Volume 5. Jet Engine Troubleshooting, Operation, Testing, And Damage Analysis

To become an expert troubleshooter, it is important to understand the function of each unit within each system. This knowledge allows the troubleshooter to identify and diagnose problems accurately. By understanding how each unit works and how it interacts with other units in the system, the troubleshooter can effectively troubleshoot and resolve issues. This comprehensive understanding ensures that the troubleshooter is equipped with the necessary knowledge to handle any troubleshooting scenario.

Most engine monitoring gauges and instruments require a transmitter and indicator. The transmitter is responsible for converting the physical parameters (such as temperature, pressure, or speed) into electrical signals, which are then transmitted to the indicator. The indicator, on the other hand, receives these electrical signals and displays them in a readable format for the operator. This setup allows for accurate and real-time monitoring of the engine's performance.

The correct answer is troubleshooting charts. Aircraft power plant and engine intermediate maintenance technical orders (TO) provide information on troubleshooting, which is presented in the form of troubleshooting charts. These charts help maintenance personnel to identify and resolve issues with the aircraft's power plant and engine systems. They typically include step-by-step instructions and flowcharts to guide the troubleshooting process and ensure efficient and accurate problem-solving.

Using the wrong cleaning agent on a jet engine part could destroy it. Different cleaning agents have specific properties and are formulated to work effectively and safely on specific materials. Using the wrong cleaning agent could cause damage to the part, such as corrosion, erosion, or degradation of the material. This can lead to a loss of structural integrity and potentially render the part unusable or unsafe for operation. It is crucial to use the correct cleaning agent to ensure the longevity and proper functioning of the jet engine part.

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 avoids any potential errors or discrepancies. By checking and verifying these numbers on the engine data plate, the accuracy of the log sheet can be maintained.

The correct answer is "be operable with all known discrepancies corrected." This means that when an engine arrives for a test run at the test cell, it should be in a condition where all known issues or problems have been fixed and it is ready to be operated without any major concerns. This ensures that the engine can be properly tested and evaluated without any hindrances or potential safety risks.

Bearings are used to 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 are used to support the rotating blades of the fan and low pressure turbine, ensuring their stability and proper functioning. Without bearings, the blades would experience excessive friction, leading to increased wear and tear, reduced efficiency, and potential damage to the entire system.

Engine manufacturers determine the expected duration that a specific part should function through extensive testing. This duration is referred to as the "service life" of the part. It represents the estimated period during which the part is expected to operate effectively before experiencing any significant issues or failure.

The oil pressure transmitter and indicator are two units that work together to indicate the correct operation of the oil system. The transmitter measures the oil pressure and sends the information to the indicator, which displays the pressure reading. This allows the operator to monitor the oil pressure and ensure that it is within the desired range for proper functioning of the system. The relief valve and synchronous unit are not directly related to indicating the oil system's operation, making them incorrect options.

A piezoelectric accelerometer is made up of certain ceramic compounds and natural crystals. These materials have the property of generating an electric charge when subjected to mechanical stress or vibration. Therefore, when the accelerometer experiences vibrations, the crystals within it generate an electric charge proportional to the applied force, allowing for the measurement of vibration levels. This type of transducer is commonly used in various industries to monitor and analyze vibration in machinery and structures.

The Air Force currently uses two types of test cells: fixed and portable. Fixed test cells are permanent structures that are built in a specific location and cannot be easily moved. They are typically used for testing larger aircraft or equipment that require a more stable and controlled environment. On the other hand, portable test cells are designed to be mobile and can be transported to different locations as needed. They are often used for testing smaller aircraft or equipment that can be easily moved.

The engine fuel-flow indicating system of most jet powered aircraft includes a transmitter and a fuel-flow indicator. The transmitter is responsible for measuring the flow of fuel and transmitting this information to the fuel-flow indicator, which displays the fuel flow rate to the pilot. This system is crucial for monitoring and managing the fuel consumption of the aircraft during flight.

The correct answer is individuals assigned. This means that the responsibility for the proper preventive maintenance of a test cell facility lies with the individuals who have been assigned to the task. It is their duty to ensure that the necessary maintenance procedures are carried out regularly and effectively in order to keep the test cell facility in proper working condition.

