Exam 2 Flashcards
Blocker doors moving to blank off the bypass fan air exit and redirect it forward on a high bypass turbofan, describes:
A clamshell reversers.
B blade reversers.
C bucket reversers.
D cold-stream reversers.
.D
What is the most critical engine condition instrument to monitor during engine start?
A N1.
B EPR.
C Turbine temperature.
D Fuel flow.
C.
If the relative humidity of the air through which an aircraft is flying increases significantly, thrust will tend to:
A increase, because of the increase in air density.
B decrease, because of the decrease in air density.
C remain the same, since the density of the air remains the same.
D decrease, because of the increase in air density.
B.
After an engine fire has been extinguished, no attempt should be made to restart the engine. Apart from the fact that a restart would re-introduce fuel and ignition to the engine, what other reason is of considerable importance?
A The engine will be contaminated with extinguishant.
B A Mayday call would have been made.
C The engine will be starved of oil.
D The extinguishing system will be diminished.
D.
Turbine engine fuel systems commonly include a heat exchanger. One reason for this is to protect against:
A. absorption of atmospheric water vapour.
B. Coverheating in the fuel lines.
C. the possibility of ice formation in the fuel.
D. additives separating from the fuel.
C.
Newton’s first law states that:
A. a body will remain in a state of uniform motion unless acted on by an external force.
B. force equals mass times acceleration.
C. PV = NRT
D. for every action there is an equal and opposite reaction.
.A
Exhaust gas temperature (EGT) indication systems operates by means of:
A. a combination of pyrometers and/or pyrocouples, arranged linearly.
B. a combination of thermometers and thermocouples, arranged in series.
C. a number of thermocouples, arranged in parallel.
D. a number of thermocouples or pyrometers, arranged in series.
C.
Newton’s second law states that:
A. for every action there is an equal and opposite reaction.
B. a body will remain in a state of uniform motion unless acted on by an external force.
C. opposites attract.
D. force equals mass times acceleration
D.
The primary function of air seals within a turbine engine is to:
A. pressurise the compressor rotor area and cool the hot section areas.
B. pressurise labyrinth and carbon seals.
C. prevent ram air from escaping the air inlet system.
D. prevent turbine outlet air from escaping the nozzle system.
B.
What percentage of normal forward thrust is normally achieved and used for reverse thrust, during reverse thrust operation?
A. Somewhat less than 50%.
B. 100%.
C. About 135%.
D. About 10%.
A.
- Pressure-thrust comes from flow which becomes sonic at the throat of a ________________ exhaust nozzle.
A convergent-divergent
B convergent
C divergent
D divergent-convergent
A.
Which of the following types of turbine engine can be described as a ducted propeller?
A) An aft fan, or hyper ducted fan.
B) A propfan.
C) A turboprop.
D) A turbofan.
D.
Bleeding significant amounts of air off the compressor leads to:
A) a decrease in engine efficiency.
B) a decrease in turbine temperature.
C) surging.
D) an increase in the chances of a compressor stall.
A.
What additional airframe components are often added to turboprop and turboshaft engined aircraft?
A) Vortex generators to impart swirl to the intake air in order to reduce the possibility of FOD ingestion.
B) Air intake protection devices such as particle separators, screens or bird catchers.
C) Shockwave inducing baffles.
D) Geared superchargers.
B.
What is the normal shape of the duct formed by the exhaust nozzle on a subsonic turbofan engine?
A) Divergent-convergent.
B) Convergent.
C) Constant diameter.
D) Divergent.
B.
Turbine engine ignition systems have both high and low energy capabilities. What is the purpose of the high energy system?
A) For use in turbulent conditions.
B) For in-flight engine starting.
C) For takeoff in heavy rain.
D) For use in icing conditions.
B.
With increasing temperature and high RPM, turbine blades lengthen. When the engine shuts down the blades return to normal size. With time, the blades will not return to quite the old size. What is this phenomenon called?
A) Expansion.
B) Fatigue.
C) Creep.
D) Hysteresis.
C.
The pressurisation of the air entering the intake, caused by the aircraft’s forward speed, is known as:
A) pilot pressure.
B) intake rise.
C) RAM effect.
D) P1.
C.
How does the temperature, density, pressure and velocity of a gas flow vary through a convergent duct at subsonic speed?
A) Temperature and pressure increase, while velocity and density decreases.
B) Temperature and pressure decrease, while velocity and density increases.
C) Temperature, density and pressure all increase, while velocity decreases.
D) Temperature, density and pressure all decrease, while velocity increases.
D.
Fuel exhaustion, compressor stall, high altitude flight, severe turbulence and high speed manoeuvres can all cause what phenomenon in a jet engine?
A) Reverse flow.
B) Over-temperature.
C) Flame-out.
D) Surging.
C.
What type of oil pump is generally utilised on turbine engines?
A) A piston and plunger type.
B) A variable displacement type.
C) A sliding vane type.
D) A gear type.
D.
What is best described as a system having multiple stages of rotating aerofoil blades and fixed vanes, large mass flow with high efficiency.
A) A reciprocating compressor.
B) A turbocharger.
C) An axial flow compressor.
D) A centrifugal compressor.
C.
Which of the following is an advantage of a free turbine propulsion system?
A) With a free turbine propulsive system the start is must slower and therefore less fuel is used during the start.
B) With a free turbine propulsive system the propellor or helicopter rotor can be held stationary while the engine is started, or stopped while the engine is still running.
C) With a free turbine propulsive system there is significantly less complexity, so the engine is easier and cheaper to manufacture.
D) With a free turbine propulsive system the shaft is connected directly to the propeller or helicopter rotor, so no gearbox is required, thereby significantly reducing the overall weight of the respective aircraft type.
B.
What will the effect on specific fuel consumption (SFC) and specific thrust be by increasing the compressor pressure ration of an engine?
A) SFC and specific thrust decreased.
B) SFC increased and specific thrust decreased.
C) SFC and specific thrust increased.
D) SFC decreased and specific thrust increased.
D.
