CDC 2A651S Vol. 4

1. Which of the following is not a proper troubleshooting practice?

Checking the applicable trouble areas.

Understanding the function of each engine unit.

Inspecting other areas after isolating trouble between points.

Performing easy checks, then going to more difficult checks.

Inspecting other areas after isolating trouble between points is not a proper troubleshooting practice. When troubleshooting, it is important to systematically check each possible cause of the problem before moving on to other areas. By isolating the trouble between points and then inspecting other areas, it can lead to overlooking potential causes and prolong the troubleshooting process. It is more effective to thoroughly inspect each possible trouble area before moving on to the next.

Explanation

Inspecting other areas after isolating trouble between points is not a proper troubleshooting practice. When troubleshooting, it is important to systematically check each possible cause of the problem before moving on to other areas. By isolating the trouble between points and then inspecting other areas, it can lead to overlooking potential causes and prolong the troubleshooting process. It is more effective to thoroughly inspect each possible trouble area before moving on to the next.

2. In vibration analysis, frequency is usually measured in

Mils.

Phase lags.

Cycles per second.

Phases per second.

In vibration analysis, frequency is a measure of how many cycles per second an object or system completes. It is commonly measured in cycles per second, which is also known as Hertz (Hz). This unit of measurement helps to quantify the rate at which the vibration is occurring, providing valuable information for analyzing and understanding the behavior of the system.

Explanation

In vibration analysis, frequency is a measure of how many cycles per second an object or system completes. It is commonly measured in cycles per second, which is also known as Hertz (Hz). This unit of measurement helps to quantify the rate at which the vibration is occurring, providing valuable information for analyzing and understanding the behavior of the system.

3. What supports the fan and low-pressure turbine?

Bushings.

Brackets.

Bearings.

Bulkheads.

Bearings support the fan and low-pressure turbine. Bearings are mechanical components that reduce friction between moving parts, allowing them to rotate smoothly. In this context, bearings help to support and facilitate the rotation of the fan and low-pressure turbine, ensuring their efficient operation. Bushings, brackets, and bulkheads are not specifically designed for this purpose, making bearings the correct answer.

Explanation

Bearings support the fan and low-pressure turbine. Bearings are mechanical components that reduce friction between moving parts, allowing them to rotate smoothly. In this context, bearings help to support and facilitate the rotation of the fan and low-pressure turbine, ensuring their efficient operation. Bushings, brackets, and bulkheads are not specifically designed for this purpose, making bearings the correct answer.

4. What inspection is given to all newly assigned aircraft?

Phased.

Special.

Calendar.

Acceptance.

Acceptance inspection is given to all newly assigned aircraft. This inspection is conducted to ensure that the aircraft meets all the required standards and specifications before it is put into service. It involves a thorough examination of the aircraft's systems, components, and overall condition to verify its airworthiness and readiness for operation. The acceptance inspection is crucial in ensuring the safety and reliability of the aircraft before it is used for any missions or flights.

Explanation

Acceptance inspection is given to all newly assigned aircraft. This inspection is conducted to ensure that the aircraft meets all the required standards and specifications before it is put into service. It involves a thorough examination of the aircraft's systems, components, and overall condition to verify its airworthiness and readiness for operation. The acceptance inspection is crucial in ensuring the safety and reliability of the aircraft before it is used for any missions or flights.

5. A cold compressor stall occurring at low RPM accompanied by a slight over temperature is called

An incipient.

A thermal.

A partial.

A mild.

An incipient refers to a condition where a cold compressor stall happens at low RPM along with a slight over temperature. This term is used to describe the early stage or beginning of a particular event or condition. In this case, it signifies the initial signs of a cold compressor stall occurring at low RPM with a slight over temperature.

Explanation

An incipient refers to a condition where a cold compressor stall happens at low RPM along with a slight over temperature. This term is used to describe the early stage or beginning of a particular event or condition. In this case, it signifies the initial signs of a cold compressor stall occurring at low RPM with a slight over temperature.

6. When an engine arrives for a test run at the test cell, it must

Only need replacing minor parts.

Be operable with all known discrepancies corrected.

Have the fuel line disconnected from the pump inlet.

Only need torquing of minor bits and pieces.

When an engine arrives for a test run at the test cell, it must be operable with all known discrepancies corrected. This means that any issues or problems with the engine should have been identified and fixed before it is brought to the test cell. This ensures that the engine is in proper working condition and ready to be tested without any known faults or discrepancies.

Explanation

When an engine arrives for a test run at the test cell, it must be operable with all known discrepancies corrected. This means that any issues or problems with the engine should have been identified and fixed before it is brought to the test cell. This ensures that the engine is in proper working condition and ready to be tested without any known faults or discrepancies.

7. Immediately prior to an engine test cell run, you check the engine and QEC kit (if applicable) for loose nuts, bolts, lock wire, tools, or any other material in order to

Eliminate items that could possibly cause FOD.

Assure that the instrumentation is working properly.

Prevent wasted maintenance hours due to shutdown.

Eliminate items that could cause inaccurate readings.

Before conducting an engine test, it is important to check for loose nuts, bolts, lock wire, tools, or any other material that could potentially cause Foreign Object Damage (FOD). FOD refers to any object or debris that can be ingested by the engine, causing damage and potentially leading to engine failure. By eliminating these items, the risk of FOD is reduced, ensuring the safety and proper functioning of the engine during the test run.

Explanation

Before conducting an engine test, it is important to check for loose nuts, bolts, lock wire, tools, or any other material that could potentially cause Foreign Object Damage (FOD). FOD refers to any object or debris that can be ingested by the engine, causing damage and potentially leading to engine failure. By eliminating these items, the risk of FOD is reduced, ensuring the safety and proper functioning of the engine during the test run.

8. Which of these is not considered a cause of FOD?

Formation of ice.

Ingestion of bolts.

Ingestion of rocks.

Failure of internal parts.

The ingestion of foreign objects (FOD) can cause damage to aircraft engines and other components. Formation of ice, ingestion of bolts, and ingestion of rocks are all considered causes of FOD as they can lead to engine malfunctions or damage. However, failure of internal parts is not typically considered a cause of FOD, as it is usually a result of wear and tear or mechanical issues within the engine itself, rather than the introduction of a foreign object.

Explanation

The ingestion of foreign objects (FOD) can cause damage to aircraft engines and other components. Formation of ice, ingestion of bolts, and ingestion of rocks are all considered causes of FOD as they can lead to engine malfunctions or damage. However, failure of internal parts is not typically considered a cause of FOD, as it is usually a result of wear and tear or mechanical issues within the engine itself, rather than the introduction of a foreign object.

9. Where would you begin your investigation of an engine with a possible oil consumption problem?

Inspect the compressor thrust bearing.

Talk with the oil analysis program manager.

Review AFTO Form 781H.

Review AFTO Form 244.

To investigate an engine with a possible oil consumption problem, reviewing the AFTO Form 781H would be the appropriate starting point. This form is used to record oil consumption and other maintenance data for aircraft engines. By reviewing this form, one can gather information about the engine's oil consumption history, any previous issues, and maintenance actions taken. This can provide valuable insights and help identify potential causes or patterns related to the oil consumption problem.

Explanation

To investigate an engine with a possible oil consumption problem, reviewing the AFTO Form 781H would be the appropriate starting point. This form is used to record oil consumption and other maintenance data for aircraft engines. By reviewing this form, one can gather information about the engine's oil consumption history, any previous issues, and maintenance actions taken. This can provide valuable insights and help identify potential causes or patterns related to the oil consumption problem.

10. To be considered effective tools for aviators, aircraft instruments must be light weight, easy to read, and

Be small in size.

Use digital readout.

Use analog readout.

Cheap to manufacture.

The question is asking for the characteristic that aircraft instruments must have in order to be considered effective tools for aviators. Out of the given options, the only characteristic that is mentioned as a requirement is that the instruments should be small in size. This suggests that size is an important factor in determining the effectiveness of aircraft instruments, possibly due to limited space in the cockpit or the need for easy maneuverability. Therefore, the correct answer is "be small in size."

Explanation

The question is asking for the characteristic that aircraft instruments must have in order to be considered effective tools for aviators. Out of the given options, the only characteristic that is mentioned as a requirement is that the instruments should be small in size. This suggests that size is an important factor in determining the effectiveness of aircraft instruments, possibly due to limited space in the cockpit or the need for easy maneuverability. Therefore, the correct answer is "be small in size."

11. Most engine-monitoring gauges and instruments require some type of

Electrical valve to the indicator.

Metal tubing for electron flow.

Radio frequency transmitter.

Transmitter and indicator.

Most engine-monitoring gauges and instruments require both a transmitter and an indicator. The transmitter is responsible for converting the physical measurement (such as temperature or pressure) into an electrical signal, which is then transmitted to the indicator. The indicator, on the other hand, receives the electrical signal and displays the corresponding measurement to the operator. Therefore, both components are necessary for the proper functioning of the engine-monitoring system.

Explanation

Most engine-monitoring gauges and instruments require both a transmitter and an indicator. The transmitter is responsible for converting the physical measurement (such as temperature or pressure) into an electrical signal, which is then transmitted to the indicator. The indicator, on the other hand, receives the electrical signal and displays the corresponding measurement to the operator. Therefore, both components are necessary for the proper functioning of the engine-monitoring system.

12. To become an expert troubleshooter, you must

Be a 7-level.

Have at least five years experience.

Complete college courses in troubleshooting techniques.

Understand the function of each unit within each system.

To become an expert troubleshooter, it is essential to understand the function of each unit within each system. This knowledge allows the troubleshooter to identify and diagnose problems accurately. Without a thorough understanding of how each unit works within a system, it would be challenging to effectively troubleshoot and resolve issues. The other options mentioned, such as being a 7-level, having experience, and completing college courses, can certainly contribute to becoming an expert troubleshooter, but understanding the function of each unit is the most crucial factor.

Explanation

To become an expert troubleshooter, it is essential to understand the function of each unit within each system. This knowledge allows the troubleshooter to identify and diagnose problems accurately. Without a thorough understanding of how each unit works within a system, it would be challenging to effectively troubleshoot and resolve issues. The other options mentioned, such as being a 7-level, having experience, and completing college courses, can certainly contribute to becoming an expert troubleshooter, but understanding the function of each unit is the most crucial factor.

13. The troubleshooting information contained in aircraft power plant and engine intermediate maintenance TO is presented in the form of

Fix-it diagrams.

Power plant charts.

Mechanical drawings.

Troubleshooting charts.