The control tower is the correct answer because it is responsible for monitoring and controlling the air traffic at an airport. They have access to various equipment and systems that provide real-time information about the weather conditions, including temperature and barometric pressure. The control tower communicates this information to pilots and other personnel to ensure safe and efficient operations.

A visual inspection of the combustion chamber on a disassembled engine is preferred over a borescope inspection because it allows for the possibility of spotting defects that may have been missed with the borescope. This suggests that a visual inspection provides a more comprehensive and detailed examination of the combustion chamber, potentially revealing any hidden or subtle defects that may not be easily detected with a borescope.

The engine start system (ESS) tester is used to troubleshoot a jet fuel starter (JFS) problem on an F-16 aircraft. This test equipment is specifically designed to test and diagnose the engine start system, which includes the jet fuel starter. By using the ESS tester, technicians can identify and resolve any issues with the JFS, ensuring the proper functioning of the engine start system on the aircraft.

Failure of internal parts is not considered a cause of foreign object damage (FOD). FOD refers to any damage caused to an aircraft or engine by foreign objects such as rocks, bolts, or ice. The formation of ice, ingestion of rocks, and ingestion of bolts are all examples of foreign objects that can cause FOD. However, failure of internal parts is not caused by a foreign object, but rather by internal mechanical or structural issues within the aircraft or engine.

After an occurrence of a specific or unusual condition, maintenance personnel conduct a special inspection. This type of inspection is carried out to assess the situation, identify any potential damages or issues, and determine the necessary actions or repairs required to restore normal functioning. A special inspection is different from routine or regular inspections as it is triggered by a specific event or condition that deviates from the norm.

A typical jet engine exhaust gas temperature (EGT) indicating system contains thermocouples, leads, an indicator, and a resistor. The resistor is a crucial component in the system as it helps to regulate and control the flow of current. It plays a role in converting the temperature readings from the thermocouples into a measurable and readable value on the indicator. Without the resistor, the system would not be able to accurately measure and display the exhaust gas temperature.

The oil pressure indicator receives an electrical signal from the transmitter. The transmitter is responsible for converting the physical pressure of the oil into an electrical signal that can be interpreted by the indicator. This allows the indicator to accurately display the oil pressure level in the system.

The correct answer is inspecting other areas after isolating the trouble between points. This is not a proper troubleshooting practice because once the trouble has been isolated between specific points, it is important to focus on those points and not waste time inspecting other areas that are unrelated to the issue. This can lead to confusion and delays in resolving the problem.

An understanding of the operating principles of engine instruments will help determine the meanings of the instrument readings. By knowing how the instruments work, one can interpret the readings accurately and make informed decisions about the engine. This knowledge is crucial in assessing whether the engine should be removed from the aircraft or sent to the test cell for further examination. It also aids in identifying any maintenance tools that may be required to address any issues indicated by the instrument readings.

The fuel-flow indicator is used to measure the rate at which fuel is flowing in an aircraft. This rate is typically measured in pounds per hour, as it provides a more accurate representation of the fuel consumption over time. By measuring the fuel flow in pounds per hour, pilots can better monitor their fuel usage and make informed decisions regarding fuel management during a flight.

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. This signal is then sent to the tachometer indicator, which displays the speed in revolutions per minute (RPM) on a gauge or dial. Therefore, the correct answer is "indicator" as it is one of the primary units of the tachometer indicating system.

This overheat detector unit used on aircraft engines consists of a hollow stainless-steel tube that covers two silver contacts. These contacts are likely designed to detect temperature changes and serve as a safety mechanism. When the temperature rises above a certain threshold, the contacts may come into contact with each other, completing an electrical circuit and triggering an alarm or activating a shutdown procedure to prevent engine damage or fire.

The exhaust nozzle position indicating system found on engines with afterburners is important because it helps the pilot determine engine power. By providing information about the position of the exhaust nozzle, the system allows the pilot to monitor and adjust the engine's power output. This is crucial for maintaining optimal performance and efficiency during flight.

