Question 53-1 : To ensure the centre of pressure of a rotor blade acts through the centre of gravity during manufacture ? [ Instruction Manual ]

Question 53-2 : The rotor blades that are most sensitive to humidity are those made of ?

Wood.

Question 53-3 : The purpose of the blade tip cap is 1 to reduce induced drag2 to increase the lift in hover3 to increase max air speedthe combination containing all of the correct statements is ?

1 2 3.

Question 53-4 : The purpose of the aluminium mesh which is manufactured within the skin of some fibre glass covered rotor blades is ' ?

To provide protection against lightning strikes.

Question 53-5 : The purpose of a main rotor blade tracking check is to ensure ?

That all blades have the same tip path plane.

Question 53-6 : The most difficult material from which to manufacture a homogeneous series of blades is ?

Wood.

Question 53-7 : The main spar of a main rotor blade is at approximately ?

25% of the chord.

Question 53-8 : Modern tail rotor blades are usually manufactured from ?

Question 53-9 : Low frequency vibration in the vertical plane which is only apparent in high speed flight is due to a ?

Badly adjusted tab on the main rotor blade.

Question 53-10 : Low frequency vibration in a plane parallel to the rotor plane is likely to be associated with ?

Question 53-11 : Erosion strips fitted to the leading edge of rotor blades are usually manufactured from the following alloys ?

Nickel titanium or stainless steel.

Question 53-12 : Dynamic balancing of main rotor systems ?

Is usually achieved by adding or subtracting weights to either the main rotor blade attachment pins or to the main rotor head itself.

Question 53-13 : During a flight under normal conditions a main rotor blade is seen to be flying higher than the other blades in the disc during cruise this can usually be adjusted by ?

Adjusting the trim tabs on the subject blade.

Question 53-14 : Tail rotor blade hinges arranged with a ''delta three'' hinge effect ?

Decrease their pitch angle with flap up.

Question 53-15 : Adjusting an outboard blade tab upwards will produce a ?

Nose up moment on the blade.

Question 53-16 : A rotor blade trim tab provides a corrective force ?

Indirectly by causing the pitch angle to change thus altering blade lift in the appropriate sense.

Question 53-17 : A rotor blade running out of track produces ?

A vertical vibration once per revolution.

Question 53-18 : Wind gusts have a greater adverse effect on ?

Semi rigid rotors due to their see saw flapping.

Question 53-19 : The epr engine pressure ratio is computed by ?

Dividing turbine discharge pressure by compressor inlet pressure.

Img911it is engine thrust in term of epr

Question 53-20 : A thermocouple type thermometer consists of ?

Two metal conductors of different type connected at two points.

Question 53-21 : One of the disadvantages of an electronic tachometer is the ?

Necessity of a power supply.

Question 53-22 : The principle of capacity gauges is based on the capacitance variation of ?

A capacitor with the type of dielectric.

A capacitance type fuel gauge system consists of a variable capacitor located in the fuel tank an amplifier and an indicator the complete circuit forms an electrical bridge which is continuously being rebalanced as a result of the differences between the capacitances of the tank capacitor and a reference capacitor the signal produced due to the differences in the signals is amplified to operate a motor the motor then drives the pointer to indicate the capacitance change of the tank capacitor and thus change in the fuel quantity is indicatedwe have seen the basic construction of this system now let us discuss how the electrical capacitance principle is utilized for the capacitance type fuel gauge system in aircraft the capacitors which are to be installed in the fuel tanks for the fuel quantity measurement must be different in construction from those normally employed in electrical equipment the plates of the capacitors take the form of two tubes mounted concentrically with a narrow air space between them these plates extend the full depth of a fuel tankcapacitance depends on some factors which are area of the plates distance between the two plates and the dielectric constant of the material between the two plates of the capacitorsnow in this capacitance type fuel gauge system the two factors plate area and distance between plates are fixed and the dielectric here is the fuel in the tank of the aircraft the flow of a momentary current into a capacitor establishes a potential difference across its plates the dielectric ie fuel in the aircraft's fuel tanks contains no free electrons so the current cannot flow through it but it should be remembered that potential difference sets up a state of stress in the atoms comprising it

Question 53-23 : A synchroscope is used on aircraft to ?

Question 53-24 : The bourdon tube is used to measure ?

Pressure.

Question 53-25 : If a manifold pressure gauge consistently registers atmospheric pressure the cause is probably ?

Question 53-26 : A manifold pressure gauge of a piston engine measures ?

Absolute pressure in intake system near the inlet valve.

Question 53-27 : In an engine vibration monitoring system for a turbojet any vibration produced by the engine is ?

Amplified and filtered before being fed to the cockpit indicator.

