Embraer 190 - Auxiliary Power Unit
AUXILIARY POWER UNIT QUESTIONS MADE FROM THE AOM VOL. 2
GOOD LUCK! SANTIAGO STOCKER.
Questions and Answers
- 1.
The Auxiliary Power Unit (APU) is a gas turbine engine located in the airplane tailcone, which provides pneumatic and electrical AC power. The pneumatic power is used for engine starting and to supply bleed air to the air conditioning packs of the Environmental Control System (ECS). An electrical AC generator supplies _____________ to the electrical system.
- A.
220 V 40 kVA
- B.
115 V 40 kVA
Correct Answer
B. 115 V 40 kVAExplanation
The correct answer is 115 V 40 kVA. The APU provides electrical AC power to the aircraft's electrical system, and the generator supplies power at a voltage of 115 V and a capacity of 40 kVA.Rate this question:
-
- 2.
The APU is automatically monitored and controlled through a dedicated _______ ________ ________ ________ ______ (FADEC) unit.
Correct Answer
Full Authority Digital Electronic ControlExplanation
The APU (Auxiliary Power Unit) is automatically monitored and controlled through a dedicated Full Authority Digital Electronic Control (FADEC) unit. This unit ensures that the APU operates efficiently and safely by regulating fuel flow, engine speed, and other parameters. The FADEC unit continuously monitors the APU's performance and adjusts its settings as needed to optimize its operation. By using digital electronic control, the FADEC unit provides precise and reliable control over the APU, enhancing its overall performance and reliability.Rate this question:
- 3.
APU EMERGENCY STOP BUTTON (GUARDED) PUSH IN: closes the APU ______________, shutting down the APU with no cooldown period. A white striped bar illuminates on the lower half of the button.
- A.
Fuel shutoff valve
- B.
Air bleed valve
Correct Answer
A. Fuel shutoff valveExplanation
The APU Emergency Stop Button, when pushed in, closes the fuel shutoff valve. This action shuts down the APU immediately without any cooldown period. The white striped bar illuminates on the lower half of the button, indicating that the fuel shutoff valve has been closed.Rate this question:
-
- 4.
When only DC power is available, the DC fuel pump, located in the ______ _____ _____ , provides fuel to the APU.
- A.
Left wing tank
- B.
Right wing tank
Correct Answer
B. Right wing tankExplanation
When only DC power is available, the DC fuel pump, located in the right wing tank, provides fuel to the APU. This means that the APU is being fueled from the right wing tank when there is no other power source available.Rate this question:
-
- 5.
If AC power is available and the engine is not running, fuel will be provided by the __________ .
- A.
AC fuel pump
- B.
DC fuel pump
Correct Answer
A. AC fuel pumpExplanation
When AC power is available and the engine is not running, the fuel will be provided by the AC fuel pump. This is because AC power is required to operate the AC fuel pump, which is responsible for delivering fuel to the engine. The DC fuel pump, on the other hand, operates on DC power and would not be able to provide fuel in this situation.Rate this question:
-
- 6.
When the engine is running, the _____ _____ _____ provides fuel to the APU from the right wing tank. However, it is also possible to provide fuel to the APU from the left wing tank via a crossfeed valve.
- A.
Ejector fuel pump
- B.
AC fuel pump
Correct Answer
A. Ejector fuel pumpExplanation
The correct answer is the ejector fuel pump. When the engine is running, the ejector fuel pump provides fuel to the APU from the right wing tank. However, it is also possible to provide fuel to the APU from the left wing tank via a crossfeed valve.Rate this question:
-
- 7.
The APU supplies bleed air on the ____________. However, it is used primarily as a ground pneumatic source for the air conditioning packs (ECS) and engine starting. The Air Management System (AMS) controls the operation of the APU and engine bleed valves.
- A.
Inflight only
- B.
Ground only
- C.
Ground or inflight
Correct Answer
C. Ground or inflightExplanation
The APU supplies bleed air both on the ground and in flight. While it is primarily used as a ground pneumatic source for the air conditioning packs and engine starting, it can also provide bleed air during flight. The Air Management System controls the operation of the APU and engine bleed valves, allowing for its use in both ground and inflight operations.Rate this question:
-
- 8.
A dedicated Full Authority Digital Electronic Control (FADEC) monitors and controls the _______________ sequence, fault detection and APU status.
- A.
Start
- B.
Shutdown
- C.
Start and shutdown
Correct Answer
C. Start and shutdownExplanation
A dedicated Full Authority Digital Electronic Control (FADEC) monitors and controls the start and shutdown sequence, fault detection, and APU status. This means that the FADEC is responsible for managing the process of starting and shutting down the system, as well as detecting any faults or issues that may arise during these operations.Rate this question:
-
- 9.
