2A551: Aircraft Maintenance Questions! Trivia Quiz
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Questions and Answers
- 1.
Which law of physics best explains how a jet engine produces forward thrust?
Explanation
Newton's third law of motion states that for every action, there is an equal and opposite reaction. In the case of a jet engine, the forward thrust is produced by the action of expelling high-speed exhaust gases in one direction. According to Newton's third law, the engine experiences an equal and opposite reaction force, propelling the aircraft forward. This law explains how the engine creates the necessary force to overcome air resistance and generate forward motion.Rate this question:
- 2.
What type of energy does a falling object possess?
Explanation
When an object falls, it gains speed due to the force of gravity. This increase in speed means that the object has kinetic energy, which is the energy possessed by a moving object. Kinetic energy is determined by the mass and velocity of the object. Therefore, a falling object possesses kinetic energy.Rate this question:
- 3.
Can energy pass from potential to kinetic and back to potential?
Explanation
Energy can indeed pass from potential to kinetic and back to potential. This is illustrated by the concept of mechanical energy. When an object is at a higher position, it possesses potential energy. As it falls, this potential energy is converted into kinetic energy. Once the object reaches the lowest point, all of its potential energy is transformed into kinetic energy. However, as the object starts moving upwards again, the kinetic energy is gradually converted back into potential energy. This continuous exchange between potential and kinetic energy demonstrates that energy can pass from potential to kinetic and back to potential.Rate this question:
- 4.
When a jet engine reaches idle speed, what determines how the fuel control regulates engine speed?
Explanation
The power lever setting determines how the fuel control regulates engine speed when a jet engine reaches idle speed. The power lever setting is the position of the lever that controls the amount of fuel being supplied to the engine. By adjusting the power lever setting, the pilot can increase or decrease the engine speed. Therefore, the fuel control system responds to the power lever setting to regulate the engine speed accordingly.Rate this question:
- 5.
What two forms of energy does a jet engine produces?
Explanation
A jet engine produces thrust, which is the force that propels the aircraft forward. This is achieved by expelling a high-speed jet of gases in the opposite direction. Additionally, a jet engine also produces heat as a byproduct of the combustion process. This heat is generated by burning fuel in the engine's combustion chamber, which powers the turbine and ultimately drives the engine.Rate this question:
- 6.
Approximately what percent of the energy produced by the fuel is needed to maintain the jet engine operating cycle?
Explanation
The correct answer is 60 because it states that approximately 60% of the energy produced by the fuel is needed to maintain the jet engine operating cycle. This means that a significant portion of the energy generated by the fuel is used to keep the jet engine running efficiently.Rate this question:
- 7.
Where is the point of highest pressure within a jet engine?
Explanation
The point of highest pressure within a jet engine is in the diffuser section. The diffuser section is responsible for slowing down the incoming air and increasing its pressure before it enters the combustion chamber. This is achieved by gradually expanding the cross-sectional area of the duct, which causes the air to decelerate and its pressure to rise. The high pressure in this section is crucial for efficient combustion and overall engine performance.Rate this question:
- 8.
On a jet engine that does not have an afterburner, where is the point of highest temperature?
Explanation
In a jet engine that does not have an afterburner, the point of highest temperature is in the combustion section. This is because the combustion section is where fuel is mixed with compressed air and ignited, resulting in the release of a large amount of energy. As a result, the temperature in this section is significantly higher compared to other parts of the engine.Rate this question:
- 9.
Where is the point of highest airflow velocity in a jet engine?
Explanation
The point of highest airflow velocity in a jet engine is the ejector nozzle. This is because the ejector nozzle is designed to accelerate the exhaust gases as they leave the engine, creating a high-speed jet of air. This high-speed jet of air is important for generating thrust and propelling the aircraft forward.Rate this question:
- 10.
After the gases leave the turbine section and enter the exhuast section, what type of velocity do they have?
Explanation
After the gases leave the turbine section and enter the exhaust section, they maintain an axial velocity. This means that the gases continue to flow in the same direction as they did in the turbine section, parallel to the axis of the exhaust section. Axial velocity is important for efficient exhaust flow and to maintain the overall performance of the system.Rate this question:
- 11.
Which turbine drives the front compressor on a duel- spool engine?
Explanation
The rear turbine drives the front compressor on a dual-spool engine. In a dual-spool engine, there are two separate spools or shafts, each with its own compressor and turbine. The rear turbine is connected to the front compressor through the rear shaft, and it transfers power to drive the front compressor. This arrangement allows for better efficiency and control in the engine's operation.Rate this question:
- 12.