Transient engine vibration refers to vibrations that occur intermittently, appearing and disappearing over time. Unlike other types of vibrations that persist continuously, transient vibrations are temporary and may occur due to various factors such as changes in engine load or speed. These vibrations can be caused by sudden disturbances or fluctuations in the engine system, but they do not persist as a constant vibration.

To begin troubleshooting after reviewing the aircraft/engine forms, one should observe gauge indications. This is because gauge indications provide real-time information about the performance and functioning of various systems in the aircraft/engine. By observing the gauge indications, one can identify any anomalies or deviations from normal readings, which can help in pinpointing the specific system or unit that may be experiencing a problem. This approach allows for a more targeted and efficient troubleshooting process, as it focuses on the areas that are showing abnormal readings or indications.

The turbine area should be checked for foreign object damage (FOD) prior to operation on the test cell facility. This is because the turbine area is a critical component of the engine where the combustion process takes place. Any foreign objects such as debris or particles in this area can cause damage to the turbine blades, leading to decreased engine performance or even engine failure. Therefore, it is important to inspect and ensure that the turbine area is free from any FOD before operating the engine in the test cell facility.

Periodic inspection checklists are used as an aid in test facility inspections. These checklists provide a systematic and comprehensive guide for inspecting the facility and ensuring that all necessary requirements are met. They outline specific areas and items that need to be inspected, allowing inspectors to thoroughly assess the test facility's condition and compliance with regulations. By using these checklists, inspectors can identify any potential issues or deficiencies and take appropriate actions to rectify them.

Before moving an aircraft into the hush house, it is necessary to inspect the aircraft and its forms. This means that not only should the physical condition of the aircraft be checked, but also any required documentation or paperwork related to the aircraft should be reviewed. This ensures that the aircraft is in proper working order and all necessary paperwork is in order before it is moved into the hush house.

Defects found during combustion chamber borescope inspections are continually monitored as long as they are within limits. This means that if the defects, such as cracks, are within the acceptable limits set by the inspection criteria, they do not require immediate action like engine removal or welding. Instead, they are continuously observed to ensure they do not exceed the limits. This approach allows for ongoing monitoring and maintenance of the combustion chamber without the need for immediate replacement or repair.

Dry motoring is the correct answer because it is an F-16 operational check that allows the jet fuel start (JFS) to be started without advancing the throttle to idle or supplying fuel to the aircraft engine. Dry motoring is a procedure where the JFS is started and run for a short period of time to ensure its proper functioning before starting the actual engine. It does not involve the use of fuel or the need to advance the throttle to idle position.

Rapid throttle movement can cause a compressor stall during emergency system operation. This is because sudden and careless manipulation of the throttle can disrupt the airflow in the compressor, leading to a stall. A compressor stall occurs when the airflow is disrupted to the point that it cannot maintain the necessary pressure and flow rate, resulting in a loss of engine power. Therefore, it is important to operate the throttle with caution and avoid abrupt movements to prevent compressor stalls during emergency system operation.

After running an engine in augmentation in the hush house, the augmentor tube needs to be cooled down. This is done by running the engine at idle for a certain period of time. The correct answer is 3 minutes because this is the appropriate duration required to cool down the augmentor tube effectively. Running the engine at idle for 3 minutes allows for sufficient cooling and prevents any potential damage or overheating of the augmentor tube.

Thermal cycles refer to the repeated heating and cooling of the combustion chamber in an engine. These cycles cause the material to expand and contract, leading to stress and strain on the chamber. This stress can worsen any existing defects, such as cracks, as the cycles cause them to grow and propagate. Therefore, thermal cycles aggravate the defects on the combustion chamber.

The engine remote trimmer allows you to adjust the fuel control without being under the engine. This means that you can make adjustments to the fuel control system from a remote location, without having to physically be near the engine. This can be convenient and time-saving, as it eliminates the need to access the engine directly in order to make fuel control adjustments.

The engine diagnostic unit (EDU) is the component of the F100-PW-220 engine monitoring system that acquires fault data from the digital electronic engine control (DEEC) and logs the faults with the time of their occurrence. This unit is responsible for diagnosing any issues or faults that occur in the engine and keeps a record of them. It plays a crucial role in monitoring the engine's performance and identifying any potential problems that may arise. The EDU is specifically designed for diagnostic purposes, making it the correct answer in this case.

