Electrical System

Question 1

Name some important items on the main hot battery bus

Answer 1

• spar valves
• APU and lower cargo fire extinguishers
• engine fire extinguishers
• fire unlock switches

Question 2

(Dark Airplane) When I place the battery switch to on, what busses are powered?

Answer 2

• 2 hot battery busses

- 2 battery busses

Question 3

When I place the STBY PWR selector to AUTO, what busses are powered and how?

Answer 3

APU and Main STBY busses through inverters from the APU and Main Battery Busses

Question 4

What Items are on the APU STBY bus?

Answer 4

• Left FMC
• Left ND
• Left PFD

Question 5

What items are on the MAIN STBY bus?

Answer 5

• Primary EICAS
• Left EIU, CDU, ILS, VOR, VHF
• some additional aircraft instruments

Question 6

What don’t we have when we lose all generators?

Answer 6

• No LE
• No Anti-Skid
• No Reversers
• No Auto-Speedbrakes

Question 7

During electrical emergency, when does the central IRS go offline?

Answer 7

5 minutes

Question 8

What will cause an IDG to disconnect?

Answer 8

• high oil temperature
• low oil pressure
• uncorrectable frequency fault

Question 9

Which bus charges the battery bus?

Answer 9

ground service bus

Question 10

What is the primary power source for the ground service bus?

Answer 10

AC bus 1