C-130h APU (Auxiliary Power Unit) Quiz
Questions and Answers
- 1.
You must first _________before applying bleed air?
- A.
Turn on the AC inverter
- B.
Clear the A/C packs
- C.
Clear the propellers
- D.
Inspect the engine intake and exhaust
Correct Answer
C. Clear the propellersExplanation
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.Rate this question:
-
- 2.
The cool down time after removing a load from the APU is _____ minutes.
- A.
1
- B.
4
- C.
2
- D.
3
Correct Answer
C. 2Explanation
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.Rate this question:
-
- 3.
The Job Guide for APU operation is:
- A.
1C-130H-2-70JG-00-1
- B.
1C-130E-2-49JG-00-1
- C.
1C-130H-2-05JG-00-1
- D.
1C-130H-2-49JG-00-1
Correct Answer
D. 1C-130H-2-49JG-00-1 -
- 4.
The APU starter duty cycle is:
- A.
1 minute on, 2 minutes off
- B.
2 minutes on, 1 minute off
- C.
1 minute on, 4 minutes off
- D.
I minute on, 1 minute off
Correct Answer
C. 1 minute on, 4 minutes offExplanation
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.Rate this question:
-
- 5.
What is the first thing that is done before running the APU?
- A.
Clear the props
- B.
Clear the APU
- C.
Check the aircraft forms
- D.
Service the APU oil
Correct Answer
C. Check the aircraft formsExplanation
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.Rate this question:
-
- 6.
The APU oil tank is located _________.
- A.
In the cargo compartment
- B.
In the left wheel well
- C.
Aft of the APU in the left wheel well forward fairing
- D.
Underneath the APU
Correct Answer
C. Aft of the APU in the left wheel well forward fairingExplanation
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.Rate this question:
-
- 7.
What is the frequency range of the APU generator?
- A.
300-400 Hz
- B.
380-420 Hz
- C.
112-118 Hz
- D.
120-240 Hz
Correct Answer
B. 380-420 HzExplanation
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.Rate this question:
-
- 8.
The APU oil tank and system oil quantity is ___ US quarts.
- A.
4
- B.
5
- C.
7
- D.
6
Correct Answer
D. 6Explanation
The APU oil tank and system oil quantity is 6 US quarts.Rate this question:
-
- 9.
Which radio is used for communication to the tower and for emergency calls?
- A.
VHF
- B.
UHF
- C.
HF
- D.
SCNS
Correct Answer
B. UHFExplanation
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.Rate this question:
-
- 10.
Where is the APU fuel strainer located?
- A.
In the number 2 dry bay
- B.
Underneath the right forward wheel well fairing
- C.
Underneath the APU compartment
- D.
On the bottom of the left wheel well fairing at the inboard aft corner of the APU compartment
Correct Answer
D. On the bottom of the left wheel well fairing at the inboard aft corner of the APU compartmentExplanation
The APU fuel strainer is located on the bottom of the left wheel well fairing at the inboard aft corner of the APU compartment.Rate this question:
-
- 11.
Which bus supplies power to the APU control circuit?
- A.
Main DC
- B.
Essential AC
- C.
Isolated DC
- D.
Essential DC
Correct Answer
C. Isolated DCExplanation
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.Rate this question:
-
- 12.
The APU receives its fuel from __________________.
- A.
Crossfeed manifold
- B.
#3 main tank
- C.
#2 main tank
- D.
Refuel manifold
Correct Answer
C. #2 main tankExplanation
The APU receives its fuel from the #2 main tank.Rate this question:
-
- 13.
The APU system includes:
- A.
APU door, APU, ATM, APU fuel supply, exhaust and oil subsytems
- B.
APU, APU door, APU fuel supply/ignition/starting, the bleed air and APU indicating
- C.
The APU door, APU, APU fuel supply/ignition/staring, the bleed air, APU control, APU exhaust and oil supply subsystems
- D.
The APU, APU control, APU indicating, the ATM, exhaust and oil supply
Correct Answer
C. The APU door, APU, APU fuel supply/ignition/staring, the bleed air, APU control, APU exhaust and oil supply subsystemsExplanation
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.Rate this question:
-
- 14.
You must shut down the APU if the START light does not go out within ___________.
- A.
2 minutes
- B.
1 minute
- C.
30 seconds
- D.
1.5 minutes
Correct Answer
B. 1 minuteExplanation
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.Rate this question:
-
- 15.
