Module 15 : Gas Turbine Engine
Final Practice Test
- A jet engine derives its thrust by ?
- reaction of the propelling gases
- impingement of the propelling gases on the outside air
- drawing air into the compressor
- The working fluid of a gas turbine engine is ?
- kerosene
- air
- gasoline
- In a twin spool compressor system, the first stage turbine drives the ?
- N1 and N2 compressors
- N2 compressor
- N1 compressor
- The term Pt7 means ?
- the total pressure at station No. 7
- the total inlet pressure
- pressure and temperature at station No. 7
- The pressure of supersonic air as it flows through a divergent nozzle?
- is inversely proportional to the temperature
- increases
- decreases
- A gas turbine engine comprises which three main sections?
- Compressor, diffuser, and stator
- Turbine, compressor, and combustion
- Turbine, combustion, and stator
- In what section of a turbojet engine is the jet nozzle located ?
- Turbine
- Exhaust
- Combustion
- The Brayton cycle is known as the constant ?
- mass cycle
- pressure cycle
- temperature cycle
- Standard sea level pressure is ?
- 29.00 inches Hg
- 29.29 inches Hg
- 29.92 inches Hg
- A turboprop engine derives its thrust by ?
- reaction of the prop-wash
- reaction of the propulsion gases
- impingement of the prop-wash on the outside air
- Adiabatic compression is ?
- one where there is no loss or gain of heat
- one where there is an increase in kinetic energy
- an isothermal process
- In a ducted fan engine, the fan is driven by the ?
- air passing over the compressor
- turbine
- accessory gearbox
- On a gas turbine engine, what is the fan driven by?
- I P turbine
- H P turbine
- LP turbine
- The density of gas may be expressed as ?
- volume/weight
- pressure/volume
- weight/volume
- A divergent duct will cause subsonic flow to decrease in ?
- velocity, pressure remains constant
- velocity, increase pressure
- pressure, increase velocity
- The purpose of a diffuser is to ?
- induce a swirl to the air prior to combustion
- increase the static pressure of the air
- increase the kinetic energy of the air
- On a triple spool engine, the first stage of turbines drive ?
- the LP compressor
- the I P compressor
- the HP compressor
- What type of oil is used in a gas turbine engine?
- Phosphate Ester
- Synthetic
- Mineral
- The hottest casing is the ?
- combustion chamber
- L.PT
- H.PT
- Oil pressure and scavenge pumps are usually ?
- multi-plunger pumps
- spur gear pumps
- diaphragm pumps
- After placing an engine into storage, details would be recorded in ?
- Engine log book
- Technical Log
- Aircraft log book
- Installed engines must be re-preserved after preservation at least every ?
- six weeks
- six days
- six months
- What would be indicative of a hung start?
- High E.G.T
- Engine would fail to reach self sustaining speed
- Starter would fail to disengage
- A rotation pad on an accessory drive gear box is provided for ?
- N2 rotation
- Alternate tachogenerator fitment
- F1 rotation
- During start, if a bleed valve is stuck closed ?
- E.G.T is unaffected
- E.G.T will be higher than normal
- E.G.T will be lower than normal
- Galling is a condition caused by excessive?
- scoring
- chafing
- temperatures
- If a compressor surge occurs, it is recognized by ?
- coughing in the compressor and vibration
- fluctuating RPM and fuel flow
- fluctuating E.G.T and thrust
- A hot start refers to?
- too much fuel being supplied
- early ignition
- high E.G.T before idle RPM is achieved
- What may be an indication of a bleed valve stuck in the closed position?
- Compressor stalling at low RPM
- Low E.G.T reading
- Over speed
- Engine oil sampling analysis is taken?
- after engine shut down
- when oil level is high
- at specific time after engine shut down
- Methyl Bromide fire extinguisher are installed with neck ?
- at the bottom
- at the top
- horizontal
- The most satisfactory extinguishing agent for an electrical fire is?
- carbon tetrachloride
- methyl bromide
- carbon dioxide
- A continuous loop fire detector is what type of detector?
- Overheat detector
- Spot detector
- Rate of temperature rise detector
- How is the fire extinguishing agent distributed in the engine section ?
- Nitrogen pressure and slinger rings
- Spray nozzles and fluid pumps
- Spray nozzles and perforated tubing
- A fuel or oil fire is defined as a ?
- class C fire
- class B fire
- class A fire
- Forward engine mounts take which loads ?
- Thrust, vertical and shear loads
- Centrifugal, thrust and axial
- Thrust, vertical and impact
- Auxiliary power units provide?
- pneumatic and electrical power
- hydraulic and pneumatic power
- hydraulic and electrical power
- An A.P.U is?
- a self contained variable speed gas turbine engine
- a reserved engine in case of a main engine failure
- a self contained constant speed gas turbine engine
- On a twin spool turbo-shaft engine, the free turbine is connected to the ?
- L.P gearbox
- Output gearbox
- H.P gearbox
- What type of reduction gear is used on most turboprop modern engines ?
- Helical cut parallel spur gears
- Straight cut parallel spur gears
- Epicyclic reduction gear
- Fuel trimming on a turboprop engine is?
- governor controlled
- automatic
- pilot controlled
- Water or water/methanol injected into the combustion chamber inlet increases?
- combustion chamber outlet temperatures
- mass airflow through the turbine
- fuel to air ratio by up to 20%
- Water methanol injection will increase thrust by up to?
- 70%
- 50%
- 30%
- Integrating fuel flow gives ?
- total fuel consumed
- fuel flow and acceleration
- average fuel flow
- E.G.T thermocouples are usually made of?
- chromel and platinum
- chromel and alumel
- nickel and platinum
- A thermocouple indicator is basically a ?
