Electrical

Question 1

Question: What is the lowest power source that will operate the Standby Flight Display?

Answer 1

Answer: Emergency Batteries L EMER DC R EMER DC

Question 2

Question: What is the purpose of Emergency Batteries (EBATTS)?

Answer 2

Answer: They power emergency avionics and egress lighting.

Question 3

Question: If operating on the Emergency Batteries ONLY do you have Air Data Information?

Answer 3

No

Question 4

Question: What would have to be powered to get Air Data to the SFD?

Answer 4

Answer: ESSENTIAL DC power

Question 5

Question: I press the ARM switch IN and E-BATT’s come ON. Why?

Answer 5

Answer: Senses less than 20 volts on the Essential Busses.

Question 6

Question: What would I expect to see powered under this condition?

Answer 6

Answer: 1.SFD (Both)

2.TSC 2&3

3. Emergency Exit Lights

Question 7

BATTERY switches are now Pressed IN :***

Question: What additional screens would be powered?

Answer 7

Answer:
1. All 5 TSC

2. DU 1 & 4
3. OHPTS 1 & 2

Question 8

Question: The “ON” lights are illuminated inside the battery switches. Why?

Answer 8

Answer:
1. Battery is powering the DC Essential Buses

2. Aux Hyd. Pump is operating
3. APU starting

Question 9

Question: Can I use an external DC power cart to start the APU?

Answer 9

Answer: No

Question 10

Question: When switching from AC External Power to APU Generator Power, will there be a no break power transfer or a break power transfer?

Answer 10

Answer: Break power transfer because the APU generator is not an IDG, there is no way to “sync” the power, so there will be a break power transfer.

Question 11

Question: How should the electrical panel be configured for aircraft power up?

Answer 11

Answer: 1. All 4 generator switches In 2. BUS TIE switches OUT

Question 12

Question: What is the purpose of GCUs?

Answer 12

Answer: Provide Quality of Power.

Question 13

Question: How can a GCU be reset?

Answer 13

Answer: By cycling associated generator control switch (L GEN, R GEN, APU GEN, RAT GEN) to OFF for 5 seconds and then ON. This action causes the software to re-initialize.

Question 14

Question: To ensure you get a NO break power transfer between AC power sources, what must you do?

Answer 14

Answer: Have an IDG involved.

Question 15

Question: What causes the “AC” legend of AC/DC RESET switchlight to activate?

Answer 15

Answer: A Fault in Main AC or Emergency AC bus, a logic fault within BPCU, or by a relay or component failure (Glitch, Fault, Failure).

Question 16

Question: If both AC and DC external power is connected, which has priority?

Answer 16

Answer: External AC

Question 17

Question: Describe the purpose of the fifth or Aux TRU?

Answer 17

Answer: It serves as a backup to the other TRU’s.

When not serving in a backup role, the Aux TRU powers the Aux DC bus which provides 28 VDC power to cabin loads.

Question 18

Question: What is the function of the EBHA battery?

Answer 18

Answer: It is a dedicated source of power to Electric Backup Hydraulic Actuators and Motor Controls Electronics (MCE).

Question 19

Question: What is the purpose of the UPS battery?

Answer 19

Answer: It is a dedicated source of power to Flight Control Computers (Channels 1A and 2B), BFCU, 1 of 2 power sources of REUs.

Question 20

Question: What does the RAT power?

Answer 20

Answer: L & R Ess TRU – Left and Right ESS Buses Emergency AC Bus EBHA battery charger, UPS battery charger, H-STAB Channel 1, L & R Side Window Heat,

Question 21

Question: What are the sources of power for the ground service bus?

Answer 21

Answer: Right main DC bus, external DC power cart, or right battery.

Question 22

Question: When will the Ground Service bus automatically deactivate?

Answer 22

Answer: When ALL doors are closed (Main Entrance Door, Tail Compartment Door, Security / Ground Service Door, & Refuel Panel Door)

Question 23

Question: What powers the Emergency AC Bus?

Answer 23

Answer: Left Main AC or RAT generator.

Question 24

Question: What happens on a dark airplane when the GND SVC BUS switch on the Security / Gnd Svc panel is selected to ON?

Answer 24

Answer: The right battery powers the ground service bus and the anti-collision beacon illuminates and TSC #5 is powered.

Question 25

Question: How many TSC’s can be used to simultaneously control the SSPC’s?

Answer 25

Answer: The Secondary Power Distribution System can be accessed from any two of TSC 2 thru 5. Secondary Power is not available on TSC 1.

Question 26

Question: You have deployed the RAT due to a dual generator failure. What is the Minimum speed for operation of the RAT generator?

Answer 26

200 kts

Question 27

Question: When an engine fails, what directs the operating generator to power the effected GEN bus?

Answer 27

BPCU

Question 28

Question: How would the EMERGENCY AC BUS receive power if the Left Main AC Bus failed?

Answer 28

RAT

Question 29

Question: If the Right Essential TRU fails, what will power the Right Essential DC bus?

Answer 29

Answer: Aux TRU

Question 30

Question: If we had a subsequent failure of the Left Essential TRU, what will occur?

Answer 30

Answer: Aux TRU will take over the Left ESS DC bus and the Right Ess DC bus will be powered by the BATTS.

Question 31

Question: If you had to deploy the RAT. What buses can it power?

Answer 31

Answer: Emergency AC Bus

Left and Right ESS Buses

Question 32

Question: You are departing from an airport that prohibits you from starting your APU until 10 minutes before your scheduled departure time, your aircraft is currently using an AC electric cart for electrical power. If you start the APU and it’s generator switch is IN would there be a Break Power transfer?

Answer 32

Yes

Question 33

Question: Utilizing which checklist would prevent this?

Answer 33

Answer: APU Restricted (EXT PWR) Start