The troubleshooting information in aircraft power plant and engine intermediate maintenance TO is presented in the form of troubleshooting charts. These charts provide a systematic approach to identify and solve problems that may occur in the power plant and engine systems. By following the steps and instructions in these charts, maintenance personnel can diagnose and resolve issues effectively. Fix-it diagrams, power plant charts, and mechanical drawings may provide other types of information, but for troubleshooting purposes, the TO relies on troubleshooting charts.

Explanation

The troubleshooting information in aircraft power plant and engine intermediate maintenance TO is presented in the form of troubleshooting charts. These charts provide a systematic approach to identify and solve problems that may occur in the power plant and engine systems. By following the steps and instructions in these charts, maintenance personnel can diagnose and resolve issues effectively. Fix-it diagrams, power plant charts, and mechanical drawings may provide other types of information, but for troubleshooting purposes, the TO relies on troubleshooting charts.

14. Improperly rigged throttle linkage during a test cell run can cause

Fluctuating EGT.

Fluctuating RPM.

Damage to the inlet guide vanes.

Engine overspeed.

Improperly rigged throttle linkage during a test cell run can cause engine overspeed. When the throttle linkage is not rigged properly, it can result in the engine running at a higher speed than intended. This can be dangerous as it can cause excessive wear and tear on the engine components, leading to potential damage or failure. Additionally, engine overspeed can also pose a risk to the safety of the test cell operators and equipment. Therefore, it is crucial to ensure that the throttle linkage is correctly rigged to prevent engine overspeed during test cell runs.

Explanation

Improperly rigged throttle linkage during a test cell run can cause engine overspeed. When the throttle linkage is not rigged properly, it can result in the engine running at a higher speed than intended. This can be dangerous as it can cause excessive wear and tear on the engine components, leading to potential damage or failure. Additionally, engine overspeed can also pose a risk to the safety of the test cell operators and equipment. Therefore, it is crucial to ensure that the throttle linkage is correctly rigged to prevent engine overspeed during test cell runs.

15. When used for ground operation, the SGT engine can be installed on

Pods.

An H-frame.

A two-wheel trailer.

A four-wheel trailer.

The SGT engine can be installed on a four-wheel trailer when used for ground operation. This suggests that the engine is too heavy or requires more stability than what can be provided by a two-wheel trailer or an H-frame. The four-wheel trailer would offer better balance and support for the engine during ground operations.

Explanation

The SGT engine can be installed on a four-wheel trailer when used for ground operation. This suggests that the engine is too heavy or requires more stability than what can be provided by a two-wheel trailer or an H-frame. The four-wheel trailer would offer better balance and support for the engine during ground operations.

16. You can get information such as temperature and barometric pressure from equipment at the test cell site or from

The control tower.

Information on the radio.

The local weather station.

Your immediate supervisor.

The control tower is the correct answer because it is responsible for monitoring and controlling air traffic at an airport. They have access to real-time information such as temperature and barometric pressure, which are crucial for flight operations. The control tower communicates with pilots and provides them with important weather updates and other relevant information to ensure safe and efficient operations.

Explanation

The control tower is the correct answer because it is responsible for monitoring and controlling air traffic at an airport. They have access to real-time information such as temperature and barometric pressure, which are crucial for flight operations. The control tower communicates with pilots and provides them with important weather updates and other relevant information to ensure safe and efficient operations.

17. Which type of vibration transducer is made of certain ceramic compounds and natural crystals?

Velocity.

Phase log.

Displacement accelerometer.

Piezoelectric accelerometer.

A piezoelectric accelerometer is made of certain ceramic compounds and natural crystals. These materials have the property of generating an electric charge when subjected to mechanical stress or vibration. This type of transducer is commonly used to measure acceleration and vibration in various applications, such as structural health monitoring, automotive testing, and aerospace engineering.

Explanation

A piezoelectric accelerometer is made of certain ceramic compounds and natural crystals. These materials have the property of generating an electric charge when subjected to mechanical stress or vibration. This type of transducer is commonly used to measure acceleration and vibration in various applications, such as structural health monitoring, automotive testing, and aerospace engineering.

18. What information is used as an aid in test facility inspections?

Test cell run procedures.

Unit serial number listings.

Periodic inspection checklists.

Monthly requirements listings.

Periodic inspection checklists are used as an aid in test facility inspections. These checklists provide a systematic and organized approach to ensure that all necessary inspections are conducted regularly. They outline specific criteria and requirements that need to be met during the inspections, helping to ensure that the test facility is in compliance with regulations and standards. By using periodic inspection checklists, inspectors can effectively assess the condition and safety of the test facility and identify any potential issues that need to be addressed.

Explanation

Periodic inspection checklists are used as an aid in test facility inspections. These checklists provide a systematic and organized approach to ensure that all necessary inspections are conducted regularly. They outline specific criteria and requirements that need to be met during the inspections, helping to ensure that the test facility is in compliance with regulations and standards. By using periodic inspection checklists, inspectors can effectively assess the condition and safety of the test facility and identify any potential issues that need to be addressed.

19. You can find written instructions for safe flight-line vehicle operations in

The flight-line JG.

AFI 36-2903.

The intermediate maintenance TO.

AFOSH STD 91-100.

The correct answer is AFOSH STD 91-100. This is because AFOSH STD 91-100 provides written instructions for safe flight-line vehicle operations. AFI 36-2903 is the Air Force Instruction for Dress and Personal Appearance of Air Force Personnel, which is not directly related to flight-line vehicle operations. The intermediate maintenance TO (Technical Order) would provide instructions for maintenance procedures, not specifically for safe vehicle operations on the flight-line.

Explanation

The correct answer is AFOSH STD 91-100. This is because AFOSH STD 91-100 provides written instructions for safe flight-line vehicle operations. AFI 36-2903 is the Air Force Instruction for Dress and Personal Appearance of Air Force Personnel, which is not directly related to flight-line vehicle operations. The intermediate maintenance TO (Technical Order) would provide instructions for maintenance procedures, not specifically for safe vehicle operations on the flight-line.

20. For engine shutdown on the GTCP 165 engine, what valve closes to ensure that fuel-flow is terminated?

Poppet.

Scheduling.

Fuel flow divider.

Fuel shutoff solenoid.

The fuel shutoff solenoid is the valve that closes to ensure that fuel flow is terminated during engine shutdown on the GTCP 165 engine. This solenoid is responsible for cutting off the fuel supply to the engine, effectively stopping the flow of fuel and shutting down the engine.

Explanation

The fuel shutoff solenoid is the valve that closes to ensure that fuel flow is terminated during engine shutdown on the GTCP 165 engine. This solenoid is responsible for cutting off the fuel supply to the engine, effectively stopping the flow of fuel and shutting down the engine.

21. Which metals are used in the EGT indicating system thermocouples?

Steel and iron.

Steel and alumel.

Iron and chromel.

Alumel and chromel.

The EGT (Exhaust Gas Temperature) indicating system thermocouples use alumel and chromel metals. Alumel is an alloy of nickel, aluminum, manganese, and silicon, while chromel is an alloy of nickel and chromium. These metals are chosen for their high temperature resistance and ability to accurately measure exhaust gas temperatures. Steel and iron, on the other hand, may not be suitable for such high temperature applications.

Explanation

The EGT (Exhaust Gas Temperature) indicating system thermocouples use alumel and chromel metals. Alumel is an alloy of nickel, aluminum, manganese, and silicon, while chromel is an alloy of nickel and chromium. These metals are chosen for their high temperature resistance and ability to accurately measure exhaust gas temperatures. Steel and iron, on the other hand, may not be suitable for such high temperature applications.

22. A BPO is done

With the thruflight inspection.

After the first flight of the day.

With the end-of-runway inspection.

After the last flight of the flying period.

The correct answer is "after the last flight of the flying period." This means that the BPO (Base Pre-flight Operation) is conducted after the final flight of the day. This is important because it allows for a thorough inspection of the aircraft to ensure that it is in proper condition before it is put away for the day. Conducting the BPO after the last flight of the flying period helps to identify any issues or maintenance needs that may have arisen during the day's flights, ensuring the safety and efficiency of future flights.

Explanation

The correct answer is "after the last flight of the flying period." This means that the BPO (Base Pre-flight Operation) is conducted after the final flight of the day. This is important because it allows for a thorough inspection of the aircraft to ensure that it is in proper condition before it is put away for the day. Conducting the BPO after the last flight of the flying period helps to identify any issues or maintenance needs that may have arisen during the day's flights, ensuring the safety and efficiency of future flights.

23. The portable test cell's vibration pickups are cooled by the

Engine oil.

Atmosphere.

Hydraulic fluid.

Pneumatic system.

The portable test cell's vibration pickups are cooled by the pneumatic system. This means that the pneumatic system is responsible for cooling the vibration pickups in the test cell. It is likely that the pneumatic system is designed to circulate cool air or a cooling medium to prevent the vibration pickups from overheating during operation.

Explanation

The portable test cell's vibration pickups are cooled by the pneumatic system. This means that the pneumatic system is responsible for cooling the vibration pickups in the test cell. It is likely that the pneumatic system is designed to circulate cool air or a cooling medium to prevent the vibration pickups from overheating during operation.

24. The oil pressure indicator receives an electrical signal from the

Gyro.

Transmitter.

Hydraulic unit.

Synchronous unit.

The oil pressure indicator receives an electrical signal from the transmitter. A transmitter is a device that converts a physical quantity, in this case, the oil pressure, into an electrical signal that can be easily measured and displayed on the indicator. The transmitter is responsible for sending the accurate oil pressure information to the indicator, allowing the operator to monitor the oil pressure level in the system.

Explanation

The oil pressure indicator receives an electrical signal from the transmitter. A transmitter is a device that converts a physical quantity, in this case, the oil pressure, into an electrical signal that can be easily measured and displayed on the indicator. The transmitter is responsible for sending the accurate oil pressure information to the indicator, allowing the operator to monitor the oil pressure level in the system.

25. What should you do with the engine model and serial number when making general entries on the test cell engine log sheet?

Type these items.

Check past records.

Enter these only after the test is complete.

Verify these numbers on the engine data plate.

When making general entries on the test cell engine log sheet, it is important to verify the engine model and serial number on the engine data plate. This ensures that the correct information is recorded and eliminates any potential errors or discrepancies. By checking the numbers on the engine data plate, you can be confident that the log sheet accurately reflects the engine being tested.

Explanation

When making general entries on the test cell engine log sheet, it is important to verify the engine model and serial number on the engine data plate. This ensures that the correct information is recorded and eliminates any potential errors or discrepancies. By checking the numbers on the engine data plate, you can be confident that the log sheet accurately reflects the engine being tested.

26. Observing oil on the turbine wheel or oil smoke at or near the turbine section during a test cell run is a good indication of

A damaged aft bearing oil seal.

