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GAS TURBINE ENGINES
FUNDAMENTALS (1)
1. An example of a divergent duct is the....jet pipe at the exit from the turbine
2. A turbo-prop engine derives its thrust from...reaction of the prop-wash
3. On an axial flow, dual compressor forward fan engine, the fan turns the same speed as the....low pressure turbine
4. Jet nozzle is located...at the exhaust
5. Axial flow turbojet engine highest gas pressure occurs at...compressor outlet
6. If LP shaft shears....turbine runaway occurs
7. Density of gas....weight/volume
8. Heat and mechanical energy are mutually convertible and 1 CHU is equal to....1400ft/lbs
9. Turbojet engine gives....large acceleration to a small mass of air
10. ESHP....shaft horsepower + exhaust efflux
11. Engine most likely to have noise suppressor installed....turbojet
12. In a dual axial flow or twin spool compressor system with a free power turbine, Nf would indicate...free power turbine speed
13. The noise suppression system that increases the frequency of sound is termed....multi-lobe type nozzle
14. The accessory gearbox of a high bypass engine is....on the HP compressor housing
15. The purpose of a diffuser is to....increase the static pressure of the air
16. A gas turbine engine comprises 3 main sections....turbine, compressor and combustion
17. The hottest casing is the….HPT
18. Which has the better combination....centrifugal compressor, axial flow turbine, can type combustion chamber
19. Statement that is true for a high bypass ratio turbofan....the compressor assembly is larger and combustion chamber smaller than their turbojet equivalent
20. A waisted drive shaft is primarily to....provide a fuse if the driven component is overloaded
21. A turbojet engine is smoother running that a piston engine because....it has no reciprocating parts
22. Section that provides proper mixing of fuel and efficient burning of the gasses.....combustion section only
23. Unit generally used to measure aircraft noise....effective perceived noise decibels (EPNdB)
24. Core engine or gas generator made up of following components....turbine, combustion chamber, compressor
25. There is no peak pressure in a jet engine because of....continuous flow of air
26. A nozzle is choked when the gas flow through it is....sonic
27. A high bypass engine results in....overall slower airflow and greater propulsive efficiency
28. In a free turbine....there is no mechanical connection with the compressor
29. The advantage of a geared, fan type, dual spool engine is....a geared fan does not need a separate turbine to have a different speed from the compressor and the compressor is not limited to the fan speed
30. If a volume of a mass of air is 546 cubic feet at 273K, at 273K it will be....2 cubic feet greater
31. In a pure jet engine, the rate of pressure rise is greatest at the....compressor stage
32. Ram effect is....conversion of kinetic energy to pressure energy at the face of the compressor
33. Example of a divergent duct....jet pipe at the exit from the exhaust
34. Part of the jet engine has the most potential energy....just before the combustion chamber
ENGINE PERFORMANCE (2)
1. At constant RPM, the pressure ratio of the compressor and the temp rise across the compressor....remains constant irrespective of height
2. Method of comparing engine efficiencies is by comparing....specific fuel consumption
3. Engine section that will produce the most amount of discrete noise....turbine
4. Gas pressure is greatest at the....compressor outlet
5. Thrust rating on a FADEC engine can be changed by....changing the engine rating plug
6. The RPM for max power would be....lower on a colder day
7. As the speed of an aircraft increases, the momentum thrust of an engine will....decrease (momentum thrust is a product of the difference between aircraft speed and the jet efflux speed)
8. Specific fuel consumption for a turbo prop engine....decreases with increase in aircraft speed
9. Reduction in engine efficiency can be caused by....ice formation on air intake
10. Power is adjusted in a gas turbine engine by....increasing air and fuel flow
11. Ram recovery is the point at which intake....total pressure equals ambient pressure
12. The point of maximum velocity in the engine is in the....exhaust exit nozzle
13. Through turbine rotor blades, the pressure....decreases, temp and velocity decreases
14. To maintain the selected RPM of a gas turbine at altitude....the pilot will have to throttle back
15. Ultimate limiting factor of turbine engine operation....turbine inlet temp
16. Ram effect due to aircraft forward speed will cause the thrust of the engine to....remain constant
17. Increasing ram effect with increased speed....increases thrust due to increased maximum airflow
18. Temperature of the mass airflow through a gas turbine engine....increases from the inlet, thru the compressor and the diffuser into the burner and decreases thru the turbine into the exhaust
19. Most engines try to keep a uniform...flame temp
20. If the throttle position remains constant...with increasing OAT, RPM and TGT will increase
21. What happens to thrust as an aircraft climbs with a fixed throttle position....thrust decreases
22. Compressor type that gives the greatest advantage for both starting flexibility and improved high altitude performance....split spool, axial flow
23. Some turbo prop and turbojet engines are equipped with two spool or split compressors. When these engines are operated at high altitudes, the....low pressure rotor will increase in speed as the compressor load decreases in the lower density air
24. Effect of high atmospheric humidity have on the operation of a jet engine....has little or no effect
25. The engine rating plug is.....permanently connected to the engine casing
26. Ram recovery is a measure of....intake efficiency
27. The speed of the low pressure compressor increases as the inlet temp becomes colder because...the fuel controller senses the decreased T2 and schedules an increase in fuel flow to maintain the proper fuel air ratio with the denser air
28. Flat rated thrust is defined as....the thrust at the ambient temperature point above which thrust drops below 100%
29. With an increase in forward speed, the engine thrust...decreases slightly but recover due to ram effect
30. The propulsive efficiency is...high with a low mass flow acceleration
31. At constant RPM, the pressure ratio of the compressor and the temp rise across the compressor....remains constant irrespective of height
32. Across the turbines, there is....a general temp drop
33. Hottest component in a gas turbine engine is the....nozzle guide vanes
34. Statement that is true regarding jet engines....at higher engine speeds, thrust increases rapidly with small increases in RPM
35. Turbine inlet temp is approx....850-1700 degrees celcius
36. What effect does high atmospheric humidity have on the operation of a jet engine....has little or no effect
37. Ram pressure recovery will generally take effect at aircraft speeds of....Mach 0.1-0.2
38. Factor that limits EGT is the....turbine
39. The highest heat to metal contact in a jet engine is....the turbine inlet guide vanes
40. To ensure an engine maintains self sustaining speed....idle increases with density decrease
41. The main factor considered when designing an engine is....maximum turbine temp
INLET (3)
1. Intakes are designed to…decelerate the free air stream flow
2. The inlet door of a variable geometry intake at supersonic speeds will be…closed
3. The inlet door of a variable geometry intake is open at…subsonic speeds
4. A variable geometry intake at subsonic speeds…throat area is increased
5. The purpose of a bellmouth compressor inlet is to…maximize the aerodynamic efficiency of the inlet
6. What is true for a bellmouth intake (is a convergent duct)…velocity increases and pressure decreases
7. An increase in the Ram Ratio of an intake will…increase the temp of the air
8. Intake momentum drag causes…a decrease in thrust at low airspeeds
9. In a variable geometry intake, the velocity of the air on the engine compressor face is controlled by…shock-wave pattern, ramp and spill doors
10. In a subsonic multi-engine aircraft, a normal inlet duct will…increase in size front to rear along the length of the duct
