APU Flashcards
APU Bleed Priority
- A/C on GRD
- GS below 50kts for more than 30 seconds after Touchdown
- Packs OFF and A/ I not ALL or Single Eng. Taxi
- APU Normal, APU Bleed and X-Bleed buttons are pushed In (Auto)
What provides the EICAS with APU Temp Info
2 Thermocouples located in the Exhaust section of the APU that are in the front of outgoing Exhaust Air
What Fuel pump is used to start the APU
- If NO Engine on and AC is available then ACMP2
- NO AC Power then DCMP
- Right Engine ON then Right Engine 2 Primary Ejector Pump
How many Exciters and Igniters for the APU
1 Exciter and 2 Gap-Type Igniter Plugs
What kind of APU and describe it
Sundstrand 2300
- Single Stage Impeller with a 2 Stage Axial-Flow Turbine
- Independent Oil System
- Independent AC Generator
- APU Bleeds can run Air Cond., Water Pressurization and Cabin Pressurization (Primarily on GRD)
How can APU be shutdown immediately
- APU Emer. Stop is pressed
2. BATTs are turned OFF during 1 min cooldown
How many Duplex and Simplex Fuel Injectors are used in APU Fuel distribution
6 Simplex (APU Run) from Secondary Fuel Manifold 6 Duplex (APU Run and Start) from Primary and Secondary Fuel Manifolds
What 3 things are Opened or Energized when you move APU start button to ON
- APU FADEC is Energized
- APU EICAS Messages are displayed
- APU Fuel SOV opens
What is Closed when APU Emer. Stop button is Pressed
- De-energizes APU FADEC
- Closes the APU Fuel SOV
- Overrides the APU Master Switch
What Powers APU Start sequence
BATT 1 - FADEC
BATT 2 - APU Start Bus
When does the APU Auto Shutdown in FLT and on GRD
FLT
- Overspeed
- Underspeed
- Critical Fault
GRD
- Overspeed
- Underspeed
- Critical Fault
- Low Oil Pressure
- High Oil Temp.
- Fire
- Overheat
- Sensor Failure
Max EGT for Continuous Operation
717* C is start of Red; Amber is permitted 662C - 717C