An underserviced oil system.

Leaking external oil lines.

A loose aft roller bearing.

Observing oil on the turbine wheel or oil smoke at or near the turbine section during a test cell run indicates a damaged aft bearing oil seal. This is because a damaged seal would allow oil to leak into the turbine section, leading to the presence of oil on the turbine wheel or oil smoke. The other options, such as underserviced oil system, leaking external oil lines, or a loose aft roller bearing, do not directly explain the presence of oil on the turbine wheel or oil smoke.

Explanation

Observing oil on the turbine wheel or oil smoke at or near the turbine section during a test cell run indicates a damaged aft bearing oil seal. This is because a damaged seal would allow oil to leak into the turbine section, leading to the presence of oil on the turbine wheel or oil smoke. The other options, such as underserviced oil system, leaking external oil lines, or a loose aft roller bearing, do not directly explain the presence of oil on the turbine wheel or oil smoke.

27. During a normal start on a GTCP 165 engine, the igniter plug continues firing until engine's RPM reaches

75 percent.

80 percent.

95 percent.

100 percent.

During a normal start on a GTCP 165 engine, the igniter plug continues firing until the engine's RPM reaches 95 percent. This means that the igniter plug will stop firing once the engine's RPM reaches this threshold. It is important for the engine to reach this RPM level to ensure proper functioning and stability before the igniter plug is turned off.

Explanation

During a normal start on a GTCP 165 engine, the igniter plug continues firing until the engine's RPM reaches 95 percent. This means that the igniter plug will stop firing once the engine's RPM reaches this threshold. It is important for the engine to reach this RPM level to ensure proper functioning and stability before the igniter plug is turned off.

28. A typical jet engine EGT indicating system contains thermocouples, leads, an indicator, and

A resistor.

A turbine inlet.

A control valve.

An exhaust duct.

A typical jet engine EGT indicating system contains thermocouples, leads, an indicator, and a resistor. The resistor is included in the system to provide a reference temperature for the indicator. It helps in calibrating the system and ensuring accurate temperature readings. The thermocouples measure the exhaust gas temperature, the leads transmit the temperature signals to the indicator, and the indicator displays the temperature readings. The turbine inlet, control valve, and exhaust duct are not directly related to the EGT indicating system and are not necessary components for its functioning.

Explanation

A typical jet engine EGT indicating system contains thermocouples, leads, an indicator, and a resistor. The resistor is included in the system to provide a reference temperature for the indicator. It helps in calibrating the system and ensuring accurate temperature readings. The thermocouples measure the exhaust gas temperature, the leads transmit the temperature signals to the indicator, and the indicator displays the temperature readings. The turbine inlet, control valve, and exhaust duct are not directly related to the EGT indicating system and are not necessary components for its functioning.

29. Before moving an aircraft into the hush house, you must inspect the aircraft

Red streamers.

And its forms.

Flight station.

Forms.

Before moving an aircraft into the hush house, it is necessary to inspect the aircraft and its forms. This means that not only the physical condition of the aircraft should be checked, but also any necessary paperwork or documentation related to the aircraft should be reviewed. This ensures that all necessary inspections and maintenance procedures have been completed and documented correctly before the aircraft is moved into the hush house.

Explanation

Before moving an aircraft into the hush house, it is necessary to inspect the aircraft and its forms. This means that not only the physical condition of the aircraft should be checked, but also any necessary paperwork or documentation related to the aircraft should be reviewed. This ensures that all necessary inspections and maintenance procedures have been completed and documented correctly before the aircraft is moved into the hush house.

30. Careless operation of the throttle during emergency system operation could cause a compressor stall due to

A restricted air inlet.

Rapid throttle movement.

A restricted turbine nozzle.

A malfunctioning variable geometry system.

Rapid throttle movement can lead to a compressor stall during emergency system operation. When the throttle is moved quickly, it can disrupt the airflow within the compressor, causing a disruption in the compression process and leading to a stall. This can happen because the compressor is not able to handle the sudden change in airflow and pressure. Therefore, it is important to operate the throttle carefully and smoothly during emergency situations to prevent compressor stalls.

Explanation

Rapid throttle movement can lead to a compressor stall during emergency system operation. When the throttle is moved quickly, it can disrupt the airflow within the compressor, causing a disruption in the compression process and leading to a stall. This can happen because the compressor is not able to handle the sudden change in airflow and pressure. Therefore, it is important to operate the throttle carefully and smoothly during emergency situations to prevent compressor stalls.

31. Most jet-powered aircraft engine fuel-flow indicating systems contain a fuel-flow

Transmitter and a float valve.

Control valve and a float valve.

Transmitter and a fuel-flow indicator.

Control valve and a fuel-flow transcriber.

Most jet-powered aircraft engine fuel-flow indicating systems contain a fuel-flow transmitter and a fuel-flow indicator. The fuel-flow transmitter measures the rate at which fuel is flowing through the engine, while the fuel-flow indicator displays this information to the pilot. This allows the pilot to monitor the fuel consumption of the aircraft and make necessary adjustments to ensure efficient operation. The float valve and control valve options are not correct because they do not accurately describe the components typically found in a fuel-flow indicating system.

Explanation

Most jet-powered aircraft engine fuel-flow indicating systems contain a fuel-flow transmitter and a fuel-flow indicator. The fuel-flow transmitter measures the rate at which fuel is flowing through the engine, while the fuel-flow indicator displays this information to the pilot. This allows the pilot to monitor the fuel consumption of the aircraft and make necessary adjustments to ensure efficient operation. The float valve and control valve options are not correct because they do not accurately describe the components typically found in a fuel-flow indicating system.

32. The tachometer generator's frequency is proportional to the

Engine speed.

Transformer speed.

Speed of the electrical magnet.

Speed of the alternating magnet.

The tachometer generator is a device that measures the rotational speed of an engine. It generates an electrical signal whose frequency is directly proportional to the engine speed. This means that as the engine speed increases, the frequency of the signal generated by the tachometer generator also increases. Therefore, the correct answer is engine speed.

Explanation

The tachometer generator is a device that measures the rotational speed of an engine. It generates an electrical signal whose frequency is directly proportional to the engine speed. This means that as the engine speed increases, the frequency of the signal generated by the tachometer generator also increases. Therefore, the correct answer is engine speed.

33. Turbine blade fatigue failure does not result from

Nicks.

Dents.

Blends.

Scratches.

Turbine blade fatigue failure is caused by the repeated stress and strain on the blade, which can lead to cracks and ultimately failure. Nicks, dents, and scratches can all create stress concentrations on the blade, making it more susceptible to fatigue failure. However, blends, which refer to the smooth transition between different surfaces on the blade, do not create stress concentrations and therefore do not contribute to fatigue failure.

Explanation

Turbine blade fatigue failure is caused by the repeated stress and strain on the blade, which can lead to cracks and ultimately failure. Nicks, dents, and scratches can all create stress concentrations on the blade, making it more susceptible to fatigue failure. However, blends, which refer to the smooth transition between different surfaces on the blade, do not create stress concentrations and therefore do not contribute to fatigue failure.

34. What two types of test cells does the Air Force currently use?

Fixed and portable.

Single and combined.

Permanent and temporary.

Functional and progressive.

The Air Force currently uses two types of test cells: fixed and portable. Fixed test cells are permanent structures that are built specifically for testing purposes and are usually located at a specific facility. Portable test cells, on the other hand, are designed to be easily transported and set up in different locations as needed. These two types of test cells provide flexibility and convenience for conducting various tests and evaluations in different environments.

Explanation

The Air Force currently uses two types of test cells: fixed and portable. Fixed test cells are permanent structures that are built specifically for testing purposes and are usually located at a specific facility. Portable test cells, on the other hand, are designed to be easily transported and set up in different locations as needed. These two types of test cells provide flexibility and convenience for conducting various tests and evaluations in different environments.

35. What circuit trips to stop the engine during normal GTCP 165 engine shutdown?

100-percent circuit.

110-percent circuit.

Load-control circuit.

Speed-switch control circuit.

The 110-percent circuit is responsible for tripping and stopping the engine during normal GTCP 165 engine shutdown. This circuit is designed to monitor the engine's speed and ensure that it does not exceed 110 percent of the rated speed. If the engine speed goes above this threshold during shutdown, the circuit will trip and shut down the engine to prevent any damage or unsafe conditions.

Explanation

The 110-percent circuit is responsible for tripping and stopping the engine during normal GTCP 165 engine shutdown. This circuit is designed to monitor the engine's speed and ensure that it does not exceed 110 percent of the rated speed. If the engine speed goes above this threshold during shutdown, the circuit will trip and shut down the engine to prevent any damage or unsafe conditions.

36. The pressure gauges used for an oil system pressure checks are connected at the

Inlet side of the oil pump and the vent system.

Output side of the main oil pump and the vent system.

Scavenge pump and the inlet side of oil pressure pump.

Bearing jets and the output side of the oil scavenge pump.

The correct answer is the output side of the main oil pump and the vent system. This is because pressure gauges are used to measure the pressure of the oil system, and connecting them at the output side of the main oil pump allows for accurate measurement of the pressure being generated by the pump. Additionally, connecting the gauges at the vent system provides information about the pressure in the system after it has been used, allowing for monitoring and troubleshooting of any potential issues.

Explanation

The correct answer is the output side of the main oil pump and the vent system. This is because pressure gauges are used to measure the pressure of the oil system, and connecting them at the output side of the main oil pump allows for accurate measurement of the pressure being generated by the pump. Additionally, connecting the gauges at the vent system provides information about the pressure in the system after it has been used, allowing for monitoring and troubleshooting of any potential issues.

37. The tachometer indicating system's two primary units are the tachometer generator and tachometer

Indicator.

Fuse panel.

Transformer.

Thermocouple.

The tachometer indicating system consists of two primary units, the tachometer generator and the tachometer indicator. The tachometer generator is responsible for converting the rotational speed of the engine into an electrical signal, while the tachometer indicator displays this information to the operator. The other options mentioned, such as fuse panel, transformer, and thermocouple, are not directly related to the tachometer indicating system and therefore are not the correct answer.

Explanation

The tachometer indicating system consists of two primary units, the tachometer generator and the tachometer indicator. The tachometer generator is responsible for converting the rotational speed of the engine into an electrical signal, while the tachometer indicator displays this information to the operator. The other options mentioned, such as fuse panel, transformer, and thermocouple, are not directly related to the tachometer indicating system and therefore are not the correct answer.

38. The term Pt2 means the

Total (t) pressure (P) at flange 2 (2).

Total (t) pressure (P) at station 2 (2).

