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Gas Turbine Plants

 

D While standing watch underway on a ship with the gas turbine shown in the illustration, a fire emergency stop is initiated when which of the following occurs? Illustration GT-0017 Either the primary or reserve gas turbine module CO2 system activates. The fire emergency shutdown switch located on the gas turbine module is activated. One of the UV flame detectors is activated. All of the above. New Gas Turbine Questions 2016
B Most GTE fuel nozzles have passages for all of the following EXCEPT __________. Compressed air. Cooling water. Secondary fuel flow. Primary fuel flow. New Gas Turbine Questions 2016
D For shipboard main propulsion application, how does an intercooled-recuperated (ICR) cycle gas turbine configuration compare to a combined cycle gas turbine configuration? The combined cycle configuration is lower in efficiency, lighter, and takes up less space. The ICR cycle configuration is more efficient, lighter, and takes up less space than a combined cycle configuration. The combined cycle configuration is more efficient and takes up less space than an ICR cycle configuration. Although the ICR cycle configuration is lower in efficiency, it is lighter and takes up less space than a combined cycle configuration. New Gas Turbine Questions 2016
C To ensure minimum clearance between rotor blade tips and the casing of an axial compressor, manufacturers use which of the following techniques? Loosely mounted rotors that expand during use. Abrasive coatings in the casing and hardened tips on the blades. Metal-sprayed coating of the casing and squealer tips on the blades. Closely machined tip to casing clearances. New Gas Turbine Questions 2016
A Which of the following terms refers to axial compressor stator blades? Vanes. Roots. Shrouds. Nozzles. New Gas Turbine Questions 2016
B The turbine nozzles function to direct the gases in what direction? In the direction opposite of turbine rotation In the direction of turbine rotation Parallel to the turbine axis Radial to the turbine axis New Gas Turbine Questions 2016
D What is the purpose of the Controllable-Pitch Propeller (CPP) hydraulic oil power system? Supplies low-pressure oil for both pitch control and stern tube sealing. Supplies high-pressure oil for both propeller blade actuation and stern tube sealing. Supplies low-pressure oil for propeller blade actuation and control oil for propeller pitch control. Supplies high-pressure oil for blade actuation and control oil for propeller pitch control. New Gas Turbine Questions 2016
C A body that has energy due to its motion is said to have which of the following? Potential energy Static energy Kinetic energy Dynamic energy New Gas Turbine Questions 2016
D Which of the following terms refers to axial compressor stator blades? Nozzles. Roots. Shrouds. Vanes. New Gas Turbine Questions 2016
B You are on watch on a gas turbine propelled vessel as shown in the illustration. After reducing power in response to a high lube oil supply temperature alarm, the temperature continues to increase. Your next step should be which of the following? Illustration GT-0017 Continue to reduce power. Shutdown the engine. Water wash the engine. Check oil consumption. New Gas Turbine Questions 2016
A How are the individual burners in a Can-type combustor arranged? Joined by crossover tubes. Joined by an outer combustion chamber. Separate from the air inlet to the exhaust. Joined at the igniter mounts. New Gas Turbine Questions 2016
B Which of the following conditions permits a gas turbine to produce 100% power? Maximum fuel flow. Minimum air inlet temperature. Maximum combustion temperature. Minimum air mass/weight flow. New Gas Turbine Questions 2016
C Borescope inspection of the combustor section requires which type of light source? 150 watt 500 watt 1000 watt All of the above. New Gas Turbine Questions 2016
D Why are the high-pressure turbine blades generally of the impulse/reaction type? To evenly distribute the stress over the entire blade. To keep the tip pressure higher than the root pressure thereby preventing air flow over the tip. To keep the tip pressure lower than the root pressure thereby preventing air flow over the tip. Both A and B. New Gas Turbine Questions 2016
D Assuming at least a 500 rpm for the input shaft speed from the power turbine, as shown in the illustration, the synchronous self-shifting (SSS) clutch used on marine gas turbine main propulsion gears, requires which of the following inputs or conditions to make engagement possible? Illustration GT-0018 Availability of low-pressure air to provide control air pressure for engagement. Availability of high-pressure air to provide clutch air inflation pressure. When the input shaft speed from the power turbine falls below the output shaft speed. When the input shaft speed from the power turbine rises to the output shaft speed. New Gas Turbine Questions 2016
C A compressor is operating at an inlet pressure of 14.7 (atmospheric pressure at the time of measurement) and a compressor discharge pressure of 123 psig. Calculate the absolute pressure ratio across the compressor __________. 8.2:1 8.4:1 9.4:1 10.5:1 New Gas Turbine Questions 2016
B A centrifugal flow gas turbine uses what type of combustion chamber? double-annular can can-annular annular New Gas Turbine Questions 2016
B The turbine nozzles function to direct the gases in what direction? In the direction opposite of turbine rotation In the direction of turbine rotation Parallel to the turbine axis Radial to the turbine axis New Gas Turbine Questions 2016
A Which of the following drawbacks of a gas turbine engine provides the greatest potential for injury to personnel? High pitched noise. Mechanical stresses the engine is subject to. High temperature of the exhaust gases. Susceptibility to foreign object damage. New Gas Turbine Questions 2016
B Air used to cool the combustion liners and turbine components is referred to as which of the following? Primary air. Secondary air. Control air. None of the above. New Gas Turbine Questions 2016
A The lubrication principal utilized by the Kingsbury thrust bearing is which of the following? Wedge-shaped oil film. Square-shaped oil film. Cylinder-shaped oil film. Free-sliding oil film. New Gas Turbine Questions 2017
C Which of the following are the principle factors that affect the performance of a gas turbine compressor? Bleed pressure, fuel pressure, exhaust temperature. Fuel flow, air flow, exhaust temperature. Pressure ratio, air flow, rotational speed. None of the above. New Gas Turbine Questions 2017
C Which of the following statements is true concerning axial compressor disk-type rotors? Rotor is only suitable for low-speed compressors. Rotor discs are held together by through bolts. Rotor discs are shrunk fit onto a steel shaft. Rotor consists of rings that are flanged to fit one against the other. New Gas Turbine Questions 2017
A Which of the following is the principle that a magnetic speed sensor/pickup operates on? Voltage is produced when a ferrous material moves through a magnetic field. Vibration caused by shaft rotation can determine the speed of rotation. Force is the product of mass and acceleration. Variations in the earth’s magnetic field are caused by ferrous materials. New Gas Turbine Questions 2017
A Marine GTE fuel oil systems, as shown in the illustration, require fuel oil shutdown valves to be __________. Illustration GT-0021 piped in series piped in parallel piped in series-parallel manually operated from MPCMS New Gas Turbine Questions 2017
C If after reducing power to a GTE in response to a high lube oil supply temperature alarm, the temperature continues to rise, your next step should be to __________. continue to reduce power waterwash the engine shutdown the engine check oil consumption New Gas Turbine Questions 2017
A The divergent area of the exhaust duct aids in what process? Increasing the volume of the exhaust gases. Increasing the velocity of the exhaust gases. Decreasing the volume of the exhaust gases. Increasing the pressure of the exhaust gases. New Gas Turbine Questions 2018
D While vacuum is being raised on the main unit and the turbine warmed, condensate is recirculated to the main condenser to __________. provide a condenser vacuum seal cool the main condenser shell for better vacuum maintain a proper DC heater water level ensure the condensation of air ejector steam New Gas Turbine Questions 2018
A For an emergency stop of the rotor of a main turbine while underway at sea you should __________. admit astern steam to the turbine after securing the ahead steam apply the prony brake tighten the stern tube packing gland secure all steam to the turbine New Gas Turbine Questions 2021
A How is lube oil pressure provided to a turbo-generator when starting the unit in an automated plant? the hand-operated or auxiliary lube oil pump a line from the other generator a line from the gravity tank the main lube oil pump New Gas Turbine Questions 2021
D What type of gland seal packing arrangement is shown in the illustrated turbine shaft gland? Illustration SE-0006 Straight-through labyrinth packing. Straight-through carbon packing. Stepped carbon packing. Stepped labyrinth packing. New Gas Turbine Questions 2021
B What will be the FIRST thing to occur if both the main and standby lube oil pumps failed to operate on a geared main propulsion steam turbine operating at full sea speed? Vacuum will be lost. Ahead throttle will close. Shaft brake will engage. Lube oil sump will overflow. New Gas Turbine Questions 2021
C When starting a turbine driven boiler feed pump, care should be taken to ensure that the recirculating valve is open. Which of the following valves should be closed when starting? Pump suction valve Turbine exhaust valve Pump discharge valve Turbine steam supply valve New Gas Turbine Questions 2021
D Which of the following automatically actuates the overspeed tripping device installed on an auxiliary turbine? high back pressure pneumatic force hydraulic pressure centrifugal force New Gas Turbine Questions 2021
C Why is the cycle efficiency higher in the intercooled-recuperated cycle as compared to a simple cycle gas turbine? Illustration GT-0026 The intercooler serves to increase the required high-pressure compressor power while the recuperator utilizes waste heat from the exhaust to decrease turbine inlet temperature. The intercooler serves to reduce the required high-pressure compressor power while the recuperator utilizes waste heat from the exhaust to decrease turbine inlet temperature. The intercooler serves to reduce the required high-pressure compressor power while the recuperator utilizes waste heat from the exhaust to decrease required fuel to achieve the turbine inlet temperature. The intercooler serves to increase the required high-pressure compressor power while the recuperator utilizes waste heat from the exhaust to increase turbine inlet temperature. New Gas Turbine Questions 2021
