2A651 Volume 5 Aircraft Troubleshooting

To become an expert troubleshooter, it is crucial to understand the function of each unit within each system. This knowledge allows troubleshooters to identify and diagnose problems accurately. By understanding how each unit operates within a system, troubleshooters can effectively troubleshoot and resolve issues. This expertise is essential for becoming a skilled troubleshooter and providing efficient solutions to complex problems.

The responsibility for the proper preventive maintenance of a test cell facility rests with the individuals assigned to the task. This means that it is the responsibility of the specific individuals who have been assigned to the maintenance of the test cell facility to ensure that the necessary preventive maintenance tasks are carried out. This could include tasks such as regular inspections, cleaning, and servicing of equipment to prevent any potential issues or breakdowns. It is important for these individuals to be diligent and proactive in carrying out their responsibilities to ensure the smooth functioning and longevity of the test cell facility.

Aircraft power plant and engine intermediate maintenance technical orders (TO) contain troubleshooting information, which is presented in the form of troubleshooting charts. These charts provide a systematic approach to identifying and resolving problems or malfunctions in the power plant and engine systems. By following the steps outlined in the troubleshooting charts, maintenance personnel can effectively diagnose and rectify issues, ensuring the proper functioning of the aircraft's power plant and engine.

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 prevents any errors or discrepancies. By checking the numbers on the engine data plate, you can be confident that you are accurately documenting the engine model and serial number in the log sheet.

When encountering engine trouble where more than one unit is at fault, examining the unit that requires the least amount of time to replace would be the first step. This is because replacing the unit that requires less time can help identify if it was the main cause of the trouble. By examining and potentially replacing this unit first, it can help narrow down the issue and potentially solve the problem without having to go through the more time-consuming process of replacing all suspected units or repairing the more complex unit on the spot.

The engine monitoring system (EMS) is used on most modern jet engines to gather and record engine data. This system is responsible for monitoring various parameters such as temperature, pressure, fuel flow, and vibration levels. It provides real-time data to the pilots and maintenance crew, allowing them to monitor the engine's performance and detect any abnormalities or potential issues. The recorded data can also be analyzed later for maintenance purposes and to improve engine efficiency and reliability.

A piezoelectric accelerometer is made up of certain ceramic compounds and natural crystals. These materials have the property of producing an electric charge when subjected to mechanical stress or vibration. This charge is then converted into a voltage signal, which can be measured and used to determine the magnitude and frequency of the vibration. Therefore, a piezoelectric accelerometer is the correct type of vibration transducer that is made up of these specific materials.

When operating an engine that is installed on an aircraft, it is important to position the aircraft so that the wind is blowing directly into the inlet, within +/- 45 degrees. This is because the inlet is where the engine draws in air for combustion. By positioning the aircraft in this way, the engine can receive a steady flow of air, which is crucial for proper functioning and optimal performance.

The given answer, "resistor," is correct because a typical jet engine exhaust gas temperature (EGT) indicating system includes thermocouples, leads, and an indicator, as well as a resistor. The resistor is an essential component in the system as it helps to regulate the electrical current and provide accurate temperature readings. It works in conjunction with the thermocouples to measure the temperature of the exhaust gas and transmit the data to the indicator for display.

Transient engine vibration refers to a type of vibration that occurs intermittently and does not persist continuously. It comes and goes, usually in response to certain conditions or events. This type of vibration is often caused by temporary disturbances or variations in the engine's operation or environment. It is different from forced vibration, which is caused by a steady external force, and resonance, which is a sustained vibration at a specific frequency. Transient engine vibration is not externally excited, as it originates from within the engine itself.

When using a vibration analyzer, the device will notify you when a preset signal has been exceeded by flashing channel indicator light emitting diode (LED). This means that the LED light on the analyzer will start flashing to indicate that the signal has surpassed the predetermined threshold. This visual cue is used to alert the user that the vibration levels have exceeded the acceptable range.

In the event of a problem in the F100-PW-220 aircraft engine, the digital electronic engine control (DEEC) accommodates the fault and sends the fault code to the engine diagnostic unit (EDU). This means that the DEEC is designed to handle faults within the engine and communicates the specific fault code to the EDU for further analysis and diagnosis. This allows maintenance personnel to identify the exact issue and take appropriate action to resolve it. It does not involve tripping the engine no-go flag, turning on cockpit lights, or tripping the engine monitoring unit (EMS) maintenance flag.