Temperature (t) and pressure (P) at flange 2 (2).

Temperature (t) and pressure (P) at station 2 (2).

The term Pt2 refers to the total pressure (P) at station 2 (2).

Explanation

The term Pt2 refers to the total pressure (P) at station 2 (2).

39. In addition to determining the condition of a repaired or overhauled engine, you also test engines

For training practice.

In aircraft that have been modified.

That have been involved in an incident or a mishap.

That have severe FOD damage.

Engines that have been involved in an incident or a mishap need to be tested in order to assess their condition and ensure that they are functioning properly. This is important because any damage or issues with the engine could have contributed to the incident or mishap, and it is essential to identify and address these problems to prevent future accidents. Testing these engines allows for a thorough evaluation of their performance and helps in determining if any repairs or modifications are necessary.

Explanation

Engines that have been involved in an incident or a mishap need to be tested in order to assess their condition and ensure that they are functioning properly. This is important because any damage or issues with the engine could have contributed to the incident or mishap, and it is essential to identify and address these problems to prevent future accidents. Testing these engines allows for a thorough evaluation of their performance and helps in determining if any repairs or modifications are necessary.

40. The swivel pads at the bottom of the leveling jacks on the engine thrust trailer of the portable test cell provide all of the following except

Leveling the engine being tested.

Removing the wheel and tire assemblies.

Supporting the thrust trailer at a height of 80 inches.

Adjusting for rail compatibility with engine transportation trailers.

The swivel pads at the bottom of the leveling jacks on the engine thrust trailer of the portable test cell provide leveling the engine being tested, removing the wheel and tire assemblies, and adjusting for rail compatibility with engine transportation trailers. However, they do not support the thrust trailer at a height of 80 inches.

Explanation

The swivel pads at the bottom of the leveling jacks on the engine thrust trailer of the portable test cell provide leveling the engine being tested, removing the wheel and tire assemblies, and adjusting for rail compatibility with engine transportation trailers. However, they do not support the thrust trailer at a height of 80 inches.

41. The fuel-flow indicator indicates the rate of fuel flow as

Pounds per hour.

Gallons per hour.

Pounds per minute.

Gallons per minute.

The fuel-flow indicator measures the rate at which fuel is flowing, and it does so in terms of pounds per hour. This measurement is commonly used in aviation to determine the fuel consumption of an aircraft and to calculate various performance parameters. By displaying the fuel flow in pounds per hour, pilots can accurately monitor their fuel usage and make informed decisions regarding fuel management during flight.

Explanation

The fuel-flow indicator measures the rate at which fuel is flowing, and it does so in terms of pounds per hour. This measurement is commonly used in aviation to determine the fuel consumption of an aircraft and to calculate various performance parameters. By displaying the fuel flow in pounds per hour, pilots can accurately monitor their fuel usage and make informed decisions regarding fuel management during flight.

42. Which of these inspections is a flight preparedness check?

Periodic.

Preflight.

Thruflight.

End-of-runway.

The correct answer is Preflight. A preflight inspection is conducted before each flight to ensure that the aircraft is in a safe and airworthy condition. It involves checking various components, systems, and documentation to ensure that everything is functioning properly and meets the required standards. This inspection is crucial for flight preparedness as it helps identify any potential issues or discrepancies that may affect the safety and performance of the aircraft during the flight.

Explanation

The correct answer is Preflight. A preflight inspection is conducted before each flight to ensure that the aircraft is in a safe and airworthy condition. It involves checking various components, systems, and documentation to ensure that everything is functioning properly and meets the required standards. This inspection is crucial for flight preparedness as it helps identify any potential issues or discrepancies that may affect the safety and performance of the aircraft during the flight.

43. Understanding the operating principles of engine instruments help you decide

If an engine should be removed from an aircraft.

If the engine should be sent to the test cell.

The meaning of the instrument readings.

What tools are required for maintenance.

Understanding the operating principles of engine instruments is important because it enables you to interpret the readings displayed by these instruments. By knowing the meaning of the instrument readings, you can assess the performance and condition of the engine. This knowledge helps you make informed decisions about whether the engine should be removed from the aircraft for further inspection or maintenance, or if it can be sent to the test cell for further testing. It also allows you to identify any potential issues or abnormalities with the engine, which can aid in troubleshooting and determining the appropriate course of action.

Explanation

Understanding the operating principles of engine instruments is important because it enables you to interpret the readings displayed by these instruments. By knowing the meaning of the instrument readings, you can assess the performance and condition of the engine. This knowledge helps you make informed decisions about whether the engine should be removed from the aircraft for further inspection or maintenance, or if it can be sent to the test cell for further testing. It also allows you to identify any potential issues or abnormalities with the engine, which can aid in troubleshooting and determining the appropriate course of action.

44. The modulating and shutoff valve on a GTCP 165 engine will be fully open at what percent RPM?

60.

70.

80.

90.

The modulating and shutoff valve on a GTCP 165 engine will be fully open at 90% RPM. This means that when the engine is running at 90% of its maximum speed, the valve will be fully open, allowing maximum airflow and fuel flow into the engine. At lower RPMs, the valve may be partially closed to restrict the flow and control the engine's performance.

Explanation

The modulating and shutoff valve on a GTCP 165 engine will be fully open at 90% RPM. This means that when the engine is running at 90% of its maximum speed, the valve will be fully open, allowing maximum airflow and fuel flow into the engine. At lower RPMs, the valve may be partially closed to restrict the flow and control the engine's performance.

45. One type of overheat detector unit used on aircraft engines consists of a hollow stainless-steel tube that covers

One gold contact.

Two silver contacts.

Three bronze contacts.

Four copper contacts.

The correct answer is two silver contacts. This type of overheat detector unit used on aircraft engines consists of a hollow stainless-steel tube that covers two silver contacts. These contacts are designed to detect excessive heat and trigger an alarm or warning system if the temperature exceeds a certain threshold. The use of silver contacts ensures good conductivity and reliability in detecting overheating conditions in the engine.

Explanation

The correct answer is two silver contacts. This type of overheat detector unit used on aircraft engines consists of a hollow stainless-steel tube that covers two silver contacts. These contacts are designed to detect excessive heat and trigger an alarm or warning system if the temperature exceeds a certain threshold. The use of silver contacts ensures good conductivity and reliability in detecting overheating conditions in the engine.

46. Where should you begin troubleshooting after reviewing the aircraft/engine forms?

Discuss problem with other journeymen in the shop.

Check each part of every system.

Examine most complex unit.

Observe gauge indications.

After reviewing the aircraft/engine forms, the next step in troubleshooting should be to observe gauge indications. This is because gauge indications can provide valuable information about the performance and condition of various systems in the aircraft or engine. By carefully observing the gauge indications, any abnormal readings or fluctuations can be identified, which can then help in narrowing down the potential issues and determining the appropriate course of action for troubleshooting.

Explanation

After reviewing the aircraft/engine forms, the next step in troubleshooting should be to observe gauge indications. This is because gauge indications can provide valuable information about the performance and condition of various systems in the aircraft or engine. By carefully observing the gauge indications, any abnormal readings or fluctuations can be identified, which can then help in narrowing down the potential issues and determining the appropriate course of action for troubleshooting.

47. What causes over-temperature damage to the combustion chamber from a stall condition?

An interruption of cooling airflow.

A fluid leak at the engine inlet.

An interruption of fuel flow.

Faulty fuel nozzles.

When an engine stalls, there is a significant reduction in airflow, which can lead to a buildup of heat in the combustion chamber. This increase in temperature can cause damage to the combustion chamber, resulting in over-temperature damage. The correct answer states that an interruption of cooling airflow is the cause of this damage, indicating that the lack of sufficient cooling airflow exacerbates the overheating problem and leads to damage in the combustion chamber.

Explanation

When an engine stalls, there is a significant reduction in airflow, which can lead to a buildup of heat in the combustion chamber. This increase in temperature can cause damage to the combustion chamber, resulting in over-temperature damage. The correct answer states that an interruption of cooling airflow is the cause of this damage, indicating that the lack of sufficient cooling airflow exacerbates the overheating problem and leads to damage in the combustion chamber.

48. What F100-PW–220 engine monitoring system component acquires fault data from the DEEC and logs the faults with the time of their occurrence?

DCU.

GSU

EAU.

EDU.

The EDU (Engine Data Unit) is the component of the F100-PW-220 engine monitoring system that acquires fault data from the DEEC (Digital Electronic Engine Control) and logs the faults with the time of their occurrence.

Explanation

The EDU (Engine Data Unit) is the component of the F100-PW-220 engine monitoring system that acquires fault data from the DEEC (Digital Electronic Engine Control) and logs the faults with the time of their occurrence.

49. Which test cell noise suppressors use water to cool the exhaust gases?

None.

Fixed.

Portable.

Both fixed and portable.

Both fixed and portable test cell noise suppressors use water to cool the exhaust gases. This means that regardless of whether the noise suppressor is permanently installed in a fixed location or can be moved around, they both utilize water as a cooling mechanism for the exhaust gases.

Explanation

Both fixed and portable test cell noise suppressors use water to cool the exhaust gases. This means that regardless of whether the noise suppressor is permanently installed in a fixed location or can be moved around, they both utilize water as a cooling mechanism for the exhaust gases.

50. Before installing an engine on the test cell thrust stand, make sure the

Engine is 99 percent complete.

Rail adapters are properly lubricated.

Engine manager has scheduled the engine run.

Engine rail adapters and stand are compatible.

Before installing an engine on the test cell thrust stand, it is important to ensure that the engine rail adapters and stand are compatible. This means that the adapters should be designed to fit securely onto the stand, allowing for proper alignment and stability during the engine run. Using incompatible adapters and stand can lead to safety hazards and inaccurate test results. Therefore, it is crucial to check the compatibility of the adapters and stand before proceeding with the installation.

Explanation

Before installing an engine on the test cell thrust stand, it is important to ensure that the engine rail adapters and stand are compatible. This means that the adapters should be designed to fit securely onto the stand, allowing for proper alignment and stability during the engine run. Using incompatible adapters and stand can lead to safety hazards and inaccurate test results. Therefore, it is crucial to check the compatibility of the adapters and stand before proceeding with the installation.

51. What condition describes turbine nozzles that are burned out uniformly around the whole annulus from an over-temperature condition?

Mild stall condition with normal cooling airflow.

Severe stall condition with normal cooling airflow.

Mild stall condition with disrupted cooling airflow

Severe stall condition with disrupted cooling airflow.

