :
Increasing the rpm before increasing the manifold pressure. |
|
117
The pitch angle of a constant-speed propeller
Increases with increasing true air speed. |
|
118
A propeller blade is twisted, so as to
Keep the local angle of attack constant along the blade. |
|
119
A pilot normally uses the propeller autofeather system during :
Take-off and landing. |
|
120
When increasing true airspeed with a constant engine rpm, the angle of attack of a fixed pitch propeller :
Reduces. |
|
121
The feathering pump of a hydraulic variable- pitch propeller: inoperative.
Is an electrically driven oil pump, which supplies the propeller with pressure oil, when the engine is |
|
122
To unfeather a propeller during flight you have to :
Use the electric unfeathering pump. |
|
123
If one of the 12 cells of a lead-acid battery is dead, the battery:
Is unserviceable. |
|
124
When tas increases, the pitch angle of a constant speed propeller (rpm and map levers are not moved) :
Increases. |
|
125
Electrical bonding of an aircraft is used to: 1. protect the aircraft against lightning effects. 2. reset the electrostatic potential of the aircraft to a value approximating 0 volt 3. reduce radio interference on radiocommunication systems 4. set the aircraft to a single potential the combination regrouping all the correct statements is: 5 france the low altitude radio decimetric. metric. centimetric. myriametric. 0 0 -1 0 altimeter uses the following wavelengths: 5 france the automatic decimetric. centimetric. hectometric or metric. 0 0 -1 0 the following wavelengths: 2 france a thermal circuit forbids any overcurrent. can be reset without protects the system in is a protection system 0 0 -1 0 6 france on an airplane, the leading edge flaps leading edge flaps trailing edge flaps close trailing edge flaps close 0 -1 0 0
1, 3, 4 close to the wing root |
|
126
The fuselage of an aircraft consists, among others, of stringers whose purpose is to: stress.
Assist the skin in absorbing the longitudinal traction- compression stresses. |
|
127
For a given type of oil, the oil viscosity depends on the:
Oil temperature. |
|
128
In case of engine failure during flight the blades of the constant speed propeller in a single engine aeroplane, not fitted with feathering system 1 germany for take-off, the correct (1) high (2) forward. (1) low (2) forward. (1) low (2) aft. (1) high (2) aft. 0 -1 0 0 combination of propeller pitch (1), and propeller lever position (2) at brake release is :
Move in the lowest pitch position by the centrifugal force. |
|
129
For piston engines, mixture ratio is the ratio between the :
Mass of fuel and mass of air entering the cylinder. |
|
130
On modern carburettors, the variations of mixture ratios are obtained by the adjustment of :
Fuel flow. |
|
131
To adjust the mixture ratio of a piston engine when altitude increases, means to:
Decrease the fuel flow in order to compensate for the decreasing air density. |
|
132
When applying carburettor heating :
The mixture becomes richer. |
|
133
When the pilot moves the mixture lever of a piston engine towards a lean position the :
Amount of fuel entering the combustion chamber is reduced. |
|
134
When altitude increases without adjustment of the mixture ratio, the piston engine performance is affected because of a :
Decrease of air density for a constant quantity of fuel. |
|
135
Max. exhaust gas temperature is theoretically associated with :
Mass ratio of 1/15. |
|
136
The advantages of grounding the negative pole of the aircraft structure are: 1. weight saving 2. easy fault detection 3. increase of short- circuit risk 4. reduction of short- circuit risk 5. circuits are not single-wired lines the combination regrouping all the correct statements is :
1, 2, 4 |
|
137
The main advantage of a constant speed propeller as compared to a fixed pitch propeller is a :
Higher efficiency in all operating ranges. |
|
138
A rich mixture setting has to be used during climb segments. this results in a
Lower cylinder head temperature. |
|
139
For fail-safe designed structural parts : 1 the mounting principle is parallel mounting. 2 no routine check is necessary. 3 the member is removed at the end of the calculated life cycle. 4 certain components may not be accessible. 5 the principle is the redundancy of components 6 the failure of a member causes the loads to be shared between the other system components. the combination regrouping all the correct statements is :
1,5,6 |
|
140
Duralumin alloys : 1 have an aluminium- copper base. 2 have an aluminium- magnesium base. 3 are easy to weld. 4 are difficult to weld. 5 have a good thermal conductivity. 6 have a poor air corrosion resistance the combination regrouping all the correct statements is :
1,4,5 |
|
141
Some emergency exits must be equipped with devices so as to help the occupants to get out and reach the ground if their threshold is at a height above the ground greater than:
6 ft, aeroplane on the ground, landing gear extended. |
|
142
The pitch angle of a
Reference chord line propeller is the angle between the : |
|
143
The frequency of the current provided by an alternator depends on...