11. With an electrical ice protection system, the heating elements operate…part continuous-part intermittent
12. A bellmouth compressor inlet is used on…helicopters
13. Variable Ramp Intakes restrict airflow by…creating shock-waves in the intake
14. The most efficient engine intake on subsonic or low supersonic aircraft is…pitot
15. A turboprop engine inlet anti-ice system operates….continuously
16. An aircraft flying at supersonic speed, to reduce the air velocity at the compressor, the variable intake….throat area is decreased
17. The cycling speed of the electrical de-icing mat….is affected by weather conditions
18. Ram Ratio in regard to air intakes is the relationship between….ambient pressure and compressor inlet pressure
19. Vortex dissipaters prevent engine FOD by…a stream of engine bleed air blown toward the ground ahead of the engine
20. Pitot type intakes are used in…subsonic aircraft
21. As an aircraft approaches the transonic range, the aerodynamic efficiency of a pitot type intake….decreases due to the shock wave
22. Electrical de-icing operates….continuously and intermittently
23. A well designed intake will take advantage of forward speed by…converting kinetic energy into pressure energy
24. The variable inlet guide vanes are operated….by fuel pressure
25. If an inlet is choked then the velocity….decreases and pressure increases
COMPRESSORS (4)
1. In a turbine engine with a dual spool compressor, the low speed compressor….seeks its own best operating speed
2. In flight, failure of compressor bleed valve (jammed open) will make engine run at….lower RPM than normal
3. In a dual compressor, the low pressure compressor (LPC) speed tends to change with….the CIT of LPC
4. On which blade type may a mid-span shroud most likely be used….long, narrow chord type blades
5. Advantage of centrifugal flow compressor is its high….pressure rise per stage
6. 2 types of centrifugal compressor impellers are….single entry and double entry
7. Pressure rise across a single spool axial flow compressor is in the order of….up to 15:1
8. During low RPM range, variable intake guide vanes and bleed valves area at….maximum swirl position and bleed valves open
9. Advantage of a multi-spool compressor is….quicker acceleration and better control of stall characteristics
10. Engine bleed at high speed is….sometimes open
11. Centrifugal compressor produces a compression ratio….lower than the axial flow compressor
12. Why in an axial flow compressor is the cross sectional area of the compressor air duct reduced at each stage….to maintain the velocity of the air under rising pressure
13. On a high bypass ratio engine, what medium operates the VBV….fuel pressure
14. Abradable lining around the fan is to….strengthen the EPR value
15. Compressor surge is caused by….over fuelling
16. Purpose of stator blades in the compressor section….control the direction of the airflow
17. Inlet guide vanes are fitted to….control the angle of airflow into the compressor
18. Type of combustion chamber is most suited for centrifugal compressors….multiple-can type
19. Surge margin of an axial flow compressors….the margin between the compressor working line and the surge line
20. A bleed valve….relieves compressor choking at low RPM
21. What is the function of the stator vane assembly at the discharge end of a typical axial flow compressor….to straighten airflow to eliminate turbulence
22. Which of the following can cause fan blade shingling in a turbofan engine….large, rapid throttle movements and FOD
23. Advantage of an axial flow over a centrifugal flow gas turbine engine….high peak efficiencies
24. What is the profile of a compressor blade….a cut out that reduces blade tip thickness
25. How does a dual axial flow compressor improve the efficiency of a turbojet engine….higher compression ratios can be obtained
26. The stator vanes in an axial-flow compressor….convert velocity energy into pressure energy
27. A function of a cascade vanes in a turbojet engine compressor section….to remove air swirl before the combustion chamber
28. Stall will occur in the high pressure stages of an axial flow compressor because….air mass flow is reduced when the compressor is turning at high speed
29. Purpose of bleed valve, located at the beginning stages of the compressor is to….vent some of the air overboard to prevent a compressor stall
30. No damage is permissible on….a shroud-fillet area
31. Air thru the compressor, before entering the combustion chamber passes….thru divergent passage to increase the pressure
32. Purpose of rotating guide vanes on a centrifugal compressor is to….direct the air smoothly into the impeller
33. Variable inlet guide vanes prevent….compressor stalling
34. The diffuser after the compressor, before the combustion chamber….decreases velocity, pressure increases
35. Cascade vanes in the intake of a centrifugal compressor are to….provide a pre-swirl to incoming air
36. A function of the cascade vane in a turbojet engine compressor section….to remove air swirl before the combustion chamber
37. Purpose of the diffuser vanes of a centrifugal compressor serve….to convert kinetic energy into pressure energy
38. An axial flow compressor surges when….all stages are stalled
39. Phase of engine operation will bleed valves be fully open….rapid deceleration
40. Compressor stage….one rotor plus one stator
41. Tip speed of a centrifugal compressor can reach….Mach 1.2 / 1.3
42. An axial flow compressor compresses the air by….diffusion
43. ‘Cascade Effect’ is related to….axial flow compressors
44. What is the normal pressure rise across each compressor stage of an axial flow compressor….1.2:1
45. Diffuser vanes are used in jet engines to convert….kinetic energy into potential energy thru divergence
46. Stator vanes in an axial-flow compressor….convert velocity energy into pressure energy
47. A compressor stage stalls when….smooth airflow is disrupted
48. Purpose of a counter-rotating spool in some dual or triple-spool compressors is….dampening gyroscopic effects
49. The optimum air speed for entrance into the compressor is approx….Mach 0.4
50. The effect of different stages in an axial flow compressor is….to multiply the pressure by each succeeding stage
51. An axial compressor case annulus is….convergent
52. If the RPM of an axial flow compressor remains constant, the angle of attack of the rotor blades can be changed by….changing the velocity of the airflow
53. Compressor stalls may be eliminated by using which of the following systems….compressor bleed-air system and variable vane system
54. The fan speed of a twin spool axial compressor engine is the same as the….low pressure compressor
55. The vanes of a diffuser in a centrifugal compressor….are tangential to the impeller
56. Primary factor which controls the pressure ratio of an axial flow compressor….number of stages in compressor
57. The compression ratio of an axial flow compressor is a function of….number of compressor stages
58. What units in a gas turbine engine aid in guiding the airflow during low thrust engine operations….inlet guide vanes
59. For any given power lever setting, the speed of the high pressure compressor is held constant by….the fuel control governor
60. Compressor stall is caused by….a high angle of attack airflow thru the first stages of compression
61. Energy changes that take place in the impeller of a centrifugal compressor are….pressure increase, velocity increase, temp increase
62. Compressor blades reduce in length….from LP to HP section to maintain uniform velocity in compressor
63. A bypass engine LP compressor….supplies more air than is required for combustion
64. Severe rubbing of turbine engine compressor blades will usually cause….galling
65. Stagger angle is used on the compressor blades to….maintain exit velocity of airflow at the same value along blade length
66. An axial compressor case annulus is….convergent (all axial flow compressor case annulus are convergent to maintain a constant axial velocity thru the compressor)
67. In an axial flow compressor is the cross sectional area of the compressor air duct reduced at each stage….to maintain the velocity of the air under rising pressure
68. The root of the compressor blades are loosely fitted to the compressor disks. This is because….it aids easy blade assembly and it provides a vibration damping effect