What unit determines the speed of N2 (high-pressure) rotor in a dual-spool compressor?
Explanation
The speed of the N2 (high-pressure) rotor in a dual-spool compressor is determined by the fuel control unit. The fuel control unit regulates the amount of fuel being supplied to the engine, which in turn affects the speed at which the rotor spins. By adjusting the fuel flow, the fuel control unit can control the speed of the rotor and therefore the overall performance of the compressor.Rate this question:
- 13.
Which type of compressor is more durable, the axial-flow or the centrifugal?
Explanation
The centrifugal compressor is more durable compared to the axial-flow compressor. This is because the centrifugal compressor has a simpler design with fewer moving parts, making it less prone to mechanical failures. It also operates at lower speeds, resulting in reduced wear and tear. Additionally, the centrifugal compressor can handle a wider range of operating conditions and is more resistant to surge and stall, making it a more durable option overall.Rate this question:
- 14.
What is the approximate air-to-fuel ratio that is used for the actual burning process in a combustion chamber?
Explanation
The approximate air-to-fuel ratio of 15:1 is commonly used for the actual burning process in a combustion chamber. This means that for every 15 parts of air, 1 part of fuel is required for efficient combustion. This ratio ensures that there is enough oxygen present in the air to completely burn the fuel, resulting in a clean and efficient combustion process.Rate this question:
- 15.
In a duel-orifice type of fuel nozzle, fuel is injected into the engine combustion chamber from which orifices for high-engine- thrust operation?
Explanation
In a duel-orifice type of fuel nozzle, fuel is injected into the engine combustion chamber from both the primary and secondary orifices. This means that fuel is delivered through two separate openings, allowing for a more efficient and controlled fuel injection process. By using both the primary and secondary orifices, the fuel nozzle can provide the necessary fuel flow for high-engine-thrust operation, ensuring optimal performance and power output.Rate this question:
- 16.
Name the three types of turbines.
Explanation
The three types of turbines are impulse, reaction, and reaction-impulse. Impulse turbines are driven by the force of a high-velocity jet of steam or water, which impacts the turbine blades and causes them to rotate. Reaction turbines, on the other hand, are driven by the reaction force of steam or water as it passes through the blades, causing a change in momentum. Reaction-impulse turbines combine both impulse and reaction principles to generate power.Rate this question:
- 17.
What type of turbine design is used on most jet engines?
Explanation
Most jet engines use a combination of reaction and impulse turbine design. The reaction turbine extracts energy from the expanding gases by accelerating them in the opposite direction, which in turn rotates the turbine blades. The impulse turbine, on the other hand, extracts energy from the high-speed jet of gases by redirecting it onto the turbine blades, causing them to rotate. The combination of these two designs allows for efficient extraction of energy from the exhaust gases, resulting in the high performance of jet engines.Rate this question:
- 18.
What is inserted between the rotating blades on multiple- stage turbines?
Explanation
Stationary turbine nozzle vanes are inserted between the rotating blades on multiple-stage turbines. These vanes serve the purpose of directing the flow of the working fluid (such as steam or gas) onto the rotating blades, optimizing the efficiency of the turbine. By controlling the angle and velocity of the fluid, the vanes help to extract maximum energy from the fluid as it passes through the turbine, resulting in improved power generation.Rate this question:
- 19.
What is the most frequently used method of attaching the turbine blades to the rotor disc?
Explanation
The most frequently used method of attaching turbine blades to the rotor disc is the fir tree method. This method involves the use of fir tree-shaped protrusions on the root of the turbine blades that fit into corresponding slots on the rotor disc. This design provides a secure and reliable attachment, allowing the blades to withstand the high rotational forces and vibrations experienced during operation. The fir tree method is widely used in various types of turbines, including gas turbines and steam turbines.Rate this question:
- 20.
What three types of fasteners are used to secure the turbine blades to the rotor disc?
Explanation
Steel pins, lock strips, and rivets are the three types of fasteners used to secure the turbine blades to the rotor disc. Steel pins are commonly used to provide a strong and secure connection between the blades and the disc. Lock strips are used to prevent the pins from loosening or coming out due to vibrations or other forces. Rivets are used to join different components together, providing a permanent and reliable connection. These three types of fasteners ensure that the turbine blades are securely attached to the rotor disc, allowing for efficient and safe operation of the turbine.Rate this question:
- 21.
