ATA 24

When power is supplied to one of the forward external power receptacles, the onside BPCU checks the external power for power quality. A. If the power quality is acceptable, the BPCU energizes the onside BTR and the left and right BTBs. The left and right 115 Volts (V) Alternating Current (AC) buses are now powered from the connected external power source. B. If the power quality is acceptable, the GCU energizes the onside EPC and the left and right BTBs. The left and right 115 Volts (V) Alternating Current (AC) buses are now powered from the connected external power source. C. If the power quality is acceptable, the BPCU energizes the onside EPC and the left and right BTBs. The left and right 115 Volts (V) Alternating Current (AC) buses are now powered from the connected external power source.

4 Aft External Power When the aft external power switch is selected on: A. The L1 GCU closes the aft EPC. External power is now connected to the L1 Auto Transformer Rectifier Unit (ATRU). B. The L2 GCU closes the aft EPC. External power is now connected to the L2 Auto Transformer Rectifier Unit (ATRU). C. The L2 BPCU closes the aft EPC. External power is now connected to the L2 Auto Transformer Rectifier Unit (ATRU).

5. The Three external power connections have the standard NOT IN USE light and POWER CONNECTED lights. A. If external power is connected, the NOT IN USE light is on.If external power is connected but not selected ON at the P51 panel, the CONNECTED light is on. B. If external power is connected, the CONNECTED light is on. If external power is connected but not selected ON at the P5 panel, the NOT IN USE light is on. C. If external power is connected, the CONNECTED light is OFF. If external power is connected but not selected ON at the P55 panel, the NOT IN USE light is on.

6. What are the input power (parameters) that HYD R EMP (ELECTRICAL MOTOR PUMP) receives?. A. +/- 270 VDC. B. variable frequency, variable voltage, AC power. C. The CMSCs on the 787-8 and 787-9 are rated at 105 kW (150 kW overload for two minutes).

7. The Battery Diode Module (BDM) allows only the main battery charger unit to charge the main battery. A. Prevents the main battery from being charged from the F/O battery bus. B. Prevents the main battery from being charged from the Capitan battery bus. C. Prevents the main battery from being charged from the hot battery bus.

8. The Ram Air Turbine (RAT) supplies electrical power if there is a loss of the main electrical power system on the airplane. A. The generator supplies 235 Volts (V) Alternating Current (AC) power to a maximum of 43,000 feet altitude. B. The generator supplies 115 Volts (V) Alternating Current (AC) power to a maximum of 43,000 feet altitude. C. The generator supplies 270 Volts (V) Direct Current (DC) power to a maximum of 43,000feet altitude.

9. Each receptacle has four large pins for AC power and two small pins for the Interlock: With respect to the forward external power receptacles: A. Each of two receptacles are rated at 65 kVA each. B. Each of the Three receptacles are rated at 90 kVA each. C. Each of the two receptacles are rated at 90 kVA each.

10 The ground service switch is on the master Attendant Switch Panel (ASP). A. When you push the switch, it sends a discrete through the Common Data Network (CDN) to the Bus Power Control Units (BPCU) and the green light on the master ASP turns on. B. When you push the switch, it sends a discrete through the Common Data Network (CDN) to the Solid State Power Controllers (SSPC) and the green light on the master ASP turns on. C. When you push the switch, it sends a discrete through the Common Data Network (CDN) to the Secondary Power Distribution Unit (SPDU) and the green light on the master ASP turns on.

11 The battery switch is normally OFF when external power is applied: A. If the switch is ON and external power fails, the main battery relay closes and charges the main battery. B. If the switch is ON and external power fails, the main battery relay open and discharges the main battery. C. If the switch is ON and external power fails, the main battery relay closes and discharges the main battery.

False or true question The EXT PWR switch lights on the P5 ELECTRICAL panel can show: • Blank – external power source is off or not connected • AVAIL – external power source is connected but not selected ON (only ground handling loads have power) • ON – external power source is connected and selected ON. False. True.

13. The VFSGs are on the engine accessory gearbox. The VFSGs use this mechanical input to generate 235 Volts (V) Alternating Current (AC) power rated at 250 kilovoltamperes (kVA). A. The frequency range is 360 to 440 hertz (Hz) based on engine speed. B. The frequency range is 225 to 250 hertz (Hz) based on engine speed. C. The frequency range is 360 to 800 hertz (Hz) based on engine speed.

14. What is the main function of the thermal switch in the disconnect mechanism?. A. When the oil temperature gets low level , this switch disconnects the VFSG input drive from the engine accessory gearbox. B. When the oil temperature gets too hot, this switch disconnects the VFSG input drive from the engine accessory gearbox. C. When the oil temperature gets too hot, this switch disconnects the ASG input drive from the engine accessory gearbox.

15 False or true question For oil cooling, each VFSG has its own dedicated Air/Oil Heat Exchanger (AOHE). The ASGs use the APU oil system for cooling and lubrication. True. False.

16 False or true question The Common Motor Starter Controller (CMSC) system on the 787 series airplanes supports those loads that were supported by pneumatic bleed air systems on other Boeing airplanes. It provides variable frequency, DC voltage power for airplane systems, for instance (main engine starting, and APU starting). False. True.

17 What happens if you lose power in the line that comes from TRU to L EBPSU?. A. Activates CB protection of L EBPSU. B. The LHBBC Closes. C. Towing Power goes into Automatically operation.