COMBUSTION SECTION (5)
1. A tubo-annular gas turbine combustion system consists of….a number of flame tubes in an annular air casing
2. Dilution air is placed….in the dilution zone of the combustion chamber after the primary zone
3. Why is it necessary to have a combustion chamber drain….to allow unburnt fuel to drain away….to prevent initial over-fuelling on start-up or hot start
4. A torodial vortex is….a region in the combustion chamber of low velocity recirculation
5. The main purpose of combustion is to….increase gas velocity
6. What is a cannular combustion system….a set of flame tubes, enclosed in a common air casing
7. Another name for a cannular combustion chamber is….can-annular
8. Duplex burners have….two calibrated outlets…one for low speed, second for high speed
9. Combustion sections used in turbine engines….multiple can, annular and can annular
10. Component that creates a vortex in a gas turbine flame tube….swirl vanes
11. In a turbo prop engine, combustion takes place at constant….pressure
12. Air thru the combustion chamber retains a constant….pressure
13. Percentage mass airflow taken by flame tube snout….18%
14. Percentage mass airflow which bypasses the flame tube snout….82%
15. A combustion chamber has a….divergent inlet, convergent outlet
16. The purpose of the nose or snout in a combustion chamber….to act as a diffuser to slow the airflow down
17. Combustion chamber drain valve closed….by combustion chamber gas pressure
18. Combustor air that is not used to support combustion….will film cool the liner and dilute combustion chamber exit temp
19. Air used for combustion is….primary
20. Overall air/fuel ration of a combustion chamber can vary between….45:1 and 130:1
21. Air passing thru the combustion section of a jet engine is….most used for cooling
22. In the combustion chamber….static pressure decreases slighty and volume increases
23. Flame stabilization in a combustion chamber is achieved by….the airflow pattern
24. At high rotational speed at sea level, a duple burner would be passing fuel via the….primary and the main nozzle
25. When light-up takes place….interconnectors spread the heat to adjacent flame tubes
26. Combustion liner walls cooled in a gas turbine engine….by secondary air flowing thru the combustion chamber
27. In an annular combustor (thru flow)….it requires less cooling air due to its minimal surface area
28. Fuel entering the combustion chamber from an atomizer spray nozzle enters as….a fuel/air mixture
29. A duplex burner uses….small burner at low rpm and both burners at high rpm
30. Component that creates a vortex in a gas turbine flame tube….swirl vanes
31. Hot spots in the combustion section of a turbojet engine are possibly due to….malfunctioning fuel nozzles
32. A shroud placed around fuel nozzles….prevents carbon build up
33. In which type of turbine engine combustion chamber is the case and liner removed and installed as one unit during routine maintenance….annular
34. Purpose of swirl vanes in the combustion chamber is to produce….gas re-circulation
TURBINE (6)
1. Turbine disks are attached to the shat in a gas turbine engine....bolted
2. Impulse-reaction turbine blades form....tip half reaction, root half impulse
3. Material used for LPT shaft in modern turbofan engines....Marage-250
4. Impulse blades operate cooler than reaction blades because....the airflow has a higher velocity thru an impulse turbine NGV
5. A nozzle guide vane is....hollow in construction to allow for flow of cooling air
6. Hot section inspections for many turbine engines are required....on a time cycle basis
7. The turbine section....converts dynamic pressure into mechanical energy
8. As hot gasses flow thru an impulse turbine blading, the velocity....remains constant
9. An impulse turbine blade arrangement forms....constant passage
10. A slow constant growth in a turbine blade is known as....secondary creep
11. The passage between adjacent nozzle guide vanes forms....convergent duct
12. Turbine engine components are never manufactured by....gas welding
13. Impulse turbine blades run cooler than reaction blades because....temperature drop across NGV is greater
14. Fir tree turbine blade attachment locates the blade....allows slight movement
15. Stress rupture cracks usually appear on turbine blades at....across he leading or trailing edge at the right angle to the edge
16. What is meant by a shrouded turbine....the turbine blades are shaped so that their ends forma a band or shroud
17. ‘hot streaking’ is caused by....a partially clogged fuel nozzle
18. Creep of turbine blades is....due to thermal and centrifugal forces
19. Nozzle guide vanes are fitted to....increase velocity of gas flow
20. Temperature thru the turbine stages generally....decreases
21. As the hot gasses flow thru an impulse turbine blading, the velocity....remains constant
22. Nozzle guide vane bow is an indication of....engine overheat
23. Turbine nozzle diaphragms located on the upstream side of each turbine wheel are used....to increase the velocity of the heated gasses flowing past this point
24. Alloys used for gas turbine nozzles are....inconel, nimonic and GMR-235
25. Turbine disk growth is due to.... a permanent change in disk diameter
26. Dirt particles in the air going into the compressor of a turbine engine will form a coating on all except the....turbine blades
27. How is a radial turbine driven....by change of momentum and angle of airflow
28. The forces driving a turbine round are due to....impulse and reaction
EXHAUST (7)
1. The jet pipe of a gas turbine engine….protects the airframe from heat damage
2. Lobe type exhaust noise suppressors are made from…heat resistant alloy
3. A supersonic duct is…convergent then divergent along its length
4. When should thrust reversers be used…low RPM and low forward speed
5. The purpose of a propelling nozzle (convergence) is to…increase the velocity of the air and increase thrust
6. If the exit area of the nozzle is too large, the effect is….exit velocity lower causing loss of thrust
7. As air flows out at the outflow of a choked nozzle….velocity increases and pressure decreases (convergent duct-exhaust)
8. Exhaust noise can be reduced by….increasing the mixing rate
9. A convergent exhaust nozzle produces mainly….momentum thrust
10. To have minimum friction in the jet pipe, it should be….long and small diameter
11. A convergent-divergent nozzle….makes maximum use of pressure thrust
12. The purpose of a propelling nozzle of a gas turbine engine is designed….to increase the velocity and decrease the pressure of the gas stream leaving the nozzle (increase thrust)
13. The exhaust section is designed to….impart a high exit velocity to the exhaust gasses
14. The struts on the exhaust cone….supports the exhaust cone and straighten the gas airflow
15. On front fan engines, to obtain thrust reversal…cold stream is reversed
16. Reverse thrust can only be selected when the throttle is….closed
17. Thrust reversers utilizing pneumatics actuating system receives operating pressure from….engine bleed air system
18. An exhaust cone placed aft of the turbine in a jet engine will cause the pressure in the first part of the exhaust duct to….increase and velocity to decrease
19. The function of the exhaust cone assy of a turbine engine is to….straighten and collect the exhaust gasses into a solid exhaust jet
20. Hot spots on the tail cone of a turbine engine are possible indicators of a malfunctioning fuel nozzle or….a faulty combustion chamber
21. A nozzle is ‘choked’ when the engine inlet airflow is….subsonic and supersonic
22. What is the proper operating sequence of using thrust reversers…..retard thrust levers to grd idle, select reverse thrust, then advance power levers as required, and then retard thrust reverser levers to grd idle
23. Noise from a jet wake when untreated by suppression is…low freq, high decibel
24. A choked nozzle…increases thrust
BEARINGS AND SEALS (8)
1. A carbon seal has which type of sealing arrangement....full contact with race
2. Some labyrinth seals...control the outflow of air at the turbine (can be air seals or oil seals)
3. An abradable lining in the fan case...provides acoustic medium
4. Why are oil seals pressurized...to ensure minimum oil loss
5. The highest turbine bearing temp takes place...at shut-down