The correct answer is "special". After the occurrence of a specific or unusual condition, maintenance personnel conduct a special inspection. This inspection is different from routine inspections and is specifically focused on identifying and addressing the specific or unusual condition that occurred.

The Data collection unit (DCU) is the component in the F100-PW-220 engine monitoring system that transfers information from the engine diagnostic unit (EDU) to the ground station unit (GSU). This unit is responsible for collecting and organizing data from various sensors and diagnostic systems within the engine, and then transmitting that information to the GSU for further analysis and monitoring. The DCU acts as a bridge between the EDU and the GSU, ensuring that important engine performance data is transferred accurately and efficiently.

Prior to an engine test cell run, it is important to check the engine and quick engine change (QEC) kit for loose nuts, bolts, lock wire, tools, or any other material in order to eliminate items that could potentially cause foreign object damage (FOD). FOD can be harmful to the engine and surrounding equipment, and can lead to costly repairs or failures. By ensuring that there are no loose items or debris present, the risk of FOD is minimized, promoting safe and efficient engine operation.

Most engine monitoring gauges and instruments require a transmitter and indicator. The transmitter is responsible for converting the physical measurements, such as temperature or pressure, into electrical signals. These signals are then sent to the indicator, which displays the readings in a format that can be easily interpreted by the operator. The transmitter and indicator work together to provide accurate and real-time information about the engine's performance, allowing for effective monitoring and troubleshooting.

To begin troubleshooting after reviewing the aircraft/engine forms, one should observe gauge indications. Gauge indications provide valuable information about the performance and condition of various systems in the aircraft/engine. By carefully observing gauge indications, any anomalies or discrepancies can be identified, which can then be further investigated to pinpoint the root cause of the problem. This approach allows for a systematic and focused troubleshooting process, starting with the most visible and measurable indicators of system performance.

An understanding of the operating principles of engine instruments is important in order to interpret the readings provided by these instruments. By knowing the meanings of the instrument readings, one can determine the current status and performance of the engine. This knowledge is crucial in making decisions such as whether an engine should be removed from an aircraft or sent to a test cell for further examination. Additionally, understanding instrument readings helps in identifying any maintenance or repair requirements and determining the necessary tools and procedures for maintenance.

During vibration analysis, amplitude is measured in mils. One mil is equal to 0.001 inch. This means that when measuring the amplitude of vibration, each mil represents a distance of 0.001 inch. Therefore, if the amplitude is measured as 5 mils, it would mean that the vibration is occurring with a displacement of 0.005 inch.

Both fixed and portable test cell noise suppressors use water to cool the exhaust gases. Water is an effective cooling agent that helps to reduce the temperature of the exhaust gases, preventing overheating and potential damage to the equipment. This cooling process is necessary to maintain the efficiency and performance of the test cell noise suppressors, whether they are fixed in a specific location or portable for use in different settings.

Complete loss of lubrication is the most common cause of bearing failure because lubrication is essential for reducing friction and preventing wear between the bearing surfaces. Without proper lubrication, the bearing will experience increased friction, heat, and wear, leading to premature failure. Additionally, lubrication helps to remove contaminants and debris from the bearing, further protecting it from damage. Therefore, when there is a complete loss of lubrication, the bearing is left vulnerable to excessive friction, heat, and wear, ultimately resulting in failure.

If oil is observed on the turbine wheel or oil smoke is present at or near the turbine section during a test cell run, it is a good indication that the aft bearing oil seal is damaged. The oil seal is responsible for preventing oil leakage from the bearing housing, and when it is damaged, oil can escape and come into contact with the turbine wheel, causing the observed symptoms. This suggests that there is a problem with the aft bearing oil seal, which needs to be addressed to prevent further damage and ensure proper functioning of the system.

Bearings are used to support the fan and low-pressure turbine. Bearings are mechanical devices that reduce friction between moving parts, allowing them to rotate smoothly. In this case, bearings are used to support the fan and low-pressure turbine, ensuring that they can rotate efficiently and without excessive friction. Bushings, brackets, and blades are not specifically designed for supporting rotating parts like fans and turbines, making them incorrect options.