The APU is able to supply electrical AC power up to ...
- A.
33000 ft.
- B.
21000 ft.
- C.
15000 ft.
- D.
30000 ft.
Correct Answer
A. 33000 ft.Explanation
The APU (Auxiliary Power Unit) is capable of providing electrical AC power up to 33000 ft. This means that the APU can generate and supply electricity to various systems and components of an aircraft, such as the cabin lighting, air conditioning, and other electrical equipment, while the aircraft is flying at altitudes up to 33000 ft. This is an important capability as it ensures that essential electrical power is available throughout the flight, even at higher altitudes.Rate this question:
-
- 10.
The APU is able to supply bleed air for engine starting up to ...
- A.
33000 ft.
- B.
21000 ft.
- C.
15000 ft.
- D.
30000 ft.
Correct Answer
B. 21000 ft.Explanation
The APU (Auxiliary Power Unit) is a device that provides power to start the aircraft's engines. It is also capable of supplying bleed air, which is used for various purposes such as air conditioning and engine starting. The given correct answer states that the APU is able to supply bleed air for engine starting up to 21000 ft. This means that the APU can effectively provide the necessary air pressure and temperature required for engine starting operations until the aircraft reaches an altitude of 21000 ft.Rate this question:
-
- 11.
The APU is able to supply bleed air for air conditioning and pressurization up to ...
- A.
33000 ft.
- B.
21000 ft.
- C.
15000 ft.
- D.
30000 ft.
Correct Answer
C. 15000 ft.Explanation
The APU (Auxiliary Power Unit) is capable of providing bleed air for air conditioning and pressurization. This means that it can supply the necessary air for cooling and maintaining the desired pressure inside the aircraft cabin. The given answer of 15000 ft. suggests that the APU is able to supply bleed air for air conditioning and pressurization up to an altitude of 15000 feet.Rate this question:
-
- 12.
Maximum altitude for APU start is ....
- A.
33000 ft.
- B.
21000 ft.
- C.
15000 ft.
- D.
30000 ft.
Correct Answer
D. 30000 ft.Explanation
The correct answer is 30000 ft. The maximum altitude for starting the APU (Auxiliary Power Unit) is 30000 ft. This means that the APU can be started up to an altitude of 30000 ft. The APU is a small gas turbine engine that provides electrical power and compressed air for various aircraft functions, such as starting the main engines and powering the aircraft systems when the engines are not running. Starting the APU at higher altitudes may result in reduced performance or even failure due to the thin air and lower oxygen levels.Rate this question:
-
- 13.
Rotating the APU master switch to ON powers the FADEC and APU fuel shutoff valve opens. NOTE: The SPDA sends power to APU FADEC energization only _____ after its power-up, so APU start is not available before this time period.
- A.
15 s
- B.
30 s
- C.
60 s
Correct Answer
B. 30 sExplanation
After rotating the APU master switch to ON, it takes approximately 30 seconds for the SPDA (Secondary Power Distribution Assembly) to send power to the APU FADEC (Full Authority Digital Engine Control) system. This allows the APU start sequence to begin. Therefore, the APU start is not available before this 30-second time period.Rate this question:
-
- 14.
_______ seconds after APU speed has reached 95%, electrical and pneumatic loading are available. If the APU does not reach proper speed or acceleration rate within the starting cycle time, the APU will automatically shut down.
- A.
Three
- B.
Six
Correct Answer
A. ThreeExplanation
Three seconds after the APU speed has reached 95%, electrical and pneumatic loading become available. If the APU does not reach the proper speed or acceleration rate within the starting cycle time, it will automatically shut down.Rate this question:
-
- 15.
GROUND START The FADEC initiates ignition at approximately ____ rpm and the fuel flow after 0.5 s.
- A.
6 %
- B.
30 %
Correct Answer
A. 6 %Explanation
The correct answer is 6%. This means that the FADEC (Full Authority Digital Engine Control) system initiates ignition at approximately 6% of the engine's revolutions per minute (rpm) and the fuel flow after 0.5 seconds. This is an important parameter to ensure proper engine start-up and fuel delivery for efficient combustion.Rate this question:
-
- 16.
The battery ____ energizes the electronic starter controller. After a light off occurs, the FADEC commands the starter to cutout at approximately 50% rpm.
- A.
#1
- B.
#2
Correct Answer
B. #2Explanation
The battery powers the electronic starter controller, which is responsible for starting the engine. Once the engine starts, the Full Authority Digital Engine Control (FADEC) system takes over and commands the starter to cutout at around 50% of the engine's revolutions per minute (rpm).Rate this question:
-
- 17.