6. Seals on gas turbine engine restrict leakage of oil by...air pressure
7. What is the purpose of pressure balance seal...to ensure the location bearing is adequately loaded throughout the engine thrust range
8. The function of labyrinth seals is to create...a restricted leakage of air between fixed and rotating components
9. If ball or roller bearings found with magnetism...degaussed before use
10. Main bearing oil seals used with turbine engines are usually...labyrinth and/or carbon
11. The bearings of a compressor rotor are usually….ball and roller
12. In a jet engine, the rotating assembly oil seals are maintained oil tight by means of...air pressure
13. Which of the following is true about ball and roller bearings...a ball bearing has less friction than any other type
LUBRICANTS AND FUELS (9)
1. Advantage of mineral base lube over vegetable based lube…chemical stability
2. Desirable characteristics of turbine engine oil…high flash point
3. Reid Vapour pressure…38 degrees Celsius
4. Factors that determines the proper grade of oil to use in a particular engine…operating speeds of bearings
5. High tooth pressures and high rubbing velocities in spur type gears require the use of…an EP lubricant
6. The result of operating an engine in extremely high temp using lubricant meant for much lower temp…oil pressure will be lower than normal
7. Upon what quality or characteristics of a lubricating oil is its viscosity index based…its rate of change in viscosity with temp change
8. The specific gravity of fuel affects…aircraft range
9. In addition to lubricating, engine oil…cools, seals, prevents corrosion and cushions shock loads
10. Calorific value is the…amount of heat or energy in 1 pound of fuel
11. Compared to reciprocating engine oils, the types of oils used in turbine engines…have less tendency to produce lacquer or coke
12. DERD 2494…kerosene
13. Types of water present in aviation fuel are…free and entrained both harmful
14. Ignition of fuel depends on…both volatility and atomisation
LUBRICATION SYSTEM (10)
1. The purpose of a pressure filter in a lubrication system is to….protect the oil jets
2. In a jet engine which uses a fuel oil heat exchanger, the oil temp is controlled by a thermostatic valve that regulates the flow of….oil thru the heat exchanger
3. The oil dampened main bearing utilized in some turbine engines is used to….provide an oil film between the outer race and the bearing housing in order to reduce vibration tendencies in the rotor system, and to allow for slight misalignment
4. Oil pressure and scavenge pumps are usually….spur gear pumps
5. What will happen to the return oil if the oil line between the scavenger pump and the oil cooler separates….the return oil will be pumped overboard
6. Oil pressure in the cooler is….higher than the fuel pressure
7. The possible cause when a turbine engine indicates no change in power settings parameters, but oil temp is high….engine main bearing distress
8. At cruise RPM, some oil will flow thru the relief valve of a gear type engine oil pump. This is normal as the relief valve is set at a pressure which is….lower than the pressure pump capabilities
9. The possible combined output from all the scavenge pumps in a lubrication system will be….greater than the pressure pump output
10. ‘Last chance’ filters in a lubrication system are serviced during….engine overhaul
11. What is the primary purpose of the hopper located in the oil supply tank of some dry sump engine installations….to reduce the time required to warm the oil to operating temp
12. Primary purpose of the oil breather pressurization system that is used on turbine engines….provides a proper oil spray pattern from the main bearing oil jets
13. A thread type oil seal in a lubrication system….has a thread on a stationary portion to prevent fluid leaks
14. What would be the probable result if the oil system pressure relief valve should stick in the open position on a turbine engine….insufficient lubrication
15. What determines the minimum particle size which will be excluded or filtered by a cuno type filter….the spacer thickness
16. In order to relieve excessive pump pressure in an engine’s internal oil system, most engines are equipped with a….relief valve
17. Manufacturers normally require turbine engine oil servicing within a short time after engine shut down primarily to….prevent over servicing
18. When rotating, the gerotor type oil pump….draws oil into the pump and carries it round between the gear teeth and idler
19. What filters are used to protect oil pressure spray jets….in-line thread filters
20. Low oil pressure can be detrimental to the internal engine components. however high oil pressure….should be limited to the engine manufacturer’s recommendation
21. What is the purpose of the last chance filters….to prevent damage to the oil spray nozzle
22. A turbine engine dry sump lubrication system of the self contained, high pressure design….consists of pressure, breather and scavenge subsystems
23. A full flow oil system has….a variable oil pressure dependant upon throttle setting
24. When rotating, the gear type oil pump….draws oil into the pump and carries it round between the gear teeth and casing
25. What is the primary purpose of the oil breather pressurization system that is used on turbine engines….provides a proper oil spray pattern from the main bearing oil jets
26. The air-cooled-oil-cooler has an anti-surge valve in order to….protect the cooler
27. A vane type oil pump output is controlled by….outlet pressure against spring pressure
28. Possible failure related ferrous metal particles in turbine engine oil causes an electrical indicating type magnetic chip detector to indicate their presence by….bridging the gap between the detector centre (positive) electrode and the ground electrode
29. The teeth of the gears in the accessory section of an engine normally lubricated by….splashed or sprayed oil
30. Type of oil system is usually found on turbine engines….dry sump, pressure and spray
31. A jet engine gear box breather is prevented from leaking oil to atmosphere by the action of….impeller and centrifugal force
32. Type of oil pumps most commonly used on turbine engines are….positive displacement
33. A scavenge filter is incorporated in a gas turbine lubrication system to….protect the pressure pump
34. The identification of a lubrication fluid line is the word ‘lubrication’….followed by squares
35. After making a welded repair to a pressurized type turbine engine oil tank, the tank should be pressure checked to….not less than 5psi plus the maximum operating pressure of the tank
36. Oil pressure in the cooler is….higher than the fuel pressure
37. Typical operating pressure of an oil pump in a a gas turbine lubrication system….30psi
38. What is the cause of high oil temp….a blocked pressure filter
39. Oil system generally used on most modern turboprop engines is….dry sump type
40. A spur gear pump operating in a lubrication system promotes….high flow at low pressure
41. The possible combined output from all the scavenge pumps in a lubrication system will be….greater than the pressure pump output
42. Sump pressure is maintained by the…breather system
FUEL (11)
1. What are float switches used for in the fuel system….to control refuel/defuel valves
2. To what condition does the fuel flow respond during aircraft acceleration….mass airflow rate thru the engine
3. An EEC is powered in flight by….N2 tachogenerator
4. To stabilize cams, springs and linkages within the fuel control, manufacturers generally recommend that all final turbine engine trim adjustments be made in the….increase direction
5. The maximum RPM of a turbine engine is limited by….reduction of the fuel pump stroke by a spill valve sensitive to centrifugally generated fuel pressure
6. Kinetic valves are used because….they are more sensitive
7. When a throttle is selected to increase power, the pressure drop across the Fuel Control Unit throttle orifice….drops then increases due to increasing pump output
8. During any stabilised running condition, the spill or half ball valve is….lightly seated
9. With a decrease in fuel SG, what is the result when the engine is fitted with an uncompensated fuel governor….maximum RPM increases