C Compressor characteristics are normally summarized in the form of which of the following? Venn diagram. Straight line graph. Compressor map. Spread sheet. All Other Subjects
D Accelerometers are generally used on gas turbine engines to sense which of the following? Rate of rotor speed changes. Gas generator speed with respect to power turbine speed. PLARA rate limited feedback to the FSEE. High frequency vibration. All Other Subjects
B Displacement, velocity and acceleration describe three types of which of the following? Random Access Memory. Vibration sensors. Filters. Multiplexers. All Other Subjects
D In order to get a ready indication for a normal start with a GE LM2500 gas turbine engine, what permissive(s) must be met? Bleed air valve must be closed. GG speed must be less than 1200 RPM and all engine trips reset. Fuel supply pressure must be greater than 8 psig All of the above. Bleed Air Systems
D For the GE LM2500 gas turbine engine shown in the illustration, the 13th stage bleed air is used for which of the following? Illustration GT-0017 Sump pressurization and cooling. Power turbine balance piston cavity pressurization. Power turbine cooling. High pressure turbine 2nd stage nozzle cooling. Bleed Air Systems
C For the GE LM2500 gas turbine engine shown in the illustration, the HP turbine 2nd stage nozzle vanes are cooled by which of the following? Illustration GT-0020 Frame vent bleed air. 13th stage compressor air. 16th stage compressor air. 9th stage compressor air. Bleed Air Systems
D For the GE LM2500 gas turbine engine shown in the illustration, the HP turbine 2nd stage blades are cooled by convection, with the cooling air being discharged where? Illustration GT-0011 Nose holes on the leading edge. Gill holes on the side. Trailing edge slots. Blade tips. Bleed Air Systems
D For the GE LM2500 gas turbine engine shown in the illustration, the HP turbine 1st stage nozzle vanes are cooled by which of the following? Illustration GT-0020 8th stage compressor air. 9th stage compressor air. 13th stage compressor air. 16th stage compressor air. Bleed Air Systems
D On the GE LM2500 gas turbine engine, magnetic pickups are utilized for what purpose? Determining gas generator speed. Calculating engine torque. Determining power turbine speed. All of the above. Bleed Air Systems
D In order to get a ready indication for a normal start with a GE LM2500 marine gas turbine, what permissive(s) must be met? Fuel supply pressure must be greater than 8 psig Bleed air valve must be closed. Gas generator speed must be less than 1200 RPM and all engine trips reset. All of the above. Bleed Air Systems
D In the marine gas turbine engine shown in the illustration, the 9th stage bleed air is used for which of the following? Illustration GT-0017 Compressor balance piston cavity pressurization. High pressure turbine 2nd stage nozzle cooling. Sump pressurization and cooling. Power turbine cooling. Bleed Air Systems
A In the marine gas turbine engine shown in the illustration, the 13th stage bleed air is used for which of the following? Illustration GT-0017 High pressure turbine 2nd stage nozzle cooling. Power turbine cooling. Power turbine balance piston cavity pressurization. sump pressurization and cooling Bleed Air Systems
C In the marine gas turbine engine shown in the illustration, the HP turbine 2nd stage nozzle vanes are cooled by which of the following? Illustration GT-0020 Frame vent bleed air. 9th stage compressor air. 13th stage compressor air. 16th stage compressor air. Bleed Air Systems
B As shown in the illustration, the HP turbine 2nd stage blades are cooled by convection, with the cooling air being discharged at which of the following? Illustration GT-0011 Trailing edge slots. Blade tips. Gill holes on the side. Nose holes on the leading edge. Bleed Air Systems
D In the marine gas turbine engine shown in the illustration, the HP turbine 1st stage nozzle vanes are cooled by which of the following? Illustration GT-0020 8th stage compressor air. 9th stage compressor air. 13th stage compressor air. 16th stage compressor air. Bleed Air Systems
B On a vessel equipped with propulsion gas turbines, the operators initial response to a high vibration alarm should be which of the following? Switch to the secondary channel to confirm the alarm. Reduce the engine speed. Wait for the harmonic vibration to dampen out. Change out the vibration transducer. Casualty Control
C The two main types of compressor stall are known as what? Flame out and inlet temperature stall. Over-speed and overload stall. Steady state and transient. Rapid rise and temperature inversion. Casualty Control
C Which of the following could cause compressor stall? Air flow over the lower foil section becomes turbulent and destroys the pressure zone. The angle at which the hot gases strike the turbine rotor blades is too high. The angle at which the air strikes the compressor rotor blades is too high. The angle at which the air strikes the compressor rotor blades is too low. Casualty Control
D How can compressor stall be prevented? Utilize a two-spool compressor rotor. Lowering the angle of attack on the front stages. Installing air bleed valves in the middle of the compressor. All of the above. Casualty Control
D What is the term given to the condition in which cyclic pressure changes result in a repetitive failure and recovery of compressor air flow? Laminar. Turbulence. Stall. Surge. Casualty Control
B When a compressor is in a stall condition, what will happen to the combustor and turbine temperatures? Slowly increase. Rapidly increase. Rapidly decrease. Slowly decrease. Casualty Control
A Compressor surge is caused by which of the following factors? Interrupted airflow. Maximum fuel pressure. Low ambient air temperature. Increased demand for secondary air. Casualty Control
A On a propulsion marine gas turbine, if full power temperatures become excessive, what action should the operator take? Reduce power to stay within limits. Water wash the engine. Borescope the engine. No action is needed until auto shutdown occurs. Casualty Control
D If the lube oil scavenge temperature exceeds 300 degrees Fahrenheit on the gas turbine engine shown in the illustration, and reducing power does NOT bring the temperature within limits, the operator should do which of the following? Illustration GT-0017 Continue to operate at the reduced power level. Monitor the temperature while continuing to operate. Continue to reduce power on the engine. Shutdown the engine and troubleshoot. Casualty Control
D While standing watch on a ship equipped with the gas turbine engine shown in the illustration, a fire emergency stop is initiated when which of the following situations occur? Illustration GT-0017 either the primary or reserve GTM CO2 system activates the GTM fire emergency shutdown switch located on the module is activated one of the UV flame detectors is activated All of the above. Casualty Control
D When working with gas turbine synthetic lube oil, which of the following safety measures should always be observed? thoroughly wash any area of skin contact avoid prolonged inhaling of vapors wear eye protection and rubber gloves All of the above. Casualty Control
D When working in or around intake areas, which of the following precautions should be taken? Remove all loose objects from your clothing. Inspect the intake for cleanliness. Account for all tools and equipment. All of the above. Casualty Control
D While underway on a ship with gas turbine engines, the most likely indication of an engine stall is which of the following? Combustor temperature increases. A loud bang is heard. Engine fails to accelerate. All of the above. Casualty Control
D Which of the following is the most probable cause if, while underway, the main propulsion gas turbine air intake blow-in doors open? Exhaust pressures are higher than normal. Air inlet pressures to the compressor are higher than normal. Air inlet temperatures to the compressor are higher than normal. Ice has formed on the air intakes. Casualty Control
A In which of the following ways can compressor surge cause excessive temperatures in the turbine section? By providing inadequate secondary air By overloading the compressor By providing excessive combustion air All of the above. Casualty Control
D On a ship with a marine gas turbine as shown in the illustration, a fire emergency stop is initiated when __________. Illustration GT-0017 one of the UV flame detectors is activated either the primary or reserve GTM CO2 system activates the GTM fire emergency shutdown switch located on the module is activated All of the above. Casualty Control
A On the marine gas turbine engine shown in the illustration, what temperature should be carefully monitored following a shutdown for an engine fire? Illustration GT-0017 power turbine inlet fuel manifold combustor liner compressor discharge Casualty Control
B If a fire is detected in a main propulsion gas turbine enclosure, which of the following would occur prior to automatic release of the fire extinguishing agent? Cooling water to the enclosure would be secured. If open, bleed air valves would be closed. Water wash valves to the engine would be opened. Reduction gear oil systems would be secured. Casualty Control
C If after reducing power to a gas turbine engine in response to a high lube oil supply temperature alarm, the temperature continues to rise, your next step should be which of the following? Check oil consumption. Continue to reduce power. Shutdown the engine. Water wash the engine. Casualty Control
A During an operation of a main propulsion gas turbine, the engine shuts down. Which of the following is the most probable reason for the shutdown? High vibration on the gas generator. High lube oil temperature. Low fuel supply temperature. Low sump oil level. Casualty Control
D Which of the following is the most likely cause for the main propulsion gas turbine engine tripping during start up? Inlet air ice detection. High oil filter differential pressure. Low sump oil level. Failure to achieve the minimum rpm in a certain period of time. Casualty Control