What are the two priniciple configurations of turbine blades?
Explanation
Turbine blades can be categorized into two principle configurations: shrouded and unshrouded. Shrouded blades are enclosed within a casing or shroud, which provides additional support and protection. This configuration is commonly used in high-pressure turbines to enhance the structural integrity and prevent blade vibrations. On the other hand, unshrouded blades are not enclosed and are more exposed. They are typically used in low-pressure turbines where the risk of vibrations is lower. Both configurations have their advantages and are chosen based on the specific requirements of the turbine design and operating conditions.Rate this question:
- 22.
An augmenter is classified as what type of engine?
Explanation
An augmenter is classified as a ramjet engine.Rate this question:
- 23.
What effect should augmenter operation have on engine operation?
Explanation
The augmenter operation should have no effect on the engine operation. This means that the augmenter, which is a device used to increase the thrust of a jet engine, should not cause any changes or disruptions in the normal functioning of the engine. It should not affect the engine's performance, efficiency, or any other aspects of its operation.Rate this question:
- 24.
What are the major sections of a turboprop engine?
Explanation
The major sections of a turboprop engine are the pinion input and main drive gears. These gears play a crucial role in transmitting power from the engine to the propeller. The pinion input gear receives power from the engine's power turbine, while the main drive gear transfers this power to the propeller shaft. Together, these gears ensure efficient power transmission and enable the propeller to generate thrust for the aircraft.Rate this question:
- 25.
How are propeller blades anti-iced?
Explanation
Propeller blades are anti-iced using an electrical heating element. This means that the blades are equipped with a heating element that generates heat when activated. This heat is then transferred to the blades, preventing ice from forming or melting any existing ice. The electrical heating element is an effective method to ensure that propeller blades remain ice-free during flight, ensuring optimal performance and safety.Rate this question:
- 26.
What is meant by a rich blowout?
Explanation
A rich blowout refers to a situation where the air-fuel mixture in an engine becomes too rich, meaning there is an excess of fuel compared to the amount of air. This can cause the flame in the combustion chamber to extinguish, resulting in a flameout. An overrich mixture flameout occurs when the air-fuel ratio is so imbalanced that the flame cannot be sustained, leading to a loss of engine power.Rate this question:
- 27.
What fuel control system uses a computer such as a digital electronic engine control (DEEC), digital engine control (DEC), or an electronic engine control (EEC) as primary control of fuel flow?
Explanation
An electrohydromechanical system uses a computer, such as a digital electronic engine control (DEEC), digital engine control (DEC), or an electronic engine control (EEC), as the primary control of fuel flow. This means that the computer is responsible for regulating and adjusting the amount of fuel that is delivered to the engine based on various factors such as engine speed, load, and temperature. This system combines electronic and hydraulic components to ensure precise control of fuel flow, resulting in improved engine performance and efficiency.Rate this question:
- 28.
What component regulates and distributes fuel for most efficient engine operation at all power settings?
Explanation
Fuel pumps regulate and distribute fuel for efficient engine operation at all power settings. They ensure that the engine receives the correct amount of fuel based on the power demands, maintaining a proper air-fuel ratio for combustion. By delivering fuel at the right pressure and flow rate, fuel pumps optimize engine performance, ensuring smooth and consistent power delivery. Without fuel pumps, the engine may not receive enough fuel or may experience fuel delivery issues, leading to inefficient operation and potential engine problems.Rate this question:
- 29.
What component provides a leaner mixture of fuel for engine starting?
Explanation
The fuel derichment valve is a component that provides a leaner mixture of fuel for engine starting. This means that it reduces the amount of fuel being supplied to the engine during the starting process, resulting in a mixture that has a higher air-to-fuel ratio. A leaner mixture is needed for engine starting because it allows for easier ignition and combustion, especially in colder conditions. By reducing the amount of fuel in the mixture, the fuel derichment valve helps to ensure a smooth and efficient start for the engine.Rate this question:
- 30.
What valve drains the fuel manifold on shutdown?
Explanation
The valve that drains the fuel manifold on shutdown is the pressurizing and dump valve, also known as the p&d valve. This valve is responsible for releasing the pressure in the fuel manifold and allowing any remaining fuel to be drained out.Rate this question:
- 31.
What are the principal purposes of an oil system?