The correct answer is "Severe stall condition with disrupted cooling airflow." When turbine nozzles are burned out uniformly around the whole annulus from an over-temperature condition, it indicates a severe stall condition. Stall refers to the disruption of smooth airflow, and in this case, it is severe enough to cause the turbine nozzles to burn out. Additionally, the presence of disrupted cooling airflow further confirms the severity of the stall condition.

Explanation

The correct answer is "Severe stall condition with disrupted cooling airflow." When turbine nozzles are burned out uniformly around the whole annulus from an over-temperature condition, it indicates a severe stall condition. Stall refers to the disruption of smooth airflow, and in this case, it is severe enough to cause the turbine nozzles to burn out. Additionally, the presence of disrupted cooling airflow further confirms the severity of the stall condition.

52. The pneumatic air bled from the small gas turbine engine cannot be used to

Inflate aircraft tires.

Remove snow and ice from aircraft surfaces.

Supply pneumatic power to aircraft pneumatic starters.

Provide pneumatic power for air-conditioning systems.

The pneumatic air bled from the small gas turbine engine cannot be used to inflate aircraft tires because the air bled from the engine is typically at a high temperature and pressure, which may not be suitable for inflating tires. Additionally, the air bled from the engine may contain contaminants or impurities that could potentially damage the tires. Therefore, alternative sources of compressed air, such as ground-based air compressors, are typically used to inflate aircraft tires.

Explanation

The pneumatic air bled from the small gas turbine engine cannot be used to inflate aircraft tires because the air bled from the engine is typically at a high temperature and pressure, which may not be suitable for inflating tires. Additionally, the air bled from the engine may contain contaminants or impurities that could potentially damage the tires. Therefore, alternative sources of compressed air, such as ground-based air compressors, are typically used to inflate aircraft tires.

53. What engine vibration does not persist, but comes and goes?

Forced.

Transient.

Resonance.

Externally excited.

Transient engine vibration refers to vibrations that occur for a short duration and then disappear. These vibrations are not continuous or persistent but rather intermittent, coming and going at irregular intervals. This can be caused by various factors such as changes in load, speed, or operating conditions. Unlike resonance or externally excited vibrations which are continuous, transient vibrations are temporary and do not persist.

Explanation

Transient engine vibration refers to vibrations that occur for a short duration and then disappear. These vibrations are not continuous or persistent but rather intermittent, coming and going at irregular intervals. This can be caused by various factors such as changes in load, speed, or operating conditions. Unlike resonance or externally excited vibrations which are continuous, transient vibrations are temporary and do not persist.

54. What converts the exhaust nozzle's position on engines with afterburners into an electrical signal?

Rheostat.

Rectifier.

Transducer.

Transformer.

A transducer is a device that converts one form of energy into another. In this case, the transducer converts the physical position of the exhaust nozzle on engines with afterburners into an electrical signal. This allows the engine control system to monitor and adjust the position of the nozzle as needed. A rheostat is a variable resistor used to control current, a rectifier is a device that converts alternating current to direct current, and a transformer is used to transfer electrical energy between circuits. None of these options would be suitable for converting the exhaust nozzle's position into an electrical signal.

Explanation

A transducer is a device that converts one form of energy into another. In this case, the transducer converts the physical position of the exhaust nozzle on engines with afterburners into an electrical signal. This allows the engine control system to monitor and adjust the position of the nozzle as needed. A rheostat is a variable resistor used to control current, a rectifier is a device that converts alternating current to direct current, and a transformer is used to transfer electrical energy between circuits. None of these options would be suitable for converting the exhaust nozzle's position into an electrical signal.

55. How is inlet Pt2 transmitted from its sensing point?

Electrically.

Mechanically.

Hydraulically.

Through tubing.

The correct answer is "Through tubing." This means that the inlet Pt2 is transmitted from its sensing point using tubing. This suggests that there is a physical connection between the sensing point and the location where the inlet Pt2 is being transmitted. This method allows for the transfer of the inlet Pt2 information in a reliable and efficient manner.

Explanation

The correct answer is "Through tubing." This means that the inlet Pt2 is transmitted from its sensing point using tubing. This suggests that there is a physical connection between the sensing point and the location where the inlet Pt2 is being transmitted. This method allows for the transfer of the inlet Pt2 information in a reliable and efficient manner.

56. Which jet engine temperature is not measured?

Combustion inlet.

Fan turbine inlet.

Turbine inlet.

Exhaust gas.

The question asks which jet engine temperature is not measured. The correct answer is "Combustion inlet." In a jet engine, various temperatures are measured to monitor the performance and ensure safety. The fan turbine inlet temperature, turbine inlet temperature, and exhaust gas temperature are all critical measurements. However, the combustion inlet temperature is not typically measured directly, as it is difficult to access and monitor accurately. Therefore, the combustion inlet temperature is the correct answer.

Explanation

The question asks which jet engine temperature is not measured. The correct answer is "Combustion inlet." In a jet engine, various temperatures are measured to monitor the performance and ensure safety. The fan turbine inlet temperature, turbine inlet temperature, and exhaust gas temperature are all critical measurements. However, the combustion inlet temperature is not typically measured directly, as it is difficult to access and monitor accurately. Therefore, the combustion inlet temperature is the correct answer.

57. For an operational check of the fire warning system, you press

Only the TEST switch.

Both TEST and NORMAL switches.

Only the TEST WARNING ON switch.

Both TEST ON and TEST OFF switches.

To perform an operational check of the fire warning system, you only need to press the TEST switch. This switch is specifically designed to initiate a test of the system, ensuring that all components are functioning properly. Pressing both the TEST and NORMAL switches or only the TEST WARNING ON switch would not provide a comprehensive check of the system. Additionally, pressing both the TEST ON and TEST OFF switches is not necessary as they serve different functions and are not relevant to the operational check of the fire warning system.

Explanation

To perform an operational check of the fire warning system, you only need to press the TEST switch. This switch is specifically designed to initiate a test of the system, ensuring that all components are functioning properly. Pressing both the TEST and NORMAL switches or only the TEST WARNING ON switch would not provide a comprehensive check of the system. Additionally, pressing both the TEST ON and TEST OFF switches is not necessary as they serve different functions and are not relevant to the operational check of the fire warning system.

58. In a fixed test cell, the test bay access doors are sealed to

Control dirt and dust in the test bay.

Control unauthorized entry during a test run.

Prevent unwanted noise from getting into the control room.

Prevent carbon monoxide from getting into the control room.

The test bay access doors are sealed in order to prevent unwanted noise from getting into the control room. This is important because excessive noise can interfere with the testing process and make it difficult for the operators in the control room to accurately monitor and control the test. By sealing the doors, the test bay can be kept quiet and free from any noise that could potentially disrupt the control room operations.

Explanation

The test bay access doors are sealed in order to prevent unwanted noise from getting into the control room. This is important because excessive noise can interfere with the testing process and make it difficult for the operators in the control room to accurately monitor and control the test. By sealing the doors, the test bay can be kept quiet and free from any noise that could potentially disrupt the control room operations.

59. The display range of the test cell IC temperature indicator is

–100 to +1,000 °F.

–75 to +1,400 °F.

–50 to +1,600 °F.

–25 to +1,800 °F.

The correct answer is –50 to +1,600 °F. This is because the test cell IC temperature indicator has a display range that starts from -50 °F and goes up to +1,600 °F. This means that it can accurately measure and display temperatures within this range.

Explanation

The correct answer is –50 to +1,600 °F. This is because the test cell IC temperature indicator has a display range that starts from -50 °F and goes up to +1,600 °F. This means that it can accurately measure and display temperatures within this range.

60. Air for the load control system on a GTCP 165 engine is extracted from the

Torus.

Combustor.

Turbine plenum.

Compressor deswirl vanes.

The air for the load control system on a GTCP 165 engine is extracted from the turbine plenum. The turbine plenum is a chamber located between the turbine and the combustor. It collects the hot gases from the turbine and provides a stable source of air for various systems, including the load control system. This system helps regulate the load on the engine by adjusting fuel flow and other parameters to maintain optimal performance. Extracting air from the turbine plenum ensures that the load control system receives a consistent and reliable air supply.

Explanation

The air for the load control system on a GTCP 165 engine is extracted from the turbine plenum. The turbine plenum is a chamber located between the turbine and the combustor. It collects the hot gases from the turbine and provides a stable source of air for various systems, including the load control system. This system helps regulate the load on the engine by adjusting fuel flow and other parameters to maintain optimal performance. Extracting air from the turbine plenum ensures that the load control system receives a consistent and reliable air supply.

61. Which inspection is a combination of the BPO/hourly post-flight and periodic inspection (PE) requirements?

Minor.

Major.

Phased.

Periodic.

A phased inspection is a combination of the BPO/hourly post-flight and periodic inspection requirements. This type of inspection involves both a detailed examination of specific components after each flight or a certain number of flight hours (BPO/hourly post-flight inspection) and a more comprehensive inspection conducted at regular intervals (periodic inspection). By combining these two types of inspections, a phased inspection ensures that both immediate and long-term maintenance needs are addressed, making it an efficient and comprehensive approach.

Explanation

A phased inspection is a combination of the BPO/hourly post-flight and periodic inspection requirements. This type of inspection involves both a detailed examination of specific components after each flight or a certain number of flight hours (BPO/hourly post-flight inspection) and a more comprehensive inspection conducted at regular intervals (periodic inspection). By combining these two types of inspections, a phased inspection ensures that both immediate and long-term maintenance needs are addressed, making it an efficient and comprehensive approach.

62. What type of vibration causes unnecessary engine removals and unwarranted repairs?

Forced.

Transient.

Unbalanced.

Externally excited.

Externally excited vibrations refer to vibrations that are caused by external factors, such as nearby machinery or equipment. These vibrations can lead to unnecessary engine removals and unwarranted repairs because they can cause additional stress and strain on the engine components, leading to premature wear and damage. Unlike forced, transient, or unbalanced vibrations which are typically caused by internal factors within the engine, externally excited vibrations are caused by external factors outside the engine system.

Explanation

Externally excited vibrations refer to vibrations that are caused by external factors, such as nearby machinery or equipment. These vibrations can lead to unnecessary engine removals and unwarranted repairs because they can cause additional stress and strain on the engine components, leading to premature wear and damage. Unlike forced, transient, or unbalanced vibrations which are typically caused by internal factors within the engine, externally excited vibrations are caused by external factors outside the engine system.

63. Aircraft noise suppressors have how many primary air silencers to help reduce turbine whine?

2.

4.

6.

8.

Aircraft noise suppressors have two primary air silencers to help reduce turbine whine. These silencers are designed to absorb and dissipate the noise generated by the turbine, reducing the overall noise level produced by the aircraft. By having two primary air silencers, the aircraft can effectively suppress the turbine whine and minimize the impact of noise pollution on the surrounding environment and communities.