10. An increase in fuel S.G. will cause….a reduction in maximum RPM
11. What power supplies the EEC during normal operation….a dedicated generator
12. A FADEC system takes measurements from engine speed….temperature and pressure
13. If the knife-edge blade in a kinetic valve is fully in….servo pressure is being bled off
14. A fuel heater prevents….entrained water in fuel freezing
15. A fuel heater prevents….LP filter icing
16. In a FADEC system, how are the power supply windings for channel A and channel B wound….on one generator with 2 separate windings
17. Out of the following thrust lever resolver angles, which one is the forward idle setting….40 degrees
18. When the EEC supervisory circuit senses a fault on the engine, the fault annunciator light will be on and the EEC will….remove fuel, down trimming signal immediately
19. BPC controls the FCU by….pressure sensing
20. What is the primary purpose for trimming a turbine engine fuel control unit…to obtain maximum thrust output when desired
21. What would be the effect on the engine if the BPC half ball valve in the servo line sticks open….a reduction in fuel flow, therefore a decrease in RPM
22. A kinetic valve is a device used to control HP pump output. This is achieved by movement of a…..knife blade
23. Which of the following inputs does the fuel control system combine to operate a gas turbine engine….engine speed, altitude, exhaust temperature and throttle position
24. In a FADEC system, the signal to the HMC is the difference between….actual N1 and computed N1
25. Purpose of a fuel flow divider in a turbine engine duplex fuel nozzle….creates the primary and secondary fuel supplies
26. Purpose of the LP fuel pump is to….ensure the HP fuel pump does not cavitate
27. Purpose of a silver strip on a fuel filter….to detect sulphur in fuel
28. On approach….RPM should be above the minimum idle for maximum acceleration
29. Why is the high pressure fuel pump fitted in a gas turbine engine….to provide the majority of the fuel pressure to the engine
30. How is servo pressure, which is used to control fuel pump ‘swash plate’ angle obtained….from pump delivery pressure through a fixed restriction
31. During acceleration, the fuel flow is increased at a controlled rate in order to….prevent surge and the risk of flame-out
32. Where is the engine fuel shutoff valve usually located…downstream of the engine driven fuel pump
33. Why is it necessary to control fuel supply to the engine during rapid acceleration….to prevent excessively high EGT and possible compressor surge
34. What moves the swash plate away from the minimum stroke position….a spring
35. During aerobatic manoeuvres, what prevents fuel form spilling out of fuel tank vents….float operated valves
36. Which of the following influences the operation of an automatic fuel control unit on a turbojet engine….burner pressure
37. The basic concept of an HP fuel control is….constant adjustment of the swash plate angle of the HP fuel pump
38. A FADEC consists of….electronic controls (EEC), sensors and an HMU
39. During acceleration, the fuel flow is increased at a controlled rate in order to….prevent surge and the risk of flame out
40. A fuel trimmer unit is adjusted at altitude….automatically via a fuel trim unit
41. The fuel trimmer on a turbo-prop engine is operated….automatically controlled in conjunction with FCU
42. When considering a centrifugal type engine speed governor, n increase in fuel S.G. will cause….a reduction in maximum RPM
43. A barometric pressure controller controls….fuel flow to suit atmospheric pressure changes
44. The burner fuel flow is at a maximum at….I.S.A. sea level
45. What must be done after the FCU has been replaced…..retrim the engine
46. On an engine powered by a FADEC, each engine has….1 FADEC with one channel active and the other channel monitoring with its output drivers de-energised
47. The position of fuel heater in fuel system is….before the LP fuel filter
48. HMU receives signals form….EEC
49. The EEC receives its primary power from….separate permanent magnet alternator
50. In a FADEC system, what is the result of channel A failing to recive information from a sensor….channel A will take the info from channel B
51. Why is an ACU fitted to a gas turbine engine…..it limits the rate of increase in fuel flow during sudden acceleration
52. The swash plate in a fuel pump when static is….in the maximum position
53. When trimming a turbine engine, the fuel control is adjusted to….set idle RPM and maximum speed or EPR
54. In flight, the engine EEC controls….fuel flow
55. To prevent compressor surge and overheating of the combustion chamber due to over fuelling…..an acceleration control unit (ACU) is fitted
56. In a FADEC system, what determines which channel is in control….whichever is the best channel
57. What are the positions of the pressurization valve and the dump valve in a jet engine fuel system when the engine is shut down….pressurization valve closed, dump valve open
58. What would be the effect on the engine if the BPC half ball valve in the servo line sticks open….a reduction of fuel flow, therefore a decrease in RPM
59. Why is a hydro-mechanical governor fitted to a gas turbine engine fuel pump….to enable the engine to operate over a wide range of SGs
60. The density of air is very important when mixing fuel and air to obtain a correct fuel to air ratio. Which of the following weighs the most….100 parts of dry air
61. What causes the fuel divider valve to open in a turbine engine duplex fuel nozzle….fuel pressure
62. Baffles in a rigid fuel tank….prevents surge
63. Why is the barometric pressure controller (BPC) fitted in a turbo-shaft engine fuel system….to vary pressure pump output in relation to the pressure variation at the intake
64. Which valve ensures the adequate fuel flow….the fuel metering valve
65. Specific fuel consumption at altitude will….remain constant
66. If the swash plate of a positive displacement swash plate pump is perpendicular to the axis of the pump, the flow will be….zero
67. What are the principal advantages of the duplex fuel nozzle used in many turbine engines….provides better atomization and uniform flow pattern
68. After a bag tank replacement, where would you disconnect the system to carry out the flow checks….at the engine
69. What is the purpose of the attenuator fitted between the HP fuel pump and the BPC in a fuel system….it damps out pulsations in the fuel delivery to the BPC
70. Conditions when trimming of a turbine engine be most accurate….no wind and low moisture
71. Opening of fuel valve after shut down will cause….risk of fire in turbine
72. When a re-light is required in flight on a FADEC engine….igniter is selected automatically
AIR SYSTEMS (12)
1. Bleed air pressure and shut-off cock pressure is...200psi
2. Turbine case cooling utilizes...fan air
3. If air is taken from the compressor for air cond / anti-icing...thrust will decrease, EGT will increase
4. Engine anti-ice is taken from...HP compressor
5. In an axial flow turbine engine, compressor bleed air is sometimes used to aid in cooling the... turbine, vanes, blades and bearings
6. Air bleed for an anti-ice system is...sent through a pressure regulator
7. When electrical anti-icing is on...power decreases
8. Anti-ice bleed is controlled by...regulator valve
9. On a gas turbine engine, thermal wing de-icing system derives air...through a pressure regulating shut-off valve (PRSOV)
10. Inlet for cooling air for the 1st stage turbine blades are fed via the...blade root
STARTING AND IGNITION SYSTEMS (13)
1. In a gas turbine engine dc capacitor discharge ignition system, where are the high voltage pulses formed…at the triggering transformer
2. In the HEIU the choke….prolongs the discharge
3. A hot start is associated with….high EGT
4. A safety feature usually employed in pneumatic starters that is used to prevent the starter from reaching burst speed if inlet air does not terminate on schedule is the…..stator nozzle design that chokes airflow and stabilizes turbine wheel speed
5. Advantage of pneumatic starter over electric starters is….high power-to-weight ratio
6. An igniter plug for a large gas turbine takes the form of a….surface discharge plug