Engines that have been involved in an incident or a mishap need to be tested in addition to determining their condition after repair or overhaul. This is because such engines may have undergone damage or experienced stress during the incident or mishap, which could affect their performance and safety. Testing these engines is crucial to ensure that they are functioning properly and to identify any potential issues that may have arisen as a result of the incident or mishap.

During an inspection of the hush house, the engine being tested is not required to be checked. The hush house is a facility used for testing aircraft engines and reducing noise levels. The focus of the inspection would be on other aspects such as concrete deterioration, fire suppression system, and engine tie-down assemblies, which are more critical for safety and maintenance purposes.

If an engine stalls or surges during a test cell run, the variable stator vanes should be investigated. Variable stator vanes are components in a gas turbine engine that help control the airflow and optimize engine performance. If these vanes are malfunctioning or not operating correctly, it can cause issues such as stalling or surging. Therefore, it is important to investigate the variable stator vanes when experiencing these problems during a test cell run.

It is necessary to measure all parameters to identify a vibration source because displacement alone may not provide enough information to determine the cause of the vibration. Displacement refers to the distance an object moves from its equilibrium position, and it can be the same in two different problems even if the underlying causes of the vibrations are different. By measuring all parameters such as frequency, amplitude, and phase, it becomes possible to analyze the complete vibration profile and accurately identify the source of the vibration.

The N2 tachometer generator is typically driven from the tachometer drive located on the engine accessory section. This section of the engine houses various accessories such as the generator, hydraulic pump, and fuel pump. The tachometer drive on the engine accessory section connects to the N2 tachometer generator, which measures the rotational speed of the engine's N2 compressor. This information is crucial for monitoring and controlling the engine's performance.

The correct answer is "accessory gearbox". To borescope the high-pressure turbine (HPT) rotor blades, the rear compressor needs to be rotated. This rotation is achieved by using the core engine rotating device, which is connected to the accessory gearbox. The accessory gearbox is responsible for transmitting power from the engine to various accessories, including the rear compressor. Therefore, rotating the rear compressor is possible by using the core engine rotating device on the accessory gearbox.

AFOSH STD 91-100 provides written instructions for safe flight line vehicle operations. This document is a standard that outlines the safety requirements and procedures for operating vehicles on the flight line. It is important for individuals working in this environment to be familiar with these instructions to ensure the safety of themselves and others. AFI 36-2903 is a regulation that pertains to dress and appearance in the Air Force, and the flight line job guide (JG) and intermediate maintenance TO are not specifically related to safe flight line vehicle operations.

After the last flight of the flying period, a basic post-flight inspection (BPO) is done. This is because the BPO is a routine inspection that is conducted after each flight to ensure the aircraft is in proper working condition and ready for the next flight. By conducting the BPO after the last flight of the flying period, any issues or damages that may have occurred during the day can be identified and addressed before the aircraft is grounded for the night. This helps to maintain the safety and airworthiness of the aircraft for the next day's operations.

When properly adjusted, the accuracy of the text cell N1 and N2 speed indicator will be within 2 RPM. This means that the speed indicator may have a maximum deviation of 2 RPM from the actual speed. It is important to adjust the indicator correctly to ensure accurate readings and avoid any potential errors in monitoring the speed.

The engines are mounted from a cradle mount. This means that the engines are supported and held in place by a cradle-like structure. This type of mounting allows for stability and ease of testing, as the engines can be securely attached to the cradle and easily maneuvered as needed. It also provides a safe and controlled environment for testing, ensuring that the engines remain in the desired position throughout the testing process.

The correct answer is to review AFTO Form 781H, Aerospace Vehicle Flight Status and Maintenance. This form contains important information about the flight history and maintenance records of the engine. By reviewing this form, one can gather valuable insights into the engine's performance, any previous oil consumption issues, and the maintenance activities that have been performed on the engine. This information can help in identifying any patterns or potential causes of the oil consumption problem and guide further investigation.

The temperature of the jet engine combustion inlet is not measured.