APU - Airbusdriver.net

1 2014 2015 (RC 1) TGS Study Guide _____. Technical Ground School Study Guide AIRBUS A330. May 1, 2014 to April 30, 2015. Updated : 3/3/2015. Send corrections/comments to: Bob Sanford, E-mail: APU. Scenario #1: Madrid: You are taxiing to the runway and have received the final weight and balance from CLP. It is a hot day and your aircraft is close to the maximum gross weight, therefore you will be required to make an APU BLEED ON takeoff. 1. Fifteen minutes prior to departure the Captain attempts to start the APU.

2 The first start attempt is unsuccessful. How many more start attempts can be made? a. Two more attempts can be made then a cooling period of 30 minutes is required before making additional attempts. b. Three more attempts can be made then a cooling period of 60 minutes is required before making additional attempts. c. Two more attempts can be made then a cooling period of 60 minutes is required before making additional attempts. d. Two more attempts can be made then a cooling period of 90 minutes is required.

3 Reference: PH After 3 starter motor duty cycles, wait 60 minutes before attempting 3 more cycles. 2. (True or False) The APU START pb green AVAIL light signifies the APU is on speed at 100% and is available for use? (Note - Poor question, is the point really asking 95 vs. 100%?). Reference: TM AVAIL: This green light illuminates when N reaches 95%. Scenario #1 continued: Because of a long line of aircraft during Taxi out the Captain has elected to shut down engine #2 and single engine taxi. 3. With the APU running will the APU generator be powering either electrical bus?

4 Reference: TM Yes, AC BUS 2. Operation of the electrical system is automatic. Normal priority for supplying electrical power to each of the two main AC buses is: 1. Corresponding engine generator a. APU generator or external power A (If both are connected, the APU generator has priority for AC BUS. 1, and EXT A has priority for AC BUS 2.). 2. External power B (If both EXT A and EXT B are connected, EXT B has priority for AC BUS 1 and EXT A. has priority for AC BUS 2.). 3. Opposite engine generator 4. (Yes or No) In the event of an APU fire on the ground the APU will automatically shut down and automatically discharge the fire bottle.

5 Reference: TM On the ground, detection of an APU fire causes automatic APU shutdown and extinguisher discharge. In flight, there is no automatic APU shutdown and the extinguisher must be manually discharged. 5. Where can you find the procedure to make an APU BLEEDS ON takeoff? Reference: PH PH or _____. Unofficial Airbus Study Site 2014 2015 (RC 1) TGS Study Guide _____. 6. In preparation for the takeoff you select the APU BLEED pb to ON. What does this accomplish? a. Closes the Crossbleed valve, Opens the APU Bleed valve and closes the Engine Bleed valves.

6 B. Opens the Crossbleed valve, Opens the APU Bleed valve and closes the Engine Bleed valves. c. Opens the Crossbleed valve, Opens the APU Bleed valve and opens the Engine Bleed valves. d. Closes the Crossbleed valve, closes the APU Bleed valve and closes the Engine Bleed valves. Reference: TM When the APU BLEED pb is ON the BMCs command the crossbleed valve to open (with the X BLEED. selector in AUTO), and the engine bleed valves to close. The APU bleed air supplies the pneumatic system provided APU speed is more than 95%.

7 The APU bleed valve automatically closes when climbing through 25,000 and remains closed until descending through 23,000 regardless of APU BLEED pb position. The APU can be used to supply bleed air for air conditioning operation during takeoff, allowing additional thrust to be obtained from the engines. Scenario #2: You have departed Madrid and are climbing out on the departure, APU Bleed On . 7. When should you select the APU BLEED pb to OFF? Reference: PH After thrust reduction 8. What are the altitude limits for APU generator and bleed air?

8 (Note - Poor question since no specified APU. generator altitude limit). Reference: PH No specific APU generator altitude limit but Maximum Altitude for APU Operation. 41,000 feet (25,000 feet if using JET B or JP4 fuel). Maximum altitude for APU bleed operation: 22,500 feet Scenario #2 continued: Immediately after selecting the APU BLEED pb OFF and prior to initiating the APU shutdown procedure the APU experiences an auto shutdown. 9. What are some of the things that could cause this in flight? a. Overspeed, critical ECB internal failures, underspeed, low oil pressure, high oil temperature, Fire, DC power interrupt, EGT overtemp.

9 B. Overspeed, critical ECB internal failures, underspeed, low oil pressure, high oil temperature, APU generator failure, DC power interrupt, EGT overtemp. c. In flight the APU will only auto shut down for an overspeed and certain critical ECB internal failures. d. Overspeed, critical ECB internal failures, underspeed, low oil pressure, high oil temperature, DC. power interrupt, EGT overtemp. Reference: TM FAULT: This amber light illuminates and a caution appears on ECAM, when an automatic APU shutdown occurs, which happens in case of: Fire (on ground only).

10 Reverse flow Air inlet flap not open Low oil pressure Overspeed High oil temperature No acceleration ECB failure Slow start Loss of overspeed protection EGT overtemperature Underspeed No flame DC power loss. (BAT OFF when aircraft on batteries only). 10. After an auto shutdown of the APU you should expect to see the ___FAULT__ light illuminated in the APU MASTER SW pb. Reference: TM _____. Unofficial Airbus Study Site 2014 2015 (RC 1) TGS Study Guide _____. Electrical. Scenario #1: KPHL to EGKK flight. Your aircraft is located at the maintenance hangar where you will be picking it up and taxiing to your departure gate.