APU Panel Flashcards
When starting the APU, how long do you wait before pressing the APU start pb after pressing the APU Master SW pb?
3 seconds
After engine start and turning off the ignition, what are the next two pb in the sequence with regards to the APU?
The APU Bleed then the APU Master SW
After switching off the APU, note that the AVAIL in green stays. It will stay for how long and why does it stay?
60-120 seconds, cool down period
the APU Master SW pb: Lights Out 2
Lights Out:
- The APU is off or
- The APU is in a Manual Shutdown
the APU Master SW pb: On position 3
On Position
- It controls the electric power supply for the operation of the APU and it’s protective features.
- The APU is in operation or
- Is in the beginning of the:
- Starting sequence
- Shutdown sequence
the APU Master SW pb: Fault position 4
Fault position
1. In amber
2. Indicates an automatic APU shutdown has occured
3. ECAM APU Auto (Emer) Shutdown appears
4. Examples for automatic shutdown:
Fire (on ground), EGT over temp, low oil pressure, ECB failure, air inlet flap closed (many more)
APU start sequence 3
A. If APU is started using the batteries (dark cockpit): switch both on and above 25.5v
B. APU Master Switch
- Press pb
- Electric power goes to the APU and the ECB performs a power up test
- The APU air intake flap opens
- The APU fuel isolation valve opens
- If no fuel in the fuel tank pump is running, the APU fuel pump operates
- **If the aircraft has ground power/main generator power: the APU page appears on the ECAM display
C. APU Start pb
- Wait 3 secs., press pb, blue light on
- When the APU inlet flap is fully open, the Starter energizes
- 1.5 secs later after the Starter is energized, Ignition turns on
- When N = 60%, Starter is de-energized and Ignition is turned off
- 2 seconds after N = 95% or when N>99.5% the On light goes off, Avail Light in green
- **Batteries only start: 10 secs. later, ECAM APU page appears