Explanation

Aircraft noise suppressors have two primary air silencers to help reduce turbine whine. These silencers are designed to absorb and dissipate the noise generated by the turbine, reducing the overall noise level produced by the aircraft. By having two primary air silencers, the aircraft can effectively suppress the turbine whine and minimize the impact of noise pollution on the surrounding environment and communities.

64. The aircraft noise suppressor shutdown procedure is important because it

Prevents aircraft inlet damage.

Prevents engine turbine wheel damage.

Ensures the noise suppressor will be operational for the next aircraft.

Ensures that the noise suppressor is not damaged by improper engine shutdown procedures.

The correct answer is "ensures the noise suppressor will be operational for the next aircraft." This is because the shutdown procedure is necessary to ensure that the noise suppressor is properly turned off and can be used again for the next aircraft. By following the correct shutdown procedure, any potential damage to the noise suppressor can be prevented, and it can continue to function effectively for future use.

Explanation

The correct answer is "ensures the noise suppressor will be operational for the next aircraft." This is because the shutdown procedure is necessary to ensure that the noise suppressor is properly turned off and can be used again for the next aircraft. By following the correct shutdown procedure, any potential damage to the noise suppressor can be prevented, and it can continue to function effectively for future use.

65. Galling of bearing rolling elements and races is characterized by

Flaking of metal.

Transfer of metal.

Magnetization.

Discoloration.

Galling of bearing rolling elements and races refers to the process where metal is transferred between the surfaces in contact, leading to damage and wear. This occurs due to the high pressure and friction between the rolling elements and races, causing the metal to transfer from one surface to another. The transferred metal can result in surface roughness, increased friction, and ultimately, the failure of the bearing. Therefore, the correct answer is "transfer of metal."

Explanation

Galling of bearing rolling elements and races refers to the process where metal is transferred between the surfaces in contact, leading to damage and wear. This occurs due to the high pressure and friction between the rolling elements and races, causing the metal to transfer from one surface to another. The transferred metal can result in surface roughness, increased friction, and ultimately, the failure of the bearing. Therefore, the correct answer is "transfer of metal."

66. The basic portable test cell's thrust trailer rails adjust to a height of

20 inches.

40 inches.

60 inches.

80 inches.

The correct answer is 40 inches. The question states that the basic portable test cell's thrust trailer rails adjust to a height of. This implies that the height can be adjusted to different levels. Out of the given options, the only height mentioned is 40 inches. Therefore, the correct answer is 40 inches.

Explanation

The correct answer is 40 inches. The question states that the basic portable test cell's thrust trailer rails adjust to a height of. This implies that the height can be adjusted to different levels. Out of the given options, the only height mentioned is 40 inches. Therefore, the correct answer is 40 inches.

67. What controls turbine discharge temperature on a GTCP 165 engine?

PMG.

Fuel flow divider valve.

Pneumatic thermostat.

Governor.

The pneumatic thermostat controls the turbine discharge temperature on a GTCP 165 engine. It regulates the flow of air to the turbine to maintain the desired temperature range. The other options, such as the PMG, fuel flow divider valve, and governor, do not directly control the turbine discharge temperature in this specific engine.

Explanation

The pneumatic thermostat controls the turbine discharge temperature on a GTCP 165 engine. It regulates the flow of air to the turbine to maintain the desired temperature range. The other options, such as the PMG, fuel flow divider valve, and governor, do not directly control the turbine discharge temperature in this specific engine.

68. Which component on a GTCP 165 engine shuts the engine down if the oil pressure drops below the safe minimum operating limit?

Oil/air cooler.

Oil filter assembly.

Oil pressure switch.

Oil pressure regulator valve.

The oil pressure switch is the component on a GTCP 165 engine that shuts the engine down if the oil pressure drops below the safe minimum operating limit. It is responsible for monitoring the oil pressure and sending a signal to the engine control system to shut down the engine if the pressure falls below a certain threshold. This is a crucial safety feature to prevent damage to the engine and ensure proper operation.

Explanation

The oil pressure switch is the component on a GTCP 165 engine that shuts the engine down if the oil pressure drops below the safe minimum operating limit. It is responsible for monitoring the oil pressure and sending a signal to the engine control system to shut down the engine if the pressure falls below a certain threshold. This is a crucial safety feature to prevent damage to the engine and ensure proper operation.

69. Which testing engine is equipped with a QEC kit?

TF39-1C.

F110-GE–129

F100-PW–220.

F100-PW–229.

The correct answer is TF39-1C. This engine is equipped with a QEC kit, which stands for Quick Engine Change kit. This kit allows for the rapid replacement of an engine in an aircraft, reducing downtime and increasing operational efficiency. The other engine options listed, F110-GE-129, F100-PW-220, and F100-PW-229, do not mention being equipped with a QEC kit, so they are not the correct answer.

Explanation

The correct answer is TF39-1C. This engine is equipped with a QEC kit, which stands for Quick Engine Change kit. This kit allows for the rapid replacement of an engine in an aircraft, reducing downtime and increasing operational efficiency. The other engine options listed, F110-GE-129, F100-PW-220, and F100-PW-229, do not mention being equipped with a QEC kit, so they are not the correct answer.

70. Which F100-PW–220 engine monitoring system component transfers information from the EDU to the GSU?

DCU.

EAU.

Mn test system.

SCS.

The correct answer is DCU. The DCU, or Digital Control Unit, is responsible for transferring information from the Engine Data Unit (EDU) to the Generator Control Unit (GSU). The DCU acts as an interface between these two components, allowing for the monitoring and control of the engine. It plays a crucial role in ensuring the proper functioning of the engine monitoring system.

Explanation

The correct answer is DCU. The DCU, or Digital Control Unit, is responsible for transferring information from the Engine Data Unit (EDU) to the Generator Control Unit (GSU). The DCU acts as an interface between these two components, allowing for the monitoring and control of the engine. It plays a crucial role in ensuring the proper functioning of the engine monitoring system.

71. What engine vibration usually causes the most concern?

Forced.

Transient.

Unbalanced.

Externally excited.

Forced engine vibration usually causes the most concern because it is induced by external factors or components within the engine, such as misalignment, loose parts, or worn bearings. Unlike transient vibration, which occurs temporarily and then stops, forced vibration persists and can lead to more severe damage if not addressed. Unbalanced vibration, on the other hand, is caused by uneven distribution of mass within the engine and may cause discomfort but is generally not as concerning as forced vibration. Externally excited vibration is caused by external sources, such as aerodynamic forces or ground disturbances, and can also be a cause for concern.

Explanation

Forced engine vibration usually causes the most concern because it is induced by external factors or components within the engine, such as misalignment, loose parts, or worn bearings. Unlike transient vibration, which occurs temporarily and then stops, forced vibration persists and can lead to more severe damage if not addressed. Unbalanced vibration, on the other hand, is caused by uneven distribution of mass within the engine and may cause discomfort but is generally not as concerning as forced vibration. Externally excited vibration is caused by external sources, such as aerodynamic forces or ground disturbances, and can also be a cause for concern.

72. When using a vibration analyzer how are you notified when a preset signal has been exceeded?

A horn alarm.

Flashing red lights.

A buzzer sounding

A flashing channel indicator LED.

When using a vibration analyzer, a flashing channel indicator LED is used to notify the user when a preset signal has been exceeded. This LED serves as a visual indicator, alerting the user to the exceeded signal. It is a convenient and effective way to quickly identify when the vibration levels have surpassed the predetermined threshold.

Explanation

When using a vibration analyzer, a flashing channel indicator LED is used to notify the user when a preset signal has been exceeded. This LED serves as a visual indicator, alerting the user to the exceeded signal. It is a convenient and effective way to quickly identify when the vibration levels have surpassed the predetermined threshold.

73. Primary aids that outline minimum inspection requirements are called

Sequence charts.

Inspection checklists.

Inspection work cards.

Work schedule guides.

Primary aids that outline minimum inspection requirements are called inspection work cards. These cards provide a detailed checklist of the specific tasks and items that need to be inspected during an inspection process. They serve as a guide for inspectors to ensure that all necessary inspections are carried out and that no important steps are missed. Inspection work cards help maintain consistency and accuracy in the inspection process by providing a standardized format for recording inspection results.

Explanation

Primary aids that outline minimum inspection requirements are called inspection work cards. These cards provide a detailed checklist of the specific tasks and items that need to be inspected during an inspection process. They serve as a guide for inspectors to ensure that all necessary inspections are carried out and that no important steps are missed. Inspection work cards help maintain consistency and accuracy in the inspection process by providing a standardized format for recording inspection results.

74. The vertical baffles in the fixed test cell's exhaust stack are designed to remove

Low-volume sound.

High-volume sound.

Low-frequency sound.

High-frequency sound.

The vertical baffles in the fixed test cell's exhaust stack are designed to remove low-frequency sound. Baffles are commonly used to control and reduce noise levels by absorbing or reflecting sound waves. In this case, the vertical baffles are specifically designed to target and eliminate low-frequency sounds, which typically have longer wavelengths and are more difficult to attenuate. By incorporating these baffles, the fixed test cell's exhaust stack can effectively mitigate the low-frequency noise generated during testing processes.

Explanation

The vertical baffles in the fixed test cell's exhaust stack are designed to remove low-frequency sound. Baffles are commonly used to control and reduce noise levels by absorbing or reflecting sound waves. In this case, the vertical baffles are specifically designed to target and eliminate low-frequency sounds, which typically have longer wavelengths and are more difficult to attenuate. By incorporating these baffles, the fixed test cell's exhaust stack can effectively mitigate the low-frequency noise generated during testing processes.

75. The portable test cell's noise suppressor is not equipped with

A fuel trailer.

An exhaust muffler.

Two air intake mufflers.

A water tank semitrailer.

The portable test cell's noise suppressor is not equipped with a fuel trailer. This means that the noise suppressor does not have a fuel trailer attached to it. This is important because a fuel trailer is not necessary for the functioning of the noise suppressor. The noise suppressor is designed to reduce noise from the test cell, and it does not require a fuel trailer for this purpose.

Explanation

The portable test cell's noise suppressor is not equipped with a fuel trailer. This means that the noise suppressor does not have a fuel trailer attached to it. This is important because a fuel trailer is not necessary for the functioning of the noise suppressor. The noise suppressor is designed to reduce noise from the test cell, and it does not require a fuel trailer for this purpose.

76. Which of the following is not an inspection phase?

Fix.

Look.

Preinspection.

HSC.

