EASA : Module15 Gas Turbine Engine Question
EASA : Module15 Gas Turbine Engine Question-Answer
A turbo jet engine gives.
a) large acceleration to a small mass of air.
b) large acceleration to a large weight of air.
c) small acceleration to a large mass of air.
Ans:A
The highest turbine bearing temperature takes place
a) at shutdown
b) at start-up
c) all the time
Ans:A
On an EGT thermocouple system, the hot junction
a) is placed downstream of the combustion chamber
b) is placed up stream of the combustion chamber
c) is placed in cockpit
Ans:A
Increasing ram effect with increased speed
a) reduces thrust due to reduced turbine temperature
b) reduces thrust due to reduced compressor efficiency
c) increases thrust due to increased maximum airflow
Ans:C
On an rpm system using a synchronous generator, the pointer is deflected by
a) potentiometer
b) ac servomotor
c) wheatstone bridge
Ans:B
Fuel system inhibiting oil is
a) kerosene
b) mineral oil
c) light anti-freeze oil
Ans:B
Fire detection systems which are routed through another zone
a) must be protected by the use of heat sinks
b) must be protected from heat sources in the zone
c) are not allowed
Ans:B
Torque pressure is usually read from
a) direct reading pressure gauge
b) torque meter
c) tension gauge
Ans:A
A high bypass engine results in
a) overall slower airflow and greater propulsive efficiency
b) overall faster airflow
c) greater propulsive efficiency
Ans:A
Shrouded blades allow
a) higher turbine inlet temperatures
b) thinner more efficient blade sections to be used
c) smaller inlets to be used
Ans:B
When using Prist or Biopor
a) It is left and burnt with the fuel
b) it is flushed out immediately
c) it is diluted with water to a 3-1 mix
Ans:A
NGV's form
a) parallel ducts
b) convergent ducts
c) divergent ducts
Ans:B
In the combustion chamber
a) static pressure and volume remains constant
b) static pressure decreases slightly and volume increases
c) static pressure and volume decreases
Ans:B
On an injection system
a) town water/methanol is injected
b) methanol is injected neat
c) de-mineralized water/methanol is injected
Ans:C
The working fluid of constant speed drive (CSD) is
a)taken from the engine lubrication system
b) within the unit
c)from separate tank
Ans:B
Pipe, electrical cables and associated components of a fire-detection system should be
a) fire proof
b) fire resistant
c) fire retardant
Ans:B
The drag cup in a Tacho-generator is balanced by
a) calibrated hairspring
b) adjustment screw
c) adjustable counterbalance weights
Ans:A
After placing an engine in a MVP envelope
a) check humidity indicator after 24 hours
b) check humidity indicator after 12 hours
c) check humidity indicator after 48 hours
Ans:A
The EPR system reads just over 1
a) this is a normal condition and does not need attention
b) the system has failed and needs attention
c) the system needs re-calibration back to “1”
Ans:C
On a vapour proof cocoon, there is a
a) temperature indicator
b) moisture indicator
c) humidifier
Ans:B
When an installed engine is not to be used for a period of up to 7 days
a) it is necessary to inhibit the engine
b) it is only necessary to blank off all apertures
c) run the engine as prescribed in the Flight Manual
Ans:B
With a decrease in fuel SG, what is the result on uncompensated governor?
a) Max RPM up
b) Max RPM decrease
c) No effect
Ans:A
Installed engines must be re-preserved after preservation at least every
a) six months
b) six days
c) six weeks
Ans:A
At altitude idling rpm is
a) higher than at sea level
b) lower than at sea level
c) same as at sea level
Ans:A
In a choked nozzle velocity increases
a) pressure decreases
b) pressure increases
c) density decreases
Ans:B
When the engine is not running. The EPR gauge shows 1.0 then
a) the transmitter is faulty
b) it is normal
c) the receiver is faulty
Ans:B
Fuel flow indication is taken from
a) after either HP Pump or LP Pump
b) after the HP pump
c) after the LP pump
Ans:A
The test switch of a continuous loop detector gives a
a) continuity check
b) bonding check
c) insulation check
Ans:A
When using water methanol in an axial flow compressor, it is injected in
a) burner
b) compressor inlet or burner section
c) intake
Ans:B
What are the types of continuous fire detection system?