The APU supplies what?
- A.
Electrical power and bleed air for starting engines
- B.
Bleed air for starting engines and operating other bleed air systems
- C.
Electrical power
- D.
Hydraulic power
Correct Answer
B. Bleed air for starting engines and operating other bleed air systemsExplanation
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.Rate this question:
-
- 16.
What is the voltage range of the APU generator?
- A.
110-120v
- B.
120-240v
- C.
110-118v
- D.
112-118v
Correct Answer
D. 112-118vExplanation
The voltage range of the APU generator is 112-118v.Rate this question:
-
- 17.
The purpose of draining the fuel strainer is to ensure that:
- A.
There is fuel in the system
- B.
The fuel shutoff valve is open
- C.
The fuel shutoff valve is closed
- D.
There is no dirt in the system
Correct Answer
C. The fuel shutoff valve is closedExplanation
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.Rate this question:
-
- 18.
The APU bleed air check from 30 to 15 psi should be no less than ____________.
- A.
8.5 seconds
- B.
20 seconds
- C.
16 seconds
- D.
18 seconds
Correct Answer
C. 16 secondsExplanation
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.Rate this question:
-
- 19.
If an overspeed condition exists, what shuts down the APU?
- A.
95% switch
- B.
The three speed switch
- C.
110% switch
- D.
Centrifugal switch
Correct Answer
B. The three speed switchExplanation
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.Rate this question:
-
- 20.
Under normal conditions,the APU must warm up ___ minutes before applying a load.
- A.
1
- B.
2
- C.
3
- D.
4
Correct Answer
B. 2Explanation
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.Rate this question:
-
- 21.
Where is the APU located?
- A.
In the left wheel well
- B.
Underneath the pilot and copilot
- C.
In the forward left wheel well fairing
- D.
Forward of the left wheel well fairing
Correct Answer
C. In the forward left wheel well fairingExplanation
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.Rate this question:
-
- 22.
How many quarts does the APU oil tank hold?
- A.
3
- B.
4
- C.
5
- D.
6
Correct Answer
B. 4Explanation
The correct answer is 4. This suggests that the APU oil tank holds 4 quarts.Rate this question:
-
- 23.
The minimum battery voltage for operating the APU is _____.
- A.
28v
- B.
24v
- C.
21v
- D.
12v
Correct Answer
C. 21vExplanation
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.Rate this question:
-
- 24.
What happens at 95% RPM?
- A.
The 95% switch shuts down the APU
- B.
The ON SPEED light goes out
- C.
The START light goes out
- D.
The ON SPEED light comes on
Correct Answer
D. The ON SPEED light comes onExplanation
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.Rate this question:
-
- 25.
A FIRE condition in the APU is identified by:
- A.
A steady light in the APU handle and a flashing MASTER CAUTION light
- B.
A flashing light in the APU handle and a flashing MASTER CAUTION light
- C.
A flashing light in the APU handle and a steady FIRE light
- D.
A steady light in the APU handle and a steady FIRE light
Correct Answer
D. A steady light in the APU handle and a steady FIRE lightExplanation
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.Rate this question:
-
- 26.
Frost on the APU inlet is acceptable prior to start
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
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.Rate this question:
-
- 27.
The APU CONTROL switch has what three functions?
- A.
STOP, START & RUN
- B.
OFF, ON & RUN
- C.
OFF, START, & RUN
- D.
STOP, START & ON
Correct Answer
A. STOP, START & RUNExplanation
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.Rate this question:
-
- 28.
Hearing protection is required for which personnel while APU is in operation?
- A.
Ground man
- B.
All personnel in vicinity of aircraft
- C.
Personnel standing directly next to APU
- D.
Personnel on flight deck
Correct Answer
B. All personnel in vicinity of aircraftExplanation
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.Rate this question:
-
- 29.
Start timing when bleed air manifold pressure has dropped to ___ psi.
- A.
15
- B.
16
- C.
30
- D.
9
Correct Answer
C. 30Explanation
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.Rate this question:
-
- 30.
End timing when bleed air manifold pressure has dropped to ___ psi.
- A.
15
- B.
16
- C.
30
- D.
9
Correct Answer
A. 15Explanation
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.Rate this question:
-
Quiz Review Timeline +
Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.
-
Current Version
-
Mar 22, 2023Quiz Edited by
ProProfs Editorial Team -
Dec 05, 2010Quiz Created by
Ewilds
Back to top