Vibrations are picked up by accelerometers so you measure accelerations piezzo electric or capacity type pickups giving after conversion displacement square seconda first integration will give displacement speed displacement per second a second integration will give displacementeach integration may introduce or amplify measurement errors but the initial acceleration signal is not practical for use depending on the engine type and the bearing location the displacement speed usually noted in inch per second ips is usedthe vibration frequency is filtered for the cockpit indication to indicate only vibration in a frequency band corresponding to the spool speed n1 n2 n3 that's why engines can have vibrations which are not related to spools rotating speed not being indicated in the cockpit

Question 53-28 : According to the range of pressure to be measured low medium high different types of pressure sensors are used1 bellows type2 bourdon tube type3 aneroid capsule classify the following sensors by order of increasing pressure for which they are suitable ?

3 1 and 2.

Question 53-29 : A vibration indicator receives a signal from different sensors accelerometers it indicates the ?

Vibration amplitude at a given frequency.

Question 53-30 : The transmitter of rpm indicator may consist of 1 a magnetic sensor supplying an induced ac voltage2 a dc generator supplying a dc voltage3 a single phase ac generator supplying an ac voltage4 a three phase ac generator supplying a three phase voltagethe combination of correct statements is ?

1 2 3 4.

Statement 1 it refers to a permanent magnet that is coupled to the engine and as it rotates within a 3 phase stator the resulting 3 phase ac supply drives a 3 phase ac synchronous motor that rotates a drag cup around a permanent magnet the magnet rotates against a hairspring and indicates the rpmstatement 2 it refers to a device that converts ac signals into dc that drives a dc motor the output is then compared to a dc reference output and the difference indicates the rpmstatement 3 it refers to a device that is used on some jet engine aircraft to sense the shaft speed of the lp compressor during the engine start up cycle it uses a single ac phase of a normal tachogenerator to show that the shaft is rotating and is automatically isolated after the start cycle has been successfully completedstatement 4 it refers to a direct drive 3 phase ac generator that is operated in conjunction with a 3 phase ac synchronous motor to indicate the rpm

Question 53-31 : The indication of a fuel float gauge varies with 1 pitch attitude 2 accelerations 3 fuel temperaturethe combination that regroups all of the correct statements is ?

1 2 3.

In 1904 the first float arm gas gauge appeared a float mounted on a hinged arm moved a mechanical pointer on gauge on the outside of the fuel tank to indicate the fuel levelidea was taken one step further when vehicles started to get better electrical systems by connecting the hinged float arm to a rheostat this allows an electrically operated fuel gauge to be mounted in the vehicle's dashboard and that's the basic operating principle that's still in use todaybut airplane attitude and accelerations will affect the accuracy of the indication due to the movements of the fuel in the tank temperature will modify the volume thus the indication

Question 53-32 : If the tanks of your aircraft only contain water the capacitor gauges indicate ?

A mass of water different from zero but inaccurate.

Question 53-33 : The float type fuel gauges provide information on ?

Volume whose indication varies with the temperature of the fuel.

Question 53-34 : The sensors used to measure the exhaust gas temperature on an aircraft equipped with gas turbine engine are ?

Thermocouples.

A thermocouple type thermometer consists of two metal conductors of different type connected at two points the operating principle of a thermocouple is a conductor that is subject to a thermal gradient generates a voltagethis voltage is measured and interpreted by a thermocouple thermometer millivoltmeter

Question 53-35 : The measurement of the turbine temperature or of the tgt turbine gas temperature is carried out at the ?

High pressure turbine outlet.

A thermocouple type thermometer is located between the hp turbine and lp turbine allowing the measurement of the turbine temperature

Question 53-36 : The two main sources of information used to calculate turbojet thrust are the ?

Fan rotation speed or n1 or the epr engine pressure ratio .

Question 53-37 : The advantages of an electric fuel float gauge are 1 easy construction2 independence of indications with regard to airplane attitude3 independence of indications with regard to the accelerations4 independence of indications with regard to temperature variations5 independence of indications with ?

1.

In 1904 the first float arm gas gauge appeared a float mounted on a hinged arm moved a mechanical pointer on gauge on the outside of the fuel tank to indicate the fuel levelidea was taken one step further when vehicles started to get better electrical systems by connecting the hinged float arm to a rheostat this allows an electrically operated fuel gauge to be mounted in the vehicle's dashboard and that's the basic operating principle that's still in use todaybut airplane attitude and accelerations will affect the accuracy of the indication due to the movements of the fuel in the tank temperature will modify the volume thus the indication

Question 53-38 : The disadvantages of an electric fuel float gauge are 1 the design is complex 2 the indications are influenced by the airplane attitude variations 3 the indications are influenced by the accelerations 4 the indications are influenced by temperature variations 5 that an alternative current supply ?

2 3 4.

Question 53-39 : On an electronic flight instrument system efis the following fuel flow parameters may be displayed 1 present fuel flow of each engine2 mean fuel flow over 1 minute3 maximum admission fuel flowthe combination regrouping all the correct statements is ?

1.

An efis displays fuel flow to engine it displays also fuel used since last reset fuel flow is usually shown in kilograms per hour

Question 53-40 : The aircraft outside air temperature probe measures the ?

Total air temperature minus kinetic heating effects in order to obtain the static temperature.

This question has been seen in july 2022 with this correct answer total air temperature this must be corrected for ram rise and recovery factor to obtain the static air temperature the other wrong answers remain unchanged