Failure of internal parts is not considered a cause of FOD because FOD (Foreign Object Damage) refers specifically to damage caused by foreign objects entering and damaging an aircraft or its components. Ingestion of bolts, rocks, or formation of ice are all examples of foreign objects that can cause FOD. However, failure of internal parts is an internal issue and not related to foreign objects entering the system.

If an engine stalls or surges during a test cell run, the variable stator vanes should be investigated. Variable stator vanes are responsible for adjusting the airflow in the engine, and any malfunction or issue with them can cause disruptions in the engine's performance. Therefore, it is necessary to examine the variable stator vanes to identify and address any problems that may be causing the engine to stall or surge.

Dry motoring is the correct answer because it refers to the operational check that allows you to start the jet fuel starter (JFS) without advancing the throttle to idle or supplying fuel to the aircraft engine. This check is performed to ensure that the JFS is functioning properly and can start the engine without the need for additional fuel or throttle adjustments.

The correct answer is "that have been involved in an incident or a mishap." This means that in addition to testing engines that have been repaired or overhauled, engines that have been involved in an accident or incident are also tested. This is important to ensure that the engine is still functioning properly and to identify any potential issues or damage that may have occurred as a result of the incident.

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, there is a need for compact instruments that do not take up too much space. Additionally, smaller instruments are easier to install and arrange in the cockpit, allowing for better visibility and accessibility for the pilot. Therefore, small size is an important characteristic for aircraft instruments to ensure their effectiveness in aviation operations.

Engines are mounted from a cradle mount, which means they are supported and held in place by a secure framework. This type of mounting allows for stability and easy access to the engine for testing purposes. The cradle mount ensures that the engine is securely attached and can withstand the forces exerted during testing. This method of mounting is commonly used in fixed test cells to ensure accurate and reliable testing of engines.

A preflight inspection is a flight preparedness check that is conducted before every flight. It involves a thorough examination of the aircraft to ensure that it is in proper working condition and ready for flight. This inspection includes checking the fuel levels, control surfaces, landing gear, engine, and other crucial components. By performing a preflight inspection, pilots can identify any potential issues or malfunctions that could jeopardize the safety of the flight. Therefore, the correct answer to this question is preflight.

During engine coast down, the vehicle's engine is allowed to naturally slow down and come to a stop. This step is important because it allows any potential leaks in the test cell to become more noticeable. As the engine cools down and the pressure inside the test cell decreases, any leaks present will become more apparent. Therefore, the final check for leaks is accomplished during engine coast down.

The turbine area should be checked for FOD (Foreign Object Debris) prior to operation on the test cell facility. This is because the turbine area is a critical part of the engine where the combustion process occurs, and any foreign objects present in this area can cause damage to the turbine blades and disrupt the engine's performance. Therefore, it is important to inspect and remove any debris from the turbine area 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 standardized set of criteria and guidelines for inspectors to follow during inspections. They ensure that all necessary areas and equipment are thoroughly examined and evaluated. By using these checklists, inspectors can easily identify any potential issues or discrepancies that may exist in the test facility. This helps to maintain the quality and safety of the facility and ensures that it meets the required standards and regulations.

The vibration pickups on the portable test cell are cooled by the pneumatic system. This means that the pneumatic system is responsible for cooling the vibration pickups.

Pressing only the TEST switch during an operational check of the fire warning system ensures that the system is functioning properly. This switch is specifically designed to initiate a test of the fire warning system, allowing the operator to verify that the system is capable of detecting and alerting for potential fires. By pressing only the TEST switch, the operator can isolate the test function and ensure that the system is not inadvertently switched to a different mode or setting. Pressing any other switches could potentially interfere with the accuracy of the test or compromise the system's functionality.

The oil pressure indicator receives an electrical signal from the transmitter. This means that the transmitter is responsible for sending the information about the oil pressure to the indicator. The transmitter is likely connected to the oil system and measures the pressure, converting it into an electrical signal that can be interpreted by the indicator. Without the transmitter, the oil pressure indicator would not receive any information and would not be able to display the oil pressure accurately.

