C-130h APU (Auxiliary Power Unit) Quiz

All personnel in the vicinity of the aircraft are required to wear hearing protection while the APU is in operation. The APU (Auxiliary Power Unit) is a small engine located in the tail section of an aircraft that provides power to various systems when the main engines are not running. The APU generates noise, which can be harmful to hearing. Therefore, to prevent hearing damage, all personnel who are near the aircraft, regardless of their specific role or location, should wear hearing protection.

The APU receives its fuel from the #2 main tank.

Before applying bleed air, it is necessary to clear the propellers. This is because bleed air is taken from the engine's compressor section, and any debris or foreign objects on the propellers could potentially cause damage to the compressor blades or the bleed air system. Therefore, clearing the propellers ensures that there are no obstructions or hazards that could affect the safe operation of the bleed air system.

UHF stands for Ultra High Frequency and is commonly used for communication with towers and for emergency calls. UHF radio waves have a shorter wavelength and higher frequency, allowing for better signal quality and penetration through obstacles. This makes UHF radios ideal for communication in urban areas and indoor environments. Additionally, UHF radios have a wider bandwidth, allowing for more channels and less interference. Therefore, UHF is the correct answer for the radio used for communication to the tower and for emergency calls.

The correct answer is 15 because the question is asking for the specific pressure at which the bleed air manifold pressure should drop to in order to end timing.

not-available-via-ai

Before running the APU, the first thing that is done is to check the aircraft forms. This is important to ensure that all necessary documentation and records are in order before starting the APU. Checking the aircraft forms helps to verify the maintenance history, any recent repairs or inspections, and any outstanding issues that need to be addressed before powering up the APU. By checking the aircraft forms, the operator can ensure that all necessary procedures and safety checks have been completed, minimizing the risk of any potential issues or malfunctions during APU operation.

The APU CONTROL switch has three functions: STOP, START, and RUN. The STOP function is used to shut down the APU completely. The START function is used to initiate the APU's startup process. The RUN function is used to keep the APU running once it has been started.

The frequency range of the APU generator is 380-420 Hz. This means that the generator produces electrical power at a frequency between 380 and 420 Hertz. The frequency range is important because it determines the compatibility of the generator with other electrical systems and equipment that require a specific frequency to operate efficiently.

Draining the fuel strainer is done to ensure that the fuel shutoff valve is closed. This is important because if the valve is open, fuel will continue to flow and potentially cause leaks or other hazards. By draining the fuel strainer, any remaining fuel in the system can be removed, indicating that the valve is indeed closed. This helps to prevent any fuel from entering the system when it is not needed or when maintenance work is being performed.

The correct answer is "aft of the APU in the left wheel well forward fairing." This means that the APU oil tank is located behind the APU (Auxiliary Power Unit) in the left wheel well forward fairing.

The correct answer includes all the components of the APU system, which are the APU door, APU, APU fuel supply/ignition/starting, the bleed air, APU control, APU exhaust, and oil supply subsystems. These components work together to ensure the proper functioning of the APU, which is responsible for providing auxiliary power to the aircraft when the main engines are not running.

The minimum battery voltage required to operate the APU is 21v. This means that the APU will not function properly if the battery voltage drops below 21v.

The correct answer is 30 because the question asks for the specific pressure at which the timing should start. Therefore, the timing should begin when the bleed air manifold pressure has dropped to 30 psi.

Frost on the APU inlet is acceptable prior to start because it does not pose a significant risk to the operation of the APU. The APU inlet is designed to handle the cold temperatures and the presence of frost does not affect its functionality. However, it is important to note that the frost should be removed before the aircraft takes off as it can cause airflow restrictions and affect the performance of the APU.

When the RPM (Revolutions Per Minute) reaches 95%, the ON SPEED light comes on. This indicates that the engine is operating at the desired speed and is functioning properly. This is an important indicator for pilots to ensure that the engine is running smoothly and within the recommended range.

The APU starter duty cycle refers to the pattern of operation for the auxiliary power unit (APU) starter. In this case, the APU starter is operated for 1 minute, followed by a 4-minute interval of being turned off. This cycle allows the APU starter to cool down and prevents overheating, ensuring its proper functioning and longevity.

The APU fuel strainer is located on the bottom of the left wheel well fairing at the inboard aft corner of the APU compartment.

The correct answer is 4. This suggests that the APU oil tank holds 4 quarts.

Under normal conditions, the APU must warm up for 2 minutes before applying a load. This warm-up period allows the APU's components to reach their optimal operating temperatures and ensures that the APU is ready to handle the load efficiently and safely. Applying a load before the APU has warmed up can cause damage to the components and reduce the overall performance of the APU. Therefore, it is important to wait for the specified warm-up time before applying any load to the APU.

The APU bleed air check from 30 to 15 psi should be no less than 16 seconds. This means that when the APU bleed air pressure is reduced from 30 psi to 15 psi, it should take at least 16 seconds for the pressure to decrease. This check is important to ensure that the APU bleed air system is functioning properly and maintaining the correct pressure levels.

When a FIRE condition is identified in the APU, it is indicated by a steady light in the APU handle and a steady FIRE light. This means that there is a fire in the APU and immediate action needs to be taken to address the situation. The steady lights indicate a serious and urgent situation, requiring the crew to follow the appropriate emergency procedures to extinguish the fire and ensure the safety of the aircraft and its occupants.

The voltage range of the APU generator is 112-118v.

The APU oil tank and system oil quantity is 6 US quarts.

If the START light does not go out within 1 minute, it is necessary to shut down the APU. This indicates that the APU has failed to start properly within the expected time frame, which could indicate a potential issue or malfunction. Shutting down the APU in such cases is a precautionary measure to prevent any further damage or safety hazards.

The cool down time after removing a load from the APU is 2 minutes. This suggests that after removing a load from the APU, it takes 2 minutes for the APU to cool down before it can be used again.

The APU supplies bleed air for starting engines and operating other bleed air systems. Bleed air is used to start the engines by providing the necessary airflow and pressure. It is also used to power various other systems that require high-pressure air, such as air conditioning and pressurization systems. The APU does not supply electrical power or hydraulic power, as these are typically provided by separate systems.

The three-speed switch is responsible for shutting down the APU in case of an overspeed condition. This switch is designed to monitor and control the speed of the APU, and when it detects that the speed has exceeded a certain threshold (indicating an overspeed condition), it triggers a shutdown sequence to prevent any potential damage or hazards.

The APU control circuit is supplied power by the Isolated DC bus. This bus is separate from the Main DC and Essential DC buses, and its purpose is to provide power to critical systems that require isolation from other electrical systems. Therefore, the Isolated DC bus is the correct answer for this question.

The APU (Auxiliary Power Unit) is located in the forward left wheel well fairing. This means that it is situated in the area of the aircraft's left wheel well that is located towards the front of the aircraft.