AS 411 QUESTIONS AND ANSWERS
What is the purpose of a "bus" in an aircraft electrical system? - Answers -safety - to
reduce wiring
What supplies the power for the entire 28 Volt Direct Current system? - Answers -
Transformer Rectifier (TR) Units
What is the Auxiliary Power Unit (APU) battery rating? - Answers -24 Volts rated at 43
ampere hours
What is the main battery rating? - Answers -24 volts 17 ampere hours
Why is the APU battery bigger and more powerful than the main battery? - Answers -it
needs that cranking power to start turning the APU
What is the ADG, and what does it provide? - Answers -Air Driven Generator- in the
case of a full AC electrical failure, it provides power for the 3B hydraulic pump, ESS AC
bus, slats/flaps, and STAB TRIM CH2
The Main and APU batteries are kept in a charged condition by battery chargers, which
are powered by: - Answers -AC BUS No. 1 and AC Service bus
Where is the external AC power receptacle located on the aircraft? - Answers -forward
right side
Electrical warning and caution messages are displayed (normally) on: - Answers -the
EICAS primary page
Electrical system status and advisory messages are normally displayed on: - Answers -
the EICAS status page
What does the Integrated Drive Generator (IDG) convert? - Answers -variable engine
speed to constant generator speed
The IDGs may be disconnected from the gearbox by: - Answers -Disconnect switches
located in the cockpit
Once disconnected, the IDG: - Answers -can only be manually reconnected on the
ground by maintenance
The IDGs convert variable engine speed to a constant generator speed of ______RPM
- Answers -12,000
, Fault protection inside each generator is provided by: - Answers -The Generator
Control Units
The priority for powering the AC Bus 1, in order, is: - Answers -IDG 1, APU, IDG 2,
External AC
IDG 2 normally powers: - Answers -AC bus 2, service bus
The ADG supplies power to: - Answers -3B hydraulic pump, AC essential, ADG bus,
EICAS, slats, flaps, and STAB TRIM CH2
115 VAC is supplied to TRUs for DC static conversion, and each TRU is rated at: -
Answers -120 amps
DC Main Tie, Cross Tie, and Ess Tie Contactors: - Answers -are automatic, and
controlled only by the DCPCs
In flight, the ADG auto-deploy monitors the three main AC generators and the main AC
buses for - Answers -complete AC power failure
What does the AMBER IDG Fault light/Caution light indicate? - Answers -HOTLOP
(High Oil Temperature, Low Oil Pressure) in the IDG
What does the "AUTO XFER FAIL" light (amber) on the electrical panel mean? -
Answers -the generator has experienced an over-current or bus fault
What are the components powered by the DC Emergency Bus? - Answers -fuel shutoff
valves
hydraulic shutoff valves
engine and APU fire extinguishing system
What is the hydraulic pump that can be powered in an emergency involving full loss of
all AC power? (just the pump name) - Answers -3B
With the switch in the AUTO position, pump 3B will be operating during normal takeoffs
and landings. - Answers -True
What is normal (or "nominal") hydraulic system pressure in the CRJ (and in most other
large jets)? ________psi - Answers -3000
The pump directly powered by the ADG is an engine-driven pump. - Answers -False
AC motor pumps 1B and 2B will automatically come on during an engine failure. -
Answers -False
What is the purpose of a "bus" in an aircraft electrical system? - Answers -safety - to
reduce wiring
What supplies the power for the entire 28 Volt Direct Current system? - Answers -
Transformer Rectifier (TR) Units
What is the Auxiliary Power Unit (APU) battery rating? - Answers -24 Volts rated at 43
ampere hours
What is the main battery rating? - Answers -24 volts 17 ampere hours
Why is the APU battery bigger and more powerful than the main battery? - Answers -it
needs that cranking power to start turning the APU
What is the ADG, and what does it provide? - Answers -Air Driven Generator- in the
case of a full AC electrical failure, it provides power for the 3B hydraulic pump, ESS AC
bus, slats/flaps, and STAB TRIM CH2
The Main and APU batteries are kept in a charged condition by battery chargers, which
are powered by: - Answers -AC BUS No. 1 and AC Service bus
Where is the external AC power receptacle located on the aircraft? - Answers -forward
right side
Electrical warning and caution messages are displayed (normally) on: - Answers -the
EICAS primary page
Electrical system status and advisory messages are normally displayed on: - Answers -
the EICAS status page
What does the Integrated Drive Generator (IDG) convert? - Answers -variable engine
speed to constant generator speed
The IDGs may be disconnected from the gearbox by: - Answers -Disconnect switches
located in the cockpit
Once disconnected, the IDG: - Answers -can only be manually reconnected on the
ground by maintenance
The IDGs convert variable engine speed to a constant generator speed of ______RPM
- Answers -12,000
, Fault protection inside each generator is provided by: - Answers -The Generator
Control Units
The priority for powering the AC Bus 1, in order, is: - Answers -IDG 1, APU, IDG 2,
External AC
IDG 2 normally powers: - Answers -AC bus 2, service bus
The ADG supplies power to: - Answers -3B hydraulic pump, AC essential, ADG bus,
EICAS, slats, flaps, and STAB TRIM CH2
115 VAC is supplied to TRUs for DC static conversion, and each TRU is rated at: -
Answers -120 amps
DC Main Tie, Cross Tie, and Ess Tie Contactors: - Answers -are automatic, and
controlled only by the DCPCs
In flight, the ADG auto-deploy monitors the three main AC generators and the main AC
buses for - Answers -complete AC power failure
What does the AMBER IDG Fault light/Caution light indicate? - Answers -HOTLOP
(High Oil Temperature, Low Oil Pressure) in the IDG
What does the "AUTO XFER FAIL" light (amber) on the electrical panel mean? -
Answers -the generator has experienced an over-current or bus fault
What are the components powered by the DC Emergency Bus? - Answers -fuel shutoff
valves
hydraulic shutoff valves
engine and APU fire extinguishing system
What is the hydraulic pump that can be powered in an emergency involving full loss of
all AC power? (just the pump name) - Answers -3B
With the switch in the AUTO position, pump 3B will be operating during normal takeoffs
and landings. - Answers -True
What is normal (or "nominal") hydraulic system pressure in the CRJ (and in most other
large jets)? ________psi - Answers -3000
The pump directly powered by the ADG is an engine-driven pump. - Answers -False
AC motor pumps 1B and 2B will automatically come on during an engine failure. -
Answers -False
