Observation > CPL : 'vapour lock' is the phenomenon by which ?

Question 29-1 : Heat produces vapour bubbles in the fuel line water vapour plugs are formed in the intake fuel line following the condensation of water in fuel tanks which have not been drained for sometime burnt gas plugs forming and remaining in the exhaust manifold following an overheat and thereby disturbing the exhaust abrupt and abnormal enrichment of the fuel/air mixture following an inappropriate use of carburettor heat

exemple 129 heat produces vapour bubbles in the fuel line. — The vapour lock is a stoppage in a fuel feeding line caused by a fuel vapour bubble heat produces vapour bubbles in the fuel line.

For a piston engine the chemically correct fuel/air ratio ?

Question 29-2 : Is 1 15 is 1 9 is 1 5 is 1 12

exemple 133 is 1:15 — Rich 9 1.correct 15 1.weak 20 1 is 1:15

The function of the primer pump in a reciprocating engine is to ?

Question 29-3 : Provide additional fuel for an engine start serve as an alternate pump in case of an engine driven pump failure to serve as main supply pump in a fuel injection system inject additional fuel during engine acceleration

exemple 137 provide additional fuel for an engine start. — provide additional fuel for an engine start.

One of the advantages of a turbocharger is ?

Question 29-4 : To make the power available less affected by altitude an increased propulsive efficiency that there is no torsion at the crankshaft that there is no danger of detonation

exemple 141 to make the power available less affected by altitude. — to make the power available less affected by altitude.

Assume an initial condition at a high cruise altitude with a constant speed ?

Question 29-5 : The manifold absolute pressure map value may exceed the maximum allowed value the power of the engine will decrease the blade angle may reach the full fine limit the manifold absolute pressure map value will stay constant

exemple 145 the manifold absolute pressure (map) value may exceed the maximum allowed value. — .with the engine producing power at low altitudes the turbocharger will be potentially over productive to prevent over boosting the wastegate will allow surplus exhaust energy to bypass the turbocharger at higher altitudes where the air is considerably less dense the wastegate will close off allowing the turbocharger to deliver the selected boost .during a descent from a high cruising altitude with the throttle fully open the turbocharger will be over productive and the manifold absolute pressure map value may exceed the maximum allowed value the manifold absolute pressure (map) value may exceed the maximum allowed value.

If the engine with a fixed pitch propeller is detonating during climb out after ?

Question 29-6 : Reduce the throttle increase the rate of climb lean the mixture apply carburettor heat

exemple 149 reduce the throttle. — reduce the throttle.

If when the magneto selector switch is set to the off position a piston engine ?

Question 29-7 : On a magneto the grounding wire is broken there is a carbon deposit on the spark plugs electrodes there are local hot points in the engine probably due to overheating of the cylinder heads a wire from the magneto is in contact with a metallic part of the engine

exemple 153 on a magneto, the grounding wire is broken. — The ignition system provides the spark that ignites the fuel/air mixture in the cylinders and is made up of magnetos spark plugs high tension leads and the ignition switch . 901..a magneto uses a permanent magnet to generate an electrical current completely independent of the aircraft's electrical system the magneto generates sufficiently high voltage to jump a spark across the spark plug gap in each cylinder the system begins to fire when you engage the starter and the crankshaft begins to turn it continues to operate whenever the crankshaft is rotating.most standard certificated airplanes incorporate a dual ignition system with two individual magnetos separate sets of wires and spark plugs to increase reliability of the ignition system each magneto operates independently to fire one of the two spark plugs in each cylinder the firing of two spark plugs improves combustion of the fuel/air mixture and results in a slightly higher power output if one of the magnetos fails the other is unaffected the engine will continue to operate normally although you can expect a slight decrease in engine power the same is true if one of the two spark plugs in a cylinder fails.the operation of the magneto is controlled in the cockpit by the ignition switch the switch has five positions.1 off.2 r right.3 l left.4 both.5 start..with right or left selected only the associated magneto is activated the system operates on both magnetos with both selected.you can identify a malfunctioning ignition system during the pretakeoff check by observing the decrease in rpm that occurs when you first move the ignition switch from both to right and then from both to left a small decrease in engine rpm is normal during this check around 100 to 150 rpm .if the engine stops running when you switch to one magneto or if the rpm drop exceeds the allowable limit do not fly the airplane until the problem is corrected the cause could be fouled plugs broken or shorted wires between the magneto and the plugs or improperly timed firing of the plugs it should be noted that 'no drop' in rpm is not normal and in that instance the airplane should not be flown.following engine shutdown turn the ignition switch to the off position even with the battery and master switches off the engine can fire and turn over if you leave the ignition switch on and the propeller is moved because the magneto requires no outside source of electrical power the potential for serious injury in this situation is obvious.loose or broken wires in the ignition system also can cause problems for example if the ignition switch is off the magneto may continue to fire if the ignition switch ground wire is disconnected if this occurs the only way to stop the engine is to move the mixture lever to the idle cutoff position then have the system checked by a qualified aviation maintenance technician on a magneto, the grounding wire is broken.