A transducer is a device that converts one form of energy into another. In the case of engines with afterburners, the position of the exhaust nozzle needs to be converted into an electrical signal. A transducer is capable of converting the mechanical motion of the nozzle into an electrical signal, allowing it to be measured and controlled. This makes transducer the most suitable option among the given choices.

Service inspections on test cell are conducted daily. This frequency ensures that the test cell is regularly checked for any issues or malfunctions that may affect its performance. Daily inspections help in identifying and addressing any potential problems promptly, ensuring the smooth functioning of the test cell and accurate test results. It also allows for regular maintenance and upkeep of the equipment, minimizing the risk of breakdowns or failures during testing operations.

Rapid throttle movement can cause a compressor stall during emergency system operation. This is because sudden and careless movement of the throttle can disrupt the airflow and create turbulence within the compressor. This turbulence can disrupt the proper functioning of the compressor, leading to a stall. It is important to operate the throttle carefully and smoothly to avoid such issues.

Alumel and chromel are used in the thermocouples of the exhaust gas temperature (EGT) indicating system. Thermocouples are temperature sensors that work based on the principle of the Seebeck effect, which generates a voltage when there is a temperature difference between two different metals. Alumel and chromel are specific alloys that are commonly used in type K thermocouples, which are suitable for measuring high temperatures, such as those found in exhaust gas systems. Therefore, alumel and chromel are the correct metals used in the EGT indicating system.

A portable test cell is a self-contained unit used for testing various equipment or systems. It is designed to be easily transported and set up in different locations. The control cab is the area where the operator controls and monitors the test processes. The thrust trailer is used to measure and analyze the thrust produced by the equipment being tested. The miscellaneous equipment kit contains various tools and accessories necessary for conducting the tests. The hydraulically operated pylon mount cradle is a mechanism used to securely mount and position the equipment being tested. Since the portable test cell is not equipped with a hydraulically operated pylon mount cradle, it means that the equipment being tested is not mounted and positioned using this specific mechanism.

The filter selector switch on the vibration analyzer allows the user to select the necessary filter. This is important because different filters are used to analyze different frequencies of vibration. By selecting the appropriate filter, the user can focus on specific frequency ranges and eliminate unwanted noise or interference, thereby obtaining accurate and reliable vibration analysis results.

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.

The oil pressure transmitter and indicator are two units that work together to indicate the oil system is operating correctly. The transmitter measures the oil pressure and sends a signal to the indicator, which displays the pressure reading. This allows the operator to monitor the oil pressure and ensure it is within the desired range.

The accuracy of the test cell N1 and N2 speed indicator in revolutions per minute (RPM) will be within 2 RPM when properly adjusted. This means that the indicated speed on the test cell will be within 2 RPM of the actual speed.

The correct answer is -50 to +1,600. This range is the widest among the given options and covers a larger span of temperatures. It allows for a more comprehensive display of temperatures, ranging from very low temperatures (-50 degrees Fahrenheit) to high temperatures (+1,600 degrees Fahrenheit). This range is suitable for a test cell integrated circuit temperature indicator as it can accommodate a wide range of temperature variations that may be encountered in different testing scenarios.

During vibration analysis, frequency is usually measured in cycles per second. This is because frequency represents the number of complete cycles or oscillations that occur in one second. It is a fundamental parameter used to analyze vibrations and is commonly expressed in cycles per second, also known as Hertz (Hz). This measurement helps in identifying the rate or speed at which the vibration is occurring, allowing for further analysis and understanding of the vibration behavior.

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. As the engine speed increases, the frequency of the generated signal also increases. Therefore, the correct answer is "engine speed".

The combustion inlet temperature is not measured in a jet engine. Temperature measurements are typically taken at the exhaust gas, turbine inlet, and fan turbine inlet. The combustion inlet refers to the area where the air and fuel mix and ignite, and it is not necessary to measure the temperature at this point.

After running an engine in augmentation in the hush house, the augmentor tube is cooled by running the engine at idle for a period of 3 minutes. This is because running the engine at idle allows the airflow to pass through the augmentor tube, dissipating the heat generated during the augmentation process. By running the engine at idle for 3 minutes, enough time is given for the augmentor tube to cool down sufficiently before shutting off the engine.