APU Flashcards
What is the power source for the APU boost pump?
24-28V DC (battery)
What systems does the APU indirectly supply?
Hydraulics and Generators
What is the Nr range to avoid during APU operation?
94-96%
What is the maximum number of APU start attempts permitted in one hour?
3
What precaution is to be taken for when unauthorized personnel will be in the cockpit?
Pop the APU circuit breaker (right EFAB)
What is the only APU warning?
APU fire
What is the only APU caution?
APU on
Where does the APU receive fuel from?
AFT fuel cell
APU oil level is found where?
The sight glass
When is APU bleed air provided?
Once APU reaches 95%
Where is the APU located?
Inboard of the right engine nacelle in the aft equipment bay under a Kevlar enclosure
What is the approximate fuel burn for the APU per hour?
175 lbs/hour
What three things does the APU enclosure provide for the APU
- Allows cool air to flow across the APU for cooling
- The inlet screen is used to allow ambient air to be used for combustion
- Confines the APU in the event of fire for extinguishing purposes
What does the APU electronic control unit provide?
Provides for operational sequencing control for automatic starting PTO clutch operation, normal operations and APU operation
What does the PTO clutch provide?
Provides the coupling and de-coupling between the APU and the main XMSN accessory gearbox, through the number 7 driveshaft