Ignition occurs in each cylinder of a four stroke engine tdc = top dead centre ?

Question 29-8 : Before tdc at each second crankshaft revolution before tdc at each crankshaft revolution behind tdc at each crankshaft revolution behind tdc at each second crankshaft revolution

exemple 157 before tdc at each second crankshaft revolution. — before tdc at each second crankshaft revolution.

The lubricating system of an air cooled piston engine is used to ?

Question 29-9 : Reduce internal friction and provide cooling keep the engine warm to operate the fuel control unit operate constant speed propellers

exemple 161 reduce internal friction and provide cooling. — reduce internal friction and provide cooling.

The first indication of carburettor icing in aeroplanes equipped with constant ?

Question 29-10 : Decrease in manifold pressure decrease in rpm rough running engine followed by an increase in manifold pressure rough running engine followed by loss in rpm

exemple 165 decrease in manifold pressure. — On engines fitted with constant speed propellers a drop in power is indicated by a drop in manifold pressure the rpm remaining constant decrease in manifold pressure.

The mixture control for a carburettor achieves its control by ?

Question 29-11 : Varying the fuel supply to the main discharge tube moves the butterfly valve through a separate linkage to the main throttle control altering the depression on the main discharge tube varying the air supply to the main discharge tube

exemple 169 varying the fuel supply to the main discharge tube. — varying the fuel supply to the main discharge tube.

The mechanism to change the propeller blade angle of a small piston engine ?

Question 29-12 : Hydraulically by engine oil hydraulically by hydraulic fluid manually by the pilot by aerodynamic forces

exemple 173 hydraulically by engine oil. — Pdf656 hydraulically by engine oil.

The use of too low an octane fuel may cause ?

Question 29-13 : Detonation higher manifold pressure a cooling effect on cylinders vapour locking

Which one of the following factors would be most likely to increase the ?

Question 29-14 : Using too lean a fuel/air mixture the use of a fuel with a high octane rating as compared to the use of one with a low octane rating using an engine with a low compression ratio slightly retarding the ignition timing

Detonation is nothing less than a series of small explosions that take place within an engine's combustion chambers it can be extremely destructive breaking pistons rod bearings and anything else from the pistons down that a large hammer could damage .weak air/fuel mixtures can result in very uneven mixtures within the chamber uneven burning pressure spikes and detonation

Vents in oil tanks are primarily to ?

Question 29-15 : Prevent excessive pressure from building up in tank prevent overthrow allow for expansion of hot oil eliminate foaming

exemple 185 prevent excessive pressure from building up in tank. — prevent excessive pressure from building up in tank.

The cylinder head and oil temperatures may exceed their normal operating ranges ?

Question 29-16 : A lower octane rating than specified for the engine is used a higher octane rating than specified for the engine is used the engine is operated at a higher than normal oil pressure the engine is operated at a too rich mixture

When starting the engine or when the engine is running at idle rpm on the ?

Question 29-17 : Rich to make starting possible and to cool the engine sufficiently when idling rich because the choke valve is closed rich because carburettor heat is switched on weak to prevent the engine consuming too much fuel

exemple 193 rich, to make starting possible and to cool the engine sufficiently when idling. — rich, to make starting possible and to cool the engine sufficiently when idling.

The cylinder head and oil temperature gauges are to exceed the normal operating ?

Question 29-18 : Uses fuel that has a rating lower than specified for the engine operates with the mixture control set too rich uses fuel that has a rating higher than specified for the engine operating with higher than normal oil pressure

exemple 197 uses fuel that has a rating lower-than-specified for the engine — uses fuel that has a rating lower-than-specified for the engine

The lubricating system of an aircraft engine is used to ?

Question 29-19 : Aid in dissipation of heat keep the engine warm operate ground adjustable propellers prevent inter crystalline corrosion

exemple 201 aid in dissipation of heat — aid in dissipation of heat

On design purpose the relationship between the fuel octane rating and the ?