7. When removing turbine engine igniter plug, to eliminate possibility of receiving a lethal shock, the ignition switch is turned off and…..the transformer exciter input lead is disconnected and the centre electrode grounded to the engine after disconnecting the igniter lead from the plug and waiting the prescribed time
8. Pneumatic starters are usually designed with what types of airflow impingement systems….redial inward flow turbine and axial-flow turbine
9. Voltage at the igniter plug depends on….gap in the ignition system box
10. A starter has 2 hole to check the….level of oil
11. A glow plug may be used in place of a spark plug on….small engines
12. An electrical starter-generator is….series wound with high torque
13. On a gas turbine engine DC starting circuit, if there is an open circuit on the contact of the over speed relay….no supply is connected to the starter motor
14. To avoid lethal electric shock from ignition system, ground….the ignition lead
15. A ‘hot start’ with excessive temperatures may be caused by….throttle partly open
16. High energy ignition is required because of the….high flash point of the fuel
17. The resistor in a DC starter motor….prevents current surge when motor is at low rpm
18. Purpose of the current limiting resistor in a starter circuit….is to prevent an initial current surge
19. On a low energy dual ignition system (<3 joules), if a relight is necessary….pilot selects both igniters
20. Airflow to the pneumatic starter from a ground unit is normally prevented from causing starter overspeed during engine start by….activation of a flyweight cutout switch
21. A HEIU is rated in…joules
22. A DC starter motor disconnects due to….current decreasing switching off an overspeed relay
23. Why do turbine engine ignition systems require high energy….to ignite the fuel under conditions of high altitude and low temp
24. A clicking sound heard at engine coast-down in a pneumatic starter incorporating a sprag clutch ratchet assembly is a n indication of….the pawls re-contacting and riding on the ratchet gear
25. Air turbine starters are generally designed so that reduction gear distress or damage may be detected by….inspection of a magnetic chip detector
26. In the HEIU, the discharge resistors….allows the capacitors to discharge when the unit is switched off
27. When is ignition used….for relight and start up
28. Type used on turbine engine….capacitor discharge
29. A safety feature usually employed in pneumatic starters that is used if the clutch does not release from the engine drive at the proper time during start is the….drive shaft shear point
30. A dry motoring cycle would be required to….clear engine after a wet start
31. A glow plug….operates electrically….used on small engines
32. Caution when handling damaged hermetically sealed turbine igniter transformer because….some contain radioactive material
33. A HEIU works by….a discharging capacitor
34. When an engine being started by an air starter reaches self sustaining speed….the starter valve is disconnected by the fly weight cut-out switch in the starter
35. After an unsuccessful start of a n engine….unburnt fuel can be evacuated by motoring the engine with HP cock closed
36. Voltage at the igniter plug is….governed by the air gap in the HEIU box
37. In a gas turbine engine DC capacitor discharge ignition system where are the high voltage pulses formed….at the triggering transformer
38. The field of the DC starter motor used on gas turbine engine is….series or compound
39. The purpose of an under current relay in a starter-generator system is to….disconnect power from the starter-generator and ignition when sufficient engine speed is reached
40. In an electrical starting system, the slow start resistor is short circuited by the….time switch
41. First instrument indication of a successful start of a turbine engine….a rise in the exhaust gas temp
42. Inspection of pneumatic starters by maintenance technicians usually includes checking the….oil level and magnetic drain plug condition
43. Turbine blade is most commonly used in air starter motors….impulse
44. If the engine fails to light-up, the starter cycle is cancelled by….a time switch
ENGINE INDICATING SYSTEMS (14)
1. In what units are gas turbine engine tachometers calibrated….percent of engine RPM
2. Fuel flow is measured in…. lbs/hrs or kg/hrs
3. Instruments that measure relatively high fluid pressures, such as oil pressure gauges are usually what type….bourdon tube
4. A common type of electrically operated oil temp gauge utilizes….either a wheatstone bridge or ratiometer circuit
5. EGT indicator on a gas turbine engine provides a relative indication of the….turbine inlet temp
6. Engine pressure ration is the total pressure ratio between the…front of the compressor and the rear of the turbine
7. What happens when bulb type thermometer resistive element goes open circuit….reads more than ambient
8. In a thermocouple temp sensing system, what is the purpose of the compensating resistor….to correct for varying ambient temp at the cold junction
9. What power supply is required for a thermocouple system work….neither of the above
10. Thermocouple metals most frequently used are….constantan and copper
11. Regarding an engine EGT detection system, which of the following statements is true….chromel is positive and alumel is negative
12. How are EGT thermocouples connected….parallel
13. Motor driven impeller and turbine fuel flow transmitted are designed to transmit data….using aircraft electrical system power
14. Fuel flow indication is taken from….after either HP pump or LP pump
15. In a tachometer generator….frequency output is proportional to engine speed
16. A thermocouple indicator is basically a….milivoltmeter
17. Instruments that provide readings of low or negative pressure, such as manifold pressure gauges are usually….diaphragm and bellows type
18. The gauge on a bulb type temp indicator shows zero. This could be caused by….two cables shorting together by the sensor
19. What unit in a tachometer system sends information to the indicator….3 phase AC generator
20. In a multi-thermocouple loop, if one thermocouple goes open circuit, the indication…..will have no effect on temp indication
21. Vibration signals when picked up….the frequencies are filtered to exclude unwanted frequencies
22. A tachogenerator to indicate revs/min requires….no power
23. N2 is taken from….a tachometer on the accessory gearbox
24. A thermocouple indicator is connected to the….cold junction
25. EGT gauge indication….needs NO POWER, it is self generating
26. When testing an EGT system….the OAT is always taken into consideration
27. What instrument on a gas turbine engine should be monitored to minimize the possibility of a ‘Hot Start’….turbine inlet temp
28. The indication on a thermocouple-type EGT indicator is produced by….a current generated by the temp difference between dissimilar metal hot and cold junctions
29. On an aircraft turbine engine operating at a constant power, the application of engine anti-icing will result in….noticeable shift in EPR
30. What will the EPR reading be if the P1 sensor probe becomes blocked on take-off….EPR reading higher than actual
31. Thrust in a high bypass fan engine is indicated by….N1 RPM or EPR
32. What indication is available to show that thrust reverser has been selected….an amber ‘reverser unlocked’ light illuminates
33. Torsional deflection in a turboprop engine shaft is an indication of what variable….horsepower
34. Thrust in a high bypass engine….is not indicated in flight
35. A ballast resistor is fitted…in series, to give identical resistance values to all airframe
36. Torque pressure is usually read from a….direct reading pressure gauge
37. Modern oil pressure servo transmitters sense….differential pressure
38. Engine oil temp gauges indicate the temp of the oil….at the oil cooler
39. On an EGT thermocouple system, the hot junction….placed downstream of the combustion chamber
40. Motor driven impeller and turbine fuel flow transmitters are designed to transmit data….using aircraft electrical system power
41. EGT is displayed in….degrees celsius
42. Torque measurement in a gas turbine engine is….required only when the turbine drives a propeller
43. EGT thermocouples are usually made of….chromel and alumel
44. Oil temp thermocouples are usually constructed of…iron constantan