The question asks for the inspection phase that is not included in the given options. The options provided are "Fix," "Look," "Preinspection," and "HSC." Out of these options, "HSC" is not an inspection phase. Therefore, "HSC" is the correct answer.

Explanation

The question asks for the inspection phase that is not included in the given options. The options provided are "Fix," "Look," "Preinspection," and "HSC." Out of these options, "HSC" is not an inspection phase. Therefore, "HSC" is the correct answer.

77. When inspecting the hush house, you are not required to check the

Engine being tested.

Concrete deterioration.

Fire suppression system.

Engine tie-down assemblies.

When inspecting the hush house, the focus is on examining various aspects related to the engine testing process. This includes checking for concrete deterioration, ensuring the functionality of the fire suppression system, and inspecting the engine tie-down assemblies to ensure they are secure. However, the engine being tested itself does not need to be checked as it is the central component of the testing process and is already being monitored and evaluated during the testing procedure.

Explanation

When inspecting the hush house, the focus is on examining various aspects related to the engine testing process. This includes checking for concrete deterioration, ensuring the functionality of the fire suppression system, and inspecting the engine tie-down assemblies to ensure they are secure. However, the engine being tested itself does not need to be checked as it is the central component of the testing process and is already being monitored and evaluated during the testing procedure.

78. What procedure ensures that the fan and low-pressure turbine are correctly balanced?

Engine trim.

Fan rotor trim balance

Low-pressure turbine rotor trim balance.

High-pressure turbine rotor trim balance.

The procedure that ensures that the fan and low-pressure turbine are correctly balanced is fan rotor trim balance. This involves adjusting the fan rotor to ensure that it is properly aligned and balanced, which helps to optimize the performance and efficiency of the engine. By balancing the fan rotor, any vibrations or uneven forces can be minimized, resulting in smoother operation and improved overall performance of the engine.

Explanation

The procedure that ensures that the fan and low-pressure turbine are correctly balanced is fan rotor trim balance. This involves adjusting the fan rotor to ensure that it is properly aligned and balanced, which helps to optimize the performance and efficiency of the engine. By balancing the fan rotor, any vibrations or uneven forces can be minimized, resulting in smoother operation and improved overall performance of the engine.

79. Where do you find the instructions for installing vibration pickups at the test cell?

Test cell technical order.

Intermediate maintenance manual.

Organizational maintenance manual.

The intermediate maintenance manual is the correct source for finding the instructions for installing vibration pickups at the test cell. This manual provides detailed guidance and procedures for maintenance tasks that are more complex than those covered in the organizational maintenance manual. It is a comprehensive resource that technicians can refer to for step-by-step instructions on how to install vibration pickups correctly.

Explanation

The intermediate maintenance manual is the correct source for finding the instructions for installing vibration pickups at the test cell. This manual provides detailed guidance and procedures for maintenance tasks that are more complex than those covered in the organizational maintenance manual. It is a comprehensive resource that technicians can refer to for step-by-step instructions on how to install vibration pickups correctly.

80. The steps in removing the engine and test equipment from the test cell are

Very hazardous.

The reverse of the installation sequence.

Completed only by 7-level craftsmen.

Exactly the same as the installation sequence.

The correct answer is "the reverse of the installation sequence." This means that when removing the engine and test equipment from the test cell, the steps should be carried out in the opposite order of how they were installed. This is important because it ensures that the process is done correctly and safely, minimizing any potential hazards that may arise during the removal process.

Explanation

The correct answer is "the reverse of the installation sequence." This means that when removing the engine and test equipment from the test cell, the steps should be carried out in the opposite order of how they were installed. This is important because it ensures that the process is done correctly and safely, minimizing any potential hazards that may arise during the removal process.

81. The hush house exhaust deflector is constructed of

Flexible soft metal filled with noise reduction material.

Cylinder-type tubing filled with noise reduction material.

Small panel modules filled with noise reduction material.

Panels and air cooling ports filled with noise reduction material.

The correct answer is small panel modules filled with noise reduction material. This answer suggests that the hush house exhaust deflector is made up of small panel modules that are filled with a material specifically designed to reduce noise. This construction method allows for flexibility and adaptability, as the small panel modules can be easily adjusted or replaced as needed. Additionally, the use of noise reduction material further enhances the effectiveness of the exhaust deflector in reducing noise levels.

Explanation

The correct answer is small panel modules filled with noise reduction material. This answer suggests that the hush house exhaust deflector is made up of small panel modules that are filled with a material specifically designed to reduce noise. This construction method allows for flexibility and adaptability, as the small panel modules can be easily adjusted or replaced as needed. Additionally, the use of noise reduction material further enhances the effectiveness of the exhaust deflector in reducing noise levels.

82. What hush house feature allows flexibility when running an engine that has been removed from the airframe?

Tailhook connects to the engine.

Wheel chocks restrain the engine.

The thrust stand slides into position on tracks.

Engines can be run while on the ALC 3000 trailer.

The thrust stand sliding into position on tracks allows flexibility when running an engine that has been removed from the airframe. This feature enables the engine to be securely positioned and adjusted as needed during testing or maintenance. It ensures stability and precision while the engine is being operated outside of the aircraft, providing a safe and controlled environment for engine testing.

Explanation

The thrust stand sliding into position on tracks allows flexibility when running an engine that has been removed from the airframe. This feature enables the engine to be securely positioned and adjusted as needed during testing or maintenance. It ensures stability and precision while the engine is being operated outside of the aircraft, providing a safe and controlled environment for engine testing.

83. The test cell's EGT selector allows selecting

The EGT parameter for transit speeds.

The accuracy check switch during adjustment.

Digital or analog readings for the EGT indicator.

Individual thermocouple inputs or an average of these inputs.

The test cell's EGT selector allows the user to choose between individual thermocouple inputs or an average of these inputs. This means that the user can either monitor the EGT parameter for each individual thermocouple separately or view an average value of all the thermocouples. The selector provides flexibility in monitoring and analyzing the EGT parameter based on the user's preference or specific requirements.

Explanation

The test cell's EGT selector allows the user to choose between individual thermocouple inputs or an average of these inputs. This means that the user can either monitor the EGT parameter for each individual thermocouple separately or view an average value of all the thermocouples. The selector provides flexibility in monitoring and analyzing the EGT parameter based on the user's preference or specific requirements.

84. The impeller wheel and two turbine wheels in the turbine section of the GTCP 165 engine are connected by

Couplings on a common shaft.

A gear reduction gearbox.

Helical splines.

Tie bolts.

The impeller wheel and two turbine wheels in the turbine section of the GTCP 165 engine are connected by couplings on a common shaft. This means that the impeller wheel and the two turbine wheels are linked together through a common shaft, which allows for the transfer of power and rotation between them. Couplings are commonly used in machinery to connect rotating parts and transmit torque, making them an appropriate choice for connecting the components of the turbine section in the GTCP 165 engine.

Explanation

The impeller wheel and two turbine wheels in the turbine section of the GTCP 165 engine are connected by couplings on a common shaft. This means that the impeller wheel and the two turbine wheels are linked together through a common shaft, which allows for the transfer of power and rotation between them. Couplings are commonly used in machinery to connect rotating parts and transmit torque, making them an appropriate choice for connecting the components of the turbine section in the GTCP 165 engine.

85. When doing an anti-ice valve operational check on an F-16C/D before starting the engine you place the anti-ice engine switch to

ON.

OFF.

START.

MANUAL.

Before starting the engine on an F-16C/D, the anti-ice engine switch should be placed in the OFF position. This is because the anti-ice system is used to prevent ice formation on critical components of the aircraft, such as the engine inlet and the wings. By placing the switch in the OFF position, it ensures that the anti-ice system is not activated during the engine start, which could potentially cause damage to the system.

Explanation

Before starting the engine on an F-16C/D, the anti-ice engine switch should be placed in the OFF position. This is because the anti-ice system is used to prevent ice formation on critical components of the aircraft, such as the engine inlet and the wings. By placing the switch in the OFF position, it ensures that the anti-ice system is not activated during the engine start, which could potentially cause damage to the system.

86. What indicates the amount of thrust a dual-compressor engine is producing?

EPR.

RPM.

EGT.

TIT.

EPR (Engine Pressure Ratio) is a measure of the amount of thrust a dual-compressor engine is producing. It is calculated by dividing the total pressure at the engine inlet by the total pressure at the engine exhaust. EPR provides an indication of the engine's efficiency and the amount of pressure being generated, which directly relates to the thrust produced. RPM (Revolutions Per Minute) measures the speed of the engine, EGT (Exhaust Gas Temperature) indicates the temperature of the exhaust gases, and TIT (Turbine Inlet Temperature) measures the temperature at the turbine inlet. None of these directly indicate the amount of thrust being produced.

Explanation

EPR (Engine Pressure Ratio) is a measure of the amount of thrust a dual-compressor engine is producing. It is calculated by dividing the total pressure at the engine inlet by the total pressure at the engine exhaust. EPR provides an indication of the engine's efficiency and the amount of pressure being generated, which directly relates to the thrust produced. RPM (Revolutions Per Minute) measures the speed of the engine, EGT (Exhaust Gas Temperature) indicates the temperature of the exhaust gases, and TIT (Turbine Inlet Temperature) measures the temperature at the turbine inlet. None of these directly indicate the amount of thrust being produced.

87. The sidewalls of the hush house test bay is constructed of

Air inlet modules.

Observation ports.

Air exhaust modules.

High-grade steel panels.

The correct answer is air inlet modules. The sidewalls of the hush house test bay are constructed of air inlet modules. This implies that these modules are responsible for allowing air to enter the test bay. The other options, such as observation ports, air exhaust modules, and high-grade steel panels, do not specifically relate to the function of allowing air to enter the test bay.

Explanation

The correct answer is air inlet modules. The sidewalls of the hush house test bay are constructed of air inlet modules. This implies that these modules are responsible for allowing air to enter the test bay. The other options, such as observation ports, air exhaust modules, and high-grade steel panels, do not specifically relate to the function of allowing air to enter the test bay.

88. The N2 tachometer generator is usually driven from the tachometer drive located on the

Fuel control.

Combustion case.

Engine turbine section.

Engine accessory section.

The N2 tachometer generator is typically driven from the engine accessory section. This section of the engine includes various components such as the fuel pump, oil pump, and generator. Since the N2 tachometer generator is responsible for measuring the rotational speed of the engine's high-pressure compressor, it makes sense for it to be driven from the engine accessory section where other important engine systems are located.

Explanation

The N2 tachometer generator is typically driven from the engine accessory section. This section of the engine includes various components such as the fuel pump, oil pump, and generator. Since the N2 tachometer generator is responsible for measuring the rotational speed of the engine's high-pressure compressor, it makes sense for it to be driven from the engine accessory section where other important engine systems are located.