Its rotation speed |
|
144
On a a normally aspirated engine (non turbo-charged), the manifold pressure gauge always indicates...
A lower value than atmospheric pressure when the engine is running. |
|
145
When the magneto selector switch is set to "off" position, the piston engine continues to run normally. the most probable cause of this failure is that:
On a magneto, a grounding wire is broken. |
|
146
During a power change on an engine equipped with a constant speed propeller, a wrong combination of manifold pressure and rpm values results in excessive pressures in the cylinders. this is the case when one simultaneously selects a ...
High manifold pressure and low rpm. |
|
147
When in flight, a piston engine is stopped and the propeller blade pitch angle is near 90�? , the propeller is said to be...
Feathered. |
|
148
The resistors r1 and r2 are connected in parallel. the value of the equivalent resistance (req) so obtained is given by the following formula:
1/req = 1/r1 + 1/r2 |
|
149
The function of the generator breaker is to close when the voltage of the :
Generator is greater than battery voltage and to open when the opposite is true |
|
150
Evacuation slide inflation is ensured by :
A pressurized gas canister combined with the slide itself. |
|
151
In a piston engine, magnetos are used to produce the spark which ignites the fuel/air mixture. the operating principle of magnetos consists in :
Breaking the primary current in order to induce a low amp high volt current which is distributed to the spark plugs. |
|
152
Vapor lock is the phenomenon by which:
Heat produces vapour plugs in the fuel line. |
|
153
Spark plug fouling is more likely to happen if : too long.
The aircraft climbs without mixture adjustment. |
|
154
Static dischargers : 1. are used to set all the parts of the airframe to the same electrical potential 2. are placed on wing and tail tips to facilitate electrical discharge 3. are used to reset the electrostatic potential of the aircraft to a value approximating 0 volts 4. are located on wing and tail tips to reduce intererence with the on- board radiocommunication systems to a minimum 5. limit the risks of transfer of electrical charges between the aircraft and the electrified clouds the combination regrouping all the correct statements is :
2,4,5. |
|
155
The octane rating of a fuel characterises the :
The anti-knock capability |
|
156
"fail safe construction" is : components if a part of the structure fails.
A type of construction in which the load is carried by other |
|
157
The reason for using inverters in an electrical system is ..
To change dc into ac. |
|
158
In aeronautics, the most commonly used batteries are nicd because...
They weigh less than lead-acid batteries. |
|
159
The essential difference between aircraft ac alternators and dc generators (dynamos) is that the: inductor (field) coil.
Induced (output) windings of the alternators are fixed (stator), and the dynamos have a fixed |
|
160
In an alternator rotor coil you can find :
Ac. |
|
161
Fuses are rated to a value by :
The number of amperes they will carry. |
|
162
Consider the variable- pitch propeller of a turbo-prop. during deceleration : engine power.
When braking, the propeller supplies negative thrust and absorbs engine power. |
|
163
Among the different types of aircraft structures, the shell structures efficiently transmit the: 1. normal bending stresses 2. tangent bending stresses 3. torsional moment 4. shear stresses the combination regrouping all the correct statements is :
1, 2, 3 |
|
164
The purpose of static wick dischargers is to : interference as a result of static electricity.
Dissipate static charge of the aircraft inflight thus avoiding radio |
|
165
The type of windings commonly used in dc starter motors are :
Series wound. |
|
166
The output of a generator is controlled by :
Varying the field strength. |
|
167
The detection of a feeder fault on a direct current circuit results in: 1. automatic disconnection of the generator from the aircraft ac busbar 2. opening of generator field current relay 3. opening of the main relay of the generator breaker 4. opening of balancing circuit connecting two generators 5. lighting of an indicator lamp the combination of correct statements is:
1, 2, 3, 4, 5 |
|
168
A feeder fault on a direct current circuit results from a flux unbalance between the:
Voltage coil and the series winding turn. |
|
169
A dc generator fitted to a aircraft is cooled by :
Air via a ram air intake. |
|
170
On board present aircraft, the batteries used are mainly cadmium-nickel. their advantages are: 1. low risk of thermal runaway 2. high internal resistance, hence higher power 3. good charging and discharging capability at high rating 4. wider permissible temperature range 5. good storage capability 6. sturdiness owing to its metal casing 7. the electrolyte density remains unchanged during charging. the combination of correct statement is:
3, 4, 5, 6 |
|
171
The richness of a fuel/air mixture ratio is the :
Real mixture ratio relative to the theoretical ratio. |
|
172
The voltage regulator of a dc generator is connected in :
Series with the shunt field coil. |
|
173
Assume a constant speed dc generator providing a constant output voltage. if the electrical load increases, the voltage regulator will :
Increase the intensity of the excitation current. |
|
174
The so-called "hot buses" or "direct buses" are:
Directly connected to the battery. |