45. A red triangle, dot or diamond mark on an engine instrument face or glass indicates….the maximum limit for high transients such as starting
46. On an RPM system using a synchronous generator, the pointer is deflected by….an AC servometer
47. On an aircraft turbine engine operating at a constant power, the application of engine anti-icing will result in….noticeable shift in EPR
48. A CIT sensor is made up of….platinum-rhodium
49. Why do helicopters require a minimum of two synchronous tachometer systems….one indicates engine RPM and the other main rotor RPM
50. In addition to fuel quantity, a computerized fuel system (CFS) with a totalizer indicator provides indication of how many of the following….fuel flow rate, fuel used since reset or initial start up, fuel time remaining at current power setting
51. If the thermocouple leads were inadvertently crossed at installation, what would the EGT gauge pointer indicate….moves off scale on the zero side of the meter
52. Thermocouple leads….are designed for a specific installation and may not be altered
53. The fuel flow indication data sent from motor driven impeller and turbine, and motorless type fuel flow transmitters is a measure of….fuel mass flow
54. Engine pressure ration is determined by….dividing turbine outlet total pressure by engine inlet total pressure
55. In a capacitive type fuel quantity indicating system the tank units are connected….in parallel
56. The resistance of a temp bulb is….increases with an increase in temp
57. The indicator of a tachometer system is responsive to change in….frequency
58. The RPM indication of a synchronous AC motor tachometer is governed by the generator….frequency
59. How is the N! and N2 measured on a triple spool engine….pulse type speed probes
60. The compensation device on an EGT system…..does not need calibration
61. Integrating fuel flow gives….total fuel consumed
62. In a thermocouple system, the size of the EMF that is produced is a result of….the difference between the hot and cold junction
63. What is the primary purpose of the tachometer on an axial compressor turbine engine….monitor engine RPM during starting and to indicate overspeed conditions
64. Engine vibration is monitored using….piezoelectric accelerometer
65. The turbine discharge pressure indicator sensor is located….immediately aft of the last turbine stage
66. Where is Turbine Outlet Temperature (TOT) measured….downstream of the turbine
67. If there is a restriction in the oil pressure line, the gauge will….read low
68. A bourdon tube instrument may be used to indicate….pressure and temperature
69. Vibration pick-ups are located….on both fan and turbine cases
70. On an EGT thermocouple system, the hot junction….is placed downstream of the combustion chamber
71. thrust in a bypass engine….is not indicated in flight
72. The fuel flow indicator rotor and needle for a motor impeller and turbine indicating system is driven by….an electrical signal
POWER AUGMENTATION SYSTEMS (15)
1. Water methanol injection is used…at a combination of higher than normal air temp & high altitude take off conditions
2. During operation of the engine equipped with water injection system, the metering of the coolant to the system is…due to atmospheric pressure
3. When reheat is selected and in operation, the mass gas flow…remains the same
4. The main reason for adding methanol to the water is to…prevent mixture freezing
5. Methanol is added to water when augmenting thrust in order to…reclaim lost heat at the turbines
6. Water used in a thrust augmentation system should be demineralised to prevent…fouling the blades and vanes
7. When reheat is used, EPR…remains constant
8. On a turboprop engine, water methanol for cooling is injected into the…compressor inlet or outlet
9. Water/methanol is injected…at high temp or high altitudes
10. Afterburning is initiated in order to…increase the local speed of sound at the jet nozzle
11. When using water methanol in an axial flow compressor, it is injected into the…compressor inlet or burner section
12. How is the flame stabilised in the reheat system of a gas turbine engine…by ensuring that the gas velocity is grater than the flame velocity
13. Injection of water/methanol into compressor inlet causes…increase in power without the need for burning extra fuel
14. Water methanol injection will increase thrust by up to…30%
15. Screech liners in the afterburning jet pipe…prevents cyclic vibrations of large amplitude
16. The primary purpose of water injection is to…cool the turbine
17. Water or water/methanol injected into the combustion chamber inlet increases…mass airflow through the turbine
18. Reheat is the term used to describe…adding fuel in the exhaust section
19. The reheat ignition system which incorporates a platinum/rhodium element is known as…catalytic ignition
TURBO-PROP ENGINES (16)
1.If an EPR gauge is installed on turbofans as a measure of power output, what is used on a turbo-prop…torque meter
2. What type of reduction gear is used on most turboprop modern engines…epicyclic reduction gear
3. In a turboprop the propellers produce…75-85% of total thrust
4. Torque measurement is taken from the…reduction gearbox
5. A free turbine is usually found on a…turbo-prop
6. A free turbine is…connected directly to the power output shaft
7. A direct drive turboprop engine…uses a reduction gearbox to reduce RPM of propeller
8. A turboprop reduction gear is normally…10:1
9. What controls the fuel trimmer on a turboprop engine…Engine Speed Governer
10. A propeller engine oil has…higher viscosity than turbojets
11. The fuel flow in a turboprop engine within the constant speed range is controlled…automatically
12. Fuel trimming on a turboprop engine is…governer controlled
TURBO-SHAFT (17)
1. On a twin spool turbo-shaft engine, the free turbine is connected to the...output gearbox
2. A turbo-shaft engine has...a power shaft which is not connected to the compressor
3. In the majority of helicopters, the thrust generated by the gas generator is absorbed by the...free power turbine
4. Which type of torquemeters are used on turbo-shaft engines...electro-mechanical and oil
5. A curvic coupling...accurately aligns the driving and driven shafts
APU (18)
1. Usually most of the load placed on an APU occurs when…the bleed air valve is opened
2. The function of an APU air inlet plenum is to…stabilize the pressure of the air before it enters the compressor
3. 2 most important signals when monitoring APU…EGT and oil pressure
4. An APU shut down is initiated by…low oil pressure, fire warning, hot oil temp
5. Electrical speed control switches on an APU are set at…35%, 95% and 100%
6. An APU start cycle is completed at…95%
7. An APU consists of…a power compressor and a load compressor
8. An APU is usually rotated during start by…an electric starter
9. One of the accessories driven from the APU gearbox is a centrifugal switch, the purpose of which is to…cancel the ignition circuits and arm the overspeed protection circuits
10. APU cooling before shutdown may be accomplished by…closing the bleed air valve
11. Generally, when maximum APU shaft output power is being used in conjunction with pneumatic power…pneumatic loading will be automatically modulated to maintain safe EGT
12. What initiates APU shutdown…fire detection, low oil pressure, high oil temperature
POWERPLANT INSTALLATION (19)
1. Feeders are…heavy duty electrical generator cables
2. The spring back and cushion on an engine power lever is…used to prevent the controls hitting the fuel control stops
3. Fibrous metallic lining for noise suppression is used…in hot area
4. Rubber anti-vibration pads are fitted to engine…pylons to prevent vibration thru the airframe
5. The minimum bend radius for a continuous loop type fire wire…1 inch
6. Forward engine mounts take which loads…thrust, vertical and shear loads
7. What are installed in an engine mounting to tune out the worst engine vibrations…rubber encased wire-mesh vibration isolators
8. Engine thrust is transmitted thru mountings that…allows for radial and axial expansion
9. Acoustic linings made from composite materials used on engine …cold section only
10. Rubber clips which hold the electrical wires are used for…heat absorption
11. When checking the effect of inertia on the engine after heavy landing, check the…module alignment first
FIRE PROTECTION SYSTEMS (20)