89. The portable test cell is not equipped with a

Fuel trailer.

Thrust trailer.

Control cab trailer.

Model 3000 trailer.

The correct answer is "model 3000 trailer." This means that the portable test cell is not equipped with a model 3000 trailer. The question implies that the portable test cell may be equipped with other types of trailers such as a fuel trailer, thrust trailer, or control cab trailer, but not a model 3000 trailer.

Explanation

The correct answer is "model 3000 trailer." This means that the portable test cell is not equipped with a model 3000 trailer. The question implies that the portable test cell may be equipped with other types of trailers such as a fuel trailer, thrust trailer, or control cab trailer, but not a model 3000 trailer.

90. When preparing to install the miscellaneous kit prior to a test cell run, you inspect all indicators and controls for

Improper torque.

Possible damage.

Appropriate indication and positioning.

Proper lubrication and component sealing.

When preparing to install the miscellaneous kit prior to a test cell run, it is important to inspect all indicators and controls for possible damage. This ensures that the kit is in good working condition and will not cause any issues during the test cell run. By checking for possible damage, any faulty or broken components can be identified and replaced, preventing any potential problems or accidents during the test.

Explanation

When preparing to install the miscellaneous kit prior to a test cell run, it is important to inspect all indicators and controls for possible damage. This ensures that the kit is in good working condition and will not cause any issues during the test cell run. By checking for possible damage, any faulty or broken components can be identified and replaced, preventing any potential problems or accidents during the test.

91. Which signals are used by the fuel control unit to control engine operation on a GTCP 165 engine?

Engine speed and pneumatic thermostat (load control) air pressure.

Ambient inlet pressure and turbine exhaust pressure.

Engine speed and turbine inlet temperature.

Pt0 and Pt7.

The fuel control unit on a GTCP 165 engine uses engine speed and pneumatic thermostat (load control) air pressure signals to control engine operation. Engine speed is an important parameter as it indicates the rotational speed of the engine, which directly affects fuel consumption and power output. The pneumatic thermostat air pressure signal is used to determine the load on the engine, allowing the fuel control unit to adjust the fuel flow accordingly to maintain optimal performance. The other options, such as ambient inlet pressure, turbine exhaust pressure, and Pt0 and Pt7, are not directly related to fuel control in this engine.

Explanation

The fuel control unit on a GTCP 165 engine uses engine speed and pneumatic thermostat (load control) air pressure signals to control engine operation. Engine speed is an important parameter as it indicates the rotational speed of the engine, which directly affects fuel consumption and power output. The pneumatic thermostat air pressure signal is used to determine the load on the engine, allowing the fuel control unit to adjust the fuel flow accordingly to maintain optimal performance. The other options, such as ambient inlet pressure, turbine exhaust pressure, and Pt0 and Pt7, are not directly related to fuel control in this engine.

92. What is the probable cause of compressor rotor shift?

Rotor out of round.

Roller bearing failure.

Thrust bearing failure.

Incipient compressor stall.

The probable cause of compressor rotor shift is thrust bearing failure. Thrust bearings are designed to handle axial loads and prevent the rotor from moving forward or backward. When the thrust bearing fails, it can no longer support the axial loads, causing the rotor to shift. This can lead to various issues such as increased vibration, decreased efficiency, and potential damage to other components of the compressor.

Explanation

The probable cause of compressor rotor shift is thrust bearing failure. Thrust bearings are designed to handle axial loads and prevent the rotor from moving forward or backward. When the thrust bearing fails, it can no longer support the axial loads, causing the rotor to shift. This can lead to various issues such as increased vibration, decreased efficiency, and potential damage to other components of the compressor.

93. Trim means to adjust the engine systems for optimum performance according to the TO's limits. The two methods used to trim an engine are

Hydraulic and mechanical.

Hydraulic and electronic.

Manual and mechanical.

Manual and electronic.

The correct answer is manual and electronic. Trimming an engine involves adjusting its systems for optimal performance within the limits specified in the TO (Technical Order). This can be done using two methods: manual and electronic. Manual trimming refers to adjusting the engine systems manually, while electronic trimming involves using electronic controls to make the necessary adjustments. Both methods are used to ensure that the engine operates at its best performance levels.

Explanation

The correct answer is manual and electronic. Trimming an engine involves adjusting its systems for optimal performance within the limits specified in the TO (Technical Order). This can be done using two methods: manual and electronic. Manual trimming refers to adjusting the engine systems manually, while electronic trimming involves using electronic controls to make the necessary adjustments. Both methods are used to ensure that the engine operates at its best performance levels.

94. When testing a TF34 engine at test cell, which test ensures that all operating limits and schedules from idle to maximum power are within limits?

Break-in run.

Transient check.

Vibration survey.

Max power engine trim.

The transient check ensures that all operating limits and schedules from idle to maximum power are within limits when testing a TF34 engine at a test cell. This test is important to ensure the engine's performance and functionality during different power levels and operating conditions. The break-in run is a separate test conducted to ensure proper engine break-in, while the vibration survey is performed to assess and mitigate any excessive vibrations. Max power engine trim is not directly related to testing operating limits and schedules.

Explanation

The transient check ensures that all operating limits and schedules from idle to maximum power are within limits when testing a TF34 engine at a test cell. This test is important to ensure the engine's performance and functionality during different power levels and operating conditions. The break-in run is a separate test conducted to ensure proper engine break-in, while the vibration survey is performed to assess and mitigate any excessive vibrations. Max power engine trim is not directly related to testing operating limits and schedules.

95. When connected to an engine oil pressure line the direct oil pressure gauge on a test cell indicates oil pressure without using wiring, indicator, or

Aircraft transformer.

Engine transformer.

Aircraft transmitter.

Engine transmitter.

The correct answer is aircraft transmitter. When connected to an engine oil pressure line, the direct oil pressure gauge on a test cell indicates oil pressure without using wiring, indicator, or aircraft transformer. Instead, it uses an aircraft transmitter to transmit the oil pressure readings.

Explanation

The correct answer is aircraft transmitter. When connected to an engine oil pressure line, the direct oil pressure gauge on a test cell indicates oil pressure without using wiring, indicator, or aircraft transformer. Instead, it uses an aircraft transmitter to transmit the oil pressure readings.

96. The accessory drive section aft housing on a GTCP 165 engine contains the

Fuel control unit.

Oil pump assembly.

Vane-axial fan assembly.

Compressor front shaft bearing.

The accessory drive section aft housing on a GTCP 165 engine contains the compressor front shaft bearing. This bearing is responsible for supporting the front shaft of the compressor, which is an essential component in the engine. It helps to reduce friction and ensure smooth rotation of the compressor shaft, allowing for efficient operation of the engine. The other options mentioned, such as the fuel control unit, oil pump assembly, and vane-axial fan assembly, may be present in other sections of the engine but not specifically in the accessory drive section aft housing.

Explanation

The accessory drive section aft housing on a GTCP 165 engine contains the compressor front shaft bearing. This bearing is responsible for supporting the front shaft of the compressor, which is an essential component in the engine. It helps to reduce friction and ensure smooth rotation of the compressor shaft, allowing for efficient operation of the engine. The other options mentioned, such as the fuel control unit, oil pump assembly, and vane-axial fan assembly, may be present in other sections of the engine but not specifically in the accessory drive section aft housing.

97. The test cell fuel-flow rate indicator automatically controls the fuel module's solenoid valves in order to divert fuel flow through the

Fuel control.

Flow turbines.

Flow cascades.

Fuel-oil coolers.

The test cell fuel-flow rate indicator controls the solenoid valves of the fuel module to redirect the fuel flow through the flow turbines. This indicates that the flow turbines are an integral part of the fuel control system and are used to regulate the fuel flow.

Explanation

The test cell fuel-flow rate indicator controls the solenoid valves of the fuel module to redirect the fuel flow through the flow turbines. This indicates that the flow turbines are an integral part of the fuel control system and are used to regulate the fuel flow.

98. When checking the turbine section, you do not measure

FTIT.

TIT.

EGT.

IGT.

When checking the turbine section, you do not measure IGT. IGT stands for Inlet Guide Vane Temperature, which is a measurement taken in the compressor section of a gas turbine engine. The turbine section is responsible for extracting energy from the combustion gases and converting it into mechanical energy to drive the compressor and other components. Therefore, it is not necessary to measure IGT in the turbine section.

Explanation

When checking the turbine section, you do not measure IGT. IGT stands for Inlet Guide Vane Temperature, which is a measurement taken in the compressor section of a gas turbine engine. The turbine section is responsible for extracting energy from the combustion gases and converting it into mechanical energy to drive the compressor and other components. Therefore, it is not necessary to measure IGT in the turbine section.

99. The accessory drive section forward housing on a GTCP 165 engine provides mounts for components, including the fuel control unit, oil pump assembly, oil filter element, vane-axial fan assembly, and

Air/oil cooler.

Fuel/oil cooler.

Ignition exciter

PMG.

The accessory drive section forward housing on a GTCP 165 engine provides mounts for various components, including the fuel control unit, oil pump assembly, oil filter element, vane-axial fan assembly, and the air/oil cooler. The air/oil cooler is one of the components that is mounted on the accessory drive section forward housing.

Explanation

The accessory drive section forward housing on a GTCP 165 engine provides mounts for various components, including the fuel control unit, oil pump assembly, oil filter element, vane-axial fan assembly, and the air/oil cooler. The air/oil cooler is one of the components that is mounted on the accessory drive section forward housing.

100. What inspection and maintenance concept provides a method for performing required inspections on a scheduled and controlled basis?

Planned.

Periodic.

Scheduled.

Supervised.

The concept of planned inspection and maintenance provides a method for performing required inspections on a scheduled and controlled basis. This means that inspections are planned in advance, taking into consideration the specific requirements and schedules of the equipment or system being inspected. By following a planned approach, inspections can be conducted regularly and systematically, ensuring that any potential issues or maintenance needs are identified and addressed in a timely manner. This helps to prevent unexpected breakdowns or failures, prolong the lifespan of the equipment, and maintain optimal performance.

Explanation

The concept of planned inspection and maintenance provides a method for performing required inspections on a scheduled and controlled basis. This means that inspections are planned in advance, taking into consideration the specific requirements and schedules of the equipment or system being inspected. By following a planned approach, inspections can be conducted regularly and systematically, ensuring that any potential issues or maintenance needs are identified and addressed in a timely manner. This helps to prevent unexpected breakdowns or failures, prolong the lifespan of the equipment, and maintain optimal performance.

CDC 2a651s Vol. 4