B On the marine gas turbine shown in the illustration, the gas generator speed sensor is located where? Illustration GT-0017 At the compressor inlet. On the accessory gearbox. Within the high pressure turbine. Within the compressor. Casualty Control
B What are two common methods of power turbine blade retention? Riveting and fir-free Bulb and dovetail Fir-tree and bolting Bulb and bolting Configurations
A Which of the following is a feature of a power turbine blade that is not found on a high temperature turbine blade? Interlocking shrould tips. Solid blades. Dovetail roots. Bulb roots. Configurations
C Aboard ship, single-shaft gas turbines are used mostly as prime movers for which of the following applications? Multi-screw ships Single-screw ships Generators Auxiliary power units Configurations
C Which of the following is an advantage of a single-shaft gas turbine engine compared to a split-shaft gas turbine engine? Lower starting torque Reversible Fewer moving parts Better fuel economy Configurations
B In a single shaft, cold-end drive gas turbine, the power output speed has what relationship to the speed of the compressor? It varies independently of compressor speed. It is the same or in a direct relationship through reduction gears. It is in an inverse relationship through reduction gears. None of the above. Configurations
C In a twin-spool turbine, secondary air is most essential for cooling in what section? HP compressor. LP turbine. HP turbine. LP compressor. Configurations
C What type of starter is commonly used on smaller gas turbine engines? Pneumatic Air turbine Electric Hydraulic Configurations
B Accelerating the compressor to the self sustaining speed of the engine is the function of which of the following components? Compressor extension shaft Starter PT shaft Mechanical driveshaft Configurations
A What type of engine starter motor is commonly found on the marine gas turbine shown in the illustration? Illustration GT-0006 Hydraulic motor AC synchronous motor AC induction motor DC series wound electric motor Configurations
D Which of the following components removes the oil from the transfer gearbox? Lube oil storage and conditioning assembly Air-Oil separator Duplex filter assembly Lube and scavenge pump Configurations
A What is the purpose of the air/oil separator shown in the illustration of the gas turbine lube oil system? Illustration GT-0024 Minimize oil consumption by separating oily vapors being vented to the atmosphere. Reduce oil foaming. Maintain oil pressure in the sumps. All of the above. Configurations
B all or roller antifriction bearings are used to support gas turbine rotors for all EXCEPT which of the following? To accommodate both axial and radial loads To offer maximum rotational resistance To facilitate precision alignment To withstand high momentary overloads Configurations
A What type of air seal is used in the sump and turbine areas of a gas turbine engine? Labyrinth-Honeycomb Lip Type Fishmouth Pneumatic carbon ring Configurations
D What type of air seal is used in the combustor and turbine midframe of a gas turbine? Pneumatic carbon ring Labyrinth-Honeycomb Lip-Type Fishmouth Configurations
D What type of seal is used in the gearbox of a gas turbine engine? Lip-type Fishmouth Labyrinth-Windback Carbon ring Configurations
B What is the purpose of the spring in a lip-type oil seal? To remove burrs and dirt from the shaft To keep the neoprene snugly fit around the shaft To seal against maximum fluid pressure To prevent air from entering the sump Configurations
C Which of the following statements is true concerning the fuel oil ignition system of the gas turbine engine shown in the illustration? Illustration GT-0017 The igniters will only energize if the exhaust gas temperature falls below a preset value. The igniters will de-energize when the power turbine exceeds a preset RPM. The igniters will de-energize when the gas generator exceeds a preset RPM. The igniters remain energized throughout the normal operation of the engine. Construction
C How many shock mounts are used to secure the GE LM2500 gas turbine enclosure to the ship's foundation? 16 24 32 40 Construction
D Where are the carbon dioxide nozzles located in the GE LM2500 gas turbine enclosure? Above and below the combustor section On either side of the PT Above the compressor On the cross beam under the compressor front frame Construction
C What type of combustor is used by the GE LM2500 gas turbine? Can-annular Can Annular Cannular Construction
D The gas generator section of the GE LM2500 gas turbine is composed of all of the following components EXCEPT which of the following? FOD screen Bellmouth Two stage HP turbine Six stage LP turbine Construction
B The struts of the GE LM2500 compressor front frame provide passages for all of the following mediums EXCEPT which of the following? Scavenge oil Fuel oil Seal-pressurization air Lube oil Construction
C What is the primary purpose of the diffuser and distributor on the GE LM2500 gas turbine? To provide uniform air flow to the compressor To provide even temperature distribution at the compressor To provide uniform airflow to the combustor To provide uniform airflow to the turbine Construction
B Which of the following components prevent(s) objects smaller than 1/4 inch from entering the GE LM2500 gas turbine engine? Inlet louvers FOD screens Centerbody Demister pads Construction
C How is the HP turbine rotor of the GE LM2500 gas turbine cooled? By synthetic lube oil By the ship's service seawater cooling system By a continuous flow of compressor discharge air By an air to air heat exchanger Construction
C What is the primary function of the main fuel control on the GE LM2500 gas turbine engine? To control fuel pump inlet pressure To control stator vane angle and bleed air discharge To control stator vane angle and GG speed To control fuel temperature Construction
D As shown in the illustration of a gas turbine fuel oil system, when the engine fuel oil valves are de-energized, the remaining fuel left in the system is recirculated back to which of the following? Illustration GT-0021 Day tank. High pressure relief valve. Fuel purge manifold. Fuel pump inlet. Construction
B What is the purpose of the GE LM2500 gas turbine enclosure heater? To ensure enclosure temperature is maintained at 145 degrees F To ensure fuel viscosity is maintained while the GTE is secured To warm up the enclosure for maintenance personnel To increase inlet air temperature Construction
B How many stages are in the HP turbine of the GE LM2500 gas turbine engine? One Two Three Four Construction
B The power turbine (PT) of the GE LM2500 gas turbine engine has a total of how many stages? Four Six Seven Eight Construction
C A total of how many shock mounts are used to secure the LM2500 enclosure to the ship's foundation? 16 24 32 40 Construction
A Where are the CO2 nozzles located in the GE LM2500 gas turbine enclosure? On the cross beam under the compressor front frame Above and below the combustor section On either side of the PT Above the compressor Construction
D What type of combustor is used by the GE LM2500 gas turbine engine? Can-annular Can Cannular Annular Construction
D The gas generator section of the GE LM2500 gas turbine engine is composed of all of the following components EXCEPT for which of the following? Bellmouth Two stage HP turbine FOD screen Six stage LP turbine Construction
A The struts of the compressor front frame provide passages for all of the following mediums EXCEPT for which of the following? Fuel oil Scavenge oil Seal-pressurization air Lube oil Construction
B What is the primary purpose of the diffuser and distributor on the GE LM2500 gas turbine engine? To provide even temperature distribution at the compressor To provide uniform airflow to the combustor To provide uniform air flow to the compressor To provide uniform airflow to the turbine Construction
C Which of the following components prevent(s) objects smaller than 1/4 inch from entering the engine? Centerbody Demister pads FOD screens Inlet louvers Construction
D How is the HP turbine rotor of the GE LM2500 gas turbine engine cooled? By the ship's service seawater cooling system By synthetic lube oil By an air to air heat exchanger By a continuous flow of compressor discharge air Construction
B What is the primary function of the main fuel control on the GE LM2500 gas turbine engine? To control fuel temperature To control stator vane angle and GG speed To control fuel pump inlet pressure To control stator vane angle and bleed air discharge Construction
A As shown in the illustration of a gas turbine fuel oil system, when the engine fuel oil valves are de-energized, the remaining fuel left in the system is recirculated back to which of the following? Illustration GT-0021 fuel pump inlet high pressure relief valve day tank fuel purge manifold Construction
A Which of the following statements is true about the "lockout control" on a synchronous self-shifting (SSS) clutch? Permits operation of the GTE without the rotation of the main reduction gear. It is an automatically operated control. The mechanism is incorporated into the input assembly of the clutch. None of the above. Drive Systems
B How is the clutch shown in the attached illustration engaged? Illustration GT-0018 Pneumatic pressure from the compressor engages the clutch. Clutch engages automatically when input shaft flange is rotating faster than the output assembly. Clutch is engaged manually prior to start up. Clutch engages automatically once the output assembly begins rotating. Drive Systems
C How do you manually lockout an SSS clutch? Remove the SSS clutch locking pawls. Calculate the engagement speed of the SSS clutch. Using the special wrench provided. Using air pressure. Drive Systems
A The term "lockout" on the Synchro-Self-Shifting (SSS) clutch system means that the __________. SSS clutch will not engage shaft will not rotate above 10 RPM's reduction gear will not rotate shaft will not rotate Drive Systems
C The bleed air surge relief valve differs from a normal relief valve in which of the following ways? Opens completely at a specified lift pressure and then immediately closes. Closed completely at a specified lift pressure and slowly opens as system pressure drops. Opens completely at a specified lift pressure and remains open until a preset pressure is attained. Closes completely at a specified pressure and remains closed. Drive Systems