Explanation
The principal purposes of an oil system are to clean, cool, and lubricate. Oil plays a crucial role in removing dirt, debris, and contaminants from the engine, ensuring its proper functioning. It also helps in cooling the engine by dissipating heat generated during operation. Additionally, oil acts as a lubricant, reducing friction between moving parts and preventing wear and tear. Overall, the oil system is essential for maintaining the performance and longevity of the engine.Rate this question:
- 32.
What is positioned on some oil tanks to give a visual indication of oil level?
Explanation
Sight gages are positioned on some oil tanks to provide a visual indication of the oil level. These gages typically consist of a transparent tube or glass window that allows the user to see the level of oil inside the tank. By observing the oil level through the sight gage, individuals can easily determine if the tank needs to be refilled or if there are any issues with the oil level. This visual indicator is a convenient and efficient way to monitor the oil level in tanks.Rate this question:
- 33.
Classified as to function, what two basic pumps are used in a jet engine oil system?
Explanation
In a jet engine oil system, two basic pumps are used: a pressure pump and a scavenge pump. The pressure pump is responsible for supplying oil under pressure to various components of the engine, such as bearings and gears, ensuring proper lubrication. On the other hand, the scavenge pump is used to remove excess oil and prevent oil accumulation in certain areas of the engine. These two pumps work together to maintain the oil system's functionality and optimize engine performance.Rate this question:
- 34.
Classified as to structure, what three types of pumps are used most often in jet engine oil systems? Which of these three is the most common?
Explanation
Gear, gerotor, and sliding vane are the three types of pumps used most often in jet engine oil systems. Among these three, the gear type pump is the most common.Rate this question:
- 35.
What are the two types of oil nozzles?
Explanation
The two types of oil nozzles are restrictive tube and internal passage. The restrictive tube type of oil nozzle has a small opening that restricts the flow of oil, resulting in a finer spray pattern. On the other hand, the internal passage type of oil nozzle has a larger opening, allowing for a higher flow rate of oil and a wider spray pattern. These two types of oil nozzles offer different options for controlling the flow and spray of oil in various applications.Rate this question:
- 36.
What is the purpose of oil system seals?
Explanation
Oil system seals are designed to prevent the loss of fluid within the oil system. These seals create a barrier between different components of the oil system, such as the engine block and the oil pan, to ensure that oil does not leak out. By preventing the loss of fluid, oil system seals help to maintain the proper lubrication and functioning of the engine. Without these seals, oil could leak out and result in decreased oil pressure, increased friction, and potential damage to the engine components. Therefore, the purpose of oil system seals is to maintain the integrity of the oil system and prevent fluid loss.Rate this question:
- 37.
List three types of oil seals used in jet engine.
Explanation
The three types of oil seals used in jet engines are synthetic, labyrinth, and carbon. Synthetic oil seals are made from synthetic materials and are designed to withstand high temperatures and pressures. Labyrinth oil seals have a complex design that creates a tortuous path for the oil, preventing leakage. Carbon oil seals are made from carbon composite materials and are known for their high strength and durability. These three types of oil seals are commonly used in jet engines to ensure proper lubrication and prevent oil leakage.Rate this question:
- 38.
What two items should you check prior to replacing seals?
Explanation
Before replacing seals, it is important to check the cure date and part number. The cure date ensures that the seal is not expired and still effective. The part number ensures that the correct seal is being used for the specific application. By checking both the cure date and part number, you can ensure that the replacement seals are suitable and will function properly.Rate this question:
- 39.
Approximately how many volts does the AC ignition system develop at the igniter plug?
Explanation
The AC ignition system develops approximately 20,000 volts at the igniter plug. This high voltage is necessary to create a spark that ignites the fuel-air mixture in the combustion chamber of an engine. The ignition system uses a transformer called the ignition coil to step up the voltage from the battery to this high level. The high voltage is then delivered to the igniter plug, which generates a spark to ignite the fuel and initiate the combustion process.Rate this question:
- 40.
What are the main parts of a direct-current ignition system?
Explanation
A direct-current ignition system consists of three main parts: a vibrator, a transformer, and igniter plugs. The vibrator is responsible for interrupting the flow of current, creating a pulsating direct current. This current is then sent to the transformer, which steps up the voltage to a level that can generate a spark. Finally, the high voltage current is delivered to the igniter plugs, which create the spark necessary to ignite the fuel-air mixture in the engine. Together, these three components work to ensure proper ignition and combustion in the engine.Rate this question:
- 41.
What component provides high-temperature spark for engine starting?
