|On an axial flow, dual compressor forward fan engine, the fan turns the same speed as the high pressure compressor low pressure turbine forward turbine wheel.
A by-pass engine LP compressor supplies less air than is required for combustion supplies more air than is required for combustion supplies only the required quantity of combustion.
A turbo jet engine gives small acceleration to a large mass of air large acceleration to a small mass of air large acceleration to a large weight of air.
A jet engine derives its thrust by drawing air into the compressor impingement of the propelling gases on the outside air reaction of the propelling gases.
In a reverse flow system the last stage of an axial flow compressor is often centrifugal, this is to provide initial turning of the airflow prevent compressor surge increase the temperature rise.
In a free turbine there is a clutch between compressor and power output shaft there is no mechanical connection with the compressor there is a direct drive with a free-wheel unit.
If an electrical de-icing system is operating, thrust will decrease increase remain constant.
A method of comparing engine efficiencies is by comparing thrust to weight ratio fuel consumption specific fuel consumption.
"Ram effect" due to aircraft forward speed will cause the efficiency of the engine to remain constant increase decrease.
The efficiency of a gas turbine engine at altitude decreases increases remains constant.
Bernoulli's Theorem states that at any point in a flow of gas the static pressure is less than the dynamic pressure the static pressure and dynamic pressure are equal the total energy remains constant.
A bypass ratio of 5:1 indicates that the bypass flow is equal to 1/5 of the hot stream five times the cold stream five times the hot stream.
In a turbo jet engine, combustion occurs at constant velocity constant volume constant pressure.
The working fluid of a gas turbine engine is air gasoline kerosene.
As subsonic air flows through a convergent nozzle the velocity increases decreases remains constant.
The stator vanes in an axial-flow compressor convert velocity energy into pressure energy convert pressure energy onto velocity energy direct air into the first stage rotor vanes at the proper angle.
What units in a gas turbine engine aid in stabilisation of the compressor during low thrust engine operations? Bleed air valves Stator vanes Inlet guide vanes.
A nozzle is ‘choked’ when the gas flow or air flow at the throat is subsonic sonic supersonic.
In the dual axial-flow or twin spool compressor system, the first stage turbine drives the N1 and N2 compressors N2 compressor N1 compressor.
During the high RPM range on an axial flow gas turbine engine, in what position are the variable intake guide vanes and bleed valves at maximum swirl position, bleed valves open at maximum swirl position, bleed valves closed at minimum swirl position, bleed valves closed.
When reheat is used EPR Is reduced Is increased Remains constant.
Which of the following units are generally used to measure aircraft noise? decibels (dB) Effective perceived noise decibels (EPNdB) sound pressure.
What is the maximum practical angle through which the gas flow can be turned during thrust reversal? 180° 135° 50°.
A carbon seal has which type of sealing arrangement? full contact with race full contact with labyrinth full contact with casing.
On a FADEC engine A and B channel use the same phases of the motor A channel uses control alternator and B channel uses aircraft bus power A channel uses a separate winding of the control alternator to B channel.
A bellmouth compressor inlet is used on aircraft with low ground clearance helicopters supersonic aircraft.
Electrical de-icing operates cyclicly independent of ambient air temperature cyclicly dependent on ambient air temperature operates continuously.
The inlet door on a variable geometry intake is open at subsonic speeds supersonic speeds idle speed.
The compensation device on an EGT system must be re-calibrated after manufacture and overhaul each time a part of the system is replaced does not need calibration.
During start the ’starter light’ remains on after light up this should be neglected it should be monitored for 30 seconds and if still illuminated the engine should be shut down the engine should be shut down immediately.
Noise from the jet wake when untreated by suppression is low frequency, high decibel high frequency, high decibel low frequency, low decibel.
When testing an EGT system the OAT is neglected the OAT is always taken into consideration OAT is only taken into consideration when over 20°C.
A free turbine is usually found on a Turbo- fan Turbo-jet Turbo prop.
If the LP shaft shears turbine runaway occurs compressor overspeed occurs compressor underspeed occurs.
A turbo-shaft engine has a mechanical connection between compressor and turbine the power shaft is not connected to the compressor none of the above.
Normal fuel/air ratio for successful combustion is? 15:1 10:1 25:1.
A magnetic chip detector inspection should be carried out within a specified time from shut down with engine running with engine cold.
A fire wire is installed to withstand inertia, vibration, etc, encountered during normal operation vertically horizontally.
APU has automatically controlled thrust and is self contained constant speed and is self contained variable speed and is self contained.
Anti-ice is recommended during; when OAT is below –10°C thunderstorms when OAT is +10°C and visible moisture.
Of the following, which engine type would most likely have a noise suppresser unit installed? turboprop turbojet turboshaft.
Bleed valves are normally spring loaded to the closed position mid-position open position.
Foreign object damage on compressor, when boroscoping is indicated by tip curl nicks and scores flats.
A magnetic chip detector detects particles held in suspension magnetised particles particles which are too small for the naked eye.
Resistive and capacitive type firewires are tested with megger/ohmeter megger/voltmeter multimeter.
Engine anti-ice is taken from HP compressor LP compressor Turbine.
Fire wire clips have rubber in them to insulate the fire wire electrically stop heat transfer to the element support the wire.