B The purpose of the main reduction gear in a marine gas turbine propulsion installation is which of the following? Increase gas turbine speed to engage the clutch. Transfer high-speed gas turbine rotation to low-speed propeller rotation. Transfer low-speed gas turbine rotation to high-speed propeller rotation. Reduce gas turbine speed to engage the cutch. Drive Systems
B What type of main reduction gear arrangement prevents independent axial and rotational movement of the pinions? Independent suspension Locked train Unlocked train Hydraulic suspension Drive Systems
D The main reduction gear performs which of the following functions? It transfers low-speed gas turbine rotation to high-speed propeller rotation It increases gas turbine speed for clutch engagement It reduces gas turbine speed for clutch engagement It transfers high-speed gas turbine rotation to low-speed propeller rotation Drive Systems
A What feature is commonly used on articulated reduction gear arrangements for the correction of misalignment between the 1st reduction gear and the 2nd reduction pinions? Quill shafts. Fixed block pads. Torsion pads. Locked train shims. Drive Systems
D Rotation of the Controllable Pitch Propeller (CPP) blades is achieved through axial movement of what component in the hub body assembly? The servomotor piston The sliding block The crankpin ring The crosshead Drive Systems
A In a typical gas turbine propulsion plant, the main thrust bearing directly positions which part(s) of the main reduction gear? Low-speed gear High-speed gear Low-speed pinions High-speed pinions Drive Systems
C What does the term "lock-out" of a synchro-self-shifting (SSS) clutch system mean? Illustration GT-0018 Reduction gear will not rotate. Shaft will not rotate above 10 RPM. SSS clutch will not engage. Shaft will not rotate. Drive Systems
B How is the clutch shown in the attached illustration engaged? Illustration GT-0018 Pneumatic pressure from the compressor engages the clutch. Clutch engages automatically when input shaft flange is rotating faster than the output assembly. Clutch engages automatically once the output assembly begins rotating. Clutch is engaged manually prior to start up. Drive Systems
D On a gas turbine powered vessel equipped with a synchro self shifting (SSS) clutch, you are preparing for a power turbine over speed test. What would be an important action to take prior to starting the engine? Remove the SSS clutch locking pawls. Calculate the engagement speed of the SSS clutch. Engage the SSS clutch using air pressure. Manually lockout the SSS clutch from engaging using the special wrench provided. Drive Systems
A What type of main reduction gear arrangement prevents independent axial and rotational movement of the pinions? Locked train Hydraulic suspension Unlocked train Independent suspension Drive Systems
A The purpose of the main reduction gear in a marine gas turbine propulsion installation is which of the following? Transfer high-speed gas turbine rotation to low-speed propeller rotation. Reduces gas turbine speed to engage the clutch. Transfer low-speed gas turbine rotation to high-speed propeller rotation. Increases gas turbine speed to engage the clutch. Drive Systems
A The main thrust bearing directly positions which part(s) of the main reduction gear? Bull gear. Low-speed pinion. High-speed pinion. High-speed gear. Drive Systems
D The lubrication principal used by the Kingsbury thrust bearing is which of the following? Cylinder-shaped oil film. Free sliding oil film. Square-shaped oil film. Wedge-shaped oil film. Drive Systems
C When performing a static check to determine tooth contact, you should use which of the following compounds to coat the gear teeth? Copper sulfate. An indelible marker. Prussian Blue. Persian Blue. Drive Systems
D Gear backlash is best described as which of the following? Clearance of the gears operating in parallel. Clearance of the gears that do not mesh. Radial play between the pinion teeth and bearings. Play between the surfaces of the teeth in mesh. Drive Systems
A In cases where both the pinion and gear teeth of the main reduction gear have been slightly indented by foreign material, what action should you take? Both the pinion and gear should be relieved of all raised metal around the indentation. Closely monitor the damage to see if it spreads. Remove the foreign material that caused the indentation and return the unit to service. Replace both the pinion and gear. Drive Systems
D The fuel oil system of a gas turbine engine provides all EXCEPT which of the following? Acts as a hydraulic medium to actuate the fuel control Provides accurately metered fuel for combustion Controls the angle of the variable stator vanes Acts as a cooling medium for the lube oil cooler Fuel Systems
C Gas turbine fuel manifold pressure is established by which of the following actions? Closing the fuel recirculating valve. Starting the fuel service pumps on low speed. Rotating the gas generator. Starting the fuel service pumps on high speed. Fuel Systems
D The secondary passages on the gas turbine engine fuel nozzles shown in the illustration are designed to open at approximately what pressure? Illustration GT-0005 30 PSIG 130 PSIG 230 PSIG 330 PSIG Fuel Systems
B How many fuel igniters would be installed on the marine gas turbine engine shown in the illustration? Illustration GT-0017 1 2 3 4 Fuel Systems
D The fuel oil back pressure regulator on the fuel system shown in the illustration, returns fuel to the which of the following? Illustration GT-0021 Booster pump suction. Purge valve discharge. Fuel oil day tank. Booster pump discharge. Fuel Systems
D The main fuel control module used on a marine gas turbine engine as shown in the illustration, is responsible for managing which function(s)? Illustration GT-0021 deceleration schedule variable stator vane feedback lever acceleration schedule All of the above. Fuel Systems
D The purpose of the air shroud (swirl cup) around the tip of the fuel nozzle of an GE LM2500 gas turbine engine is which of the following? cool the nozzle tip promote air turbulence promote air/fuel mixing All of the above. Fuel Systems
C A fuel analysis report for a gas turbine propelled vessel indicates a calcium level in excess of 0.5 ppm. High calcium levels in distillate fuels for gas turbines can cause which of the following? Abrasive wear in the compressor section of the turbine. Clogged fuel filters in the fuel service system. Calcium deposits which can clog cooling holes in the turbine section. Corrosion in the combustor section of the turbine. Fuel Systems
A During an operation of a gas turbine equipped with an intercooler and recuperator, a low combustion air temperature to the combustor section could be caused by which of the following? Low exhaust temperature. High fuel pressure to the combustor section. Low water pressure to the intercooler. High exhaust temperature. Fuel Systems
D A gas turbine engine is experiencing a high rate of corrosion in the hot section of the engine. Which of the following fuel contamination issues could be associated with this problem? High ash content in the fuel. High particle content in the fuel. Low pour point of the fuel. High saltwater content in the fuel. Fuel Systems
A The gas generating sections of marine gas turbine engines are based on which of the following? Aircraft jet engines. Radial piston engines. Oil-fired auxiliary boilers. Free piston engines. Fundamentals
B Compared to other types of engines, what is the biggest advantage of a gas turbine engine? Simplicity of the control circuits. Highest power-to-weight ratio. Low power-to-weight ratio. Simplicity of installation. Fundamentals
D An open cycle gas turbine engine is best described by which of the following statements? Energy is neither created nor destroyed and the cycle is therefore perpetual. Energy is added externally. Working fluids are taken in, transformed, and then recuperated. Working fluids are taken in, transformed, and then discarded. Fundamentals
A What is the difference between an open cycle and a closed cycle gas turbine engine? An open cycle discards the working fluid and a closed cycle retains the working fluid. A closed cycle heats the working fluid from an internal source and an open cycle uses an external source for heating the working fluid. There is no difference because both use the same working fluid. An open cycle retains the working fluid and a closed cycle discards the working fluid. Fundamentals
D The Brayton Cycle is a series of events best described by which of the following statements? Intake, pressurization, ignition, exhaust. Intake, compression, combustion, explosion, exhaust. Intake, decompression, combustion, expansion, exhaust. Intake, compression, combustion, expansion, exhaust. Fundamentals
D Why is a gas turbine considered to operate on the Brayton cycle? Combustion causes large increase in pressure. Combustion causes no increase in volume. Combustion causes an increase in total mass flow. Combustion occurs with no increase in pressure. Fundamentals
D The thermal energy added to the gas as it flows through the combustion section has what effect on the gas? Increase pressure. Decrease volume. Decrease pressure. Increase volume. Fundamentals
D In a gas turbine, the air charge is permitted to be compressed adiabatically by what factor, process, or condition? Rapid heat transfer Low-compression ratio Interstage cooling Speed of the process Fundamentals
C Why is the cycle efficiency higher in the intercooled-recuperated cycle as compared to a simple cycle gas turbine? Illustration GT-0031 The intercooler serves to increase the required high-pressure compressor power while the recuperator utilizes waste heat form the exhaust to decrease turbine inlet temperature. The intercooler serves to increase the required high-pressure compressor power while the recuperator utilizes waste heat form the exhaust to increase turbine inlet temperature. The intercooler serves to reduce the required high-pressure compressor power while the recuperator utilizes waste heat form the exhaust to decrease required fuel to achieve the turbine inlet temperature. The intercooler serves to reduce the required high-pressure compressor power while the recuperator utilizes waste heat form the exhaust to decrease turbine inlet temperature. Fundamentals
B A gas turbine engine in which exhaust gas heat energy is added to the compressor air charge before entering the combustor, is classified as which of the following? Reheat cycle. Regenerative cycle. Combined cycle. ICR cycle. Fundamentals
C The acronym CDP stands for which of the following? Choke Down Point. Coupling Disassembly Point. Compressor Discharge Pressure. Compressor Discharge Pyrometer. Fundamentals
