APU

Question 1

When is the APU available?

Answer 1

> 99.5 % or 2 seconds after N is above 95%

Question 2

Automatic shut down occurs:

Answer 2

High Oil Temp
Overspeed
Temperature (Hot EGT)
Underspeed
Overspeed
Fire (on ground)
No acceleration
No Flame
ECB Failure
Slow-start
*AOM 49.20.2

Question 3

APU service ceiling

Answer 3

FL398

Question 4

Max Altitude to supply electrical power

Answer 4

SFC - FL398

Question 5

Max Altitude for APU start with battery only

Answer 5

SFC - FL250

Question 6

Max Altitude for APU bleed (One Pack)

Answer 6

SFC - FL200

Question 7

Max Altitude for APU bleed (Two Pack)

Answer 7

SFC - 15,000 FT

Question 8

Max Altitude to start an Engine

Answer 8

SFC - 8,000 FT

Question 9

What does the APU Fire PB do?

Answer 9

Shuts OFF APU without a cooling period

Question 10

Why must you leave the batteries on after shutting down the APU and how long?

Answer 10

1. To ensure Fire Protection until complete shutdown
2. Ensure intake flaps close
3. APU computer remains powered through shutdown
4. APU scavenge oil to APU sump to prevent cabin fogging on subsequent starts

Question 11

How do you know you’re using APU electrical power?

Answer 11

1. An UP arrow from the APU SD page
2. Load is displayed on the APU SD page

Question 12

How much time is required in order to push the START PB after MASTER has been pushed?

Answer 12

At least 5 seconds

Question 13

APU is available when?

Answer 13

Approximately 1 minute after START PB pushed
AVAIL in APU SD Page
AVAIL displayed in START PB button

Question 14

How much battery power is required if starting the APU with the battery only? And how much time do you have with the batteries to start?

Answer 14

At least 25.5 or greater
30 minutes

Question 15

What condition in the APU system would cause an external horn to sound?

Answer 15

APU Fire