The symbol for designating the speed of a single compressor engine is N.G N N1.
APU shut down is initiated by low oil pressure, fire warning low oil pressure, fire warning, hot oil temperature high oil pressure, fire warning, hot oil temperature.
What happens when bulb type thermometer resistive element goes open circuit? read less than ambient read more than ambient no reading given.
A fixed throttle with increased mass airflow EPR goes up EPR goes down EPR remains constant.
Fuel heater prevents HP filter icing LP filter icing Neither.
When a volume of air is compressed no heat is lost or gained heat is lost heat is gained.
On a FADEC engine the EEC has electronic control of the hydro-mechanical fuel control unit in all modes has electronic control of the hydro-mechanical fuel control in some modes has mechanical control of the hydro-mechanical fuel control system.
Fire extinguishers work by combining with remaining oxygen to get rid of it creating more oxygen reducing oxygen.
The air used for combustion is Primary Secondary Primary and secondary.
Compression occurs across rotors across stators across stators and rotors.
Ignitor plugs are cleaned by compressed air and brushing lightly with soft brush light sand blasting steel wool.
On a FADEC engine, the channel reset always selects A channel selects standby which becomes active on the next start selects B channel.
HEIU works by a contact breaker a discharging capacitor ac busbar.
Water methanol for cooling is injected compressor inlet or outlet combustion chamber engine hot zone.
The highest turbine bearing temperature takes place at shutdown at startup all the time.
On an EGT thermocouple system, the hot junction is placed downstream of the combustion chamber is placed up stream of the combustion chamber is placed in cockpit.
Increasing ram effect with increased speed reduces thrust due to reduced turbine temperature reduces thrust due to reduced compressor efficiency increases thrust due to increased maximum airflow.
On an rpm system using a synchronous generator, the pointer is deflected by potentiometer ac servomotor wheatstone bridge.
Fuel system inhibiting oil is kerosene mineral oil light anti-freeze oil.
Fire detection systems which are routed through another zone must be protected by the use of heat sinks must be protected from heat sources in the zone are not allowed.
Torque pressure is usually read from direct reading pressure gauge torque meter tension gauge.
A high bypass engine results in overall slower airflow and greater propulsive efficiency overall faster airflow greater propulsive efficiency.
Shrouded blades allow higher turbine inlet temperatures thinner more efficient blade sections to be used smaller inlets to be used.
When using Prist or Biopor It is left and burnt with the fuel it is flushed out immediately it is diluted with water to a 3-1 mix.
NGV's form parallel ducts convergent ducts divergent ducts.
In the combustion chamber static pressure and volume remains constant static pressure decreases slightly and volume increases static pressure and volume decreases.
On an injection system town water/methanol is injected methanol is injected neat de-mineralized water/methanol is injected.
The working fluid of constant speed drive (CSD) is taken from the engine lubrication system within the unit from separate tank.
Pipe, electrical cables and associated components of a fire-detection system should be fire proof fire resistant fire retardant.
The drag cup in a Tacho-generator is balanced by calibrated hairspring adjustment screw adjustable counterbalance weights.
After placing an engine in a MVP envelope check humidity indicator after 24 hours check humidity indicator after 12 hours check humidity indicator after 48 hours.
The EPR system reads just over 1 this is a normal condition and does not need attention the system has failed and needs attention the system needs re-calibration back to “1”.
On a vapour proof cocoon, there is a temperature indicator moisture indicator humidifier.
When an installed engine is not to be used for a period of up to 7 days it is necessary to inhibit the engine it is only necessary to blank off all apertures run the engine as prescribed in the Flight Manua.
With a decrease in fuel SG, what is the result on uncompensated govenor? max RPM up max RPM decrease no effect.
Installed engines must be re-preserved after preservation at least every six months six days six weeks.
At altitude idling rpm is Higher than at sea level Lower than at sea level Same as at sea level.
In a choked nozzle velocity increases pressure decreases pressure increases density decreases
When the engine is not running. The EPR gauge shows 1.0 then the transmitter is faulty it is normal the receiver is faulty.
Fuel flow indication is taken from after the fuel heater after the HP pump after the LP pump.
The test switch of a continuous loop detector gives a continuity check bonding check insulation check.
When using water methanol in an axial flow compressor, it is injected in burner compressor inlet or burner section intake.
What are the types of continuous fire detection system? Capacitance and resistance Capacitance Inductance and capacitance.
Secondary air in the combustion chamber is used for combustion cooling increasing axial velocity of gases.
Bleed valves are closed at low RPM closed at high RPM always slightly open .
Inlet guide vanes are anti-iced with: thermal blankets rubber boots engine bleed air .
How is engine oil usually cooled by a fuel/oil cooler by ram air by bleed air .
Thrust decreases with low temperature increases with low temperature increases with high temperature .
The highest pressure in a gas turbine is just after the last compressor stage but before the burner at the burner exit at the nozzle exit .
Duplex burners have variable orfices a spring two calibrated outlets .
When is ignition used at high altitudes for relight and start up for continuous relight .
What power is required for EGT gauge indication 115V AC 28V DC no power - it is self generating.
What filters are used to protect oil pressure spray jets mesh screen filters threads in line micronic filters .