Explanation
The igniter plug is a component that provides a high-temperature spark for engine starting. It is designed to generate a spark that ignites the fuel-air mixture in the combustion chamber, initiating the combustion process. This spark is crucial for starting the engine, as it ignites the fuel and allows the engine to run. Without the igniter plug, the engine would not be able to start and operate efficiently.Rate this question:
- 42.
In addition to being light in weight and small in size, what other requirement must be met for aircraft instruments?
Explanation
Aircraft instruments must be easy to read in addition to being light in weight and small in size. This is crucial for pilots to quickly and accurately interpret the information displayed on the instruments during flight. The readability of the instruments is essential for maintaining situational awareness and making informed decisions. If the instruments are not easy to read, it could lead to errors or delays in responding to critical flight situations, posing a risk to the safety of the aircraft and its occupants.Rate this question:
- 43.
Oil pressure indicators measure pressure in what unit of measurment?
Explanation
Oil pressure indicators measure pressure in pounds per square inch (PSI). PSI is a commonly used unit of measurement for pressure, particularly in the United States. It represents the force applied per unit area, in this case, the force exerted by the oil in the system per square inch of area. By measuring the pressure in PSI, oil pressure indicators provide a standardized and easily understandable measurement of the oil pressure in a system.Rate this question:
- 44.
How is a tachometer powered?
Explanation
A tachometer is powered by a tachometer generator. A tachometer generator is a device that converts mechanical motion into an electrical signal. In the case of a tachometer, the mechanical motion is provided by the engine or motor being monitored. The tachometer generator then generates an electrical signal that is proportional to the speed of the engine or motor. This signal is used to power and drive the tachometer display, allowing it to accurately show the RPM (revolutions per minute) of the engine or motor.Rate this question:
- 45.
How is engine fuel-flow measured?
Explanation
Engine fuel-flow is measured in pounds per hour (pph). This unit of measurement indicates the rate at which fuel is consumed by the engine. By measuring the weight of fuel consumed over a specific time period, the fuel-flow can be determined. This measurement is important for monitoring fuel efficiency, calculating fuel consumption rates, and ensuring optimal engine performance. The abbreviation "pph" simply represents "pounds per hour", which is the standard unit used to quantify engine fuel-flow.Rate this question:
- 46.
What dissimilar metals are used in thermocouples?
Explanation
Thermocouples use dissimilar metals to generate a voltage in response to temperature changes. Alumel and chromel are commonly used in thermocouples because they have different thermoelectric properties. Alumel is an alloy of nickel, aluminum, and manganese, while chromel is an alloy of nickel and chromium. The combination of these metals allows for accurate temperature measurements within a wide range of temperatures.Rate this question:
- 47.
What is used to analyze oil samples and determine the identity of metal particles worn from oil-wetted parts?
Explanation
Spectrometric oil analysis is used to analyze oil samples and determine the identity of metal particles worn from oil-wetted parts. This technique involves using a spectrometer to measure the wavelengths of light emitted or absorbed by the metal particles in the oil sample. By comparing these measurements to known reference spectra, the type and concentration of the metal particles can be identified, providing valuable information about the condition of the oil-wetted parts and potential issues such as wear, contamination, or degradation.Rate this question:
- 48.
What problem most frequently affects sample integrity?
Explanation
Contamination is the most frequently occurring problem that affects sample integrity. When a sample gets contaminated, it means that unwanted substances or particles have been introduced into the sample, which can alter its composition and potentially lead to inaccurate results. Contamination can occur through various means, such as improper handling, environmental factors, or cross-contamination from other samples or equipment. It is crucial to maintain a sterile and controlled environment to minimize the risk of contamination and ensure the integrity of the sample.Rate this question:
- 49.
What are the two categories of oil samples that you may be required to take?
Explanation
Oil samples can be categorized into two types: routine and special. Routine oil samples are taken regularly as part of a maintenance program to monitor the condition and performance of machinery. These samples are typically collected at predetermined intervals and provide valuable information about the overall health of the equipment. On the other hand, special oil samples are taken in specific situations where there may be suspected issues or abnormalities. These samples are usually collected outside of the regular schedule and are used to investigate specific problems or concerns with the machinery.Rate this question:
- 50.
If a pump fails to operate, what component prevents the reverse flow of fuel through the pump?
Explanation
A check valve is a mechanical device that allows the flow of fluid in only one direction, preventing reverse flow. In the context of a pump failure, a check valve would ensure that fuel does not flow back through the pump, maintaining the desired direction of flow. This is important for the proper functioning of the pump and to prevent any potential damage or malfunction.Rate this question:
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