1. What are the types of continuous fire detection system….capacitance and resistance
2. What is used as an extinguishant in fire bottles….halogenated hydrocarbons
3. Electrical fire….use carbon dioxide
4. A fire detection system that operates on the rate of temp rise is a….theromocouple system
5. Co2 extinguish fire by….contact with the air converts the liquid into snow and gas which smothers the flame
6. Rubber clips supporting a firewire is to….insulate from engine vibration
7. In a resistance type firewire, when hot….resistance decreases
8. A fire detection system operates on the principle of a buildup of gas pressure within a tube proportional to temperature. Which of the following systems does this statement define….Lindberg continuous element system
9. The following fire detection systems uses heat in the normal testing of the system….the thermocouple system and the Lindberg system
10. The safest fire extinguishing agent to use from a standpoint of toxicity and corrosion hazards….bromotriflouromethane (Halon 1301)
11. Fenwall fire detection system use spot detectors wired in parallel between two separate circuits….so that a single fault may exist in the system without sounding a false alarm
12. When pulling fire handle….closes fuel shut-off valve, hydraulic shut-off valve, disconnects the generator field and arms the fire extinguishing system
13. The following fire detection systems will detect a fire when an element is inoperative but will not test when the test circuit is energized….the Kidde system and the Fenwall system
14. A continuous loop fire detector is what type of detector….overheat detector
15. Fire extinguishing agent distributed in the engine section….spray nozzles and perforated tubing
16. The most satisfactory extinguishing agent for an intake fire is….dry chemical
17. When testing a two pin fire bottle connector….short two pins together
18. Fire extinguishing systems activated by….electrically discharged cartridges
19. After a fire is extinguished or overheat condition removed in aircraft equipped with a Systron-Donner fire detector, the detection system….automatically resets
20. The fire detection system that uses two wires imbedded in a ceramic core within a tube is the….Kidde system
21. The test switch of a continuous loop detector gives a…..continuity check…it is a overheat detector
22. A fuel or oil fire is defined as a….Class B fire
23. A fire involving energized electrical equipment is defined as a….Class E fire
24. Gas type firewires operate by utilising….the change in the gas pressure
25. Methyl bromide fire extinguisher are installed with neck….at the bottom
26. Principle of operation of the continuous loop fire detector system sensor….core resistance material which prevents current flow at normal temp
27. Kidde fault free fire detection system has….2 internal wires in the sensing element
28. The fire detection system that uses a single wire surrounded by a continuous string of ceramic beads in a tube is the….Fenwall system
29. The explosive cartridge in the discharge valve of a fire extinguisher container is….a life dated unit
30. The operating principle of the spot detector sensor in a fire detection system….a bimetallic theromoswitch that closes when heated to a high temp
31. When testing a squib on a fire bottle, you use a…..low current ohmmeter
32. Which of the following fire detectors are commonly used in the power section of an engine nacelle….rate of temp rise detectors
33. Fire wire clips have rubber in them to….support the wire…insulate from engine vibration
34. For fire detection and extinguishing purposes, aircraft powerplant areas are divided into fire zones based on………the volume and smoothness of the airflow thru engine compartments
35. Two continuous-loop fire detection systems that will not test due to a broken detector element are the…Kidde and Fenwall System
36. The use of water on Class D fires….will cause the fire to burn more violently and can cause explosions
37. When testing an installed fire bottle….a safety ohmmeter is used
38. On a fire bottle, if the indicator pin was protruding, this would indicate….extinguisher had been fired
39. Omission of crushable washer on engine fire-wire connector will….allow moisture ingress
40. Extinguisher spray rings checked for freedom from obstruction….by blowing thru with compressed air
41. When testing a squib on a fire bottle, use a….low current ohmmeter
42. In a Fenwall fire detection system….the tube is inconel and wire is nickel
43. What retains the nitrogen charge and fire extinguishing agent in a high rate of discharge (HRD) container….breakable disk or fusible disk
ENGINE MONITORING AND GROUND OPERATIONS (21)
1. Which of the following is the least likely indication of a main bearing failure…high oil pressure
2. First engine instrument indication of a successful start of a turbine engine….a rise in the exhaust gas temp
3. Galling is a condition caused by excessive….chafing
4. If a burner was down, in a multi-can system, the engine would tend to….surge
5. A ‘Hot Start’ refers to….high EGT before idle RPM is achieved
6. Which engine variables is the most critical during turbine engine operation….turbine inlet temp
7. Possible cause if a gas turbine engine has high exhaust gas temp, high fuel flow and low RPM at all engine power settings….turbine damage or loss of turbine efficiency
8. After shutdown, flames are present in the exhaust pipe. The probable cause is….a defective pressurizing and dump valve
9. A cool-off period prior to shutdown of a turbine engine is done to….allow the turbine wheel to cool before the case contracts around it
10. The recurrent ingestion of dust or other fine airborne particulates into an engine can result in….erosion damage to the compressor and turbine sections
11. If the run down time is less than the minimum stated for a given engine….the rotating assembly is being restricted
12. In the event of stall occurring….close throttle
13. Run down time is indicative of….the freedom of rotation of the compressor
14. In regard to using a turbine engine oil analysis program, which is not true….generally, an accurate trend forecast may be made after an engine’s first oil sample analysis
15. A rotation pad on an accessory drive gearbox is provided for….N2 rotation
16. A ‘Hung Start’ is indicated by….failure to reach idle RPM
17. When the engine will not run up to idle after reaching starting speed, the likely fault is….FCU
18. The blending of blades and vanes in a turbine engine….should be performed parallel to the length of the blade using smooth contours to minimize stress points
19. During start, if a bleed valve is stuck closed….EGT will be lower than normal
20. Starting an engine with a bleed valve stuck closed would cause….possible stalling of the engine
21. If a turbine engine is unable to reach take off EPR before its EGT limit is reached, this is an indication that the….compressor may be contaminated or damaged
22. If a compressor surge occurs…coughing in the compressor and vibration occurs
23. Flame-out (lean) occurs due to….low pressure at low engine speeds
24. After an engine fails to light on start, u…may carry out a dry motor after a period of time prior to another start attempt
25. What should be done initially if a turbine engine catches fire when starting….turn off the fuel and continue engine rotation with the starter
26. A ‘Wet Start’ is indicated by….no temperature indication (due to lack of ignition)
27. What must not be used during an engine compressor wash….chlorine
28. Mark turbine components only with….layout dye, commercial felt tip marker or chalk
ENGINE STORAGE & PRESERVATION (22)
1. Fuel system inhibiting oil is...mineral oil
2. Which part of the engine is most likely fatal if hydraulic fluid was to leak on it...CPU
3. Installed engine must be re-preserved after preservation at least every...6 months
4. To inhibit the fuel system of an installed engine...pump oil into the engine when stationary
5. When removing engine for long-term storage, bleed valves should be...open but blanked
6. Small cuts in a MVP engine storage bag can be repaired...with adhesive PVC tape
UNVERIFIED (23)
1. Normal gas turbine engine stating sequence...starter, ignition, fuel
2. Which material is used for gas turbine engine fuel lines...stainless steel