APUS SCIENCE 138 WEEK 6 EXAM (LATEST 2024)
GRADED A+ WITH ANSWERS
How many volts are required to start the APU? - ANSWER: 22
What are the APU start cycle limits using ground power? - ANSWER: 15 seconds On -
2 minutes OFF,
15 seconds On - 20 minutes OFF,
15 seconds On - 2 minutes OFF,
15 seconds On - 40 minutes OFF.
When does the white APU starter message go out? - ANSWER: At 50 % rpm.
At what speed will the APU AVAIL light illuminate? - ANSWER: At 99 % rpm (after 4
seconds)
What conditions will cause the APU to automatically shut down in flight? - ANSWER:
Fire, Overspeed, RPM signal loss, DC power loss, ECU loss, or a slow start (less than
50% for 60 seconds).
What conditions will cause the APU to automatically shut down on the ground? -
ANSWER: Fire, Overspeed, RPM signal loss, Loss of DC power, ECU loss, Slow start,
Over temp, Over current, Low oil pressure, High oil temp, EGT signal loss, or loss of
door signal.
What four things happen when you press the APU power fuel switch? - ANSWER:
The APU SOV opens, the APU intake door opens, APU gauges appear on the MFD,
and the APU in Bite status message appears. (DIGS: Door, In-bite, Gauges, SOV)
Starting the APU requires which battery? - ANSWER: Both (The APU ECU gets power
from main battery, and APU starter gets power from APU battery).
What is the maximum time you can leave an aircraft with the APU running? -
ANSWER: 5 minutes.
What does the APU GENerator OFF message indicate? - ANSWER: The APU has been
at 100 % rpm for 30 seconds or more and the generator switch is OFF.
What is the APU's primary function? - ANSWER: To drive the 30 KVA electric
generator.
When will the APU starter auto cutoff? - ANSWER: At 50% rpm , or 60 seconds.
The APU ECU protects the APU compressor against surge by opening and closing
what? - ANSWER: The APU variable diffusers.
GRADED A+ WITH ANSWERS
How many volts are required to start the APU? - ANSWER: 22
What are the APU start cycle limits using ground power? - ANSWER: 15 seconds On -
2 minutes OFF,
15 seconds On - 20 minutes OFF,
15 seconds On - 2 minutes OFF,
15 seconds On - 40 minutes OFF.
When does the white APU starter message go out? - ANSWER: At 50 % rpm.
At what speed will the APU AVAIL light illuminate? - ANSWER: At 99 % rpm (after 4
seconds)
What conditions will cause the APU to automatically shut down in flight? - ANSWER:
Fire, Overspeed, RPM signal loss, DC power loss, ECU loss, or a slow start (less than
50% for 60 seconds).
What conditions will cause the APU to automatically shut down on the ground? -
ANSWER: Fire, Overspeed, RPM signal loss, Loss of DC power, ECU loss, Slow start,
Over temp, Over current, Low oil pressure, High oil temp, EGT signal loss, or loss of
door signal.
What four things happen when you press the APU power fuel switch? - ANSWER:
The APU SOV opens, the APU intake door opens, APU gauges appear on the MFD,
and the APU in Bite status message appears. (DIGS: Door, In-bite, Gauges, SOV)
Starting the APU requires which battery? - ANSWER: Both (The APU ECU gets power
from main battery, and APU starter gets power from APU battery).
What is the maximum time you can leave an aircraft with the APU running? -
ANSWER: 5 minutes.
What does the APU GENerator OFF message indicate? - ANSWER: The APU has been
at 100 % rpm for 30 seconds or more and the generator switch is OFF.
What is the APU's primary function? - ANSWER: To drive the 30 KVA electric
generator.
When will the APU starter auto cutoff? - ANSWER: At 50% rpm , or 60 seconds.
The APU ECU protects the APU compressor against surge by opening and closing
what? - ANSWER: The APU variable diffusers.