Question 29-20 : The higher the octane rating is the higher the maximum compression ratio is the lower the octane rating is the higher the maximum compression ratio is the higher the octane rating is the lower the maximum compression ratio is the maximum compression ratio is independent of the octane rating

exemple 205 the higher the octane rating is, the higher the maximum compression ratio is — the higher the octane rating is, the higher the maximum compression ratio is

A magnetic plug in an engine oil system can be used to ?

Question 29-21 : Collect ferrous particles collect carbon found in the oil collect static electricity prevent metallic particles from entering the oil system

exemple 209 collect ferrous particles. — The most basic type of magnetic filter is a drain plug where a magnet in the shape of a disc or cylinder is attached to its inside surface typically by adhesion periodically the magnetic plug is removed and inspected for ferromagnetic particles which are then wiped from the plug . 902.such plugs are commonly used in engine sumps gearboxes and occasionally in hydraulic reservoirs one useful advantage of mag plugs relates to examining the density of wear particles observed as a visual indication of the wear rate occurring within the machine over a fixed period of running time the appearance of these iron filings on magnets are often described in inspection reports using terms such as peach fuzz whiskers or christmas trees if one normally sees peach fuzz but on one occasion sees a christmas tree instead this would be a reportable condition requiring further inspection and remediation collect ferrous particles.

Once the engine has started ignition systems of piston engines are ?

Question 29-22 : Independent of the electrical system of the aircraft dependent on the battery dependent on the dc generator dependent on the ac generator

exemple 213 independent of the electrical system of the aircraft. — independent of the electrical system of the aircraft.

The blade angle of a propeller is the angle between the ?

Question 29-23 : Reference chord line and the propeller plane of rotation reference chord line and the relative airflow reference chord line and the propeller axis of rotation plane of rotation and the relative airflow

exemple 217 reference chord line and the propeller plane of rotation. — Blade angle usually measured in degrees is the angle between the chord of the blade and the propeller plane of rotation . 903 reference chord line and the propeller plane of rotation.

In very cold weather a slightly higher than normal engine oil pressure during ?

Question 29-24 : Is acceptable if it decreases after startup is unacceptable and requires the engine to be shut down is unacceptable but does not require the engine to be shut down requires an oil change

exemple 221 is acceptable, if it decreases after startup. — is acceptable, if it decreases after startup.

Assuming the same swept volume and no turbo charger diesel engines compared to ?

Question 29-25 : Produce less maximum power output operate at higher exhaust gas temperatures show a higher fuel flow at the same power output produce a higher maximum power output

exemple 225 produce less maximum power output. — produce less maximum power output.

The operating principle of magnetos in a piston engine ignition system consists ?

Question 29-26 : Breaking the primary circuit in order to induce a low amperage high voltage current which is distributed to the spark plugs obtaining a high amperage low voltage current in order to generate the spark accumulating in a capacitor a low voltage current from the battery and inducing it as a high voltage current at the moment the spark is generated creating a brief high intensity magnetic field that will be sent through the distributor at the appropriate time

exemple 229 breaking the primary circuit in order to induce a low amperage, high voltage current, which is distributed to the spark plugs. — breaking the primary circuit in order to induce a low amperage, high voltage current, which is distributed to the spark plugs.

In a four stroke piston engine the only 'driving' stroke is ?

Question 29-27 : Power induction compression exhaust

Excessive priming of a piston engine should be avoided because .1 it drains the ?

Question 29-28 : 2 3 4 1 2 4 1 3 4 1 2 3

exemple 237 2, 3, 4. — .a fuel primer is a small hand pump designed to put neat fuel directly into either the induction manifold near the combustion chamber or the inlet valve port before you start in the cold promote the presence of fuel vapour that will ignite to start the engine .aside from the fire hazard excessive priming should be avoided because it fouls the spark plugs and there is a risk of flooding the engine 2, 3, 4.

Which one of the following factors would be most likely to increase the ?

Question 29-29 : High cylinder head temperature the use of a fuel with a high octane rating as compared to the use of one with a low octane rating using an engine with a low compression ratio slightly retarding the ignition timing

The octane rating of a fuel characterises the ?