A The acronym FOD stands for which of the following? Foreign Object Damage. Fuel Override Demand. Flow Offset Design. Fuel Oil Discharge. Fundamentals
D The acronym MFC represents which of the following? Manifold Fuel Control. Maritime Fuel Congress. Mid Frame Compressor. Main Fuel Control. Fundamentals
C The acronym VSV represents which of the following? Variable Speed Valve. Vibration Stator Vanes. Variable Stator Vane. Vibration Shutdown Valve. Fundamentals
C The acronym GG represents which of the following? Vibration-Gas Generator Temperature-Gas Generator Gas Generator Speed-Gas Generator Fundamentals
A Boyle's law can best be defined as which of the following? The volume of an enclosed gas varies inversely with the applied pressure, provided the temperature remains constant. If the pressure is constant, the volume of an enclosed gas varies indirectly with absolute temperature. A body at rest tends to remain at rest. None of the above. Fundamentals
A In the operation of a marine propulsion gas turbine, kinetic and thermal energy required to drive the main propeller shaft are extracted by which of the following? Power turbine. COWL diffuser Multi-stage compressor. Variable Stator Vane actuators. Fundamentals
C On the gas turbine shown in the illustration, which of the following best describes the main principle of operation of the component contained within the area labeled "C"? Illustration GT-0001 Bernoulli's Law of Divergency Newton's Law of Motion Combustion at a constant pressure Otto Cycle Fundamentals
D A gas turbine that has a regenerator between the compression and combustion sections in which exhaust gas heat energy is added to the air charge is classified as what type of engine? Semi-open cycle engine. Closed cycle engine. Open cycle engine. Semi-closed cycle engine. Fundamentals
C The term used to describe a gas turbine in which air drawn from the atmosphere passes through the engine only once is which of the following? Uni-cycle. Closed cycle. Open cycle. Semi-closed cycle. Fundamentals
D The term used to describe a gas turbine in which the turbine exhaust passes through a cooler and back to the compressor inlet is which of the following? Uni-cycle. Twin cycle. Open cycle. Closed cycle. Fundamentals
D In a regenerative or recuperative gas turbine cycle configuration, the heat of the turbine exhaust gas is used to do what? Heat the LP compressor discharge air before entering the HP compressor inlet. Heat the intake air to the compressor. Heat the combustor discharge gas before entering the turbine. Heat the compressor discharge air before it enters the combustor. Fundamentals
D What type of gas turbine cycle configuration is shown in the illustration? Illustration GT-0031 Recuperative type. Simple type. Intercooled type. Intercooled-recuperated type. Fundamentals
D Which of the following statements about the intercooled-recuperated gas turbine cycle is true? Illustration GT-0031 Intercooler serves to increase the required high-pressure compressor power, while the recuperator utilizes waste heat form the exhaust to increase turbine inlet temperature. Intercooler serves to increase the required high-pressure compressor power, while the recuperator utilizes waste heat form the exhaust to decrease turbine inlet temperature. Intercooler serves to reduce the required high-pressure compressor power, while the recuperator utilizes waste heat form the exhaust to decrease turbine inlet temperature. Intercooler serves to reduce the required high-pressure compressor power, while the recuperator utilizes waste heat form the exhaust to decrease required fuel to achieve turbine inlet temperature. Fundamentals
D For the same amount of available power, how does a low speed two-stroke diesel engine compare to a recuperated gas turbine configuration? The two-stroke diesel engine would burn more fuel and the particulate and nitrogen oxide (NOx) levels in the exhaust would be higher than that of a recuperated gas turbine configuration The two-stroke diesel engine would burn less fuel and the nitrogen oxide (NOx) levels in the exhaust would be much lower than that of a recuperated gas turbine configuration. The two-stroke diesel engine would burn more fuel than a recuperated gas turbine; however, the particulate and nitrogen oxide (NOx) levels in the exhaust would be lower. The two-stroke diesel engine would burn less fuel than a recuperated gas turbine, however, the levels of particulate and nitrogen oxide (NOx) levels in the exhaust would be higher. Fundamentals
A Which of the following wrenches should NOT be used while working on a gas turbine? Adjustable wrench. Box wrench. Flare nut wrench. Crowfoot wrench. Inspection
B Wrenches that are recommended for use on gas turbine engines should be plated with which of the following elements? Bronze Nickel Carbon Silver Inspection
D Which of the following instruments is designed to help you when performing an internal inspection of the gas turbine engine? Telescope Stroboscope Oscilloscope Borescope Inspection
D All clock positions, engine references, and enclosure references apply to viewing the gas turbine engine shown in the illustration from which of the following locations? Illustration GT-0017 Right side of the compressor to the left side. Left side of the power turbine to the right side. Intake end, looking toward the exhaust end. Rear (exhaust end), looking toward the intake end. Inspection
D Routine water washing of the gas turbine engine compressor shown in the illustration, is usually performed while operating under which of the following conditions? Illustration GT-0017 At 25% power. At 75% power. At full power. With the starter motor drive. Inspection
A When removing the gas turbine engine as shown in the illustration, how is the engine removal accomplished? Illustration GT-0022 By removing the inlet screen, barrier wall and module front panel, then installing the rails and moving the engine into the engine room and up through the soft patch to the main deck. By removing the exhaust boot, HSCS and PT, then lifting the engine up the exhaust stack. By removing the inlet screen and barrier wall, then installing the rails and lifting the engine out through the inlet duct. By removing the upper half casing and separately lifting out the compressor and power turbine rotors. Inspection
C You are preparing for a borescope inspection of a gas turbine engine. Prior to the inspection it is recommended that you do which of the following? Water wash both the compressor and the power turbine. Water wash the power turbine. Water wash the compressor. Not water wash the engine prior to the inspection. Inspection
B To manually rotate the GE LM2500 gas turbine engine, you should use which of the following tools? 18-inch long 1/2-inch drive socket wrench. A socket wrench with an 18-inch long 3/4-inch drive extension. 18-inch long 3/4-inch drive socket wrench. A socket wrench with an 18-inch long 1/2-inch drive extension. Inspection
B When conducting a borescope inspection, you must be aware of all of the following factors EXCEPT which? The inspection areas and ports. The engineers experience. The internal reference points. The limitations of your equipment. Inspection
A You are preparing for a borescope inspection of a GE LM2500 gas turbine engine. You are reviewing the correct geometric orientation nomenclature which includes which of the following? All references left, right, and radial are orientated as viewed from aft looking forward on the engine. All references left, right, and radial are orientated as viewed from forward looking aft on the engine. All references are made from the combustor section, forward to the hp turbine and aft to the power turbine. All references are made from the combustor section, aft to the hp turbine and forward to the power turbine. Inspection
A The six borescope ports located in the compressor rear frame casing of the marine propulsion gas turbine shown, can be used to inspect all EXCEPT which of the following components? Illustration GT-0006 14th stage compressor blades. Fuel nozzles. Combustor. 1st stage turbine nozzle Inspection
B On an GE LM2500 gas turbine powered vessel you are conducting a borescope inspection of the compressor. What is used on each compressor stage as a reference for indexing the blades? The IGV actuator. The locking lug blades. Witness marks center punched on the #1 nozzle and blade. Scribe marks located on the stator and rotor diaphragm. Inspection
A Zero reference for the GE LM2500 gas turbine engine is established by the use of which of the following engine components? Locking lug blades. Vane blades. Carboloy blade pads. Vane shrouds. Inspection
D When conducting a borescope inspection of the compressor, why can airfoil and tip cracks be difficult to detect? Rotating the rotor too fast. Borescope optics have deteriorated. The cracks are generally tight and shallow in depth. All of the above. Inspection
A When inspecting the combustion section of a gas turbine engine, what wattage light source should you use? 1000 watt. 750 watt. 500 watt. 250 watt. Inspection
B In a gas turbine propulsion installation, the typical control system is designed to perform which of the following three functions? Operational control, speed control, and braking. Operational control, safety control, and monitoring. Pneumatic, hydraulic, and electric control. Pneumatic control, electric control and monitoring. Instrumentation And Controls
C A magnet pickup typically produces what type of signal output? high current steady DC voltage voltage pulse pure sine wave Instrumentation And Controls
B When auto starting a gas turbine engine similar to the one shown in the illustration, a "False Start" indication will initiate if which of the following conditions occurs? Illustration GT-0016 The gas generator rotor fails to reach a preset RPM after the power turbine begins to rotate. The gas generator rotor fails to reach a preset RPM after the starting motor has been energized for a preset interval. Power Turbine outlet temperature fails to reach a preset value. The power turbine fails to reach a preset RPM after the gas generator reaches a preset RPM. Instrumentation And Controls
B During an auto-start sequence on the marine gas turbine control console shown in the illustration, what would be the correct order of events required to occur after the start sequence begins? Illustration GT-0016 NGG reaches idle RPM, Power turbine reaches ignition RPM, gas temperature greater than 400 degrees F. NGG reaches ignition RPM, gas temperature greater than 400 degrees F, NGG reaches idle RPM Power turbine reaches ignition RPM, gas temperature greater than 400 degrees F, Power turbine reaches idle RPM Power turbine reaches ignition RPM, gas temperature greater than 400 degrees F, NGG reaches idle RPM Instrumentation And Controls
