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Flashcards in APU COPY Deck (15)
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What is the purpose of the Electronic Control Box (ECB)?

Basically a FADEC for the APU. The ECB is a full-authority digital electronic controller that performs the bulk of the APU system logic for all modes of engine operation such as: Sequences the start and monitor it monitors speed and temperature monitors bleed air sequences the shutdown and controls the automatic shutdown.


What occurs in case of an APU fire with no crew in the cockpit?

APU fire warnings operate in the cockpit and in the nose gear bay, the AVAIL light goes out, the FAULT light comes on, the APU shuts down and the APU fire extinguisher discharges.


How many generators has the APU?



How does the APU fuel system work?

The left fuel feed line supplies the APU. The required pressure is normally available from the tank pumps. If pressure is not available (batteries only or pumps off) the APU FUEL PUMP starts automatically. The ECB controls the fuel flow.


What is the highest altitude the APU can supply bleed air for engine start while providing electrical power?

20,000'/22,500' MSN dependant


What is the function of the APU GEN pushbutton located on the overhead electrical panel?

When selected to OFF the APU generator field is de-energized.


What is the highest altitude the APU can supply bleed air to two packs while providing electrical power?

15,000 Feet


What happens when the APU MASTER sw pushbutton is selected ON?

- Electrically powers the APU system (Blue ON light in the pushbutton)

- Electronic Control Box (ECB) performs a power up test

- APU ECAM page appears (if EXT or ENG GEN AC power is available)

- APU air intake flap opens

- APU fuel isolation valve opens

- APU fuel pump operates (if no tank pumps are on)


With the APU green AVAIL light ON and the EXT PWR blue ON light illuminated, which system is powering the aircraft?



What happens when you push the APU START pushbutton?

- Blue "ON" light illuminates

- When APU air intake flap opens the starter is energized

- Ignition is turned ON 1.5 seconds after starter is energized

- Starter is de-energized and ignition turned off at 55% N

- Blue "ON" light in start button extinguishes

- Green "AVAIL" light illuminates 2 seconds after 95% N or above 99.5% N

- APU page disappears from the ECAM 10 seconds later


With the APU green "AVAIL" light ON and the EXT PWR green "AVAIL" light on, with system is powering the aircraft?



With the APU running and supplying bleed air, how do you shut it down?

- APU BLEED pushbutton OFF


- APU will cool down and then shut down


If a mechanic pressed the APU AUTO EXTING TEST pushbutton, what would occur?

The APU will shut down


During the cool down cycle can you still use the APU?

Yes, press the APU MASTER sw pushbutton


What does an amber "FAULT" light in the APU MASTER sw pushbutton indicate?

An ECB commanded auto shutdown of the APU has occurred