Volume 4 - 2014 2a651s CDC

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 are not used in EGT indicating system thermocouples.

To become an expert troubleshooter, it is essential to have a deep understanding of the function of each unit within each system. This knowledge allows the troubleshooter to identify and diagnose issues accurately, as they are familiar with how each component operates and interacts with other units. This expertise enables them to efficiently troubleshoot and resolve problems, making them an expert in their field.

Most engine-monitoring gauges and instruments require a transmitter and indicator. This is because the transmitter is responsible for converting the physical quantity being measured (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 from the transmitter and displays the corresponding measurement value. Therefore, both the transmitter and indicator are necessary components for engine-monitoring gauges and instruments to function properly.

A typical jet engine EGT indicating system contains thermocouples, leads, an indicator, and a resistor. The resistor is an essential component in the system as it helps to calibrate and regulate the electrical signal from the thermocouples. It is used to convert the temperature readings into a measurable electrical signal that can be displayed on the indicator. Without the resistor, the system would not be able to accurately measure and display the engine's exhaust gas temperature.

Transient engine vibration refers to vibrations that occur for a short period of time and then disappear. These vibrations are not persistent and can come and go intermittently. This is in contrast to other types of engine vibrations such as forced vibrations (which are caused by a continuous external force), resonance vibrations (which occur at a specific frequency), and externally excited vibrations (which are caused by external factors). Therefore, the correct answer is transient.

The correct answer is to eliminate items that could possibly cause FOD (Foreign Object Damage). Checking for loose nuts, bolts, lock wire, tools, or any other material prior to an engine test run helps to ensure that no foreign objects are present that could potentially be sucked into the engine or cause damage during the test. This is important for the safety and proper functioning of the engine.

The correct answer is troubleshooting charts. The troubleshooting information in aircraft power plant and engine intermediate maintenance TO is presented in the form of charts. These charts provide a step-by-step guide for diagnosing and fixing issues that may arise in the power plant and engine systems of an aircraft. They help technicians identify the possible causes of a problem and guide them through the necessary steps to resolve it. This format allows for efficient and effective troubleshooting, ensuring that maintenance procedures are carried out accurately and quickly.

Inspecting other areas after isolating trouble between points is not a proper troubleshooting practice. In troubleshooting, it is important to systematically identify and address potential problem areas. Inspecting other areas after isolating trouble between points can lead to wasted time and effort, as the root cause of the issue may have already been identified. It is more effective to focus on the specific trouble areas and perform easy checks first before moving on to more difficult checks. This approach allows for a more efficient and targeted troubleshooting process.

Bearings support the fan and low-pressure turbine in a turbine engine. Bearings are mechanical devices that allow for smooth rotation by reducing friction between moving parts. In this context, bearings provide support and allow the fan and low-pressure turbine to rotate efficiently and smoothly, ensuring the proper functioning of the engine.

Rapid throttle movement during emergency system operation can cause a compressor stall. This is because sudden changes in throttle position can disrupt the airflow through the engine, leading to an imbalance between the compressor's intake and discharge pressure. This disruption can result in a decrease in compressor efficiency, causing the airflow to become unstable and potentially leading to a stall.

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 being recorded and avoids any potential errors or discrepancies. By checking and confirming these numbers, the log sheet will accurately reflect the specific engine being tested.

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 or vibration in various applications such as structural health monitoring, automotive testing, and aerospace engineering.

The fuel-flow indicator is a device that measures the rate at which fuel is flowing through the system. It provides information about how many pounds of fuel are being consumed per hour. This is an important metric for pilots to monitor as it helps them manage fuel consumption and determine the remaining fuel on board.

The Air Force currently uses two types of test cells: fixed and portable. Fixed test cells are permanent installations that are designed for long-term use and are typically located at air bases or testing facilities. Portable test cells, on the other hand, are temporary setups that can be easily transported and set up at different locations as needed. Both types of test cells serve the purpose of conducting tests and evaluations on aircraft engines and other equipment.

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 important for flight operations. The control tower communicates with pilots and provides them with necessary information for safe takeoff and landing. Therefore, if you need information such as temperature and barometric pressure, the control tower would be the appropriate source to obtain it.

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 done in the opposite order of how they were installed. This is likely because certain components or connections need to be disconnected or removed first in order to safely and efficiently remove the engine and test equipment without causing any damage or hazards.

When an engine arrives for a test run at the test cell, it must be operable with all known discrepancies corrected. This means that before the engine can be tested, any known issues or problems with the engine must be fixed or resolved. The engine should be in a condition where it can function properly and without any known faults or defects. This ensures that the test results accurately reflect the engine's performance and capabilities.

Acceptance inspection is given to all newly assigned aircraft. This inspection ensures that the aircraft meets all the necessary requirements and standards before it is put into service. It includes a thorough examination of various components, systems, and documentation to ensure that the aircraft is safe and ready for operation. The acceptance inspection is crucial in ensuring the airworthiness and reliability of the aircraft.

