APU TEST QUESTIONS AND ANSWERS
What are the Frequency limits for the APU Generator? - Answers - 400 +/-4Hz
The APU starter duty cycle is _____ Minutes on, _____ Minutes off. - Answers - 0-
What is the MAXIMUM acceleration time (Cold) that the APU must reach 100% N2? -
Answers - 60 Seconds
What is the time limit that the APU must be operating in APU/ISOL Valve (CLOSED)
position in order for the APU to shutdown normally? - Answers - 90 Seconds
What is the MAXIMUM acceleration time (Warm) that the APU must reach 100% N2? -
Answers - 45 Seconds
What switch Arms the Fire Detection System? - Answers - Battery Switch
What light goes off approx. 60 seconds after the APU Master Switch is placed in the
OFF position? - Answers - APU Door open
During the start cycle of the APU, which of the following happens AT 50% N2? -
Answers - Starter Cut-Out
During APU start, if the N2 RPM indicator stops rising for any period of _____ seconds
terminate start cycle immediately. - Answers - 4-5
In order to prevent crash engagement of the starter, when is a restart of the APU
allowed? - Answers - Allow the APU doors to fully close after turning
Prior to starting APU, make sure the ground fire warning and control panel switches are
in the _____ position. - Answers - Normal
Check CAC compartment for evidence of _____ before applying electrical power. -
Answers - Fuel vapors or leaks
With the APU control system Switch in the STBY Position, what should N1 RPM
indicate? - Answers - 75-100%
During the APU starting cycle, which light illuminates at 95% N2? - Answers - APU PWR
Avail Light
While the APU is in operation, you notice that oil quantity drops to 2.5 quarts; what is
your required course of action? - Answers - Shut down the APU and Service 107
99.07% to the proper level
, What is the minimum limit for APU oil quantity prior to APU engine start? - Answers - 6
quarts
What is the cooling time for the APU after 4 start attempts in a 20 minute Period? -
Answers - 1 Hr
What is the max allowable APU Oil Consumption Rate? - Answers - 500cc per hour
APU operation must be discontinued if the aircraft batteries are removed while unit is in
operation. When the batteries are removed/disconnected, _____ cannot be discharged.
- Answers - Fire Light
What percentage N2 must the APU Oil Pressure Low/Temp High Light extinguish? -
Answers - 50%
If cockpit air temperature is above _____, air conditioning should be provided. If air
conditioning is not available, cockpit windows and compartment access door must be
open to prevent overheat of equipment. - Answers - 85 degrees F
If you see that when the APU is On-Speed, the APU GEN OFF Light remains on; what
should you do? - Answers - Place APU Gen to (RESET)
Where is the ground fire warning and control panel located? - Answers - AFT of Left
Wheel Well
For APU operation, the number 2 tank fuel quantity must be greater than? - Answers -
1000 lbs
If the tail cone is rotated to the down position, what must be accomplished prior to
starting the APU? - Answers - Install exhaust deflector
Cabin outflow valve must be in the _____ or _____ position prior to APU start. -
Answers - Open, Auto
During night time operation, what must be done to the ground fire warning and control
panel if personnel are not gonna be occupying the flight compartment while the APU is
in operation? - Answers - Illuminate the panel with the service light
Performing the APU Fire Detection System controller Bite Test while the APU is
operating will _____. - Answers - Cause APU to Auto Shutdown
APU/ISOL VALVE Switch should be in the _____ position when all pneumatic loads
have been removed from APU. - Answers - CLOSED
The APU Master Switch must be placed in what position after an APU Auto Shutdown? -
Answers - OFF
What are the Frequency limits for the APU Generator? - Answers - 400 +/-4Hz
The APU starter duty cycle is _____ Minutes on, _____ Minutes off. - Answers - 0-
What is the MAXIMUM acceleration time (Cold) that the APU must reach 100% N2? -
Answers - 60 Seconds
What is the time limit that the APU must be operating in APU/ISOL Valve (CLOSED)
position in order for the APU to shutdown normally? - Answers - 90 Seconds
What is the MAXIMUM acceleration time (Warm) that the APU must reach 100% N2? -
Answers - 45 Seconds
What switch Arms the Fire Detection System? - Answers - Battery Switch
What light goes off approx. 60 seconds after the APU Master Switch is placed in the
OFF position? - Answers - APU Door open
During the start cycle of the APU, which of the following happens AT 50% N2? -
Answers - Starter Cut-Out
During APU start, if the N2 RPM indicator stops rising for any period of _____ seconds
terminate start cycle immediately. - Answers - 4-5
In order to prevent crash engagement of the starter, when is a restart of the APU
allowed? - Answers - Allow the APU doors to fully close after turning
Prior to starting APU, make sure the ground fire warning and control panel switches are
in the _____ position. - Answers - Normal
Check CAC compartment for evidence of _____ before applying electrical power. -
Answers - Fuel vapors or leaks
With the APU control system Switch in the STBY Position, what should N1 RPM
indicate? - Answers - 75-100%
During the APU starting cycle, which light illuminates at 95% N2? - Answers - APU PWR
Avail Light
While the APU is in operation, you notice that oil quantity drops to 2.5 quarts; what is
your required course of action? - Answers - Shut down the APU and Service 107
99.07% to the proper level
, What is the minimum limit for APU oil quantity prior to APU engine start? - Answers - 6
quarts
What is the cooling time for the APU after 4 start attempts in a 20 minute Period? -
Answers - 1 Hr
What is the max allowable APU Oil Consumption Rate? - Answers - 500cc per hour
APU operation must be discontinued if the aircraft batteries are removed while unit is in
operation. When the batteries are removed/disconnected, _____ cannot be discharged.
- Answers - Fire Light
What percentage N2 must the APU Oil Pressure Low/Temp High Light extinguish? -
Answers - 50%
If cockpit air temperature is above _____, air conditioning should be provided. If air
conditioning is not available, cockpit windows and compartment access door must be
open to prevent overheat of equipment. - Answers - 85 degrees F
If you see that when the APU is On-Speed, the APU GEN OFF Light remains on; what
should you do? - Answers - Place APU Gen to (RESET)
Where is the ground fire warning and control panel located? - Answers - AFT of Left
Wheel Well
For APU operation, the number 2 tank fuel quantity must be greater than? - Answers -
1000 lbs
If the tail cone is rotated to the down position, what must be accomplished prior to
starting the APU? - Answers - Install exhaust deflector
Cabin outflow valve must be in the _____ or _____ position prior to APU start. -
Answers - Open, Auto
During night time operation, what must be done to the ground fire warning and control
panel if personnel are not gonna be occupying the flight compartment while the APU is
in operation? - Answers - Illuminate the panel with the service light
Performing the APU Fire Detection System controller Bite Test while the APU is
operating will _____. - Answers - Cause APU to Auto Shutdown
APU/ISOL VALVE Switch should be in the _____ position when all pneumatic loads
have been removed from APU. - Answers - CLOSED
The APU Master Switch must be placed in what position after an APU Auto Shutdown? -
Answers - OFF