D A turbine stage is represented by which of the following components and in which order? One set of rotating blades, one set of stationary vanes. One set of rotating vanes, one set of stationary blades. Two sets of stationary vanes, one set of rotating blades. One set of stationary vanes, one set of rotating blades. Intake and exhaust systems
D The turbine nozzles convert heat and pressure energy to velocity energy by means of which of the following? Deflection process. Convergent-Divergent Process. Divergent process. Convergent process. Intake and exhaust systems
D In the operation of a marine propulsion gas turbine, kinetic and thermal energy required to drive the main propeller shaft are extracted by which of the following? Multi-stage compressor. Combustor. Exhaust gas. Power turbine. Intake and exhaust systems
C How do the high-velocity high-temperature gases cause the gas turbine rotor to rotate? By creating a low-pressure area before the rotor. By converting the high-velocity gas to low-velocity gas. By transferring velocity energy and thermal energy to the turbine blades. By increasing the velocity of the gases. Intake and exhaust systems
A What are the two principle functions of the turbine nozzle guide vanes? Convert the heat energy of the hot gases into kinetic energy and direct the flow of gases to the turbine rotor blades. Convert the potential energy of the hot gases into heat energy and direct the flow of gases to the turbine rotor blades. Convert the heat energy of the hot gases into potential energy and direct the flow of gases to the compressor rotor blades. Convert the heat energy of the hot gases into potential energy and direct the flow of gases to the turbine rotor blades. Intake and exhaust systems
D The circle of turbine stationary vanes that convert pressure and thermal energy to velocity energy and direct the combustion gases in the direction of turbine wheel rotation is referred to as what? Rotor assembly. Diffuser assembly. Compressor assembly. Nozzle assembly. Intake and exhaust systems
D What method is utilized to allow turbine nozzle blades to withstand high inlet temperatures? Laser cooling Thermoelectric cooling Water cooling Air cooling Intake and exhaust systems
C Which of the following designs is the most satisfactory method for attaching turbine blades to the rotor disk? Pinning design. Locking tab design. Fir-tree design. Retaining ring design. Intake and exhaust systems
A Turbine disks are commonly attached to the shaft by which of the following methods? Bolted or welded. Locking tabs or retaining rings. Pinned or Locking Tabs. Riveted or pinned. Intake and exhaust systems
C HP turbine blades are generally cooled by which of the following methods? Compressed air entering the tip and exiting the root. Cooling water entering the tip and exiting the root. Compressed air entering the root and exiting the tip. Cooling water entering the root and exiting the tip. Intake and exhaust systems
B To keep the exit pressures relatively constant across a HP turbine blade, which type of construction is generally utilized? Curtis. Impulse-Reaction. Impulse. Rateau. Intake and exhaust systems
A Assuming you maintain the same power output, how will a decrease in the compressor inlet air temperature effect a gas turbine engine's efficiency and fuel consumption? Efficiency will increase and fuel consumption will decrease. Efficiency will decrease and fuel consumption will increase. Efficiency and fuel consumption will not be affected by a change in inlet air temperature. Efficiency and fuel consumption will both increase. Intake and exhaust systems
C On a gas turbine engine, a high outside air temperature can cause high turbine inlet temperature, low mass/weight of airflow through the turbine, and which of the following conditions? A requirement for less energy to achieve adequate compression Cooler exhaust gas temperature A requirement for more energy to achieve adequate compression None of the above Intake and exhaust systems
D Assuming that the turbine inlet temperature of a gas turbine engine remains constant, which of the following operating parameter changes would be noted with an increase in the compressor inlet air temperature? The mass air flow through the gas turbine would increase. The power turbine output increases due to hot inlet air requiring less fuel to be heated to the same turbine inlet temperature. The exhaust temperature would drop significantly. The gas turbine power would drop due to reduced mass air flow. Intake and exhaust systems
A What action should you take if full power vibration limits are exceeded on a gas turbine engine? Reduce power to stay within limits. Borescope the engine. No action is needed. Water wash the engine. Intake and exhaust systems
C What is the designed compressor pressure ratio of the gas turbine compressor rotor shown in the illustration? Illustration GT-0004 10 to 1 12 to 1 16 to 1 20 to 1 Intake and exhaust systems
A The two main types of "compressor" stalls are known as which of the following? Steady state and transient. Over-speed and overload stall. Flame out and inlet temperature stall. Rapid rise and temperature inversion. Intake and exhaust systems
A What design feature is incorporated into the main propulsion gas turbine to eliminate compressor surge? Variable compressor stator vanes are used. The governor adjusts the fuel to maintain the turbine inlet temperature constant. The governor maintains the compressor turbine speed constant. Fuel modulating function is incorporated into the governor control system. Intake and exhaust systems
D To prevent overheating of the illustrated turbine blade, which of the following fluids is circulated through it via the shaped internal passages? Illustration GT-0029 Cooling water. Cooling oil. External compressed air. Bleed air. Intake and exhaust systems
B A gas turbine engine's main lube oil system pump check valve serves to maintain system prime and perform what other function? To increase system pressure. To prevent reverse flow of oil through a secured pump. To return oil to the main reduction gear sump. None of the above. Lubrication Systems
D When the main reduction gear lube oil system is secured, which of the following components maintains the air within the casing at less than 35 percent relative humidity? Rehumidifier Precipitator Reciprocator Dehumidifier Lubrication Systems
C The lube oil scavenge pressure on the marine gas turbine shown in the illustration is sensed by which of the following? Illustration GT-0017 Manometer. RTD. Transducer. Probe. Lubrication Systems
B For the gas turbine engine lube oil system shown in the illustration, what is the purpose of the lube oil supply check valves? Illustration GT-0024 Keep the lube oil lines in the engine primed. Prevent lube oil contained in the LO storage and conditioning tank from draining into gearboxes and sumps. Prevent the lube oil and scavenge pump from losing its prime. All of the above. Lubrication Systems
D How is the lube oil supplied to each bearing in a gas turbine engine controlled? Regulating valve. Flow divider. Lube oil pump. Calibrated orifice. Lubrication Systems
A The lube oil system shown in the illustration, is designed to lubricate the main bearings by what principle? Illustration GT-0023 Spray lubrication with dry sumps. Totally submerged oil bath. Splash lubrication. Self-contained partial oil bath. Lubrication Systems
B On the gas turbine engine lube oil system shown in the illustration, air and oil are primarily separated in the air/oil separator through the use of which of the following? Illustration GT- 0024 Filter Impeller Heater Strainer Lubrication Systems
B On the marine gas turbine engine shown in the illustration, the 8th stage bleed air is used for which of the following? Illustration GT-0017 Power turbine balance piston cavity pressurization. Lube oil sump pressurization and cooling. High pressure turbine 2nd stage nozzle cooling. Power turbine blade cooling.  Lubrication Systems
B As shown in the illustration, what is the purpose of pressurizing the main bearing lube oil sumps on a typical marine gas turbine? Illustration GT-0023 Provides uniform lube oil distribution around the bearing. Minimizes oil leakage from the rotor shaft. Increases lube oil penetration. Assist in cooling the lube oil. Lubrication Systems
D The lube oil system shown in the illustration, consists of which of the following sub-systems? Illustration GT-0024 Lube oil scavenging.  Sump venting. Lube oil supply. All of the above. Lubrication Systems
D Which of the following components are installed in the lube oil system shown in the illustration? Illustration GT-0024 pressurized sumps air/oil separators pressurized supply lines with separate scavenging return lines All of the above. Lubrication Systems
D How many lube oil sumps are installed on the marine gas turbine engine shown in the illustration? Illustration GT-0024 1 2 3 4 Lubrication Systems
A Which of the following is true concerning the main engine lube oil system of the marine gas turbine shown in the illustration? Illustration GT-0024 The system includes a single combined lube oil supply and scavenge pump. The lineshaft bearing lubrication system is provided for by the LOSCA. Lubrication is provided for the main reduction gears through the transfer gearbox. All of the above. Lubrication Systems
C What type of main lube oil supply and scavenging pump is installed on the marine gas turbine engine shown in the illustration? Illustration GT-0017 Reciprocating piston. Flexible diaphragm. Vane. Centrifugal. Lubrication Systems
A Which of the following is the most probable cause for the sump oil to be excessively aerated on an aero-derivative main propulsion gas turbine engine? The air oil separator is not functioning properly. Air inlet temperatures to the compressor are higher than normal. The compressor discharge pressure is lower than normal. Exhaust pressures are lower than normal. Lubrication Systems
D Your first step in response to a gas turbine engine high lube oil sump temperature alarm would be which of the following? Check the oil filter differential pressure. De-couple the engine from the main reduction gear. Check the oil pressure to the sump. Reduce engine speed. Lubrication Systems
