AC DISTRIBUTIONS SYSTEMS

How many basic types of large aircraft power distribution systems exist?

• One

• Two

• Three

Which system is common in three-engine aircraft like the DC-10 and Boeing 727?

• Split bus

• Mixed bus

• Parallel bus

Which system is typically used on four-engine aircraft?

• Split bus

• Series bus

• Parallel bus

What is “No Break Power Transfer” (NBPT)?

• Switching without interruption of power

• Delaying power restoration

• Automatic shutdown of buses

What is the role of the Bus Power Control Unit (BPCU)?

• Provides hydraulic pressure

• Controls transfer of power between buses

• Starts the APU

On which aircraft is the split bus system common?

• Airbus A320, Boeing 757/767

• Boeing 727

• DC-10

What connects loads automatically when a generator fails in a split bus system?

• Circuit breaker

• Bus tie breaker (BTB)

• Transfer relay

Who can also manually link buses using the control panel?

• Pilot

• Ground Engineer

• ATC

What happens when external power is connected and switched ON?

• Engine GBs trip and external power supplies both buses

• Only generator 1 stays online

• All buses shut down

When an engine generator switch is placed ON, what must happen first?

• The adjacent BTB must be open

• External power must be off

• RAT must deploy