18 CBIC does not monitor the TCBs in the P49 panel. True. False.

19 WHAT DOES THE GATU (GALLEY AUTO TRANSFORMER UNIT)?. A. TRANSFORMS 235/115 AC FOR FEEDING AFT GALLEY. B. TRANSFORMS 115/235 AC FOR FEEDING AFT GALLEY. C. TRANSFORMS 235/115 AC FOR FEEDING FWD GALLEY.

20 CONTROL AND MONITORING OF THE ATRUC (ATRU CONTACTOR) IS PERFORMED BY. A. Control by GCU, Protection / Monitoringby ELCU P. B. Control by ELCU-P, Protection / Monitoring by GCU. C. Control by GCU, Protection / Monitoring by ELCU C.

21 ELCC´s (ELECTRICAL LOAD CONTROL CONTACTOR) SUPPLY LOADS GREATER THAN 50 AMPERES. True. False.

22 DURING TOWING OPERATIONS, THE EBPSU´s RECEIVES POWER FROM (ONLY THE TOWING SWITCH SELECTED TO ON IN THE COCKPIT). A. TRU´s. B. ATU´s. C. Hot Baterry Bus (HBB).

23 WHICH ARE THE REASON FOR RAT AUTHOMATIC DEPLOYMENT (in flight). A. Loss of both engines. B. Loss of power to the instrument buses. C. Loss of all three hydraulic systems. D. All are true.

24 WHAT ARE THE COMPUTERS IN CHARGE OF CONTROL THE LOAD MANAGEMENT FUNCTION IN THE B787. A. BPCU´s. B. AGCU´s. C. SPDU´s.

25 WHY THE OUTPUT STATUS OF THE CIRCUIT BREAKER SHOWN IN THE IMAGE IS "OVERRIDE"_. A. One possible reason is due to load shed configuration for this load. B. that is an unknown position of the CB. C. The CB was open from CBIC.

26 MAINTENANCE PERSONEL NEEDS START RIGHT ENGINE WITH EXTERNAL POWER (APU INOP). A. MUST CONNECT ONLY THE AFT EXTERNAL POWER TO START THE ENGINE,. B. MUST CONNECT TWO FORWARD EXTERNAL POWER. C. MUST CONNEC TWO FORWARD EXTERNAL POWER AND THE AFT EXTERNAL POWER.

27 HOW THE OVERVOLTAGE TRANSIENT PROTECTION UNIT OVRPU PROTECT THE ELECTRICAL SYSTEM FROM OVERVOLTAGE. A. GROUNDING THE 3 PHASES. B. SHORT CIRCUIT THE 3 PHASES. C. CLOSING THE GNR CONTACTOR.

28 THE ELECTRONIC SWITCH (ESW) INSIDE THE SSPC IS CONTROLLED BY. A. Direct System control (DSC) and the BPCUs controlS it for load shed purposes. B. The RPDU control the second switch for load shed purposes. C. The ELCU control the second switch for load shed purposes.

29 THE ELCC (ELECTRICAL LOAD CONTROL CONTACTOR) RECEIVE CONTROL SIGNAL TO OPEN OR CLOSE FROM. A. SPDU. B. ELCU C. C. ELCU P.

30 WHAT ELECTRICAL BUS IS ENERGIZED WITH AFT EXTERNAL POWER IS CONNECTED?. A. L2 270 VDC Only. B. All electrical network through the ATRU. C. L2 270 VDC and the left and right 115 VAC Buses through the ATU.

31 WHAT IS THE FUNCTION OF THE STARTER POWER UNIT (SPU) IN THE ELECTRICAL SYSTEM. A. Provide support during APU start only in battery configuration. B. Provide support during APU start at any electrical configuration. C. Provice support during Main Engine Start (MES) only with batteries.

32 The red highlighted area, which shows the legend of "115 VAC LOADS" in the P300 thermal circuit bracker, is a delivery power of EEC electronic engine control number 1. IF LEFT ATU LOSS THE CAPACITY TO FEED THE LEFT 115VAC BUS, WHAT HAPPEN WITH THE POWER TO THE LEFT EEC?. A. The engine must be shut down since there are not 115VAC to egergize the EEC. B. The BPCU Close the LEFT AND RIGHT DC TIE RELAY to get power from the opposite side. C. The BPCU close the LEFT AND RIGHT BTB to get power from the opposite side.

33 Which BPCU can control (open/close) the captain instrument tie relay? (4 puntos). A. Just LH BPCU. B. Just RH BPCU. C. Both BPCUs.

34. The APU battery is primarily dedicated to starting the APU when operating in the battery configuration; however, it can also supply power to other aircraft systems under specific configurations. A. Ground Service, and feed the aircraft brake system. B. Ground Handling, and feed the dome light. C. Towing power, and supplies electrical power to the navigation lights, (left and right wing lights and the tail cone light).

35 If the two forward external power sources and the aft external power sources are selected ON, the BPCUs send a command signal to the GCUs. This causes the GCU to close these ATRUCs: A. L1, R1, R2. B. L2, R1, R2. C. L1, L2, R1.

36 When the APU is operating at a minimum speed of 95 percent, the ASGs supply power to the main 235V AC buses and the 115V AC and 28V DC buses through the P500 and P600 power conversion panels. In this condition, if you now set the external power switches to ON, the ASGs supply power to the 235V AC buses and external power supplies power to these: • 115V AC buses • Main 28V DC buses • 28V DC instrument buses Explain how APU generation works at the same time with external power generation. A. Opening ATUCs. B. Opening ATRUCs. C. Opening BTBs.