IN FLIGHT START The FADEC initiates ignition at approximately ____________and the fuel flow after 0.5 s. After a light off occurs, the FADEC commands the starter to cutout at approximately 50% rpm.
- A.
7% to 17% rpm
- B.
17% to 27% rpm
Correct Answer
A. 7% to 17% rpmExplanation
The FADEC initiates ignition at approximately 7% to 17% rpm and the fuel flow after 0.5 s. After a light off occurs, the FADEC commands the starter to cutout at approximately 50% rpm. This means that the FADEC system starts the ignition process when the engine reaches a speed between 7% to 17% rpm, and then the fuel flow begins after 0.5 seconds. Once the engine successfully ignites, the FADEC system instructs the starter to stop at around 50% rpm.Rate this question:
-
- 18.
Rotating the APU selector knob from ON to OFF initiates a normal APU shutdown, which is monitored and controlled by the FADEC. During a normal shutdown sequence, the APU pneumatic power is removed immediately and the electrical power is removed at the end of a _________ cooldown period. The EICAS message APU SHUTTING DOWN disappears at the end of that period.
- A.
1 minutes
- B.
2 minutes
- C.
3 minutes
Correct Answer
B. 2 minutesExplanation
During a normal APU shutdown, the electrical power is removed at the end of a 2-minute cooldown period. This cooldown period allows the APU to cool down gradually before the electrical power is completely removed. The EICAS message APU SHUTTING DOWN disappears at the end of this 2-minute cooldown period, indicating that the shutdown process is complete.Rate this question:
-
- 19.
The cooldown period is _________ , followed by a spooldown period. The EICAS message APU SHUTTING DOWN disappears at the end of spooldown period.
- A.
1 minute
- B.
3 minutes
Correct Answer
A. 1 minuteExplanation
The cooldown period is 1 minute, followed by a spooldown period. The EICAS message APU SHUTTING DOWN disappears at the end of spooldown period.Rate this question:
-
- 20.
Turning the APU selector knob back to ON position during the shutdown sequence cancels the shutdown.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Turning the APU selector knob back to the ON position during the shutdown sequence cancels the shutdown. This means that if the APU is being shut down and the selector knob is turned back to ON, the shutdown process will be stopped and the APU will remain operational.Rate this question:
-
- 21.
The FADEC provides automatic APU shutdown protection on ground as follows.
- A.
Overspeed
- B.
Underspeed
- C.
FADEC critical fault
- D.
APU fire
- E.
APU EGT overtemperature
- F.
APU high oil temperature
- G.
APU low oil pressure
- H.
Sensor fail
Correct Answer(s)
A. Overspeed
B. Underspeed
C. FADEC critical fault
D. APU fire
E. APU EGT overtemperature
F. APU high oil temperature
G. APU low oil pressure
H. Sensor failExplanation
The FADEC (Full Authority Digital Engine Control) system is responsible for controlling and monitoring the APU (Auxiliary Power Unit) on an aircraft. It provides automatic shutdown protection on the ground to prevent any potential hazards or damage. The listed reasons for automatic shutdown include overspeed, underspeed, FADEC critical fault, APU fire, APU EGT (Exhaust Gas Temperature) overtemperature, APU high oil temperature, APU low oil pressure, and sensor failure. These shutdown protections ensure the safe operation of the APU and prevent any further damage or risks.Rate this question:
-
- 22.
The FADEC provides automatic APU shutdown protection on in flight as follows.
- A.
Overspeed
- B.
Underspeed
- C.
FADEC critical fault
- D.
APU fire
- E.
APU EGT overtemperature
- F.
APU high oil temperature
- G.
APU low oil pressure
- H.
Sensor fail
Correct Answer(s)
A. Overspeed
B. Underspeed
C. FADEC critical faultExplanation
The FADEC (Full Authority Digital Engine Control) system is responsible for controlling and monitoring the APU (Auxiliary Power Unit) during flight. It provides automatic shutdown protection in case of various critical conditions. Overspeed refers to the APU rotating at a speed higher than its maximum limit, which can cause damage. Underspeed, on the other hand, refers to the APU rotating at a speed lower than the minimum required, which can lead to inefficient operation. FADEC critical fault indicates a malfunction in the FADEC system itself, which requires immediate shutdown. These protections ensure the safety and proper functioning of the APU during flight.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
-
Apr 01, 2024Quiz Edited by
ProProfs Editorial Team -
Jun 07, 2011Quiz Created by
Santisfaction
Back to top