D Lubricating oil contamination in a gas turbine bearing oil sump will most likely come from which of the following? Failure of the lube oil pump. Fuel oil contamination. Failure of the scavenging pump. Failure of seal pressurization air. Lubrication Systems
C The buildup of contamination in a gas turbine will cause all of the following conditions EXCEPT which of the following? Increased combustion gas temperatures Restricted airflow Reduced fuel consumption Turbine blade corrosion Maintenance
A Why is safety-wiring, or lock wiring of gas turbine parts required? Prevent disengagement of parts. Prevent corrosion. Maintain lubrication. Maintain fastener torque. Maintenance
B On a gas turbine powered vessel, what is the last step after an off-line water wash? Open the Variable Stator vanes. Start the engine to dry it out. Release the gas generator brake. Secure the starting system. Maintenance
A The effectiveness of an off-line water wash of a GE LM2500 gas turbine engine can be enhanced by doing which of the following? Stroking the Variable Stator Vanes to the maximum open position. Washing the power turbine while still hot. Motoring the engine just short of idle speed. Applying the power turbine brake. Maintenance
A On a gas turbine propulsion vessel, you notice a slow but steady increase in gas turbine vibration and specific fuel consumption as the voyage has progressed. What would be a good maintenance technique to use to correct these increases? Secure the engine and water wash the compressor off-line. Increase the Variable Stator Vane setting to supply more air to the combustor. Water wash the power turbine on-line. Increase gas generator RPM to a more efficient setting. Maintenance
C How do you gain access to the burner units of a can-annular combustor to perform maintenance? By removing the annular case By removing the power turbine By sliding the can-annular case aside By disassembling the engine Maintenance
D What are the two prime sources of deposits that build up on compressor blades? Carbon residue and lube oil mist Salt spray and carbon residue Lube oil mist and fuel oil spray Lube oil mist and salt spray Maintenance
B What is the power source for the ignition exciter of a gas turbine engine? Ship's 400 Hz system. Ship's 115 volt AC system. Ship's 28 volt DC system. Four lead-acid batteries. Starting Systems
B On the ignition system of a gas turbine engine, how is optimum spark achieved? Concentration of minimum energy in maximum time. Concentration of maximum energy in minimum time. Concentration of maximum energy in maximum time. Concentration of minimum energy in minimum time. Starting Systems
B What is the most common type of spark igniter used on a gas turbine engine? Resistive gap Annular gap Delayed gap Suppression gap Starting Systems
B On the marine gas turbine engine panel shown in the illustration, which of the following conditions would prevent the auto-start sequence from successfully completing? Illustration GT-0016 Propeller pitch at zero Bleed air valve open Fuel supply cutoff valve opened. Starting motor not turning. Starting Systems
D Which of the following statements correctly describes force? Force is not a vector quantity. Force is a scalar quantity. Force is work in a unit of time. Force has magnitude and direction. Thermodynamics
C Mechanical work is defined as which of the following? A measurement in pounds per square inch. Rate of doing work. A force acting through a distance. Distance traveled over time. Thermodynamics
C Power is defined as which of the following? Force applied through a distance. The rate of applying a force. The rate of doing work. Work performed through a distance. Thermodynamics
D Potential energy is defined as which of the following? The energy a body possesses due to its motion. A measurement in feet per second. A total pressure measurement. The energy a body possesses due to its position. Thermodynamics
C Which of the following terms refers to thermal energy in transition? Power Foot-Pound Heat Horsepower Thermodynamics
D What is the term given to a process that occurs without a loss or gain of heat? Exothermic. Isothermal Endothermic. Adiabatic Thermodynamics
B Rankine is the temperature scale that corresponds to which of the following? Absolute reading of a measured temperature in degrees Kelvin. Absolute reading of a measured temperature in degrees Fahrenheit. Absolute reading of a measured temperature in degrees Fahrenheit + 273. Absolute reading of a measured temperature in degrees Celsius. Thermodynamics
A Kelvin is the absolute temperature scale that corresponds to which of the following? Absolute reading of a measured temperature in degrees Celsius. Absolute reading of a measured temperature in degrees Fahrenheit. Absolute reading of a measured temperature in degrees Rankine. None of the above. Thermodynamics
D Which of the following is the definition of absolute temperature? Temperature measured with reference to 0 degrees Fahrenheit. Temperature measured with reference to 0 degrees Celsius. Temperature measured with reference to 273 degrees Rankine. Temperature measured with reference to the theoretical temperature at which all molecular motion stops. Thermodynamics
D Thermal energy is the only form of energy that can be added to or removed from a substance. How is thermal energy that is added to a substance stored? In the form of potential kinetic energy. In the form of heat. In the form of mechanical energy. In the form of internal energy. Thermodynamics
D "Standard Day" conditions, as defined by the ISO, is which of the following? 29.92 in HG @ 15 deg C. 14.69 psi @ 59 deg F. 14.69 in HG @ 59 deg C. Both A and B. Thermodynamics
D Under standard atmospheric conditions, 208.7 PSIG converts to approximately what in absolute pressure? 104.7 PSIA 214.7 PSIA 194.0 PSIA 223.4 PSIA. Thermodynamics
B A temperature of 69.5 degrees Fahrenheit converts to approximately what temperature in degrees Rankine? 342.5 degrees R. 529.5 degrees R.  590.5 degrees R. 203.5 degrees R. Thermodynamics
A A temperature of 32.5 degrees Celsius converts to approximately what temperature in degrees Kelvin? 305.5 degrees K. 240.5 degrees K. 492.5 degrees K. 427.5 degrees K. Thermodynamics
A Newton's Second Law of Motion states which of the following? An unbalancing force on a body tends to produce an acceleration in the same direction of the force applied. The acceleration of a body is inversely proportional to the applied force. An unbalancing force on a body tends to produce an acceleration in the opposite direction of the force applied. The acceleration of a body is directly proportional to the mass. Thermodynamics
B Newton's Third Law of Motion states which of the following? For every acting force there is an unequal and opposite reacting force. For every acting force there is an equal and opposite reacting force. For every acting force there is an equal reacting force in the opposite direction. For every acting force there is no reacting force in the up or down directions. Thermodynamics
A Newton's First Law of Motion states which of the following? A body in a state of rest tends to remain at rest, and a body in motion continues to stay in motion at a constant speed, unless acted upon by some external force. A body at rest will remain at rest when an external force is applied. A body in motion will continue to stay in motion, when an equal and opposite external force is applied. A body in a state of rest tends to remain at rest, and a body in motion continues to stay in motion, when an external force is applied. Thermodynamics
A Which of the following statements concerning fluid flow is true? If a fluid flowing through a tube reaches a constriction or narrowing of the tube, the velocity of the fluid flowing through the restriction increases and the pressure decreases. If a fluid flowing through a tube reaches a constriction or narrowing of the tube, the velocity of the fluid flowing through the restriction decreases and the pressure decreases. If a fluid flowing through a tube reaches a constriction or narrowing of the tube, the velocity of the fluid flowing through the restriction decreases and the pressure increases. If a fluid flowing through a tube reaches a constriction or narrowing of the tube, the velocity of the fluid flowing through the restriction increases and the pressure increases. Thermodynamics
B The term "divergent" is best described as which of the following? Maintaining an equal distance between edges. Moving away from each other, as the inner walls of a tube that flare outward. Approaching nearer together, as the inner walls of a tube that is constricted. Thermal and kinetic energy being converted to mechanical energy. Thermodynamics
D Provisions for avoiding the buildup of ice on the intake air surfaces of a gas turbine plant can be found where? In the inlet duct frame at the inlet to the engine. In the exhaust and intake ducting. In the stack intake ducting. Both A & B. Troubleshooting
D The two basic types of compressors used in gas turbine engines are which of the following? Centrifugal and reciprocating. Axial and lobe. Axial and reciprocating. Centrifugal and axial. Troubleshooting
C In comparing a centrifugal-type to an axial-type compressor, which of the following statements is true? Centrifugal compressors are more expensive to manufacture than a axial compressor. Centrifugal compressors have a lower compression ratio per stage than a axial compressor. Centrifugal compressors have a higher compression ratio per stage than an axial flow compressor. A centrifugal compressor has a lower resistance to FOD than a axial compressor. Troubleshooting
D What is the disadvantage of a dual-entry centrifugal compressor compared to a single-entry centrifugal compressor? The dual-entry compressor has a greater efficiency. The dual-entry compressor rotates at slower speeds. The dual-entry compressor is larger in diameter. The dual-entry compressor utilizes a more complicated inlet ducting. Troubleshooting
D A centrifugal compressor assembly consists of which of the following? A stationary impeller and a rotating diffuser. Stationary vanes and rotating blades Rotating pistons and stationary liners. A rotating impeller and a stationary diffuser. Troubleshooting
C Which of the following statements is true regarding centrifugal compressors? The impeller of a centrifugal compressor has a radial inlet and axial discharge. The efficiency of a centrifugal compressor is greater than that of an axial compressor. The centrifugal compressor is frequently used on small, low power turbines. Centrifugal compressors are complicated in design and heavy. Troubleshooting
