APU Flashcards

1
Q

What causes an automatic EMER. SHUTDOWN of the APU? When is this facility available?

A
  • APU fire on the ground.

- Pressing the APU fire on the exterior panel.

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2
Q

Why would the APU continue to run after being selected OFF?

A

If using APU bleed air, the APU keeps running for cooling period of 60sec.

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3
Q

What happens if excessive EGT is sensed?

A

FAULT amber light, and a caution appears on ECAM. Followed by an automatic shutdown.

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4
Q

AUTO SHUTDOWN is available during which phases of flight? And EMER SHUTDOWN (Fire)

A

1500’ – 800’

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5
Q

What causes the FLAP to OPEN? What does the message FLAP OPEN mean exactly?

A
  • When MASTER SW p/b is pressed.
  • In green when APU air intake flap is fully open.
  • In amber after 3min APU has been switched OFF.
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6
Q

What happens if the START button is pressed immediately after the MASTER button is pressed?

A

The APU start sequence begins.
- ON light goes out when N is >99.5% or 2sec after N reaches 95%
- AVAIL light comes on when N is above 95%
- APU can now be used for electrics and/or bleed

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7
Q

What is the Maximum altitude for APU start?

A
  • 41,000’ by electrical power
  • 25,000’ by battery only
  • 14,500’ on the ground
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8
Q

What are the altitude limitations for the use of APU bleed & packs?

A

2 packs: 15,000’

1 pack: 22,500’

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9
Q

What would you do if the SD showed LO OIL LVL?

A
  • Refill the oil
  • Low APU oil when the aircraft is on the ground, and the APU is not running.
  • The APU may be started and operated even if the LOW OIL LEVEL ECAM advisory is displayed.
  • Maintenance action is required within next 10hrs of APU operation.
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10
Q

What is the APU start limitation?

A

After 3 starter motor duty cycles, wait 60min before attempting 3 more cycles.

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11
Q

One.

A

How many generators has the APU?

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12
Q

The APU AVAIL appears in green when APU N is above 95%.

A

When does the APU AVAIL appear green?

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13
Q

The basic element of the APU is a single-shaft gas turbine that delivers mechanical shaft power for driving the accessory gearbox (electrical generator starter etc.) and produces bleed air (engine starting and pneumatic supply).

A

What is the basic element of the APU?

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14
Q

The APU will run for a cooling period because you have been using the APU bleed.

A

You switched the APU off. Why do you still have the APU AVAIL indications?

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15
Q

The APU can be started at any altitude using normal aircraft electrical power.

A

The APU may be started up to which altitude?

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16
Q

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.

A

What is the purpose of the Electronic Control Box (ECB)?

17
Q

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.

A

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

18
Q

In flight the APU backs up the electrical system and the air conditioning and it can be used to start the engines.

A

What is the purpose of the APU in flight?

19
Q

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.

A

How does the APU fuel system work?

20
Q

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

A

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

21
Q

The left fuel feed line supplies the APU normally via the tank pumps. The APU FUEL PUMP starts automatically if pressure is not available (batteries only or pumps off).

A

How does the fuel supply work for the APU?

22
Q

20,000 Feet

A

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

23
Q

Electric

A

Does APU air or electric have priority?

24
Q

The APU is available to provide electrical power and/or bleed air

A

What does the green “AVAIL” light on the APU start pushbutton indicate?

25
Q

25,000 Feet

A

The APU generator can supply 100% electrical load to what altitude?

26
Q

25,000 Feet

A

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

27
Q

15,000 Feet

A

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

28
Q
  • 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)
A

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

29
Q

EXT PWR

A

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

30
Q
  • 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
A

What happens when you push the APU START pushbutton?

31
Q

APU

A

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

32
Q
  • APU BLEED pushbutton OFF- APU MASTER sw OFF- APU will cool down and then shut down
A

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

33
Q

The APU will shut down

A

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

34
Q

Yes, press the APU MASTER sw pushbutton

A

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

35
Q

An ECB commanded auto shutdown of the APU has occurred

A

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