a) Capacitance and resistance
b) Capacitance
c) Inductance and capacitance
Ans:AThe inlet door on a variable geometry intake is open at
a) subsonic speeds
b) supersonic speeds
c) idle speed
Ans:A
The compensation device on an EGT system must be re-calibrated after
a) manufacture and overhaul
b) each time a part of the system is replaced
c) does not need calibration
Ans:C
A supersonic duct is
a) convergent then divergent along length
b) divergent then convergent along length
c)a convergent duct that is choked at the largest end at mach 1
Ans:A
Noise from the jet wake when untreated by suppression is
a) low frequency, high decibel
b) high frequency, high decibel
c) low frequency, low decibel
Ans:A
When testing an EGT system
a) the OAT is neglected
b) the OAT is always taken into consideration
c) OAT is only taken into consideration when over 20oC
Ans:B
A free turbine is usually found on a
a) turbo- fan
b) turbo-jet
c) turbo prop
Ans:C
If the LP shaft shears
a) turbine runaway occurs
b) compressor overspeed occurs
c) compressor underspeed occurs
Ans:A
A turbo-shaft engine has
a) a mechanical connection between compressor and turbine
b) the power shaft is not connected to the compressor
c) none of the above
Ans:B
Normal fuel/air ratio for successful combustion is
a) 15:1
b) 10:1
c) 25:1
Ans:A
A magnetic chip detector inspection should be carried out
a) within a specified time from shut down
b) with engine running
c) with engine cold
Ans:C
A fire wire is installed
a) to withstand inertia, vibration, etc, encountered during normal
operation
b) vertically
c) horizontally
Ans:A
APU has
a) automatically controlled thrust and is self contained
b) constant speed and is self contained
c) variable speed and is self contained
Ans:B
Anti-ice is recommended during
a) OAT below –10oC
b) thunderstorms
c) OAT +10oC and visible moisture
Ans:C
Of the following, which engine type would most likely have a noisesuppresser unit installed?
a) Turboprop
b) Turbojet
c) Turboshaft
Ans:B
Bleed valves are normally spring loaded to the
a) closed position
b) mid-position
c) open position
Ans:B
Foreign object damage on compressor, when boroscoping is indicated by
a) tip curl
b) nicks and scores
c) flats
Ans:C
A magnetic chip detector detects
a) particles held in suspension
b) ferrous particles only
c) particles which are too small for the naked eye
Ans:A
Resistive and capacitive type firewires are tested with
a) megger/ohmeter
b) megger/voltmeter
c) multimeter
Ans:A
Engine anti-ice is taken from the
a) HP compressor
b) LP compressor
c) turbine
Ans:A
Fire wire clips have rubber in them to
a) insulate the fire wire electrically
b) stop heat transfer to the element
c) support the wire
Ans:C
The symbol for designating the speed of a LP compressor in a twinspool engine is
a) NG
b) N
c) N1
Ans:A
APU shut down is initiated by
a) low oil pressure, fire warning
b) low oil pressure, fire warning, hot oil temperature
c) high oil pressure, fire warning, hot oil temperature
Ans:B
What happens when bulb type thermometer resistive element goes open circuit?
a) Reads less than ambient
b) Reads more than ambient
c) No reading given
Ans:B
A fixed throttle with increased mass airflow
a) EPR goes up
b) EPR goes down
c) EPR remains constant
Ans:B
Fuel heater prevents
a) HP filter icing
b) LP filter icing
c) Neither
Ans:B
When a volume of air is compressed
a) no heat is lost or gained
b) heat is lost
c) heat is gained
Ans:C
On a FADEC engine the EEC
a) has electronic control of the hydro-mechanical fuel control unit in all modes
b) has electronic control of the hydro-mechanical fuel control in some modes
c) has mechanical control of the hydro-mechanical fuel control system
Ans:A
Fire extinguishers work by
a) combining with remaining oxygen to get rid of it
b) creating more oxygen
c) reducing oxygen
Ans:A
The air used for combustion is
a) Primary
b) Secondary
c) Primary and secondary
Ans:A
Compression occurs
a) across rotors
b) across stators
c) across stators and rotors
Ans:C
Ignitor plugs are cleaned by
a) compressed air and brushing lightly with soft brush
b) light sand blasting
c) steel wool
Ans:A
On a FADEC engine, the channel reset
a) always selects A channel
b) selects standby which becomes active on the next start
c) selects B channel
Ans:B
HEIU works by
a) a contact breaker
b) a discharging capacitor
c) ac busbar
Ans:B
Water methanol for cooling is injected
a) compressor inlet or outlet
b) combustion chamber
c) engine hot zone
Ans:A
On an axial flow, dual compressor forward fan engine, the fan turns the same speed as the
a) high pressure compressor
b) low pressure turbine
c) forward turbine wheel
Ans:B
A bypass engine LP compressor
a) supplies less air than is required for combustion
b) supplies more air than is required for combustion
c) supplies only the required quantity of combustion
Ans:B
A turbo jet engine gives
a) small acceleration to a large mass of air
b) large acceleration to a small mass of air
c) large acceleration to a large weight of air
Ans:B
A jet engine derives its thrust by
a) drawing air into the compressor
b) impingement of the propelling gases on the outside air
c) reaction of the propelling gases
Ans:C
In a reverse flow system the last stage of an axial flow compressoris often centrifugal, this is to
a) provide initial turning of the airflow
b) prevent compressor surge
c) increase the temperature rise
Ans:A
In a free turbine
a) there is a clutch between compressor and power output shaft
b) there is no mechanical connection with the compressor
c) there is a direct drive with a free-wheel unit
Ans:B
If an electrical de-icing system is operating, thrust will
a) decrease
b) increase
c) remain constant.