After reviewing the aircraft/engine forms, the next step in troubleshooting should be to observe gauge indications. This is because gauge indications provide valuable information about the functioning of different systems in the aircraft/engine. By closely monitoring the gauge readings, any abnormal or out-of-range indications can be identified, which can help in pinpointing the potential issues or malfunctions. This initial observation of gauge indications can provide a starting point for further investigation and troubleshooting of the problem.

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 is necessary to ensure a proper fit and secure installation of the engine. If the rail adapters and stand are not compatible, it may result in instability or damage to the engine during testing. Therefore, compatibility between the rail adapters and stand is crucial for a successful engine installation on the test cell thrust stand.

The tachometer generator is a device that measures the speed of an engine. It works by generating a frequency that is proportional to the engine speed. Therefore, the correct answer is that the tachometer generator's frequency is proportional to the engine speed.

The formation of ice, ingestion of bolts, and ingestion of rocks are all considered causes of Foreign Object Damage (FOD). FOD refers to any object or substance that can cause damage to an aircraft or its components. However, failure of internal parts is not typically considered a cause of FOD. Instead, it is usually attributed to mechanical or operational issues within the aircraft itself, rather than external objects or substances.

Over-temperature damage to the combustion chamber from a stall condition is caused by an interruption of cooling airflow. When the engine stalls, the airflow through the engine decreases or stops completely, leading to a lack of cooling air reaching the combustion chamber. Without sufficient cooling, the temperature in the combustion chamber rises rapidly, causing damage to the engine components. Therefore, an interruption of cooling airflow is the most likely cause of over-temperature damage in this scenario.

Jet-powered aircraft engine fuel-flow indicating systems typically consist of a fuel-flow transmitter and a fuel-flow indicator. The fuel-flow transmitter measures the rate at which fuel is being consumed by the engine and sends this information to the fuel-flow indicator, which displays the fuel flow rate to the pilot. This system is crucial for monitoring fuel consumption and ensuring that the engine is operating efficiently.

The correct answer is transmitter. The oil pressure indicator receives an electrical signal from the transmitter. This suggests that the oil pressure indicator is not directly connected to the gyro, hydraulic unit, or synchronous unit. Instead, it relies on the transmitter to provide the necessary information about oil pressure.

To perform an operational check of the fire warning system, pressing only the TEST switch is sufficient. This switch is specifically designed to initiate a test sequence that simulates a fire condition and checks the functionality of the system. Pressing both the TEST and NORMAL switches or only the TEST WARNING ON switch would not be necessary or relevant for this specific check. Similarly, pressing both the TEST ON and TEST OFF switches would not serve the purpose of testing the fire warning system.

Engines that have been involved in an incident or a mishap are tested in addition to determining the condition of a repaired or overhauled engine. This suggests that the testing is done to assess the damage or any potential issues that may have occurred as a result of the incident or mishap.

To be considered effective tools for aviators, aircraft instruments must be small in size. This is because in the limited space of an aircraft cockpit, it is important for instruments to be compact and not take up too much space. Additionally, smaller instruments are easier to arrange and install in the cockpit, allowing for better visibility and accessibility for the pilot.

The tachometer indicating system consists of two primary units: the tachometer generator and the tachometer indicator. The tachometer generator is responsible for generating the electrical signal based on the rotational speed of the engine, while the tachometer indicator is the device that displays this information to the user. The other options, such as fuse panel, transformer, and thermocouple, are not directly related to the tachometer indicating system and therefore, are not the correct answer.

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. This is because a damaged seal would allow oil to leak out and come into contact with the turbine wheel, causing oil to be visible on the wheel or smoke to be produced. This suggests that there is a problem with the seal, which needs to be addressed to prevent further damage to the turbine system.

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 contains contaminants such as oil and other particles. This air is not suitable for inflating tires as it may cause damage or affect the performance of the tires.

Understanding the operating principles of engine instruments helps you determine the meaning of the instrument readings. By understanding how the instruments work and what they measure, you can interpret the readings correctly and make informed decisions about the engine's performance. This knowledge is crucial in determining if there are any issues with the engine that require further action, such as removal from the aircraft or testing in a test cell.

Jet engine temperature is measured at various points to monitor the performance and ensure safe operation. The combustion inlet is not one of these points where temperature is measured. Temperature is typically measured at the fan turbine inlet, turbine inlet, and exhaust gas. These measurements are crucial for monitoring the engine's efficiency, detecting any abnormalities, and making necessary adjustments to optimize performance. However, the combustion inlet temperature is not directly measured as it is not considered a critical parameter for engine operation and performance evaluation.