C While air is being compressed in a centrifugal flow gas turbine, what happens to the direction of air flow? Changes only once from inlet to outlet. Changes only at the compressor inlet. Changes at each separate component. Changes only at the compressor discharge. Troubleshooting
B In a centrifugal compressor, which component reduces the velocity and increases the static pressure of the air? Impeller Diffuser Eductor Volute Troubleshooting
B Before combustion can occur, the combustion air must be delivered to the combustor at a high-pressure and low-velocity. High-velocity, low-pressure air is converted to high-pressure, low-velocity air at what part of a centrifugal-type compressor? Inlet plenum. Diffuser. Turning vanes. Impeller. Troubleshooting
A A pressure stage of an axial-type compressor consists of which of the following? Set of rotor blades and a set of stator blades. Compressor rotor and a set of inlet guide vanes. Set of stator blades. Set of rotor blades. Troubleshooting
C An axial compressor basically consists of which of the following? A rotating impeller and a stationary diffuser. Rotating pistons and stationary liners. Stationary vanes and rotating blades. A stationary impeller and a rotating diffuser. Troubleshooting
B The purpose of the metal spray rub coating on the rotor and stator casing of an axial type compressor is which of the following? control airflow through the compressor provide close vane to rotor and blade to stator case clearances seal the circumferential dovetails ensure protection for the gearbox adapter when removing or replacing the bearings Troubleshooting
A Each stage of an axial-compressor of a gas turbine can compress the atmospheric air a total of how many times? 1.2 times 2.2 times 3.2 times 4.2 times Troubleshooting
A An axial compressor stage is represented by which of the following components and in which order? One set of rotating blades, one set of stationary vanes. One set of stationary vanes, one set of rotating blades. One set of rotating blades, two sets of stationary vanes. One set of rotating vanes, one set of stationary blades. Troubleshooting
D Which of the following is the main advantage of a split axial compressor case? Simpler to disassemble. Stronger construction. Cheaper to manufacture. Easier to repair and inspect. Troubleshooting
C What is the term used to describe the stationary vanes preceding the first stage of an axial compressor? Variable stator vanes. Variable inlet vanes. Inlet guide vanes. First stage stator vanes. Troubleshooting
B What is the function of the stator in a axial gas turbine compressor? To convert pressure to velocity. To convert velocity to pressure. To increase volume. To provide velocity energy. Troubleshooting
C An axial compressor stator vane that is mechanically adjusted to provide optimum compressor performance over a wide operating range is referred to as which of the following? Variable Guide Vane (VGV) Static Guide Vane (SGV) Variable Stator Vane (VSV) Inlet Guide Vane (IGV) Troubleshooting
C Variable stator vanes give an axial gas turbine compressor which of the following capabilities? Increases pressure ratios. Increased primary air flow. Efficiency at various speeds. Ability to operate at constant speeds. Troubleshooting
A Two functions of the compressor stator vanes include which of the following? Direct air flow to each rotor stage at the correct angle and deliver air to the combustor at the correct velocity and pressure. Direct air flow to rotor blades at the correct angle and are shaped to produce a velocity increase and maintain a constant pressure. Direct air flow to rotor blades at the correct angle and are shaped to cause a velocity increase and a pressure decrease. Direct air flow to rotor blades at the correct angle and are shaped to maintain a constant velocity and produce a pressure increase. Troubleshooting
B The primary function of an axial compressor rotor blade is which of the following? To use centrifugal force to increase the pressure of the air stream. To impart acceleration to the air mass, resulting in an increase in velocity. To act as a diffuser to the air flow causing an increase in pressure with a resultant decrease in velocity. To change the direction of the air flow. Troubleshooting
D What are the two common forms of axial compressor rotor blade roots? Grub and bulb. Fir tree and key. Sawtooth and knob. Fir tree and bulb. Troubleshooting
D What is a compressor midspan shrould? A support for the tips of stator blades. The center of a two-piece rotor blade. A way of securing stator blades. A brace built into the middle of a rotor blade for damping. Troubleshooting
B Why are loose-fitting blades used on the first several stages of large axial compressors? To compensate for a malfunctioning compressor support bearing. To minimize vibration while the engine is passing through critical speed ranges. To compensate for the abrasive action of the blade tips. To maintain close tolerances in the compressor. Troubleshooting
C Which of the following statements is true about an axial compressor disk-type rotor? Rotor is only suitable for low-speed compressors. Rotor discs are held together by through bolts. Rotor disks are shrunk fit onto a steel shaft. Rotor consists of rings that are flanged to fit one against the other. Troubleshooting
A In a gas turbine engine, the majority of the energy is added to the working fluid in which of the following components? Combustor. Power Turbine. Compressor. High Pressure Turbine. Troubleshooting
A The three most common types of combustors used in gas turbine engines are which of the following? Can, Annular, and Can-Annular. Can, Derivative, and Can-Derivative. Can, Vortex, and Can-Vortex. Can, Angular, and Can-Angular. Troubleshooting
B A centrifugal-flow gas turbine uses what type of combustion chamber? Double-Annular Can Can-Annular Annular Troubleshooting
D The short length of the can-annular combustion chamber provides for which of the following conditions? Maximum pressure drop of the gases between the compressor outlet and the flame area. Decreased combustor temperature. Increased combustor temperature. Minimal pressure drop of the gases between the compressor outlet and the flame area. Troubleshooting
C When dissimilar metals come in contact with a conductor, which of the following types of metal deterioration takes place? Rust erosion. Chemical corrosion. Electrochemical corrosion. Etching erosion. Troubleshooting
B A reddish-colored oxide usually forms on which of the following metals? Aluminum. Steel. Chromium. Magnesium. Troubleshooting
D A white-gray powdery deposit can usually found on which of the following metals? Steel. Magnesium. Magnetite. Aluminum. Troubleshooting
C Active corrosion on copper alloys is indicated by which of the following? A white-gray powder formation. A copper-oxide crust formation. A gray-green patina formation. A verdigris formation. Troubleshooting
D Cadmium and zinc coatings provide which of the following type of protection for the base metal? Sealant. Chemical. Thermal. Sacrificial. Troubleshooting
C Which of the following conditions will NOT be the result of a build-up of deposits in a gas turbine compressor? Increased combustion gas temperatures. Restricted air flow. Reduced fuel consumption. Turbine blade corrosion. Troubleshooting
A Compressor tip clang can be usually attributed to which of the following operating conditions? Compressor stall. Overloading. Continuous high-power operation. Continuous low-power operation. Troubleshooting
D Compressor rotor blade tip curl is usually caused by which of the following? Misalignment. Object damage. Vane rub. Blade rub. Troubleshooting
D Once a compressor is broken in, which of the following factors will most likely cause blade tips to rub? Sprayed material in the stator case Elongation of the blade tips Profiles on the blade tips Failure of a rotor bearing Troubleshooting
B What type of metallurgical failure does Item A represent in the illustration? Illustration GT-0014 Rupture. Radial cracking. Creep. Axial cracking. Troubleshooting
B What type of metallurgical failure does Item B represent in the illustration? Illustration GT-0014 Circumferential cracking. Axial cracking. Weld cracking. Radial cracking. Troubleshooting
A You are conducting a borescope inspection of the compressor section of a GE LM2500 gas turbine. In stage four, you see a slight tilt to one blade and the blade platform is raised higher than the other blades. What could be a cause of this condition and what would be your course of action? Condition could be the result of blade root failure. Engine should be taken out of service until condition can be evaluated. FOD damage could cause this condition. Engine can be operated at full load until next scheduled maintenance. Metal fatigue could cause this condition. Engine can be operated but gas generator speed should be reduced. Ice damage could cause this condition. Blade tilt should be corrected using special tool provided, then engine will be safe to operate. Troubleshooting
A A compressor blade platform that is tilted or raised may indicate which of the following failures? Blade root. Carboloy pad. Midspan damper. Tip clang. Troubleshooting
C When tip clang takes place on a gas turbine engine, the major damage occurs to what area of the blade? Chord Tip Root Midspan Troubleshooting
A You are conducting a borescope inspection of the combustor section of a GE LM2500 gas turbine engine. You observe a one square inch hole in the combustor dome where burn through has removed the metal. What would be your course of action? Record the damage and continue to operate the engine while monitoring the high pressure turbine temperatures and nozzle condition. Immediately take the engine out of service. Operate the engine only in an emergency and at reduced load. Make temporary repairs with on board repair kit to patch hole. Troubleshooting
C The dimples of a combustor dome band that has a low operating time will usually have what kind of damage? Burn away. Bowing. Cracks. Burn through. Troubleshooting
C Distortion of the combustor liner assembly is evident when you observe which of the following conditions? The inner liner bends down into the flow path., and the outer liner lifts up into the flow path Both the inner and outer liner bend into the flow path. The inner liner lifts up into the flow path, and the outer liner bends down into the flow path. Both the inner and outer liner lift up into the flow path. Troubleshooting