Ans:C
A method of comparing engine efficiencies is by comparing
a) thrust to weight ratio
b) fuel consumption
c) specific fuel consumption
Ans:C
"Ram effect" due to aircraft forward speed will cause the efficiency of the engine to
a) remain constant
b) increase
c) decrease
Ans:B
The efficiency of a gas turbine engine at altitude
a) decreases
b) increases
c) remains constant
Ans:B
Bernoulli's Theorem states that at any point in a flow of gas
a) the static pressure is less than the dynamic pressure
b) the static pressure and dynamic pressure are equal
c) the total energy remains constant
Ans:C
A bypass ratio of 5:1 indicates that the bypass flow is
a) equal to 1/5 of the hot stream
b) five times the cold stream
c) five times the hot stream
Ans:C
In a turbo jet engine, combustion occurs at
a) constant velocity
b) constant volume
c) constant pressure
Ans:C
The working fluid of a gas turbine engine is
a) air
b) gasoline
c) kerosene
Ans:A
As subsonic air flows through a convergent nozzle the velocity
a) increases
b) decreases
c) remains constant
Ans:A
The stator vanes in an axial-flow compressor
a) convert velocity energy into pressure energy
b) convert pressure energy onto velocity energy
c) direct air into the first stage rotor vanes at the proper angle
Ans:A
What units in a gas turbine engine aid in stabilisation of thecompressor during low thrust engine operations?
a) Bleed air valves
b) Stator vanes
c) Inlet guide vanes
Ans:A
A nozzle is ‘choked’ when the gas flow or air flow at the throat is
a) subsonic
b) sonic
c) supersonic
Ans:B
In the dual axial-flow or twin spool compressor system, the firststage turbine drives the
a) N1 and N2 compressors
b) N2 compressor
c) N1 compressor
Ans:B
During the high RPM range on an axial flow gas turbine engine, inwhat position are the variable intake guide vanes and bleed valves
a) at maximum swirl position, bleed valves open
b) at maximum swirl position, bleed valves closed
c) at minimum swirl position, bleed valves closed
Ans:C
When reheat is used, EPR
a) is reduced
b) is increased
c) remains constant
Ans:C
Which of the following units are generally used to measure aircraft noise?
a) Decibels (dB)
b) Effective perceived noise decibels (EPNdB)
c) Sound pressure
Ans:B
What is the maximum practical angle through which the gas flow can be turned during thrust reversal?
a) 180o
b) 135o
c) 50o
Ans:B
A carbon seal has which type of sealing arrangement?
a) Full contact with race
b) Full contact with labyrinth
c) Full contact with casing
Ans:A
On a FADEC engine
a) A and B channel use the same phases of the motor
b) A channel uses control alternator and B channel uses aircraft bus power
c) A channel uses a separate winding of the control alternator to B
channel
Ans:C
A bellmouth compressor inlet is used on
a) aircraft with low ground clearance
b) helicopters
c) supersonic aircraft
Ans:B
Electrical de-icing operates
a) cyclically independent of ambient air temperature
b) cyclically dependent on ambient air temperature
c) continuously and intermittently
Ans:C
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