- milliohmeter
- milliammeter
- millivoltmeter
- Where is Turbine Outlet Temperature (T.O.T) measured?
- Downstream of the turbine
- Upstream of the turbine
- In the combustion chamber
- oil temperature thermocouples are usually constructed of ?
- alumel constantan
- iron constantan
- chromel alumel
- What power is required for E.G.T gauge indication?
- 115V AC
- 28V DC
- No power - it is self generating
- Fuel flow indication is taken from ?
- after the LP pump
- after the H.P pump
- after either H.P Pump or LP Pump
- The resistor in a D.C. starter motor?
- prevents over speed
- prevents current surge when motor is at low rpm
- used when D.C. motor fails
- An aircraft flying through heavy rain may use, as a precaution?
- continuous ignition
- engine intake deicing
- airframe deicing
- The field of the D.C. starter motor used on gas turbine engine is ?
- shunt or compound
- series or compound
- series only
- The type of ignition system used on most turbine aircraft engines is?
- low tension
- capacitor discharge
- high resistance
- What type of turbine blade is most commonly used in air starter motors?
- Impulse-reaction
- Reaction
- Impulse
- As air is bled off the engine, EGT will?
- increase
- decrease
- remain constant
- Turbine case cooling utilizes?
- LP compressor air
- Fan air
- HP compressor air
- Engine anti-ice is taken AIR from the ?
- Turbine
- LP compressor
- HP compressor
- When does E.E.C channel change over occur?
- On fault
- On engine shut down
- On engine start up
- Fuel boost pumps are cooled using?
- Fuel pumps do not require cooling
- Fuel
- Ram air
- When FADEC is in normal mode ?
- channel A or B will be in command
- channel A will be in command
- channel B will be in command
- In-Flight the engine E.E.C controls ?
- EGT
- Throttle position
- Fuel flow
- Which of the following turbine fuel filters has the greatest filtering action?
- Small wire mesh
- Micron
- Stacked charcoal
- The swash plate in a fuel pump, when static is?
- at some intermediate position
- in the minimum position
- in the maximum position
- A fuel heater prevents?
- HP filter icing
- LP filter icing
- Neither
- The fuel pump plungers are lubricated by?
- synthetic anti-freeze oil
- grease packed bearings
- the Fuel
- Specific fuel consumption at altitude will?
- decrease
- remain constant
- increase
- A spur gear pump operating in a lubrication system promotes?
- low flow at high pressure
- low flow at low pressure
- high flow at low pressure
- A full flow oil system has?
- a hot and cold oil pressure limit
- a variable oil pressure dependant upon throttle setting
- a single fixed minimum oil pressure
- What type of oil system is usually found on turbine engines?
- Dry sump, dip, and splash
- Wet sump, spray, and splash
- Dry sump, pressure, and spray
- Which of the following is a function of the fuel oil heat exchanger on a turbojet engine?
- Increases fuel temperature
- Aerates the fuel
- Emulsifies the oil
- Calorific value is the?
- vaporisation point of fuel
- amount of heat or energy in one pound of fuel
- fuel boiling temperature
- A fuel system icing inhibitor is a fuel additive which?
- prevents the water in the fuel freezing
- prevents the fuel from freezing
- prevents both the water and the fuel freezing
- Kerosene will burn effectively at an air/fuel ratio of ?
- 45:1
- 150:1
- 15:1
- Taper roller bearings accept loads in which direction ?
- Radial and axial in both directions
- Radial and axial in one direction only
- Axial loads only
- Indentations on bearing races caused by high static loads are known as ?
- brinelling
- galling
- fretting
- A carbon seal has which type of sealing arrangement ?
- Full contact with casing
- Full contact with race
- Full contact with labyrinth
- On a Clamshell door type thrust reverser, The Clamshell doors redirect the exhaust gas stream?
- 45 degrees to the thrust line
- 90 degrees to the thrust line
- 0 degrees to the thrust line
- A convergent exhaust nozzle produces mainly ?
- momentum and pressure thrust
- momentum thrust
- pressure thrust
- Exhaust noise can be reduced by ?
- lowering the vibration frequency
- increasing the jet velocity
- increasing the mixing rate
- A Convergent-Divergent nozzle ?
- requires the aircraft to be travelling at supersonic speeds
- makes maximum use of Pressure thrust
- produces a type of thrust known as kinetic thrust
- A choked nozzle ?
- has no effect on the thrust
- increases thrust
- decreases thrust
- A slow constant growth in a turbine blade is known as?
- primary creep
- secondary creep
- tertiary creep
- Turbine engine components are never manufactured by ?
- electrical resistance welding
- argon arc welding
- gas welding
- What are blue and golden deposits evidence of, on a turbine blade ?
- Titanium
- Aluminium
- Magnesium
- An increase in turbine diameter is caused by ?
- prolonged high temperatures and centrifugal loads
- products of combustion
- over speed
- Creep, overall ?
- has no effect on turbine diameter
- decreases turbine diameter
- increases turbine diameter
- Why are nozzle guide vanes fitted ?
- To increase velocity of the air flow
- To increase velocity of the gas flow
- To decrease velocity of the gas flow
- The three main types of turbine blades are ?
- impulse, vector, and impulse-vector
- reaction, converging, and diverging
- impulse, reaction, and impulse-reaction
- A combustion chamber has a ?
- convergent inlet, divergent outlet
- convergent inlet, convergent outlet
- divergent inlet, convergent outlet
- Fuel nozzles are cleaned ?
- in-situ with detergent solution
- in-situ with carbon solution
- with a rag and solvent
- Secondary air in the combustion chamber is used for ?
- cooling
- combustion
- increasing axial velocity of gases