Periodic inspection checklists are used as an aid in test facility inspections. These checklists provide a systematic and standardized approach to conducting inspections, ensuring that all necessary areas and equipment are inspected thoroughly. They outline specific items to be checked, such as safety measures, equipment condition, and compliance with regulations. By using periodic inspection checklists, inspectors can ensure that inspections are comprehensive, consistent, and accurate, leading to effective maintenance and safety in the test facility.

The term Pt2 refers to the total pressure at station 2. This means that it represents the combined pressure exerted by all the gases present at station 2, including the static pressure, dynamic pressure, and any other components. It does not refer to the pressure at flange 2 or the temperature and pressure at either flange 2 or station 2.

To investigate an engine with a possible oil consumption problem, reviewing AFTO Form 781H would be the best starting point. AFTO Form 781H is an engine oil consumption record that provides detailed information about the amount of oil consumed by the engine over a period of time. By reviewing this form, one can gather important data and trends regarding oil consumption, which can help identify any potential issues or abnormalities in the engine's oil consumption. This information can then be used to further investigate and diagnose the problem.

When inspecting the hush house, the focus is on checking various aspects related to the engine being tested. This includes examining the concrete deterioration, ensuring the functionality of the fire suppression system, and inspecting the engine tie-down assemblies. However, the engine being tested itself does not need to be checked as it is the main object of the inspection.

A transducer is a device that converts one form of energy into another. In the context of engines with afterburners, the exhaust nozzle's position needs to be converted into an electrical signal. A transducer is capable of performing this conversion, taking the physical position of the nozzle and converting it into an electrical signal that can be used for various purposes such as control systems or monitoring. Therefore, a transducer is the correct answer in this case.

The overheat detector unit used on aircraft engines consists of a hollow stainless-steel tube that covers two silver contacts. This design allows for the detection of excessive heat by monitoring the electrical resistance between the silver contacts. When the temperature rises above a certain threshold, the resistance between the contacts changes, triggering an alarm or safety mechanism to prevent further overheating.

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, preventing any further fuel from flowing into the system. By closing this valve, the engine is effectively shut down and fuel flow is stopped, ensuring safe and controlled shutdown of the engine.

AFOSH STD 91-100 is the correct answer because it is a standard that provides guidelines and 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 unrelated to flight-line vehicle operations. The flight-line JG and intermediate maintenance TO do not provide written instructions for safe flight-line vehicle operations.

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 needs to be checked, but also any necessary paperwork or documentation related to the aircraft must be reviewed. This ensures that all necessary forms are completed and the aircraft is in proper working order before it is moved into the hush house.

Improperly rigged throttle linkage during a test cell run can cause engine overspeed. When the throttle linkage is not properly rigged, it can result in the throttle being opened wider than intended, causing the engine to run at a higher speed than it should. This can lead to excessive stress on the engine components, potentially causing damage and compromising the engine's performance and safety. Fluctuating EGT, fluctuating RPM, and damage to the inlet guide vanes may be potential consequences of engine overspeed, but the primary concern in this scenario is the risk of engine overspeed itself.

When using a vibration analyzer, the preset signal being exceeded is notified by a flashing channel indicator LED. This means that when the vibration levels go beyond the predetermined threshold, the LED on the corresponding channel will start flashing, indicating the exceeded signal. This visual indicator allows the user to easily identify which channel has exceeded the preset signal without the need for sound alarms or additional lights.

The correct answer is turbine plenum. The turbine plenum is a component in the engine where air is collected and distributed to various systems, including the load control system. This system is responsible for controlling the load on the engine, and it requires a source of air to operate effectively. Extracting air from the turbine plenum ensures that the load control system receives a sufficient and consistent supply of air for its functioning.

The correct answer is a four-wheel trailer. This means that when the SGT engine is used for ground operation, it can be installed on a trailer that has four wheels.

A preflight inspection is a flight preparedness check that is conducted by pilots before every flight. It involves a thorough examination of the aircraft's systems, controls, and overall condition to ensure that it is safe and ready for flight. This inspection includes checking fuel levels, control surfaces, landing gear, engine, instruments, and other important components. By conducting a preflight inspection, pilots can identify any potential issues or malfunctions that could affect the safety and performance of the aircraft during flight. Therefore, the correct answer is preflight.

The swivel pads at the bottom of the leveling jacks on the engine thrust trailer of the portable test cell provide leveling for 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.

The correct answer is "after the last flight of the flying period." This means that the BPO (Base Periodic Operation) is conducted after the final flight of the day. This is important because it allows for a thorough inspection of the aircraft at the end of its operational period, ensuring that any issues or maintenance requirements are addressed before the aircraft is used again. Conducting the BPO after the last flight helps to maintain the safety and reliability of the aircraft.

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 tested in different positions, angles, and orientations, ensuring accurate and reliable performance evaluations. It also allows for adjustments and fine-tuning during testing, ensuring optimal engine functioning.