Question 29-30 : Resistance to detonation fuel volatility quantity of heat generated by its combustion fuel electrical conductivity

exemple 245 resistance to detonation. — The octane rating of fuel is a measure of its performance in engines a higher octane number means that the fuel and air mixture can withstand more compression before detonating premature detonation can result in an engine making knocking pinging or rattling sounds high octane fuel therefore helps reduce or eliminate knocking pinging or rattling in engines resistance to detonation.

Both gas turbine and piston engines use a cycle made up of induction ?

Question 29-31 : I is correct ii is correct i is incorrect ii is incorrect i is incorrect ii is correct i is correct ii is incorrect

Piston engine the combustion process is intermittent governed by the rythm of the back and forth movements of the piston in a cylinder the combustion occurs at constant volume in the cylinder.turbine engine the combustion process is continuous and occurs at constant pressure

When tas increases the blade angle of a constant speed propeller will rpm and ?

Question 29-32 : Increase decrease first decrease and after a short time increase to its previous value remain constant

exemple 253 increase. — On a propeller the relative airflow is the resultant of the airflow due to rotation and to the forward speed .a constant speed propeller automatically keeps the blade angle adjusted for maximum efficiency for most conditions encountered in flight so if tas or rpm change the blade angle will change .the blade angle 'pitch angle' if you prefer is a measurement of the distance between the propeller cord and the plane of rotation . 905..with an increasing tas the blade angle will increase .a propeller is similar to a screw . 906..if we want to enter quicky in a material we need the black screw high pitch if we want to go slowly the metalic screw small pitch is more convenient . 907..an efficient propeller is one which has the least amount of slippage and therefore converts more engine horsepower into thrust a constant speed propeller keeps the propeller pitch adjusted for maximum efficiency for most conditions of flight increase.

With an aircraft fitted with a fixed pitch propeller during flight at normal ?

Question 29-33 : Loss of approximately 100 rpm an additional load on the other magneto excessive vibration the engine to overheat

exemple 257 loss of approximately 100 rpm. — loss of approximately 100 rpm.

Both gas turbine and piston engines use a cycle made up of induction ?

Question 29-34 : I is incorrect ii is incorrect i is correct ii is correct i is incorrect ii is correct i is correct ii is incorrect

exemple 261 i is incorrect, ii is incorrect. — .piston engine the combustion process is intermittent governed by the rythm of the back and forth movements of the piston in a cylinder the combustion occurs at constant volume in the cylinder.turbine engine the combustion process is continuous and occurs at constant pressure i is incorrect, ii is incorrect.

When excessively leaning the mixture for a better fuel economy but still on the ?

Question 29-35 : Cylinder head and exhaust gas temperature engine rpm oil temperature manifold pressure

exemple 265 cylinder head and exhaust gas temperature. — cylinder head and exhaust gas temperature.

Both gas turbine and piston engines use a cycle made up of induction ?

Question 29-36 : I is incorrect ii is correct i is incorrect ii is incorrect i is correct ii is correct i is correct ii is incorrect

exemple 269 i is incorrect, ii is correct. — .piston engine the combustion process is intermittent governed by the rythm of the back and forth movements of the piston in a cylinder the combustion occurs at constant volume in the cylinder.turbine engine the combustion process is continuous and occurs at constant pressure i is incorrect, ii is correct.

Given the following statements about diesel engines .1 power is set by the ?

Question 29-37 : 2 3 4 1 2 3 1 3 5 2 4 5

exemple 273 2, 3, 4. — There is no mixture control and no throttle valve the power output of a diesel engine is controlled by regulating the quantity of fuel that is injected into the cylinder the amount of air is constant diesel engines are fitted with injectors not with valves 2, 3, 4.

Diesel engines compared to petrol engines have ?

Question 29-38 : A higher compression ratio a lower compression ratio the same compression ratio a variable compression ratio

exemple 277 a higher compression ratio. — a higher compression ratio.

The power output of a diesel engine without a turbo charger is regulated by ?

Question 29-39 : Fuel flow only airflow only fuel flow and airflow mixture

exemple 281 fuel flow only . — On the gasoline engine the speed and power output is regulated by limiting the air and fuel mixture entering the engine the power output of a diesel engine is controlled by regulating the quantity of fuel that is injected into the cylinder the amount of air is constant fuel flow only .

The ignition system of a running piston engine receives electrical energy from ?

Question 29-40 : Rotating permanent magnets batteries generators capacitors

exemple 285 rotating permanent magnets. — rotating permanent magnets.

~

Exclusive rights reserved. Reproduction prohibited under penalty of prosecution.

1119 Free Training Exam Other source study: Ulm theorique examen 29